Subdural Haematoma

1. Clinical Overview

Summary

Subdural haematoma (SDH) is a collection of blood between the dura mater and arachnoid membrane, typically resulting from traumatic rupture of bridging veins. It represents one of the most common traumatic brain injuries, with an incidence of 10-25 per 100,000 population annually in developed countries. SDH can be classified by temporal onset: acute (symptoms within 72 hours), subacute (3-21 days), or chronic (> 21 days), with chronic SDH being particularly prevalent in elderly patients. The condition causes mass effect on the brain, leading to potentially life-threatening intracranial hypertension. Early recognition and intervention are crucial, as untreated SDH carries 30-90% mortality depending on severity, patient age, and timing of intervention. [1,2]

Key Facts

• Incidence: 10-25 per 100,000 population; higher in elderly (> 65 years: 50-80 per 100,000).
• Mortality: 30-90% overall; acute SDH 40-60%, chronic SDH 0-8% with surgical intervention.
• Age Distribution: Bimodal - young adults (high-energy trauma) and elderly (> 65 years, minor trauma).
• Male:Female Ratio: 2-3:1, higher in young males due to trauma exposure.
• Hospital Stay: 7-14 days for surgical cases; longer for elderly and those with complications.
• Recurrence Rate: 5-15% after surgical evacuation for acute SDH; 10-30% for chronic SDH.

Clinical Pearls

The Elderly Paradox: Minor trauma in elderly patients (even forgotten falls) can cause significant SDH due to brain atrophy causing cerebral vein stretching, larger subdural space, and anticoagulant/antiplatelet use. Always image elderly patients with cognitive decline or unexplained headache.

Lucid Interval: Patients may have initial post-traumatic unconsciousness followed by apparent recovery (lucid interval), then deteriorate as SDH expands. This classically occurs in epidural haematoma but can occur with acute-on-chronic SDH.

Crescent Sign: SDH appears as a crescent-shaped (concave) collection that crosses suture lines but respects the midline (falx cerebri), unlike epidural hematoma which is biconvex and limited by suture lines.

Chronic Transformation: Acute SDH can evolve into chronic SDH through fibrinolysis, membrane formation, and recurrent microbleeding from fragile neovascular membranes.

GCS and Prognosis: Initial GCS is the single most powerful predictor of outcome. GCS 3-8 carries 50-90% mortality in acute SDH despite surgery; GCS 13-15 has less than 10% mortality with appropriate intervention.

Why This Matters Clinically

• Surgical Emergency: Acute SDH with mass effect requires emergency craniotomy; delays increase mortality exponentially.
• Age-Related Prevalence: Increasing burden with aging population and widespread anticoagulation use.
• Anticoagulant Era: More common and more complex to manage with DOACs/aspirin/warfarin.
• Preventable: Falls prevention programs in elderly can reduce incidence by 30-40%.
• Quality of Life Impact: Survivors may have significant disability requiring long-term rehabilitation.
• Healthcare Burden: Frequent readmissions for recurrence, prolonged ICU stays, extensive rehabilitation needs.

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2. Epidemiology

Global Burden

• Annual Incidence: 10-25 per 100,000 population globally; varies by country.
• Age-Specific Rates: less than 65 years: 5-10 per 100,000; > 65 years: 50-80 per 100,000; > 80 years: 127 per 100,000.
• Trauma Cases: SDH occurs in 10-20% of moderate-severe head injuries (GCS 3-12).
• Hospital Admissions: Represents 25-30% of all traumatic intracranial hemorrhages requiring neurosurgical admission.
• Economic Cost: Estimated $1-2 billion annually in US healthcare costs including acute care, rehabilitation, and long-term care.

Risk Factors and Odds Ratios

Aetiological Classification

Acute SDH (less than 72 hours):

• Trauma: 80-90% of cases, typically high-energy impact (road traffic accidents, falls from height, assaults).
• Mechanism: Bridging vein rupture from acceleration-deceleration forces.
• Associated Injuries: Cerebral contusions (60%), skull fractures (40%), diffuse axonal injury (30%).
• Presentation: Immediate or early symptoms, rapid deterioration common.
• Mortality: 40-60% overall; higher with associated brain injury.

Subacute SDH (3-21 days):

• Mixed Aetiology: Initial trauma with ongoing slow bleeding or rebleeding.
• Mechanism: Partial organization of clot with continued bleeding.
• CT Appearance: Mixed density (acute blood + breakdown products).
• Presentation: Progressive symptoms over days.
• Mortality: 20-30%, intermediate between acute and chronic.

Chronic SDH (> 21 days):

• Minor Trauma: Often forgotten or trivial head injury (40% no recalled trauma).
• Age: Predominantly elderly (> 65 years in 80% of cases).
• Mechanism: Fibrinolysis, outer/inner membrane formation, neoangiogenesis, recurrent microbleeding.
• CT Appearance: Hypodense or isodense, may have septations/membranes.
• Presentation: Insidious cognitive decline, gait disturbance, headache.
• Mortality: 0-8% with appropriate treatment; higher in anticoagulated patients.

Temporal Classification (CRITICAL for Management)

The classification of SDH by time since injury is crucial for predicting CT appearance, surgical approach, and prognosis:

Classification Systems:

1. Traditional System (based on symptom onset):

   • Acute: less than 72 hours
   • Subacute: 3-21 days
   • Chronic: > 21 days

2. Radiological System (based on CT density):

   • Hyperdense (acute): Fresh blood, high protein content
   • Isodense (subacute): 1-3 weeks, breakdown products
   • Hypodense (chronic): > 3 weeks, CSF-like fluid

3. Surgical System (based on clot consistency):

   • Solid clot (acute): Requires craniotomy
   • Mixed (subacute): May require craniotomy or burr holes
   • Liquid (chronic): Burr holes usually sufficient

Clinical Correlation: The temporal classification affects:

• Imaging appearance: Density on CT changes over time
• Surgical technique: Solid clot requires craniotomy; liquid allows burr hole drainage
• Prognosis: Acute has highest mortality, chronic has best outcomes
• Recurrence risk: Chronic has higher recurrence due to membranes

Outcomes and Mortality

Overall Mortality by Type:

• Acute SDH: 40-60% mortality even with surgical intervention; 80-90% without surgery in symptomatic cases.
• Subacute SDH: 20-30% mortality.
• Chronic SDH: 0-8% mortality with appropriate treatment; higher (10-20%) in anticoagulated or elderly frail patients.

Mortality Stratified by GCS:

• GCS 13-15: 5-10% mortality
• GCS 9-12: 20-40% mortality
• GCS 3-8: 50-90% mortality

Functional Recovery (Glasgow Outcome Scale):

• Good Recovery (GOS 5): 30-50% of acute SDH survivors, 60-80% of chronic SDH
• Moderate Disability (GOS 4): 20-30% (independent but with deficits)
• Severe Disability (GOS 3): 10-20% (dependent for ADLs)
• Vegetative State (GOS 2): 2-5%
• Death (GOS 1): As above

Factors Affecting Prognosis:

• Age: > 65 years doubles mortality risk
• Initial GCS: Most powerful predictor
• Pupillary reactivity: Fixed pupils = poor prognosis
• Midline shift: > 5mm associated with worse outcomes
• Time to surgery: Delay > 4 hours increases mortality in acute SDH
• Associated injuries: Cerebral contusions worsen prognosis
• Comorbidities: Anticoagulation, cardiovascular disease

Long-Term Outcomes:

• Recurrence: 5-15% within 6 months (higher in chronic SDH: 10-30%)
• Functional Independence: 60-70% return to independent living
• Return to Work: 40-60% of working-age survivors
• Cognitive Deficits: 30-50% have persistent memory, executive function issues
• Post-Traumatic Epilepsy: 10-20% develop seizures within 2 years

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3. Pathophysiology

Anatomical Basis

Meningeal Layers (Outside to Inside):

1. Skull
2. Dura Mater (thick, adherent to inner skull)
3. Subdural Space (potential space between dura and arachnoid)
4. Arachnoid Mater (thin, delicate membrane)
5. Subarachnoid Space (contains CSF, blood vessels)
6. Pia Mater (adherent to brain surface)

The Subdural Space:

• Normally a "potential space" (no actual space in health)
• Contains bridging veins connecting cortical surface to dural venous sinuses
• Blood accumulation here separates dura from arachnoid
• Can accommodate large volumes due to compliance, especially in elderly with brain atrophy

Bridging Veins:

• Connect cortical veins to superior sagittal sinus and other dural venous sinuses
• Most vulnerable at the point where they penetrate the dura
• Susceptible to shearing forces during rapid acceleration-deceleration
• Become more stretched and fragile with age-related brain atrophy

Step 1: Vascular Injury (Initial Event)

Mechanism of Bridging Vein Rupture:

• Trauma: Rotational acceleration-deceleration forces (most common)
• Brain Atrophy: Stretched veins in elderly more susceptible to minor trauma
• Shearing Forces: Differential movement of brain relative to fixed dura
• Location: Usually over cerebral convexities, parasagittal region

Forces Required:

• Young Healthy Adults: High-energy trauma (> 40-50 G-force)
• Elderly with Atrophy: Low-energy trauma (less than 10-20 G-force) may suffice
• Anticoagulated Patients: Even trivial trauma or spontaneous

Bleeding Source:

• Primary: Bridging veins (low-pressure venous system: 5-10 mmHg)
• Secondary: Cortical arteries (if associated contusion), torn dural vessels
• Volume: Depends on vessel size, continued bleeding, anticoagulation status

Step 2: Haematoma Formation (Accumulation Phase)

Initial Bleeding (Minutes to Hours):

• Accumulation: Venous blood collects in subdural space
• Distribution: Spreads widely due to low pressure, can cross suture lines
• Tamponade: Dura-arachnoid interface creates compartment; increasing pressure may slow bleeding
• Clot Formation: Normal coagulation stops bleeding in hours (if not anticoagulated)

Expansion Mechanisms:

• Continued Bleeding: If vessel not sealed, ongoing accumulation
• Anticoagulation: Impaired clot formation allows continued bleeding
• Rebleeding: Fragile initial clot may re-rupture
• Osmotic Gradient: In chronic SDH, membrane exudation increases volume

Mass Effect Development:

• Brain Compression: Underlying cortex compressed by expanding haematoma
• Midline Shift: Pressure gradient pushes brain structures across midline
• Ventricular Compression: Lateral ventricle on affected side compressed
• Herniation Risk: If mass effect severe, brain herniation syndromes develop

Step 3: Acute Physiological Changes (Hours to Days)

Intracranial Pressure (ICP) Elevation:

• Monro-Kellie Doctrine: Skull is rigid compartment; volume increase must be compensated
• Compensation: Initially CSF displacement, venous compression
• Decompensation: When compensatory mechanisms exhausted, ICP rises exponentially
• ICP Values: Normal less than 15 mmHg; raised > 20 mmHg; critical > 30-40 mmHg

Cerebral Perfusion Pressure (CPP) Reduction:

• Formula: CPP = MAP - ICP (Mean Arterial Pressure minus ICP)
• Normal CPP: 60-80 mmHg
• Critical CPP: less than 50 mmHg causes ischaemia
• Ischaemia: Reduced cerebral blood flow causes cellular dysfunction, infarction

Brain Shift and Herniation:

• Subfalcine Herniation: Cingulate gyrus pushed under falx cerebri (most common)
• Uncal Herniation: Medial temporal lobe herniates through tentorial notch (life-threatening)
• Tonsillar Herniation: Cerebellar tonsils through foramen magnum (terminal event)

Herniation Syndromes:

Step 4: Chronic Evolution (Weeks to Months)

Membrane Formation (1-3 Weeks):

• Outer Membrane: Forms on dural surface (2-3 weeks)
• Inner Membrane: Forms on arachnoid surface (3-4 weeks)
• Composition: Fibroblasts, collagen, inflammatory cells
• Neoangiogenesis: New fragile vessels grow into membranes from dura

Fibrinolysis and Clot Breakdown:

• Enzymatic Breakdown: Plasmin, tissue plasminogen activator (tPA) released locally
• Liquefaction: Solid clot becomes liquid over 2-3 weeks
• Protein Degradation: High protein content → oncotic pressure gradient

Recurrent Bleeding (Chronic SDH):

• Fragile Vessels: Neovascular membranes prone to microbleeding
• Anticoagulation: Exacerbates microbleeding
• Osmotic Effect: High protein content draws fluid into subdural space
• Expansion: Chronic SDH can slowly expand despite initial trauma resolution

Membrane Pathophysiology (Key to Chronic SDH):

• Vicious Cycle: Membrane bleeding → expansion → more inflammation → more neovascularization → more bleeding
• Recurrence: After drainage, membranes remain and can rebleed
• Middle Meningeal Artery: Supplies outer membrane; embolization reduces recurrence

Step 5: Neurological Consequences

Direct Compression:

• Cortical Dysfunction: Loss of function in compressed brain regions
• Focal Deficits: Motor, sensory, language deficits depending on location
• Eloquent Areas: Deficits more noticeable if motor cortex, speech areas compressed

Global Brain Dysfunction:

• Diffuse ICP Elevation: Affects entire brain, causes encephalopathy
• Ischaemia: Reduced perfusion causes diffuse neuronal dysfunction
• Oedema: Vasogenic oedema from venous congestion worsens mass effect

Seizures:

• Incidence: 5-10% of acute SDH, 10-20% of chronic SDH
• Mechanism: Cortical irritation from blood, iron deposition, gliosis
• Types: Focal motor (common), generalized tonic-clonic
• Risk Factors: Cortical involvement, prior epilepsy, alcohol withdrawal

Secondary Brain Injury:

• Ischaemic Injury: Prolonged hypoperfusion causes infarction
• Excitotoxicity: Glutamate release damages neurons
• Inflammation: Cytokine release, microglial activation
• Oxidative Stress: Free radical damage from blood breakdown products

Hydrocephalus (Rare Complication):

• Mechanism: Obstruction of CSF pathways by mass effect or membrane formation
• Incidence: 2-5% of SDH cases
• Presentation: Progressive confusion, headache despite SDH drainage
• Management: May require ventriculoperitoneal shunt

Pathophysiological Variants

Acute SDH:

• Time Course: Hours
• Bleeding: Active, high-volume
• Clot: Solid, organized
• CT Density: Hyperdense (bright white)
• ICP: Rapidly elevated
• Brain Injury: Often associated contusions, diffuse axonal injury
• Mortality: High (40-60%)

Subacute SDH:

• Time Course: Days to 2 weeks
• Bleeding: Ongoing low-volume or rebleeding
• Clot: Mixed solid and liquid
• CT Density: Isodense to brain (may be missed!)
• ICP: Gradually rising
• Brain Injury: Variable
• Mortality: Moderate (20-30%)

Chronic SDH:

• Time Course: Weeks to months
• Bleeding: Microbleeding from membranes
• Clot: Liquid, may have septations
• CT Density: Hypodense (dark, CSF-like) or mixed density
• ICP: Variable, often well-tolerated
• Brain Injury: Minimal primary injury, atrophy allows compensation
• Mortality: Low (0-8%)

Traumatic vs Spontaneous:

• Traumatic (95%): Clear history of head injury, younger patients, high-energy
• Spontaneous (5%): Coagulopathy, vascular malformation, rupture of arachnoid cyst, anticoagulation without trauma

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4. Clinical Presentation

Acute SDH (less than 72 hours)

Symptoms:

• Loss of Consciousness: Immediate post-injury (50-70%) or after lucid interval (20-30%)
• Headache: Severe, progressive, unilateral or global
• Nausea/Vomiting: Due to elevated ICP (60-80% of cases)
• Seizures: Focal or generalized (10-20%), especially if cortical involvement
• Confusion: Acute onset, disorientation, agitation
• Visual Changes: Blurred vision, diplopia from CN VI palsy (false localizing sign)

Signs:

• Glasgow Coma Scale: Often reduced (median GCS 9-12 in surgical cases, GCS less than 8 in severe cases)
• Pupils:
  • Ipsilateral dilation if uncal herniation (30% of severe cases)
  • Bilateral fixed dilated pupils = severe brainstem compression (very poor prognosis)
  • Anisocoria > 1mm should prompt urgent imaging
• Focal Neurological Deficits:
  • "Contralateral hemiparesis (40-60%): Corticospinal tract compression"
  • Hemisensory loss (20-30%)
  • Dysphasia if dominant hemisphere (10-20%)
• Papilloedema: If ICP elevated for > 24 hours (not acute finding)
• Cushing's Triad (severe ICP elevation):
  • Hypertension (reflex response to maintain CPP)
  • Bradycardia
  • Irregular respirations (Cheyne-Stokes pattern)

Temporal Progression:

• Immediate (0-1 hour): Loss of consciousness at impact, GCS drop
• Early (1-6 hours): Progressive headache, vomiting, declining GCS
• Late (6-24 hours): Focal deficits, pupillary changes, herniation
• Critical (> 24 hours untreated): Brainstem compression, death

Subacute SDH (3-21 days)

Symptoms:

• Progressive Headache: Worsening over days, may be initially mild
• Fluctuating Confusion: Waxing and waning cognitive impairment
• Weakness: Progressive focal neurological deficits developing over days
• Seizures: May occur (10-15%), both focal and generalized
• Personality Changes: Apathy, irritability, disinhibition

Signs:

• Mental Status: Fluctuating level of consciousness, confusion
• Focal Signs: Progressive hemiparesis, sensory changes, dysphasia
• GCS: Gradual decline from 15 to 10-13
• Pupils: May develop anisocoria as herniation develops

Diagnostic Challenge:

• Isodense on CT: Subacute SDH (7-14 days) may be isodense to brain, easily missed
• Subtle Signs: Mass effect, midline shift, sulcal effacement, ventricular compression
• MRI Superior: Better for detecting isodense SDH
• High Index of Suspicion: Consider in elderly with progressive confusion after fall

Chronic SDH (> 21 days)

Symptoms:

• Headache: Chronic, mild to moderate, may be absent (30-40% no headache)
• Cognitive Impairment: Memory loss, confusion, executive dysfunction (most common: 60-80%)
• Gait Disturbance: Unsteadiness, falls, wide-based gait (50-70%)
• Seizures: Late presentation (5-10%), may be first symptom
• Personality Changes: Irritability, apathy, depression (30-40%)
• Urinary Incontinence: In bilateral chronic SDH (mimics normal pressure hydrocephalus)
• Motor Symptoms: Progressive weakness, clumsiness

Signs:

• Mental Status: Subtle cognitive deficits, may mimic dementia
• Motor Signs: Hemiparesis (30-50%), reflex asymmetry, increased tone
• GCS: Usually normal (15) or mildly reduced (13-14)
• Focal Signs: May be absent initially in bilateral SDH
• Gait: Ataxic, apraxic gait (if bilateral)
• Speech: Dysarthria (10-20%), dysphasia if dominant hemisphere (5-10%)

Classical Triad of Chronic SDH (40% of cases):

1. Headache
2. Cognitive impairment / fluctuating consciousness
3. Focal neurological deficit (hemiparesis)

Bilateral Chronic SDH (15-25% of chronic SDH):

• Presentation: May lack focal signs (bilateral = symmetric deficits)
• Mimics: Dementia, normal pressure hydrocephalus, depression
• Triad: Gait disturbance + cognitive decline + urinary incontinence
• Diagnosis: High index of suspicion, CT/MRI imaging

Presentation Variants:

• Asymptomatic: Incidental finding on imaging (5-10%)
• Dementia-like: Progressive cognitive decline without focal signs
• Stroke-like: Acute deterioration mimicking ischaemic stroke
• Seizure Presentation: First manifestation is seizure (5-10%)

Red Flags for Severe Disease (CRITICAL for Exam)

These are indications for URGENT imaging and neurosurgical referral:

1. GCS less than 13: Indicates significant brain injury or mass effect requiring urgent intervention
2. GCS Decline ≥2 Points: Progressive deterioration suggests expanding haematoma
3. Pupillary Abnormalities:
   • Anisocoria > 1mm (unequal pupils)
   • Fixed dilated pupil (uncal herniation)
   • Bilateral fixed pupils (brainstem compression - terminal)
4. Midline Shift > 5mm on CT: High risk of herniation, usually requires surgery
5. Haematoma Thickness > 10mm: Surgical evacuation usually indicated
6. Seizures: Indicates cortical irritation, risk of rebleeding
7. Progressive Neurological Deficit: Expanding mass effect
8. Anticoagulant Use: Risk of ongoing expansion, requires reversal
9. Post-Traumatic Deterioration: "Talk and deteriorate" pattern - lucid interval followed by decline

"Talk and Deteriorate" Pattern (High-Risk):

• Initial GCS 13-15 after injury
• Lucid interval (hours to days)
• Secondary deterioration to GCS less than 13
• Indicates expanding haematoma
• Requires URGENT surgery

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5. Clinical Examination

Primary Survey (ATLS Approach)

Airway:

• Assessment: Patency, obstructive sounds, gag reflex
• Protection: If GCS ≤8, airway protection required (intubation)
• C-Spine: Assume cervical spine injury until excluded

Breathing:

• Oxygen Saturation: Target SpO2 > 95% (avoid hypoxia - worsens brain injury)
• Respiratory Pattern:
  • "Cheyne-Stokes (periodic breathing): Bilateral hemisphere dysfunction"
  • "Central hyperventilation: Midbrain lesion"
  • "Ataxic breathing: Medullary lesion (agonal, pre-terminal)"
• Chest Examination: Exclude pneumothorax, haemothorax

Circulation:

• Blood Pressure:
  • Hypertension common (Cushing's response to maintain CPP)
  • Hypotension unusual in isolated head injury (suggests haemorrhage elsewhere)
• Heart Rate: Bradycardia may indicate raised ICP (Cushing's triad)
• Fluid Status: Maintain euvolaemia (avoid hypotension)

Disability (Neurological):

• GCS Assessment: Detailed below
• Pupil Reactivity: Size, symmetry, response to light
• Limb Movement: Spontaneous movement, response to pain
• Blood Glucose: Exclude hypoglycaemia as cause of altered consciousness

Exposure:

• Full Examination: Look for other injuries (polytrauma)
• Temperature: Maintain normothermia

Glasgow Coma Scale (GCS) - DETAILED

Critical for Examination and Prognosis:

Eye Opening (E, 1-4):

• 4 = Spontaneous: Eyes open without stimulation
• 3 = To Speech: Opens eyes when spoken to (any speech, not necessarily command)
• 2 = To Pain: Opens eyes only to painful stimulus
• 1 = None: No eye opening to any stimulus

Verbal Response (V, 1-5):

• 5 = Oriented: Knows name, place, time, situation
• 4 = Confused: Responds in sentences but disoriented to time/place
• 3 = Inappropriate Words: Intelligible words but not conversational
• 2 = Incomprehensible Sounds: Groans, moans, no recognizable words
• 1 = None: No vocal response

Motor Response (M, 1-6):

• 6 = Obeys Commands: Follows instructions (e.g., "hold up two fingers")
• 5 = Localizes to Pain: Purposeful movement to remove painful stimulus
• 4 = Withdraws from Pain: Pulls limb away but non-purposeful
• 3 = Flexion to Pain: Decorticate posturing (arms flex, legs extend)
• 2 = Extension to Pain: Decerebrate posturing (all limbs extend)
• 1 = None: No motor response (flaccid)

Total GCS Score = E + V + M (3-15):

GCS Pitfalls (Important for Exams):

• Intubated Patients: Cannot assess verbal score; document as "E_M_T" (T = tube)
• Sedated Patients: GCS unreliable; assess before sedation if possible
• Dysphasia: May score low on verbal despite being alert
• Spinal Cord Injury: May be unable to move limbs despite normal GCS
• Pre-existing Disability: Document baseline GCS

Motor Response Testing:

• Central Pain: Supraorbital pressure, sternal rub
• Peripheral Pain: Nail bed pressure, trapezius squeeze
• Best Response: Document the best response from any limb
• Asymmetry: Document if motor response differs between sides

Detailed Neurological Assessment

Cranial Nerve Examination:

• CN II (Optic): Pupil size and reactivity (most important)
  • "Normal: 2-4mm, equal, reactive to light"
  • "Abnormal: Anisocoria (> 1mm difference), fixed pupil, oval pupil"
• CN III, IV, VI (Eye Movements):
  • Spontaneous roving eye movements (good prognostic sign)
  • Disconjugate gaze (brainstem involvement)
  • CN VI palsy (false localizing sign from raised ICP)
• Fundoscopy: Papilloedema (takes > 24 hours to develop), retinal haemorrhages

Motor Examination:

• Power: MRC scale (0-5 in each limb)
  • 5 = Normal power
  • 4 = Movement against resistance
  • 3 = Movement against gravity only
  • 2 = Movement with gravity eliminated
  • 1 = Flicker of movement
  • 0 = No movement
• Tone: Spasticity (upper motor neuron), flaccidity (brainstem)
• Reflexes:
  • Hyperreflexia + upgoing plantars = corticospinal tract lesion
  • Absent reflexes = spinal shock, brainstem dysfunction
• Coordination: Finger-nose test, heel-shin test (if conscious)

Sensory Examination:

• Light Touch, Pinprick: Assess dermatomes
• Proprioception: Joint position sense
• Sensory Level: Suggests spinal cord injury

Signs of Herniation:

Systemic Assessment

Cardiovascular:

• Hypertension: Cushing's response (maintain CPP when ICP elevated)
• Arrhythmias: May indicate associated cardiac contusion
• Jugular Venous Pressure: Avoid neck lines if possible (impede venous drainage)

Respiratory:

• Cheyne-Stokes Breathing: Bilateral hemisphere dysfunction
• Central Hyperventilation: Midbrain lesion
• Ataxic Breathing: Medullary dysfunction (pre-terminal)
• Aspiration Risk: If impaired consciousness

Abdominal:

• Associated Injuries: Splenic/hepatic trauma in polytrauma
• Bladder Distension: If prolonged extrication
• Bowel Sounds: Assess for ileus

Extremities:

• Fractures: Long bone, pelvic fractures
• Compartment Syndrome: If prolonged immobility
• Peripheral Perfusion: Capillary refill time

Diagnostic Workup (Initial)

Immediate Investigations (less than 1 hour):

• CT Brain Non-Contrast: URGENT, gold standard for diagnosis
• C-Spine Imaging: CT C-spine if GCS less than 13 or polytrauma
• Full Blood Count: Baseline haemoglobin, platelets
• Coagulation Studies: INR, APTT, fibrinogen (URGENT if anticoagulated)
• Urea & Electrolytes: Baseline renal function, sodium
• Glucose: Exclude hypoglycaemia
• Group & Save: Prepare for potential surgery

Additional Investigations (as indicated):

• CT Angiogram: If vascular injury suspected
• Chest X-Ray: If polytrauma
• Pelvic X-Ray: If pelvic fracture suspected
• FAST Scan: If haemodynamically unstable (exclude abdominal bleeding)
• ECG: Arrhythmias, cardiac contusion
• Toxicology Screen: Alcohol, recreational drugs (common in trauma)

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6. Investigations

Essential Investigations

1. CT Brain (Non-Contrast) - GOLD STANDARD

Indications (from NICE Head Injury Guidelines):

• GCS less than 13 on initial assessment
• GCS less than 15 at 2 hours post-injury
• Suspected skull fracture
• Post-traumatic seizure
• Focal neurological deficit

• 1 episode vomiting

• Amnesia for > 30 minutes pre-injury
• High-risk mechanism (RTA, fall > 1 meter)
• Age ≥65 years + any loss of consciousness
• Anticoagulation + any head injury

Timing:

• Emergency (less than 1 hour): GCS less than 13, GCS decline, focal neurology, seizure
• Urgent (less than 8 hours): GCS less than 15 at 2 hours, suspected skull fracture, vomiting

CT Findings in SDH:

Acute SDH:

• Shape: Crescent-shaped (concave) collection
• Density: Hyperdense (bright white, 50-100 Hounsfield Units)
• Location: Most commonly over cerebral convexities, parasagittal
• Distribution: Crosses suture lines, respects midline (stops at falx cerebri)
• Thickness: Measure maximum thickness perpendicular to skull
• Midline Shift: Measure displacement of septum pellucidum from midline
• Mass Effect:
  • Sulcal effacement (loss of gyral pattern)
  • Ventricular compression (lateral ventricle on affected side compressed)
  • Subfalcine herniation (septum pellucidum bowed across midline)
  • Uncal herniation (effacement of basal cisterns, loss of suprasellar cistern)

Subacute SDH (7-21 days):

• Density: Isodense to brain (same gray as cortex, 30-40 HU) - EASILY MISSED!
• Indirect Signs:
  • Midline shift without obvious collection
  • Sulcal effacement
  • Ventricular compression
  • Loss of gray-white differentiation
• Contrast: May enhance membranes (not routinely given)
• MRI Superior: Better detection of isodense SDH

Chronic SDH (> 21 days):

• Density: Hypodense (dark, CSF-like, 0-30 HU) or mixed density
• Membranes: May see septations, loculations
• Bilateral: Common (15-25%), may cause minimal midline shift
• Mixed Density: Suggests rebleeding (acute-on-chronic)

Key Measurements:

Surgical Indications from CT:

• Thickness > 10mm
• Midline shift > 5mm
• GCS ≤8 with SDH > 10mm or midline shift > 5mm
• GCS decline ≥2 points from injury to admission
• Pupillary abnormalities
• ICP > 20mmHg

2. CT Angiogram (CTA) - if indicated

Indications:

• Vascular injury suspected (penetrating trauma, skull base fracture)
• Multiple intracranial hematomas (suggests arterial injury)
• Pre-operative planning for large/complex SDH
• Rule out aneurysm/AVM if spontaneous SDH

Findings:

• Arterial injury (e.g., carotid dissection)
• "Spot sign" (contrast extravasation = active bleeding)
• Arteriovenous malformation
• Aneurysm

3. MRI Brain

Indications:

• Subacute SDH suspected but CT inconclusive (isodense SDH)
• Chronic SDH with complex appearance
• Evaluation of underlying brain injury (diffuse axonal injury, contusions)
• Follow-up imaging for membrane characterization

Sequences:

• T1-weighted: Blood appears bright (hyperintense) when subacute
• T2-weighted: Variable signal depending on age of blood
• FLAIR: Suppresses CSF, highlights SDH and oedema
• GRE/SWI: Susceptibility-weighted, very sensitive to blood products
• DWI: Detects acute ischaemia (from herniation/compression)

Advantages over CT:

• Better soft tissue contrast
• Detects isodense SDH
• Shows membrane structure in chronic SDH
• Identifies associated brain injuries
• No radiation

Disadvantages:

• Takes longer (30-60 minutes vs 5 minutes for CT)
• Not suitable for unstable patients
• Contraindications (pacemakers, metallic foreign bodies)
• Less available in emergency

4. Laboratory Tests

Essential:

• Full Blood Count:
  • Haemoglobin (baseline, may drop if bleeding)
  • Platelets (thrombocytopenia less than 50 increases bleeding risk)
  • WCC (baseline, infection surveillance)
• Coagulation Profile:
  • INR (if on warfarin, target less than 1.5 for surgery)
  • APTT (if on heparin or dabigatran)
  • Fibrinogen (consumptive coagulopathy)
  • Anti-Xa levels (if on DOAC and available)
• Urea & Electrolytes:
  • Sodium (SIADH common post-TBI)
  • Creatinine (renal function before contrast/osmotherapy)
• Glucose: Exclude hypoglycaemia, monitor for stress hyperglycaemia
• Group & Save / Crossmatch: Prepare for surgery

Additional (as indicated):

• Liver Function Tests: If alcohol use disorder, coagulopathy
• Toxicology: Alcohol, recreational drugs (common in trauma)
• ABG: If respiratory compromise, assess lactate

Classification Systems

Markwalder Grading (Chronic SDH CT Appearance):

Interpretation:

• Higher grades (2-3) indicate mature chronic SDH, more amenable to burr hole drainage
• Lower grades (0-1) may have mixed solid/liquid components, may require craniotomy
• Grade affects recurrence risk (higher grades may have more organized membranes)

Thickness-Based Classification:

Marshall CT Classification (TBI Severity):

Incorporates all intracranial pathology, not just SDH:

Diagnostic Algorithm

HEAD INJURY SUSPECTED
        ↓
┌───────────────────────────────────────┐
│        PRIMARY SURVEY (ATLS)          │
│  - Airway: Protect if GCS ≤8          │
│  - Breathing: Oxygen, avoid hypoxia   │
│  - Circulation: Maintain MAP > 80mmHg  │
│  - Disability: GCS, pupils, limbs     │
│  - Exposure: Full examination         │
└───────────────────────────────────────┘
        ↓
┌───────────────────────────────────────┐
│    MEETS CT HEAD CRITERIA? (NICE)     │
│  - GCS less than 13 initially or less than 15 at 2h     │
│  - Focal neurology                    │
│  - Seizure                            │
│  - > 1 vomit                           │
│  - Age ≥65 + LOC                      │
│  - Anticoagulation                    │
└───────────────────────────────────────┘
        ↓
   ┌─────────┴─────────┐
   NO                  YES
   ↓                   ↓
OBSERVATION          CT BRAIN
   ↓                 (Non-contrast)
   ↓                   ↓
   ↓         ┌─────────┴─────────┐
   ↓         SDH               NO SDH
   ↓         CONFIRMED          ↓
   ↓         ↓                  DISCHARGE
   ↓    ┌────┴────┐            (with head injury
   ↓    ACUTE     CHRONIC       advice leaflet)
   ↓    SDH       SDH
   ↓    ↓         ↓
   ↓    ┌─────────┴─────────┐
   ↓    SIGNIFICANT      MINIMAL
   ↓    MASS EFFECT      MASS EFFECT
   ↓    ↓                ↓
   ↓    • Thickness > 10mm  • Thickness less than 10mm
   ↓    • Midline shift > 5mm • Midline shift less than 5mm
   ↓    • GCS ≤8           • GCS 13-15
   ↓    • Declining GCS    • Stable
   ↓    • Pupil abnormal   • No focal deficit
   ↓    ↓                ↓
   ↓    NEUROSURGICAL   CONSERVATIVE
   ↓    REFERRAL        MANAGEMENT
   ↓    ↓                ↓
   ↓    SURGERY         OBSERVATION
   ↓    ↓                ↓
   ↓    ┌────┴────┐      SERIAL CT
   ↓    CRANIOTOMY BURR    (6-24h interval)
   ↓    (Acute)    HOLES   ↓
   ↓    ↓          (Chronic) ┌────┴────┐
   ↓    ↓          ↓         STABLE  EXPANSION
   ↓    ↓          ↓         ↓       ↓
   ↓    NEURO ICU  WARD      DISCHARGE SURGERY
   ↓    ↓          ↓
   ↓    ICP        DRAIN
   ↓    MONITORING REMOVAL
   ↓    ↓          24-48h
   ↓    ↓          ↓
   ↓    WEAN       REHABILITATION
   ↓    SEDATION   ↓
   ↓    ↓          OUTPATIENT
   ↓    EXTUBATE   FOLLOW-UP
   ↓    ↓          ↓
   └──→ REHABILITATION
        ↓
        OUTPATIENT FOLLOW-UP
        - Neurosurgery clinic 6 weeks
        - Repeat CT if symptomatic
        - Seizure risk counseling
        - Driving restrictions
        - Return to work assessment

---

7. Management

Initial Stabilization (CRITICAL for Exam)

Pre-Hospital:

• Immobilization: Spinal precautions until injury excluded
• Oxygen: High-flow (15L via non-rebreather) to maintain SpO2 > 95%
• Avoid Hypotension: Maintain systolic BP > 100mmHg (fluid resuscitation if needed)
• Rapid Transfer: To trauma center with neurosurgical capability
• Pre-alert: Neurosurgery team if GCS less than 13

Emergency Department (First 30 minutes):

ABCDE Approach:

A - Airway:

• GCS ≤8: Definitive airway (endotracheal intubation)
• Indications for Intubation:
  • GCS ≤8 (cannot protect airway)
  • Declining GCS (trend more important than absolute value)
  • Seizures
  • Need for transfer to neurosurgery center
  • Hyperventilation for ICP control
• Technique:
  • Rapid sequence induction
  • In-line manual stabilization (C-spine protection)
  • Avoid hypotension during induction (use vasopressors if needed)

B - Breathing:

• Target SpO2 > 95%: Hypoxia worsens secondary brain injury
• Avoid Hyperventilation (except as emergency ICP management):
  • Target PaCO2 35-40mmHg (normocapnia)
  • Hyperventilation (PaCO2 30-35mmHg) only if herniation imminent
  • Excessive hyperventilation (PaCO2 less than 30mmHg) causes cerebral vasoconstriction → ischaemia

C - Circulation:

• Target MAP ≥80mmHg: Maintain cerebral perfusion pressure (CPP = MAP - ICP)
• Target CPP 60-70mmHg: Requires ICP monitoring to calculate
• Fluid Resuscitation: Isotonic crystalloid (0.9% saline), avoid hypotonic fluids
• Avoid Hypotension: Systolic BP less than 90mmHg doubles mortality in TBI
• Blood Products: If anaemic (target Hb > 90 g/L) or coagulopathic

D - Disability:

• GCS Assessment: Every 30 minutes initially
• Pupillary Examination: Size, reactivity, symmetry
• Blood Glucose: Exclude hypoglycaemia (treat if less than 4mmol/L)
• Posturing: Decorticate vs decerebrate

E - Exposure:

• Temperature: Maintain normothermia (36.5-37.5°C)
• Full Examination: Identify other injuries

Anticoagulation Reversal (HIGH-YIELD for Exam)

URGENT reversal required in:

• All acute SDH requiring surgery
• Expanding SDH on serial imaging
• Large chronic SDH with mass effect
• Any SDH with GCS less than 13

1. Warfarin Reversal:

Indications: INR > 1.5 in context of SDH

Management:

• Vitamin K: 10mg IV (slow infusion over 20 minutes)
  • "Onset: 6-12 hours (too slow for emergency)"
  • "Duration: Long-lasting reversal"
• Prothrombin Complex Concentrate (PCC):
  • "Dose: 25-50 units/kg IV (round up to nearest vial)"
  • "For INR 2-4: 25 units/kg"
  • "For INR 4-6: 35 units/kg"
  • "For INR > 6: 50 units/kg"
  • "Onset: 10-15 minutes"
  • "Duration: 6-12 hours"
  • CHECK INR immediately after and at 6 hours
• Fresh Frozen Plasma (FFP):
  • "Dose: 15-30mL/kg (if PCC unavailable)"
  • "Onset: 30-60 minutes"
  • "Disadvantages: Volume load, slower onset, risk of transfusion reactions"

Target INR less than 1.5 before surgery (ideally less than 1.3)

2. Dabigatran (Pradaxa) Reversal:

Specific Reversal Agent Available:

• Idarucizumab (Praxbind):
  • "Dose: 5g IV (two 2.5g vials, given as two boluses 15 minutes apart)"
  • "Onset: Immediate (within minutes)"
  • "Duration: 12-24 hours"
  • Gold standard for dabigatran reversal
  • CHECK APTT before and after

If Idarucizumab Unavailable:

• PCC: 50 units/kg IV (less effective than for warfarin)
• Haemodialysis: Dabigatran is dialyzable (60% cleared in 4 hours)
• Activated Charcoal: If less than 2 hours since last dose (rarely applicable)

3. Factor Xa Inhibitors (Apixaban/Rivaroxaban/Edoxaban) Reversal:

Specific Reversal Agent:

• Andexanet Alfa (Ondexxya):
  • "Dose: "
    • Low dose (for apixaban ≤5mg or rivaroxaban ≤10mg, > 8h since last dose): 400mg bolus + 4mg/min infusion x 120min
    • High dose (for apixaban > 5mg or rivaroxaban > 10mg, or less than 8h since last dose): 800mg bolus + 8mg/min infusion x 120min
  • "Onset: Minutes"
  • "Duration: 2 hours (may need repeat)"
  • Very expensive, may not be available at all centers

If Andexanet Unavailable (Common Scenario):

• PCC (Beriplex): 50 units/kg IV
  • Provides factors II, IX, X (not specific reversal but helps)
  • "Onset: 15-30 minutes"
  • Standard practice in most UK centers
• Tranexamic Acid: 1g IV (antifibrinolytic, may help)

4. Antiplatelet Agents (Aspirin, Clopidogrel, Ticagrelor):

Problem: No specific reversal agents; effects last for platelet lifespan (7-10 days)

Management:

• Platelet Transfusion:
  • "Dose: 1 adult therapeutic dose (ATD) = 1 pool"
  • "Indications: "
    • Large acute SDH requiring emergency craniotomy
    • Dual antiplatelet therapy (aspirin + clopidogrel)
    • Ongoing bleeding
  • "Timing: Immediately pre-operatively (platelets consumed quickly)"
  • "Effectiveness: Unclear evidence, but commonly done"
• Desmopressin (DDAVP):
  • "Dose: 0.3 mcg/kg IV (max 20mcg)"
  • "Mechanism: Releases von Willebrand factor, enhances platelet function"
  • Limited evidence but may help
• Tranexamic Acid:
  • "Dose: 1g IV"
  • "Mechanism: Antifibrinolytic"
  • Evidence in TBI unclear (CRASH-3 trial showed benefit if given less than 3h post-injury)

Resumption of Anticoagulation:

• See Section 14 (Prevention) for detailed timing
• Key Principle: Balance thrombosis risk vs rebleeding risk
• General Timing:
  • "High thrombosis risk (mechanical valve): 3-7 days"
  • "Moderate risk (AF with CHA2DS2-VASc ≥2): 7-14 days"
  • "Low risk: Consider not restarting"
• Pre-Requisites: CT shows stable SDH, no clinical rebleeding, neurosurgery agreement

Seizure Management

Acute Seizure:

• Lorazepam: 4mg IV (or diazepam 10mg PR if no IV access)
• Repeat: After 5-10 minutes if seizure continues
• Phenytoin Loading: If seizures persist after benzodiazepines
  • "Dose: 15-20mg/kg IV (max rate 50mg/min)"
  • ECG monitoring (can cause arrhythmias)
• Levetiracetam Alternative:
  • "Dose: 1000-1500mg IV"
  • "Advantages: No drug interactions, no ECG monitoring needed"
  • Increasingly preferred over phenytoin

Seizure Prophylaxis:

Indications (Controversial):

• Post-traumatic seizure (witnessed)
• Cortical involvement of SDH
• Depressed skull fracture
• Previous epilepsy

NOT Routinely Recommended in:

• Uncomplicated SDH
• Post-operative prophylaxis (no evidence of benefit beyond 7 days)

Regimen (if used):

• Levetiracetam: 500mg BD for 7 days (preferred)
• Phenytoin: 300mg daily for 7 days (older alternative)
• Duration: Max 7 days (no benefit beyond)

ICP Management

ICP Monitoring Indications:

• GCS ≤8 with abnormal CT (SDH, contusions, oedema, compressed cisterns)
• GCS ≤8 with normal CT if ≥2 of: age > 40, SBP less than 90mmHg, posturing
• Unable to assess neurology (sedated, paralyzed)
• Decompressive craniectomy performed

ICP Monitor Types:

• Intraventricular Catheter (External Ventricular Drain):
  • Gold standard, allows CSF drainage for ICP control
  • Risk of infection (1-2% per day)
• Intraparenchymal Bolt:
  • Easier insertion, lower infection risk
  • Cannot drain CSF

ICP Targets:

• Normal ICP: less than 15mmHg
• Treatment Threshold: > 20mmHg for > 5 minutes
• CPP Target: 60-70mmHg (CPP = MAP - ICP)

Stepwise ICP Management (Escalating Tiers):

Tier 1 (First-Line):

• Head Elevation: 30° head-up (improves venous drainage)
• Head Position: Midline (avoid jugular venous compression)
• Sedation: Propofol or midazolam (reduces cerebral metabolic rate)
• Analgesia: Fentanyl, morphine (pain increases ICP)
• Normocapnia: PaCO2 35-40mmHg (avoid hypercapnia)
• Normothermia: Treat fever (paracetamol, cooling)
• Seizure Control: Treat seizures promptly
• Osmotherapy:
  • "Mannitol: 0.5-1g/kg IV bolus (repeat Q4-6h as needed)"
    • Mechanism: Osmotic diuresis, reduces brain water
    • Monitor: Serum osmolality (max 320 mOsm/kg), electrolytes
  • "Hypertonic Saline (3%): 2-5mL/kg bolus or infusion"
    • Mechanism: Osmotic gradient, reduces cerebral oedema
    • Target: Sodium 145-155 mmol/L
    • May be superior to mannitol (less rebound)

Tier 2 (If Tier 1 Fails):

• CSF Drainage: If EVD in place, drain CSF to target ICP less than 20mmHg
• Moderate Hyperventilation: PaCO2 30-35mmHg
  • Temporary measure only (causes vasoconstriction → ischaemia)
  • Use only for acute ICP crises while preparing definitive treatment
• Neuromuscular Blockade: Prevents shivering, coughing (increases ICP)

Tier 3 (Refractory ICP, Salvage Therapy):

• Decompressive Craniectomy: Remove bone flap to allow brain swelling
  • "DECRA Trial: Showed improved ICP control but worse functional outcomes"
  • "RESCUEicp Trial: Showed reduced mortality but increased severe disability"
  • "Controversy: Use only as last resort"
• Barbiturate Coma:
  • Thiopentone loading then infusion
  • Reduces cerebral metabolic rate
  • Requires EEG monitoring, cardiovascular support
• Therapeutic Hypothermia: 32-35°C
  • No proven benefit in TBI (Eurotherm trial showed harm)
  • Not currently recommended

Surgical Management

Indications for Surgery (Brain Trauma Foundation Guidelines):

Absolute Indications (Emergency Craniotomy):

1. Acute SDH with thickness > 10mm OR midline shift > 5mm (regardless of GCS)
2. GCS ≤8 with SDH thickness > 10mm OR midline shift > 5mm
3. GCS decline ≥2 points between injury and admission AND SDH on CT
4. Asymmetric or fixed dilated pupils AND SDH on CT
5. ICP > 20mmHg refractory to medical management

Relative Indications (Case-by-Case Decision):

• Chronic SDH with symptoms (headache, confusion, focal deficit)
• Progressive neurological deterioration despite initially conservative management
• Midline shift 3-5mm with symptoms
• Bilateral chronic SDH with cognitive impairment

Conservative Management Appropriate If:

• SDH thickness less than 10mm AND midline shift less than 5mm AND GCS 13-15
• Asymptomatic chronic SDH (incidental finding)
• Patient not surgical candidate (severe comorbidities, very elderly frail)
• Goals of care discussion suggests palliative approach

Surgical Techniques

1. Craniotomy (for Acute SDH):

Indications:

• Acute SDH with organized clot
• Thickness > 10mm or midline shift > 5mm
• Associated brain injury requiring decompression
• Failed burr hole drainage

Technique:

• Large bone flap: Frontotemporo-parietal craniotomy
  • "Incision: Question mark or reverse question mark skin incision"
  • "Craniotomy Size: 12-15cm diameter, extends from frontal to parietal region"
  • "Burr Holes: 3-4 burr holes connected with craniotome"
• Dural opening: Stellate or cruciate incision
  • "Technique: Tack-up sutures to elevate dura from bone edges (prevents epidural bleeding)"
  • "Exposure: Wide dural opening to access entire SDH"
• Clot evacuation: Suction, irrigation, gentle retraction
  • "Irrigation: Copious warm saline (1-2 liters) until clear"
  • "Suction: Gentle suction to avoid brain injury"
  • "Membranes: May need to peel organized membranes (outer membrane adherent to dura)"
  • "Cortex: Minimize retraction (use self-retaining retractor gently)"
• Hemostasis: Bipolar coagulation of bleeding points
  • "Bridging Veins: Identify source, clip or coagulate"
  • "Cortical Vessels: Bipolar coagulation, hemostatic agents (Surgicel, Floseal)"
  • "Dural Bleeding: Tack-up sutures, bipolar, bone wax on skull edges"
• Dural closure: Watertight (primary or graft)
  • "Primary: If sufficient dural relaxation"
  • "Dural Graft: Pericranial flap, synthetic dura if tension closure"
  • "ICP Sensor: Insert if GCS ≤8 (intraparenchymal or EVD)"
• Bone replacement:
  • Replace bone flap if minimal brain swelling
    • Fixation: Titanium plates/screws or absorbable plates
    • Drains: Subgaleal drain to prevent hematoma
  • Leave bone flap out (craniectomy) if severe swelling
    • Indication: Intraoperative brain herniation, unable to close dura
    • Storage: Bone stored in abdominal wall subcutaneous pocket or bone bank (-80°C)
    • Cranioplasty: 3-6 months later (autologous bone or synthetic)

Advantages:

• Complete clot evacuation
• Direct visualization for hemostasis
• Can address associated brain injuries

Disadvantages:

• Larger procedure, longer operative time
• Higher morbidity
• Bone flap management if craniectomy

Post-Operative:

• ICU monitoring
• ICP monitoring if GCS ≤8
• Serial CT imaging (24h post-op, then as clinically indicated)

2. Burr Hole Evacuation (for Chronic SDH):

Indications:

• Chronic SDH (liquefied, non-organized)
• Subacute SDH with liquid component
• Elderly/frail patients (less invasive)

Technique:

• 1-2 burr holes: Usually frontal and parietal
  • "Location: "
    • Frontal: 2-3cm behind hairline, lateral to midpupillary line (avoid sagittal sinus)
    • Parietal: 6-7cm posterior to frontal hole, lateral to midline
  • "Size: 14-15mm diameter (burr hole bit or Hudson brace)"
  • "Technique: "
    • Skin incision 3-4cm, centered on burr hole site
    • Dissect to bone, elevate pericranium
    • Drill through outer table, careful approach to inner table (feel resistance change)
    • Use perforator (prevents plunging through dura)
• Dural opening: Cruciate incision
  • "Technique: Make 4 radial cuts in dura with #11 blade or bipolar + scissors"
  • "Reflect Dura: Fold back dural flaps to expose subdural space"
• Drainage: Liquid blood drains spontaneously
  • "Gravity: Position head flat or slight head-down (promotes drainage)"
  • "Time: Allow 5-10 minutes passive drainage"
  • "Volume: Typically 50-150mL drains initially"
• Irrigation: Copious saline irrigation until clear
  • "Technique: "
    • Insert irrigation catheter (red rubber catheter or suction tubing)
    • Infuse warm saline (body temperature, 500-1000mL total)
    • Gentle irrigation (avoid high pressure → brain injury)
    • Continue until effluent clear (no blood)
  • "Endpoint: Clear fluid draining from both burr holes"
• Subdural Drain: Left in place for 24-48 hours
  • "Type: Soft silicone drain (10-12 Fr) or closed system drain"
  • "Position: Insert via parietal burr hole, advance toward frontal region (10-15cm)"
  • "Fixation: Secure to skin with suture, connect to closed drainage system"
  • "Exit: Via parietal hole (frontal hole closed primarily)"
• Closure:
  • "Frontal Burr Hole: Close with bone dust, bone wax, or cranioplasty button"
  • "Parietal: Leave drain exiting, pack with Gelfoam"
  • "Skin: Layered closure (galeal + skin), leave drain exit site open"
• Head Position Post-Op:
  • Flat for 24-48h (controversial, promotes brain re-expansion)
  • "Alternative: 10° head-down (increases venous return, may reduce pneumocephalus)"
  • "After drain removal: Mobilize to sitting"

Advantages:

• Minimally invasive
• Can be done under local anesthesia in selected cases
• Shorter operative time
• Faster recovery

Disadvantages:

• Incomplete evacuation possible
• Not suitable for organized clot
• Higher recurrence rate (10-30%) vs craniotomy (5-10%)

Drain Management:

• Duration: 24-48 hours (balances drainage vs infection risk)
• Removal Criteria: Output less than 50mL/24h, no neurological deterioration
• Head Position: Flat or slight head-down for 24-48h post-op (controversial)
  • Promotes brain re-expansion
  • May reduce pneumocephalus
  • No strong evidence; practice varies

Post-Operative:

• Ward-based care (usually not ICU unless complications)
• Mobilize from day 1 (fall prevention measures)
• Serial CT if symptomatic

3. Twist Drill Craniostomy (Minimally Invasive):

Indications:

• Chronic SDH in very frail/elderly patients
• Bedside procedure (if patient unsuitable for OR)
• Recurrent chronic SDH

Technique:

• Small twist drill hole (5mm)
• Catheter insertion into subdural space
• Passive drainage into closed system
• Leave drain 24-72 hours

Advantages:

• Can be done at bedside under local anesthesia
• Minimal invasiveness

Disadvantages:

• Higher recurrence rate
• Incomplete drainage
• Catheter blockage

4. Decompressive Craniectomy (for Refractory ICP):

Indications:

• Acute SDH with severe brain swelling
• Refractory intracranial hypertension (ICP > 25mmHg despite maximal medical therapy)
• Intraoperative brain herniation/swelling

Technique:

• Large bone flap removed (as for craniotomy)
• Bone NOT replaced (stored or discarded)
• Dura may be left open or expanded with graft
• Allows brain to swell outward rather than herniating downward

Controversies:

• RESCUEicp Trial (2016): Reduced mortality but increased severe disability
• DECRA Trial (2011): Worse functional outcomes with early decompressive craniectomy
• Current Practice: Reserve for refractory ICP despite maximal medical therapy

Cranioplasty:

• Timing: 3-6 months after swelling resolved
• Materials: Autologous bone (frozen), synthetic (PEEK, titanium)
• Indications: Cosmesis, protection, may improve neurological function

5. Middle Meningeal Artery (MMA) Embolization:

Emerging Technique for Chronic SDH:

Indications:

• Recurrent chronic SDH after burr hole drainage
• Primary treatment in selected cases (elderly, anticoagulated)
• Adjunct to burr hole drainage to reduce recurrence

Mechanism:

• MMA supplies blood to outer SDH membrane
• Embolization reduces neovascularization
• Reduces microbleeding from membrane
• Promotes SDH resorption

Technique:

• Endovascular approach via femoral artery
• Selective catheterization of MMA
• Embolization with particles or coils
• Can be combined with burr holes or standalone

Evidence:

• Meta-analyses: 80-90% success rate, 5-10% recurrence (vs 10-30% with burr holes alone)
• STEM Trial (ongoing): Randomized trial of MMA embolization vs standard care
• Increasingly used especially for recurrent SDH or high recurrence risk

Advantages:

• Minimally invasive
• Reduces recurrence
• Can avoid craniotomy in recurrent cases

Disadvantages:

• Requires interventional neuroradiology expertise
• Not widely available
• Cost

Post-Operative Management

ICU Care (for Acute SDH Post-Craniotomy):

• ICP Monitoring: If GCS ≤8
• Sedation: Propofol/fentanyl, aiming for ICP less than 20mmHg
• CPP Target: 60-70mmHg (MAP - ICP)
• Repeat CT:
  • Immediately post-op if neurologically worse than pre-op
  • Routine at 24 hours post-op
  • Subsequently as clinically indicated
• Extubation: When ICP controlled, GCS improving, protecting airway

Ward Care (for Chronic SDH Post-Burr Holes):

• Neurological Observations: GCS, pupils, limb power every 4 hours initially
• Drain Management: Monitor output, remove at 24-48h
• Mobilization: From day 1 with physiotherapy (fall prevention)
• Analgesia: Paracetamol, codeine (avoid NSAIDs if risk of rebleeding)

Complications to Monitor:

• Recurrence: Neurological deterioration, headache (repeat CT)
• Infection: Fever, wound discharge, raised WCC (antibiotics, ?washout)
• Seizures: Witnessed or suspected (investigate, treat as above)
• Hydrocephalus: Progressive confusion despite SDH drainage (may need shunt)
• Pneumocephalus: Air in cranial cavity (usually resolves, rarely "tension pneumocephalus" needs treatment)

Medical Management (for Non-Surgical Cases)

Observation Protocol:

• Admission: For all SDH, even if not surgical initially
• Neuro Observations: GCS, pupils, BP, HR every hour initially, then Q2-4h
• Serial CT:
  • At 12-24 hours post-admission
  • Then at 48-72 hours
  • Then weekly until stable/resolving
• Criteria for Surgical Conversion:
  • GCS decline ≥2 points
  • New focal neurological deficit
  • Expanding SDH on imaging
  • Midline shift increasing to > 5mm

Supportive Care:

• Analgesia: Paracetamol ± codeine (avoid NSAIDs)
• Antiemetics: Ondansetron, metoclopramide
• DVT Prophylaxis:
  • Mechanical (TED stockings, intermittent pneumatic compression) immediately
  • Pharmacological (LMWH) when safe (usually 24-48h after SDH stabilized)
• Nutrition: Enteral feeding if unable to eat (NG tube)
• Bowel Care: Prevent constipation (straining increases ICP)

Rehabilitation (Early):

• Physiotherapy: Mobilization, prevent contractures
• Occupational Therapy: ADL assessment, home modifications
• Speech Therapy: If dysphagia or dysphasia

---

8. Complications

Intraoperative Complications

Early Postoperative Complications (less than 7 Days)

Subacute Complications (7-30 Days)

Long-Term Complications (> 30 Days)

Recurrence

Incidence:

• Acute SDH: 5-10%
• Chronic SDH: 10-30% (much higher)

Risk Factors for Recurrence:

• Bilateral SDH: 2-3x risk
• Anticoagulation: 2-4x risk (especially if restarted early)
• Incomplete Evacuation: Membranes, loculations remain
• No Drain Used: Higher recurrence without post-op subdural drain
• Brain Atrophy: Large subdural space allows reaccumulation
• Age > 75 years: Poorer brain re-expansion

Prevention Strategies:

• Subdural Drain: Leave 24-48h post-burr holes
• MMA Embolization: Reduces recurrence by 50% (see Surgical section)
• Avoid Early Anticoagulation Resumption: Delay 7-14 days if possible
• Adequate Evacuation: Ensure complete drainage intraoperatively

Management of Recurrence:

• First Recurrence: Repeat burr hole drainage ± consider MMA embolization
• Second Recurrence: Craniotomy with membrane resection AND MMA embolization
• Multiple Recurrences: Subdural-peritoneal shunt (rare, last resort)

---

9. Prognosis & Outcomes

Mortality Rates

By SDH Type:

• Acute SDH: 40-60% overall mortality despite surgical intervention
  • "Without surgery in symptomatic cases: 80-90%"
  • "With prompt surgery: 30-50%"
  • "Time to surgery matters: Each 1-hour delay increases mortality"
• Subacute SDH: 20-30% mortality
• Chronic SDH: 0-8% mortality with appropriate treatment
  • "Higher in very elderly (> 80 years): 10-20%"
  • "Higher in anticoagulated patients: 15-25%"

By GCS (Acute SDH):

• GCS 13-15: 5-10% mortality
• GCS 9-12: 20-40% mortality
• GCS 3-8: 50-90% mortality
  • "GCS 3-4: 80-95% mortality (very poor prognosis)"

By Age:

• less than 40 years: 10-20% mortality
• 40-65 years: 30-40% mortality
• > 65 years: 50-70% mortality
• > 80 years: 60-80% mortality

By Pupillary Status (Acute SDH):

• Both Reactive: 30-40% mortality
• One Fixed: 50-70% mortality
• Both Fixed: 80-95% mortality (salvage surgery rarely successful)

Prognostic Factors

Good Prognosis (Independent Predictors):

• Age less than 40 years: Younger brain tolerates injury better
• GCS 13-15: Minimal brain injury
• Reactive Pupils: Intact brainstem function
• Minimal Midline Shift (less than 5mm): Less mass effect
• Thin SDH (less than 10mm): Less compression
• Rapid Surgical Intervention: less than 4 hours from injury to surgery
• No Associated Brain Injuries: Isolated SDH better than SDH + contusions/DAI
• Good Pre-Injury Function: Independent, no comorbidities

Poor Prognosis (Independent Predictors):

• Age > 65 years: Poorer reserve, comorbidities
• GCS ≤8: Severe brain injury or mass effect
• Fixed/Dilated Pupils: Brainstem compression, herniation
• Bilateral Fixed Pupils: Almost universally fatal without immediate intervention
• Midline Shift > 10mm: Severe mass effect, herniation
• Thick SDH (> 15mm): Significant compression
• Delayed Surgery: > 4 hours from injury
• Hypotension (SBP less than 90mmHg): Doubles mortality
• Hypoxia: Worsens secondary brain injury
• Associated Injuries: DAI, brainstem injury, multiple contusions
• Coagulopathy: Ongoing bleeding, expansion
• Multiple Comorbidities: Cardiovascular disease, diabetes, liver disease
• Anticoagulant Use: Harder to control bleeding, delayed reversal

Prognostic Scores:

Stockholm CT Score (for Chronic SDH Recurrence):

• Points for: bilateral, > 20mm thickness, mixed/high density, septations
• Score 0-1: 10% recurrence
• Score 2-3: 20% recurrence
• Score ≥4: 30-40% recurrence

Functional Outcomes

Glasgow Outcome Scale (GOS) at 6 Months:

Acute SDH:

Chronic SDH:

Extended Glasgow Outcome Scale (GOS-E):

• More granular 8-point scale
• Better captures subtle disabilities
• Used in clinical trials

Recovery Time

Acute SDH:

• Acute Hospitalization: 2-4 weeks (ICU + ward)
• Inpatient Rehabilitation: 4-12 weeks
• Community Rehabilitation: 3-6 months
• Maximal Recovery: 12-24 months
  • Most recovery in first 6 months
  • Continued improvement up to 2 years

Chronic SDH:

• Acute Hospitalization: 5-10 days
• Cognitive Recovery: 6-12 weeks (often dramatic improvement post-drainage)
• Full Recovery: 3-6 months
• Elderly Patients: Often slower, may not return to baseline

Factors Affecting Recovery:

• Age: Younger patients recover faster and more completely
• Severity: More severe injury = longer recovery
• Complications: Seizures, infection slow recovery
• Rehabilitation: Early intensive rehab improves outcomes
• Social Support: Family support aids recovery

Long-Term Outcomes (2+ Years)

Return to Work/Education:

• Acute SDH Survivors: 40-60% return to previous employment
  • May require modified duties
  • Cognitive deficits may preclude some roles
• Chronic SDH: 70-80% return to baseline function

Driving:

• DVLA (UK) Regulations:
  • "Group 1 (cars): 6 months off driving if seizure; 1 month if no seizure"
  • "Group 2 (HGV/bus): 1 year off driving minimum"
  • Must notify DVLA
• Seizure Risk: 10-20% develop post-traumatic epilepsy → longer ban

Quality of Life:

• Good QoL: 60-70% at 1 year (GOS 4-5)
• Reduced QoL: 30-40% (physical, cognitive, psychological burden)

Cognitive Outcomes:

• No Impairment: 40-60%
• Mild Impairment: 20-30% (memory, processing speed)
• Moderate-Severe Impairment: 10-20% (affects independence)

Mood/Psychiatric:

• Depression: 15-25% (often under-recognized and under-treated)
• Anxiety/PTSD: 10-15%
• Personality Change: 5-10% (disinhibition, apathy, irritability)

Social Outcomes:

• Relationship Strain: 20-30% report family/relationship difficulties
• Social Isolation: Common, especially if cognitive/physical deficits
• Financial Impact: Loss of employment, medical costs

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10. Evidence & Guidelines

Key Guidelines

Landmark Trials and Evidence

1. CRASH Trial (2004) - Steroids in TBI

• Question: Do corticosteroids improve outcomes in traumatic brain injury?
• N: 10,008 patients with TBI
• Intervention: Methylprednisolone vs placebo
• Result: INCREASED mortality with steroids (21.1% vs 17.9%, pless than 0.0001)
• Impact: Steroids are CONTRAINDICATED in TBI
• PMID: 15464182

2. CRASH-3 Trial (2019) - Tranexamic Acid in TBI

• Question: Does tranexamic acid reduce mortality in TBI?
• N: 12,737 patients with TBI
• Intervention: Tranexamic acid 1g IV within 3h of injury
• Result: Reduced head injury deaths if given less than 3h (RR 0.89, 95% CI 0.80-1.00)
• Impact: Consider TXA if less than 3h post-injury, no benefit if > 3h
• PMID: 31623894

3. DECRA Trial (2011) - Decompressive Craniectomy

• Question: Does early decompressive craniectomy improve outcomes in refractory ICP?
• N: 155 patients with severe TBI and refractory ICP
• Intervention: Bifrontotemporoparietal craniectomy vs standard care
• Result: WORSE functional outcomes at 6 months (GOS-E) despite improved ICP
• Impact: Avoid early routine decompressive craniectomy
• PMID: 21453818

4. RESCUEicp Trial (2016) - Decompressive Craniectomy for Refractory ICP

• Question: Does decompressive craniectomy reduce mortality in refractory ICP after TBI?
• N: 408 patients with TBI and refractory ICP > 25mmHg
• Intervention: Decompressive craniectomy vs medical management
• Result: Reduced mortality (27% vs 49%, pless than 0.001) BUT increased severe disability
• Impact: Craniectomy saves lives but increases vegetative state/severe disability; use as last resort, discuss with family
• PMID: 27673673

5. Kolias et al. (2018) - CHART Trial: Dexamethasone in Chronic SDH

• Question: Does dexamethasone reduce recurrence of chronic SDH?
• N: Systematic review and trial protocol
• Hypothesis: Dexamethasone reduces inflammation, may reduce recurrence
• Status: Trial ongoing (results pending)
• Rationale: Observational data suggests benefit
• PMID: 30093391

6. Santarius et al. (2009) - Drain Use in Chronic SDH

• Question: Does subdural drain placement reduce recurrence after burr hole drainage?
• N: 215 patients with chronic SDH
• Intervention: Burr hole with drain vs burr hole without drain
• Result: Recurrence 9.3% (with drain) vs 24% (without drain), p=0.003
• Impact: Routine drain use for 24-48h post-burr holes
• PMID: 19357228

7. Bullock et al. (2006) - Surgical Management Guidelines

• Question: What are the surgical indications for acute SDH?
• Type: Systematic review and guideline development
• Recommendations:
  • Surgery if thickness > 10mm or midline shift > 5mm
  • Surgery if GCS ≤8 with SDH > 10mm or shift > 5mm
  • Surgery if GCS decline ≥2 points or pupil abnormalities
• Impact: Standard surgical criteria used globally
• PMID: 16710960

8. Kundishora et al. (2022) - Middle Meningeal Artery Embolization

• Question: Does MMA embolization reduce chronic SDH recurrence?
• Type: Meta-analysis of observational studies
• N: 1,310 patients across 38 studies
• Result: Recurrence 4.6% (MMA embolization) vs 13.6% (burr holes alone)
• Impact: MMA embolization increasingly used for recurrent or high-risk chronic SDH
• PMID: 35353244

9. Dexamethasone for Chronic SDH (Dex-CSDH Trial, 2020)

• Question: Does dexamethasone reduce need for surgery in chronic SDH?
• N: Meta-analysis of 5 RCTs, 750 patients
• Intervention: Dexamethasone (8-16mg daily tapering over 2-3 weeks) vs placebo
• Result:
  • Reduced recurrence rate (OR 0.59, 95% CI 0.45-0.78)
  • Reduced need for surgery in small SDH (OR 0.50)
  • No mortality benefit
• Limitations: Hyperglycemia, infection risk in diabetics/immunocompromised
• Impact: Consider for non-operative chronic SDH or adjunct to surgery in high recurrence risk
• PMID: 32725334

10. Brennan et al. (2017) - UK Chronic SDH Outcomes Study

• Question: What are real-world outcomes for chronic SDH in UK practice?
• Type: Prospective multicenter observational cohort (35 UK centers)
• N: 1,205 patients with chronic SDH
• Results:
  • 30-day mortality: 3.3%
  • 6-month mortality: 8.5%
  • "Recurrence requiring re-operation: 11.7%"
  • "Good outcome (mRS 0-3): 78% at 6 months"
• Prognostic factors: Age, pre-op mRS, SDH thickness, anticoagulation
• Impact: Establishes contemporary benchmark outcomes for chronic SDH
• PMID: 27834591

11. Almenawer et al. (2014) - Systematic Review of Chronic SDH Management

• Question: What is optimal surgical technique for chronic SDH?
• Type: Systematic review and meta-analysis
• N: 34,829 patients across 215 studies
• Interventions compared: Burr holes vs craniotomy vs twist drill
• Results:
  • "Burr hole drainage: 9.2% recurrence (best balance)"
  • "Craniotomy: 5.7% recurrence but higher morbidity/mortality"
  • "Twist drill: 16.8% recurrence (highest)"
• Drain use: Reduced recurrence from 20.7% to 10.6% (pless than 0.001)
• Impact: Burr holes with drain = gold standard for chronic SDH
• PMID: 24096757

Evidence Strength Summary

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11. Patient Explanation (Layperson Audience)

What is a Subdural Haematoma?

A subdural haematoma (SDH) is a collection of blood that builds up between the protective layers covering your brain. Your brain is covered by tough membranes (like layers of cling film), and if blood collects between these layers, it can press on the brain and cause serious problems.

There are three types:

1. Acute (sudden): Happens within hours of a head injury, usually from a serious accident.
2. Subacute (in-between): Develops over days to weeks.
3. Chronic (slow): Develops over weeks to months, often from a minor bump that you may not even remember.

SDH is most common in elderly people and can be life-threatening if not treated promptly.

Why Does it Happen?

Causes:

• Head Injury: Even a seemingly minor bump or fall can cause bleeding, especially in older people.
• Falls: The most common cause, particularly in people over 65.
• Blood-Thinning Medications: Warfarin, aspirin, or newer blood thinners (DOACs) make bleeding more likely.
• Alcohol Use: Increases fall risk and affects blood clotting.
• Brain Shrinkage with Age: As we age, the brain shrinks slightly, stretching the blood vessels and making them easier to tear.

How it Happens: When you hit your head, small veins that connect your brain to the skull can tear. Blood slowly leaks out and collects in the space around the brain. This blood presses on the brain, causing symptoms.

Who Gets It?

• Elderly People (over 65): Most common group due to brain changes with age.
• People on Blood Thinners: Warfarin, aspirin, clopidogrel, DOACs.
• Men: More common than women, especially young men (from injuries).
• People Who Drink Alcohol Heavily: Higher risk of falls and bleeding.
• Anyone with a Significant Head Injury: Car accidents, falls from height.

What are the Symptoms?

Acute SDH (develops within hours of injury):

• Severe Headache: Getting worse over time
• Confusion or Drowsiness: Becoming less alert
• Weakness on One Side of the Body: Arm or leg weakness
• Nausea and Vomiting: Due to pressure on the brain
• Seizures (Fits): Shaking or loss of consciousness
• Loss of Consciousness: Either immediately or after initially being awake

Chronic SDH (develops over weeks, common in elderly):

• Mild Headache: Persistent but not severe
• Memory Problems: Forgetfulness, confusion (may be mistaken for dementia)
• Difficulty Walking: Unsteadiness, increased falls
• Personality Changes: Irritability, apathy, mood changes
• Weakness: Gradual onset, may affect one side
• Urinary Incontinence: In some cases

Red Flags - Call 999 Immediately If:

• Severe headache after a head injury
• Loss of consciousness
• Confusion or unusual drowsiness
• Weakness in arms or legs
• Seizures
• Vomiting repeatedly
• Unequal pupils (one larger than the other)
• Difficulty speaking or understanding speech

How is it Diagnosed?

CT Scan (Brain Scan):

• Main Test: A quick scan that shows if there is blood around the brain
• Takes 5-10 minutes: You lie still while the scanner takes pictures
• No needles or pain: Just lie on a table that moves through a donut-shaped machine
• Shows: The size of the bleed, how much it's pressing on the brain, whether surgery is needed

Other Tests:

• Blood Tests: Check how well your blood clots, especially if you take blood thinners
• MRI Scan: Sometimes used for chronic bleeds (takes longer than CT)
• Neurological Exam: Doctor tests your strength, reflexes, memory, coordination

How is it Treated?

Treatment depends on the size of the bleed and your symptoms.

Surgery (for larger bleeds or if you have symptoms):

1. Burr Holes (for chronic SDH):

   • Small holes drilled in the skull (under anesthetic, you won't feel it)
   • Blood drained out through a tube
   • Tube left in for 1-2 days to keep draining
   • Less invasive, faster recovery
   • Most common for elderly patients with chronic SDH

2. Craniotomy (for acute SDH):

   • Larger operation to remove a section of skull temporarily
   • Blood clot removed directly
   • Skull piece replaced (or left out if brain swollen)
   • Needed for large or solid blood clots
   • Requires intensive care after surgery

Medical Treatment (for small bleeds that aren't pressing on brain):

• Observation: Stay in hospital with regular checks
• Repeat Scans: To make sure bleed isn't getting bigger
• Reverse Blood Thinners: If you take warfarin or other blood thinners, medication given to stop the bleeding
• Seizure Prevention: Medicine to prevent fits
• Pain Relief: Paracetamol for headaches

Recovery:

• Hospital Stay:
  • "Burr holes: 5-10 days"
  • "Craniotomy: 2-4 weeks, including intensive care"
• Rehabilitation: Physiotherapy, occupational therapy to help you regain strength and independence
• Follow-Up: Clinic appointments to check recovery, repeat scans
• Return to Normal:
  • "Chronic SDH: Most people return to normal in 3-6 months"
  • "Acute SDH: May take 6-12 months, some people have lasting effects"

What are the Risks?

From the Bleed Itself:

• Brain Damage: Pressure on the brain can cause permanent injury
• Death: Especially with acute SDH (40-60% don't survive despite treatment)
• Disability: May have lasting weakness, memory problems, or need for care

From Surgery:

• Infection: Wound or brain infection (1-2%)
• Seizures: May develop fits (10-20%)
• Bleeding Again: Blood can reaccumulate (10-30% need repeat surgery)
• Stroke: Small risk during or after surgery

Long-Term:

• Cognitive Problems: Memory, concentration difficulties (20-40%)
• Weakness: May have residual arm or leg weakness
• Epilepsy: 10-20% develop recurrent seizures
• Depression: Common after brain injury

Can it be Prevented?

Fall Prevention (Most Important for Elderly):

• Home Safety:
  • Remove trip hazards (loose rugs, clutter)
  • Install grab rails in bathroom
  • Improve lighting, especially stairs and hallways
  • Non-slip mats in bath/shower
• Exercise: Strength and balance training (yoga, tai chi)
• Vision: Get eyes tested, treat cataracts
• Medications Review: Some medications cause dizziness (ask GP to review)
• Footwear: Wear well-fitting, non-slip shoes

Blood Thinner Management:

• Review Regularly: Ask GP if you still need blood thinners
• Fall Risk: If you fall frequently, discuss risks vs benefits with doctor
• MedicAlert Bracelet: Wear identification that you're on blood thinners

Head Protection:

• Helmets: For cycling, motorcycling, contact sports, construction work
• Seatbelts: Always wear in cars

Alcohol:

• Reduce Intake: Reduces fall risk and improves blood clotting
• Support: Seek help if you have alcohol problems

What Happens After Recovery?

Most People:

• Chronic SDH: 60-80% make a full or near-full recovery
• Acute SDH: 30-50% make a good recovery (depending on severity)

Ongoing Care:

• Driving: Usually can't drive for 6-12 months (must inform DVLA)
• Work: Many people return to work, may need lighter duties initially
• Activities: Gradual return to normal activities as symptoms allow
• Medication: May need seizure medication for some time
• Follow-Up: Regular clinic appointments and scans

Support:

• Family and Carers: Important for recovery, especially for elderly
• Rehabilitation Services: Physiotherapy, occupational therapy, speech therapy
• Charities: Headway (brain injury charity) provides support and information
• GP: Regular reviews, medication management, referrals

If You Have Symptoms: If you or a loved one has had a head injury and develops headaches, confusion, weakness, or any concerning symptoms, seek medical attention immediately. Early treatment can be life-saving.

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12. Prevention

Primary Prevention (Reducing Incidence)

Fall Prevention Programs (Most Effective for Elderly):

Evidence-Based Interventions:

• Multifactorial Fall Prevention: Reduces fall risk by 30-40% in community-dwelling elderly [23]
  • Home safety assessment by occupational therapist
  • Medication review (reduce sedatives, antihypertensives)
  • Exercise programs (strength, balance, gait training)
  • Vision correction (cataract surgery, updated glasses)
  • Vitamin D supplementation if deficient
• Exercise Programs: Tai chi, group exercise classes reduce falls by 23-29% [24]
• Home Modifications: Grab rails, improved lighting, remove trip hazards [25]

Environmental Safety:

Head Protection:

• Helmets:
  • "Cycling: 69% reduction in head injuries [26]"
  • "Motorcycling: 72% reduction in severe TBI [27]"
  • "Construction work: Mandatory in high-risk settings"
• Contact Sports: Protective headgear (rugby, boxing, ice hockey)
• Skiing/Snowboarding: Helmets reduce TBI risk by 35% [28]

Alcohol Reduction:

• Fall Risk: Heavy alcohol use increases fall risk 3-4 fold
• Coagulopathy: Alcohol-related liver disease impairs clotting
• Brain Atrophy: Chronic alcohol causes premature brain shrinkage
• Intervention: Brief alcohol counseling reduces consumption and fall risk [29]

Secondary Prevention (Early Detection)

Imaging Protocols for High-Risk Patients:

NICE Head Injury Guidelines (CG176) - Imaging Criteria: All patients meeting ANY of these criteria should have urgent CT brain:

• GCS less than 13 on initial assessment in emergency department
• GCS less than 15 at 2 hours after injury
• Suspected open or depressed skull fracture
• Any sign of basal skull fracture
• Post-traumatic seizure
• Focal neurological deficit

• 1 episode of vomiting

• Age ≥65 years with ANY loss of consciousness or amnesia
• Anticoagulation (warfarin, DOACs) with ANY head injury
• Dangerous mechanism (pedestrian struck, fall > 1 meter)

Anticoagulated Patients - Low Threshold for Imaging:

• Any head injury: CT brain even if seemingly minor
• Delayed Imaging: Repeat CT at 24h if initial negative but patient on anticoagulant [30]
• Reason: Risk of delayed expansion despite initial negative scan

Observation Protocols:

• Admit for Observation: GCS 13-14, skull fracture, anticoagulation
• Neuro Observations: GCS, pupils, BP, HR every 30 min for 2h, then hourly for 4h, then 2-hourly
• Repeat CT Indications: GCS decline, new focal signs, persistent headache/vomiting

Tertiary Prevention (Preventing Recurrence)

Post-Operative Strategies:

1. Subdural Drain Use (Level Ib Evidence):

• Santarius 2009 RCT: Drain reduces recurrence from 24% to 9.3% (p=0.003) [7]
• Technique: Leave drain 24-48 hours post-burr holes
• Drainage: Target less than 50mL/24h before removal
• Position: Flat or 10° head-down for 24-48h (promotes brain re-expansion, controversial)

2. Middle Meningeal Artery Embolization:

• Primary Adjunct: Reduces recurrence to 4-5% in high-risk cases [16,17]
• Indications for Adjunctive MMA Embolization:
  • Bilateral chronic SDH
  • Mixed-density SDH (suggests ongoing bleeding)
  • Previous recurrence
  • Continued anticoagulation required
  • Thick membranes on imaging (> 2mm)
• Standalone MMA Embolization: Emerging as alternative to surgery in selected cases [31]

3. Anticoagulation Management (Critical for Recurrence Prevention):

Risk Stratification for Anticoagulation Resumption:

Pre-Requisites for Anticoagulation Resumption:

• CT brain shows stable or improving SDH (no expansion)
• No clinical signs of rebleeding (stable GCS, no new headache)
• Neurosurgery team agreement
• Discussion with patient/family regarding risks

Bridging Anticoagulation:

• NOT recommended in first 7 days post-SDH evacuation
• LMWH bridging: Consider after 7-14 days if very high thrombosis risk (mechanical valve)
• Monitor: Weekly CT for first month if anticoagulated

4. Lifestyle Modifications:

• Fall Prevention: Continue home safety measures, exercise programs
• Avoid Recurrent Head Trauma: Helmets for cycling, avoid contact sports for 6-12 months
• Medication Review: Rationalize sedatives, antihypertensives (cause postural hypotension)
• Alcohol Cessation: Reduces fall risk and improves brain health

5. Surveillance Imaging:

• Post-Operative CT:
  • Day 1 post-op (routine)
  • 6 weeks post-op (clinic follow-up)
  • PRN if symptomatic
• Chronic SDH Surveillance:
  • "If recurrence at 6 weeks: Consider MMA embolization"
  • "If stable: Discharge from neurosurgery follow-up"

Special Population Strategies

Elderly Patients (> 75 years):

• Comprehensive Geriatric Assessment: Address multifactorial fall risk
• Home Occupational Therapy: Pre-discharge home visit, equipment provision
• Medication Rationalization: Deprescribe unnecessary drugs
• Balance Training: Group classes, tai chi (evidence-based)
• Bone Health: Treat osteoporosis (fractures worsen falls)

Anticoagulated Patients:

• Regular Review: Is anticoagulation still indicated? (e.g., AF > 1 year post-CVA)
• Fall Risk Assessment: If recurrent falls, consider stopping anticoagulation vs left atrial appendage occlusion device [32]
• MedicAlert Bracelet: Identify anticoagulation status in emergencies
• Patient Education: Seek urgent medical attention for any head injury

Contact Sports Athletes:

• Concussion Protocols: Rest until asymptomatic (reduces SDH risk from second impact)
• Graduated Return to Play: Stepwise increase in activity after concussion
• Protective Equipment: Helmets, mouthguards

Public Health Measures

Population-Level Interventions:

• Road Traffic Safety: Seatbelt enforcement, speed limits (reduce TBI incidence)
• Helmet Laws: Mandatory helmets for cyclists, motorcyclists (69-72% reduction in head injuries)
• Workplace Safety: Hard hats in construction, fall protection equipment
• Alcohol Licensing: Reduce alcohol availability (reduces intoxication-related falls and assaults)

Health System Interventions:

• Anticoagulation Clinics: Monitor INR, reduce supratherapeutic anticoagulation
• Falls Clinics: Multidisciplinary assessment and intervention for recurrent fallers
• Care Home Training: Staff training in fall prevention, early recognition of deterioration

Cost-Effectiveness of Prevention

Economic Impact:

• Fall Prevention Programs: Save $3-5 per $1 invested (reduced hospitalizations, care costs) [33]
• MMA Embolization: Reduces recurrence surgery costs by 50-70% in high-risk patients
• Early CT Imaging: Anticoagulated patients - cost-effective to image liberally (prevents delayed presentation with larger SDH)

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13. References

Primary Guidelines

1. National Institute for Health and Care Excellence (NICE). Head injury: assessment and early management. Clinical guideline [CG176]. Updated January 2023. Available at: www.nice.org.uk/guidance/cg176
2. Carney N, Totten AM, O'Reilly C, et al. Guidelines for the Management of Severe Traumatic Brain Injury, Fourth Edition. Neurosurgery. 2017;80(1):6-15. PMID: 27654000.
3. Bullock MR, Chesnut R, Ghajar J, et al. Surgical Management of Acute Subdural Hematomas. Neurosurgery. 2006;58(3 Suppl):S16-24. PMID: 16710960.

Landmark Trials

4. Kolias AG, Chari A, Santarius T, Hutchinson PJ. Chronic subdural haematoma: modern management and emerging therapies. Nat Rev Neurol. 2014;10(10):570-578. PMID: 25224156.
5. Cooper DJ, Rosenfeld JV, Murray L, et al. Decompressive craniectomy in diffuse traumatic brain injury (DECRA Trial). N Engl J Med. 2011;364(16):1493-1502. PMID: 21434843.
6. Hutchinson PJ, Kolias AG, Timofeev IS, et al. Trial of Decompressive Craniectomy for Traumatic Intracranial Hypertension (RESCUEicp). N Engl J Med. 2016;375(12):1119-1130. PMID: 27602507.
7. Santarius T, Kirkpatrick PJ, Ganesan D, et al. Use of drains versus no drains after burr-hole evacuation of chronic subdural haematoma: a randomised controlled trial. Lancet. 2009;374(9695):1067-1073. PMID: 19782872.
8. CRASH-3 Trial Collaborators. Effects of tranexamic acid on death, disability, vascular occlusive events and other morbidities in patients with acute traumatic brain injury (CRASH-3): a randomised, placebo-controlled trial. Lancet. 2019;394(10210):1713-1723. PMID: 31623894.

Systematic Reviews and Meta-Analyses

9. Adhiyaman V, Asghar M, Ganeshram KN, Bhowmick BK. Chronic subdural haematoma in the elderly. Postgrad Med J. 2002;78(916):71-75. PMID: 11807187.
10. Miranda LB, Braxton E, Hobbs J, Quigley MR. Chronic subdural hematoma in the elderly: not a benign disease. J Neurosurg. 2011;114(1):72-76. PMID: 20868214.
11. Ducruet AF, Grobelny BT, Zacharia BE, et al. The surgical management of chronic subdural hematoma. Neurosurg Rev. 2012;35(2):155-169. PMID: 21909694.
12. Kundishora AJ, Pinkas M, Weintraub A, et al. The biology of chronic subdural hematoma and the role of thromboinflammation in recurrence. J Neurosurg. 2022;137(5):1445-1453. PMID: 35353244.

Anticoagulation Reversal

13. Pollack CV Jr, Reilly PA, van Ryn J, et al. Idarucizumab for Dabigatran Reversal - Full Cohort Analysis. N Engl J Med. 2017;377(5):431-441. PMID: 28693434.
14. Connolly SJ, Crowther M, Eikelboom JW, et al. Full Study Report of Andexanet Alfa for Bleeding Associated with Factor Xa Inhibitors. N Engl J Med. 2019;380(14):1326-1335. PMID: 30730782.
15. Frontera JA, Lewin JJ 3rd, Rabinstein AA, et al. Guideline for Reversal of Antithrombotics in Intracranial Hemorrhage: A Statement for Healthcare Professionals from the Neurocritical Care Society and Society of Critical Care Medicine. Neurocrit Care. 2016;24(1):6-46. PMID: 26714677.

Middle Meningeal Artery Embolization

16. Srivatsan A, Mohanty A, Nascimento FA, Hafeez MU, Srinivasan VM. Middle Meningeal Artery Embolization for Chronic Subdural Hematoma: A Meta-analysis and Systematic Review. World Neurosurg. 2019;122:613-619. PMID: 30472363.
17. Shotar E, Meyblum L, Premat K, et al. Middle Meningeal Artery Embolization Reduces the Post-operative Recurrence Rate of At-Risk Chronic Subdural Hematoma. J Neurointerv Surg. 2020;12(12):1209-1213. PMID: 32345677.

Epidemiology and Outcomes

12. Balser D, Farooq S, Mehmood T, Reyes M, Samadani U. Actual and projected incidence rates for chronic subdural hematomas in United States Veterans Administration and civilian populations. J Neurosurg. 2015;123(5):1209-1215. PMID: 26274998.
13. Rauhala M, Luoto TM, Huhtala H, et al. The incidence of chronic subdural hematomas from 1990 to 2015 in a defined Finnish population. J Neurosurg. 2019;132(4):1147-1157. PMID: 30835690.
14. Teasdale G, Jennett B. Assessment of coma and impaired consciousness. A practical scale. Lancet. 1974;2(7872):81-84. PMID: 4136544.
15. Jennett B, Bond M. Assessment of outcome after severe brain damage: a practical scale. Lancet. 1975;1(7905):480-484. PMID: 46957.

Additional Important References

22. Greenberg MS. Handbook of Neurosurgery. 9th ed. New York: Thieme Medical Publishers; 2020.
23. Gillespie LD, Robertson MC, Gillespie WJ, et al. Interventions for preventing falls in older people living in the community. Cochrane Database Syst Rev. 2012;(9):CD007146. PMID: 22972103.
24. Sherrington C, Michaleff ZA, Fairhall N, et al. Exercise to prevent falls in older adults: an updated systematic review and meta-analysis. Br J Sports Med. 2017;51(24):1750-1758. PMID: 27707740.
25. Keall MD, Pierse N, Howden-Chapman P, et al. Home modifications to reduce injuries from falls in the Home Injury Prevention Intervention (HIPI) study. Lancet. 2015;385(9964):231-238. PMID: 25255696.
26. Thompson DC, Rivara FP, Thompson R. Helmets for preventing head and facial injuries in bicyclists. Cochrane Database Syst Rev. 2000;(2):CD001855. PMID: 10796827.
27. Liu BC, Ivers R, Norton R, et al. Helmets for preventing injury in motorcycle riders. Cochrane Database Syst Rev. 2008;(1):CD004333. PMID: 18254047.
28. Russell K, Christie J, Hagel BE. The effect of helmets on the risk of head and neck injuries among skiers and snowboarders: a meta-analysis. CMAJ. 2010;182(4):333-340. PMID: 20123802.
29. Kaner EF, Beyer FR, Muirhead C, et al. Effectiveness of brief alcohol interventions in primary care populations. Cochrane Database Syst Rev. 2018;2(2):CD004148. PMID: 29476653.
30. Menditto VG, Lucci M, Polonara S, et al. Management of minor head injury in patients receiving oral anticoagulant therapy: a prospective study of a 24-hour observation protocol. Ann Emerg Med. 2012;59(6):451-455. PMID: 22221840.
31. Link TW, Boddu S, Paine SM, Kamel H, Knopman J. Middle meningeal artery embolization for chronic subdural hematoma: a series of 60 cases. Neurosurgery. 2019;85(6):801-807. PMID: 30476308.
32. Reddy VY, Doshi SK, Kar S, et al. 5-Year Outcomes After Left Atrial Appendage Closure: From the PREVAIL and PROTECT AF Trials. J Am Coll Cardiol. 2017;70(24):2964-2975. PMID: 29103847.
33. Davis JC, Robertson MC, Ashe MC, et al. International comparison of cost of falls in older adults living in the community: a systematic review. Osteoporos Int. 2010;21(8):1295-1306. PMID: 20195846.
34. Yuan Y, Wang QP, Cao YL, et al. Dexamethasone for chronic subdural haematoma: a systematic review and meta-analysis. Acta Neurochir (Wien). 2020;162(11):2651-2658. PMID: 32725334.
35. Brennan PM, Kolias AG, Joannides AJ, et al. The management and outcome for patients with chronic subdural hematoma: a prospective, multicenter, observational cohort study in the United Kingdom. J Neurosurg. 2017;127(4):732-739. PMID: 27834591.
36. Edlmann E, Giorgi-Coll S, Whitfield PC, Carpenter KLH, Hutchinson PJ. Pathophysiology of chronic subdural haematoma: inflammation, angiogenesis and implications for pharmacotherapy. J Neuroinflammation. 2017;14(1):108. PMID: 28535786.
37. Soleman J, Lutz K, Schaedelin S, et al. Subperiosteal vs subdural drain after burr-hole drainage of chronic subdural hematoma: a randomized clinical trial (cSDH-Drain-Trial). Neurosurgery. 2019;85(6):E1030-E1038. PMID: 31169893.
38. Almenawer SA, Farrokhyar F, Hong C, et al. Chronic subdural hematoma management: a systematic review and meta-analysis of 34,829 patients. Ann Surg. 2014;259(3):449-457. PMID: 24096757.

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14. Examination Focus

Common Exam Questions (MRCS, FRCS, MRCP)

1. "A 75-year-old man on warfarin presents with confusion 3 weeks after a fall. CT shows a crescent-shaped hypodense collection. What is the diagnosis and management?"

• Answer: Chronic subdural haematoma. Check INR, reverse anticoagulation if elevated, neurosurgical referral for burr hole drainage with subdural drain. Discuss timing of warfarin resumption (balance stroke vs bleeding risk).

2. "What are the surgical indications for acute subdural haematoma?"

• Answer:
  • Thickness > 10mm OR midline shift > 5mm (regardless of GCS)
  • GCS ≤8 with SDH thickness > 10mm OR midline shift > 5mm
  • GCS decline ≥2 points between injury and admission
  • Asymmetric or fixed dilated pupils
  • ICP > 20mmHg refractory to medical management

3. "How do you differentiate subdural from epidural hematoma on CT?"

• Answer:
  • "SDH: Crescent-shaped (concave), crosses suture lines, respects midline (stops at falx), associated with bridging vein injury"
  • "EDH: Biconvex (lens-shaped), does not cross suture lines, limited by dural attachments, associated with skull fracture and middle meningeal artery injury"

4. "A patient with acute SDH has a GCS of 6 and bilateral fixed dilated pupils. What is the prognosis?"

• Answer: Very poor prognosis (80-95% mortality). Bilateral fixed pupils indicate severe brainstem compression from transtentorial herniation. Emergency decompressive craniectomy may be attempted but salvage rarely successful. Discuss with family regarding goals of care.

5. "What is the role of middle meningeal artery embolization in chronic SDH?"

• Answer: Endovascular procedure to embolize the MMA, which supplies the outer SDH membrane. Reduces neovascularization and microbleeding from the membrane, decreasing recurrence from 10-30% to 5-10%. Indicated for recurrent chronic SDH or high recurrence risk (bilateral, anticoagulated, thick membranes).

6. "Describe the GCS components and scoring."

• Answer:
  • "Eyes (1-4): None, to pain, to speech, spontaneous"
  • "Verbal (1-5): None, sounds, words, confused, oriented"
  • "Motor (1-6): None, extension, flexion, withdraws, localizes, obeys"
  • "Total: 3-15"
  • "Interpretation: 13-15 mild, 9-12 moderate, 3-8 severe TBI"
  • GCS ≤8 = "coma", requires intubation and airway protection

7. "How do you reverse anticoagulation in a patient with SDH on dabigatran?"

• Answer:
  • "First-line: Idarucizumab (Praxbind) 5g IV (two 2.5g vials)"
  • "If unavailable: PCC 50 units/kg + consider haemodialysis (dabigatran is dialyzable)"
  • Check APTT before and after reversal
  • "Timing of resumption: 7-14 days post-op after CT confirms stability"

Viva Points (Structured Answer Framework)

Opening Statement (30 seconds): "Subdural haematoma is a traumatic intracranial hemorrhage caused by rupture of bridging veins, resulting in blood collection between the dura mater and arachnoid membrane. It has an incidence of 10-25 per 100,000 population annually, with a bimodal age distribution affecting young trauma victims and elderly patients. Classification by timing—acute (less than 72 hours), subacute (3-21 days), and chronic (> 21 days)—determines CT appearance, surgical approach, and prognosis. Acute SDH carries 40-60% mortality despite surgery, while chronic SDH has 0-8% mortality with burr hole drainage. Key management includes urgent CT imaging, anticoagulation reversal if applicable, and neurosurgical intervention guided by thickness, midline shift, and GCS."

Epidemiology (30 seconds):

• Incidence 10-25/100,000/year; higher in elderly (50-80/100,000 in > 65 years)
• Risk factors: age > 65 (OR 4-6), anticoagulation (OR 3-5), alcohol (OR 3-4), male sex (OR 2-3)
• Bimodal distribution: young adults (high-energy trauma), elderly (low-energy falls)
• Rising incidence due to aging population and widespread anticoagulation use

Pathophysiology (45 seconds):

• Bridging vein rupture from rotational acceleration-deceleration forces
• Blood accumulates between dura and arachnoid (subdural space)
• Acute: hyperdense clot, rapid ICP elevation, mass effect, herniation risk
• Chronic: membrane formation (outer/inner), neoangiogenesis, microbleeding → recurrence
• Mass effect → midline shift → herniation syndromes (subfalcine, uncal, tonsillar)
• Brain atrophy in elderly creates larger subdural space, allowing larger hematomas before symptoms

Clinical Features (45 seconds):

• Acute: GCS reduced (median 9-12), headache, vomiting, focal deficits (hemiparesis 40-60%), seizures (10-20%), pupil abnormalities (ipsilateral dilation if uncal herniation)
• Chronic: headache (may be mild or absent), cognitive impairment mimicking dementia (60-80%), gait disturbance (50-70%), personality changes, often bilateral (15-25%)
• Red flags: GCS less than 13, GCS decline ≥2 points, fixed dilated pupil, midline shift > 5mm

Investigations (30 seconds):

• CT brain non-contrast: Gold standard
  • "Acute: Crescent-shaped hyperdense (bright), crosses sutures, respects midline"
  • "Subacute: Isodense (easily missed!), indirect signs (midline shift, sulcal effacement)"
  • "Chronic: Hypodense (dark, CSF-like) or mixed density, may have membranes"
• Key measurements: thickness (> 10mm surgical), midline shift (> 5mm significant), volume
• Coagulation studies: INR, APTT (urgent if anticoagulated)

Management (60 seconds):

• Resuscitation: ABCDE, GCS ≤8 intubate, target MAP ≥80mmHg, SpO2 > 95%, avoid hypotension/hypoxia
• Anticoagulation reversal (if applicable):
  • "Warfarin: PCC 25-50 units/kg + vitamin K 10mg IV, target INR less than 1.5"
  • "Dabigatran: Idarucizumab 5g IV"
  • "Apixaban/Rivaroxaban: Andexanet alfa or PCC 50 units/kg"
• Surgical:
  • "Acute SDH: Craniotomy if thickness > 10mm OR shift > 5mm OR GCS ≤8 with mass effect"
  • "Chronic SDH: Burr holes with subdural drain (24-48h), consider MMA embolization if recurrent"
• ICP management: Head elevation 30°, sedation, osmotherapy (mannitol or 3% saline), target ICP less than 20mmHg, CPP 60-70mmHg
• Post-op: ICU if acute (ICP monitoring), ward if chronic, serial CT, rehabilitation

Prognosis (30 seconds):

• Acute: 40-60% mortality; GCS 13-15: 5-10%, GCS 3-8: 50-90%
• Chronic: 0-8% mortality, 60-80% good recovery
• Prognostic factors: Age (> 65 worse), GCS (most powerful predictor), pupils (fixed = poor), midline shift, time to surgery
• Recurrence: Acute 5-10%, chronic 10-30% (higher without drain or in bilateral/anticoagulated)

Evidence to Cite

Essential Trials:

1. "Bullock 2006 guidelines state surgery indicated if SDH thickness > 10mm or midline shift > 5mm" (PMID 16710960)
2. "Santarius 2009 RCT (n=215) showed subdural drain reduced chronic SDH recurrence from 24% to 9.3%" (PMID 19782872)
3. "RESCUEicp trial 2016 (n=408) demonstrated decompressive craniectomy reduced mortality (27% vs 49%) but increased severe disability in refractory ICP" (PMID 27602507)
4. "CRASH-3 trial 2019 (n=12,737) found tranexamic acid reduced head injury deaths if given less than 3h post-injury" (PMID 31623894)

Classification to Quote: "Subdural haematoma is classified temporally as acute (less than 72 hours, hyperdense on CT, solid clot requiring craniotomy, 40-60% mortality), subacute (3-21 days, isodense, mixed consistency, 20-30% mortality), and chronic (> 21 days, hypodense, liquid, burr hole drainage, 0-8% mortality). The Markwalder grading system further classifies chronic SDH CT appearance from grade 0 (homogeneous high density) to grade 3 (homogeneous low density), guiding surgical planning and predicting recurrence risk."

Common Mistakes (What Fails Candidates)

Clinical Errors:

• ❌ Missing isodense subacute SDH on CT (7-21 days post-injury, appears same density as brain)
• ❌ Confusing SDH with EDH (SDH crosses sutures, EDH does not; SDH crescent, EDH biconvex)
• ❌ Discharging elderly patient with "dementia" without imaging (chronic SDH mimics dementia)
• ❌ Not recognizing bilateral chronic SDH (may have no midline shift, presents with dementia-like picture)
• ❌ Delaying surgery in symptomatic acute SDH (every hour delay increases mortality)

Management Errors:

• ❌ Forgetting to reverse anticoagulation before surgery (ongoing bleeding)
• ❌ Not checking INR/APTT in anticoagulated patients (need to document correction)
• ❌ Using craniotomy for all SDH (burr holes sufficient and preferred for chronic)
• ❌ Not using subdural drain after burr holes (increases recurrence 24% vs 9%)
• ❌ Restarting anticoagulation too early post-op (increases rebleeding risk)

Dangerous Errors to Avoid:

• ⚠️ Missing "talk and deteriorate" pattern (lucid interval then decline = expanding SDH)
• ⚠️ Undertreating ICP in severe TBI (leads to herniation and death)
• ⚠️ Hyperventilating excessively (PaCO2 less than 30mmHg causes cerebral ischaemia)
• ⚠️ Delaying neurosurgical referral for fixed dilated pupil (herniation = emergency)
• ⚠️ Not discussing prognosis with family in severe cases (bilateral fixed pupils = 80-95% mortality)

Outdated Practices (Do NOT mention):

• Routine ICP monitoring in all SDH (only if GCS ≤8 or unable to assess neurology)
• Steroids for brain swelling in TBI (CRASH trial 2004 showed increased mortality - CONTRAINDICATED)
• Prophylactic anticonvulsants beyond 7 days (no evidence of benefit, may harm)
• Primary craniotomy for all chronic SDH (burr holes now first-line)
• Prolonged bed rest post-chronic SDH drainage (early mobilization preferred)

Examiner Follow-Up Questions

Expect These:

1. "Why are elderly patients at higher risk of chronic SDH?"

• Answer: Age-related brain atrophy increases subdural space and stretches bridging veins, making them more fragile. Minor trauma (often forgotten) is sufficient to rupture veins. Additionally, elderly often on anticoagulation (AF, VTE), have comorbidities, and higher fall risk.

2. "Describe the components of the Glasgow Coma Scale and its limitations."

• Answer:
  • "Components: Eyes (1-4), Verbal (1-5), Motor (1-6), total 3-15"
  • Limitations: Cannot assess verbal in intubated patients (record as "E_M_T"), unreliable if sedated/paralyzed, dysphasia may lower verbal score despite being alert, pre-existing disability affects baseline
  • Best motor response most predictive of outcome

3. "What is 'tension pneumocephalus' and how is it managed?"

• Answer: Rare complication post-burr hole drainage where air trapped in subdural space under pressure acts like mass lesion ("Mount Fuji sign" on CT - frontal lobes separated). Occurs if excessive CSF drainage creates negative pressure. Management: burr hole aspiration or 100% oxygen (nitrogen washout technique). Prevention: avoid over-drainage, maintain subdural drain at appropriate height.

4. "When would you restart anticoagulation post-SDH evacuation?"

• Answer:
  • "High thrombosis risk (mechanical mitral valve, recent VTE less than 3 months): 3-7 days post-op"
  • "Moderate risk (AF with CHA2DS2-VASc ≥2): 7-14 days"
  • "Low risk (AF with CHA2DS2-VASc less than 2, remote VTE): consider not restarting"
  • "Pre-requisites: CT confirms stable SDH, no clinical signs of rebleeding, neurosurgery team agreement, documented discussion with patient/family"

5. "What is the 'spot sign' on CT angiography?"

• Answer: Contrast extravasation within haematoma on CTA, indicating active bleeding. Predicts haematoma expansion and poor outcome. May guide decision for surgery or intensive monitoring. Seen in acute SDH/EDH/ICH.

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15. Differential Diagnosis

Conditions to Consider

Subdural hematoma must be distinguished from other causes of headache, altered consciousness, and focal neurology after trauma or in elderly patients:

Subdural vs. Extradural Hematoma (HIGH-YIELD)

Clinical Challenge: Both present with head injury, decreased consciousness, and focal neurology

Key Point: EDH is a neurosurgical EMERGENCY. Any symptomatic EDH requires immediate craniotomy. SDH urgency depends on type and symptoms.

Chronic SDH vs. Dementia (CRITICAL - Easily Missed)

Clinical Challenge: Both present with progressive cognitive decline in elderly

Key Point: Always image elderly patients with subacute cognitive decline to exclude treatable causes like chronic SDH. Surgery can be curative.

Acute SDH vs. Intracerebral Hemorrhage

"Can't Miss" Diagnoses

1. Acute Subdural Hematoma with Uncal Herniation (Life-Threatening Emergency):

• Clues: GCS decline, ipsilateral fixed dilated pupil (CN III compression), contralateral hemiparesis, decreased consciousness
• Mechanism: Medial temporal lobe (uncus) herniates through tentorial notch, compressing CN III and cerebral peduncle
• CT: Large SDH, midline shift > 5mm, effaced basal cisterns, obliterated suprasellar cistern
• Management: EMERGENCY craniotomy, osmotherapy while preparing for surgery, intubation, avoid hyperventilation less than 30mmHg (causes ischaemia)
• Prognosis: Poor if delayed (> 1 hour); mortality 50-90%

2. Bilateral Chronic SDH in Elderly (Treatable "Dementia"):

• Clues: Elderly with subacute cognitive decline, gait disturbance, urinary incontinence (mimics NPH), NO focal signs (bilateral = symmetric), forgotten falls
• Diagnosis: High index of suspicion, CT shows bilateral hypodense crescents, may have minimal midline shift
• Management: Bilateral burr holes, dramatic improvement post-op in 60-80%
• Key: Don't label as "dementia" without imaging

3. Anticoagulated Patient with Expanding SDH:

• Clues: Patient on warfarin/DOAC with minor head injury, initially well, then deteriorates over hours to days
• Mechanism: Ongoing bleeding due to coagulopathy, SDH expands despite minor initial trauma
• Diagnosis: Serial CT shows expanding SDH, check INR/APTT/anti-Xa
• Management: URGENT anticoagulation reversal (PCC, idarucizumab, andexanet), neurosurgical referral even if initially small
• Prevention: Low threshold for imaging anticoagulated patients after head injury

4. Isodense Subacute SDH (Easily Missed on CT):

• Clues: 7-21 days post-trauma, progressive symptoms, CT appears "normal" at first glance
• Diagnosis: Look for INDIRECT signs:
  • Midline shift without obvious collection
  • Sulcal effacement
  • Ventricular compression
  • Loss of gray-white differentiation
• Investigation: MRI superior (shows SDH clearly on all sequences)
• Management: Once identified, treat as SDH (burr holes or craniotomy depending on consistency)

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16. Special Populations

Elderly Patients (> 75 years)

Epidemiology:

• Highest Incidence: 127 per 100,000 in > 80 years (10x higher than general population)
• Most Common Type: Chronic SDH (80% of chronic SDH occur in > 65 years)
• Bimodal Peak: Second peak of SDH incidence

Pathophysiology:

• Brain Atrophy: Normal aging causes 2-3% brain volume loss per decade after age 60
  • Enlarges subdural space
  • Stretches bridging veins, making them fragile
  • Allows large hematomas before symptoms (compensated)
• Fragile Vessels: Age-related vessel wall degeneration
• Minor Trauma Sufficient: Fall from standing height or even no recalled trauma (40%)

Risk Factors Specific to Elderly:

• Polypharmacy: Anticoagulants (AF common), antiplatelets (stroke/MI prevention), sedatives (increase falls)
• Falls: Leading cause (60% of chronic SDH in elderly)
• Comorbidities: AF, hypertension, diabetes, previous stroke
• Frailty: Poor reserve, multiple medical issues

Clinical Presentation:

• Insidious Onset: Often no recalled trauma, symptoms over weeks to months
• Atypical Presentation: May present as "confusion" or "not coping at home" rather than focal neurology
• Mimics Other Conditions:
  • Dementia (cognitive decline)
  • Stroke (focal deficit)
  • Normal pressure hydrocephalus (gait, cognitive, urinary triad)
  • Depression (apathy, withdrawal)
• Bilateral Common: 15-25% of elderly chronic SDH is bilateral (presents without focal signs)

Diagnostic Challenges:

• Low Threshold for Imaging: Any elderly patient with falls + cognitive change should have CT
• Isodense SDH: May be missed if 2-3 weeks post-injury
• Incidental Findings: Small asymptomatic SDH may be found on imaging for other reasons

Management Adjustments:

Prognosis in Elderly:

• Mortality:
  • "Chronic SDH: 10-20% (higher than younger patients despite benign condition)"
  • "Acute SDH: 60-80% (very poor prognosis)"
• Functional Recovery:
  • 60-70% return to baseline (slower recovery, 3-6 months vs 1-3 months in younger)
  • 20-30% have persistent deficits requiring ongoing care
• Competing Mortality: Many die from other causes (cardiovascular, infection) during recovery
• Recurrence: Similar to younger (10-30%) but often more frail to tolerate repeat surgery

Special Considerations:

• Goals of Care Discussion: Involve family early, especially if frail or multiple comorbidities
• Palliative Approach: May be appropriate in very elderly frail with poor baseline function
• Delirium Prevention: Avoid sedatives, maintain sleep-wake cycle, familiar environment, early mobilization
• Medication Review: Deprescribe unnecessary medications, rationalize anticoagulation

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Paediatric Patients (\u003c18 years)

Epidemiology:

• Incidence: Lower than adults (2-5 per 100,000 children)
• Most Common: Birth trauma (neonate), non-accidental injury (infants), sports/trauma (adolescents)
• Chronic SDH: Rare in children except post-birth trauma or NAI

Pathophysiology:

• Paediatric Skull: More flexible, absorbs impact differently
• Bridging Veins: Shorter distance to travel, less prone to tearing than elderly
• Birth Trauma: Instrumental delivery (forceps, vacuum) can cause SDH in neonates
• Non-Accidental Injury (NAI): Shaken baby syndrome causes acute SDH with retinal hemorrhages

Clinical Presentation:

• Neonates: Seizures, apnoea, bulging fontanelle, poor feeding, lethargy
• Infants/Toddlers: Vomiting, irritability, enlarged head circumference (if chronic), developmental delay
• Older Children: Similar to adults (headache, vomiting, focal deficit)
• NAI Red Flags: Multiple injuries of different ages, inconsistent history, retinal hemorrhages, subdural hematoma without plausible trauma history

Diagnosis:

• CT Brain: First-line for acute presentation
• MRI: Better for chronic SDH, shows membranes, dating of blood
• Skeletal Survey: If NAI suspected (exclude other fractures)
• Ophthalmology Review: Retinal hemorrhages (NAI marker)
• Safeguarding Assessment: MANDATORY if NAI suspected

Management:

• Conservative: Many paediatric SDH (especially birth-related) resolve spontaneously with observation
• Surgical: If symptomatic, significant mass effect, or expanding
  • Burr holes or subdural taps (via fontanelle in infants)
  • Craniotomy if large/organized
• NAI: Safeguarding referral, multi-agency approach, may require legal proceedings

Prognosis:

• Birth Trauma: Most resolve without sequelae
• Accidental Trauma: Good outcomes if isolated SDH, treated promptly
• NAI: Poorer outcomes due to associated diffuse brain injury, high recurrence risk if child returns to unsafe environment

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17. Key Takeaways

For Exams (High-Yield Facts)

Definition:

• Blood collection between dura mater and arachnoid membrane from bridging vein rupture

Epidemiology:

• Incidence: 10-25/100,000/year (50-80/100,000 in \u003e65 years)
• Bimodal: young adults (high-energy trauma) + elderly (low-energy falls)
• Risk factors: age \u003e65 (OR 4-6), anticoagulation (OR 3-5), alcohol (OR 3-4)

Classification:

• Acute (\u003c72h): hyperdense, solid clot, craniotomy, 40-60% mortality
• Subacute (3-21d): isodense (EASILY MISSED), mixed, 20-30% mortality
• Chronic (\u003e21d): hypodense, liquid, burr holes, 0-8% mortality

CT Imaging:

• Crescent-shaped (concave), crosses suture lines, respects midline
• Acute: hyperdense (bright), subacute: isodense, chronic: hypodense (dark)
• Differentiate from EDH: SDH crescent/crosses sutures, EDH lens-shaped/limited by sutures

Surgical Indications:

• Thickness \u003e10mm OR midline shift \u003e5mm (regardless of GCS)
• GCS ≤8 with SDH \u003e10mm or shift \u003e5mm
• GCS decline ≥2 points or pupil abnormalities

Management:

• Acute SDH: Craniotomy (emergency)
• Chronic SDH: Burr holes + subdural drain 24-48h (reduces recurrence 24% → 9%)
• Anticoagulation reversal: Warfarin (PCC + vit K), dabigatran (idarucizumab), Xa inhibitors (andexanet/PCC)
• ICP management: Head 30°, sedation, osmotherapy (mannitol/3% saline), target ICP \u003c20mmHg, CPP 60-70mmHg

Prognosis:

• GCS most powerful predictor
• Acute SDH: GCS 13-15 (5-10% mortality), GCS 3-8 (50-90% mortality)
• Chronic SDH: 60-80% good recovery post-burr holes

Evidence:

• Santarius 2009: Subdural drain reduces recurrence (Level 1b)
• RESCUEicp 2016: Decompressive craniectomy reduces mortality but increases severe disability
• CRASH trial 2004: Steroids CONTRAINDICATED in TBI (increase mortality)

For Clinical Practice

Red Flags:

• GCS \u003c13, GCS decline ≥2, fixed dilated pupil, midline shift \u003e5mm, seizures

Don't Miss:

• Isodense subacute SDH (7-21 days): look for midline shift without obvious collection
• Bilateral chronic SDH in elderly: mimics dementia, REVERSIBLE with surgery
• Anticoagulated patient with expanding SDH: needs URGENT reversal

Key Errors to Avoid:

• Not imaging elderly with subacute cognitive decline (may be treatable chronic SDH)
• Delaying surgery in acute SDH with mass effect (each hour increases mortality)
• Hyperventilating excessively (PaCO2 \u003c30mmHg causes ischaemia)
• Giving steroids in TBI (increases mortality - CRASH trial)

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