Chronic Pain Assessment

Quick Answer

Chronic pain assessment is a fundamental competency in anaesthesia and pain medicine, with approximately 1 in 5 Australians living with chronic pain (20% of population). The biopsychosocial model provides the optimal framework for assessment, evaluating biological (pathology, genetics), psychological (mood, coping), and social (occupational, relationship) factors. Validated tools include the Brief Pain Inventory (BPI), Pain Disability Index (PDI), and Neuropathic Pain Scale (DN4), which quantify pain intensity, interference with function, and neuropathic qualities. Assessment domains encompass: pain characteristics (location, intensity, quality, temporal pattern), functional impact (activities of daily living, work capacity), psychological status (depression, anxiety, catastrophizing), medication review (opioids, adjuvants), and red flag screening (malignancy, infection, fracture, cauda equina). Physical examination focuses on identifying generators of nociception (musculoskeletal, neuropathic, visceral) while recognizing non-organic pain (central sensitization, psychological factors). Multidisciplinary management involving physiotherapy, psychology, occupational therapy, and interventional procedures provides optimal outcomes. Indigenous patients have higher prevalence of chronic pain (particularly musculoskeletal) and face barriers to accessing specialist pain services, requiring culturally safe communication, involvement of Aboriginal Health Workers, and consideration of cultural healing practices alongside evidence-based medicine. [1-10]

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Pathophysiology

Pain Classification

International Association for the Study of Pain (IASP) Definition:

"Pain is an unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage."

Key Components:

• Sensory: Nociceptive input from tissue damage
• Emotional: Affective, cognitive response to pain
• Subjective: Patient's self-reported experience is primary
• Influenced by: Psychological, social, cultural factors

Pain Duration Classifications:

Acute Pain:

• Duration: <3 months (or tissue healing time)
• Purpose: Protective, warning signal
• Pathology: Nociceptive (tissue injury)
• Management: Treat underlying cause, analgesics

Chronic Pain:

• Duration: >3 months (or beyond tissue healing)
• Purpose: Maladaptive, persistent without protective function
• Pathology: Complex (neuropathic, central sensitization)
• Management: Multidisciplinary, functional restoration

Subacute Pain:

• Duration: 1-3 months
• Transition zone: Between acute and chronic
• Opportunity: Early intervention may prevent chronification

Pain Mechanisms:

1. Nociceptive Pain (Tissue Injury):

Somatic Nociception:

• Origin: Muscles, bones, skin, joints
• Characteristics: Localized, well-defined, described as "aching," "sore," "tender"
• Pathology: Inflammation, mechanical injury
• Examples: Postoperative pain, fracture pain, arthritic pain

Visceral Nociception:

• Origin: Organs (gastrointestinal, genitourinary, cardiovascular)
• Characteristics: Poorly localized, described as "deep," "pressure," "cramping," often referred
• Pathology: Ischaemia, distension, inflammation
• Examples: Pancreatitis pain, renal colic, myocardial ischaemia

2. Neuropathic Pain (Nervous System):

Mechanisms:

• Peripheral neuropathy: Damage to peripheral nerves (diabetic neuropathy, post-herpetic neuralgia)
• Central sensitization: Altered central nervous system processing (fibromyalgia, complex regional pain syndrome)
• Deafferentation: Phantom limb pain, post-amputation pain

Characteristics:

• Quality: Burning, tingling, "electric shock," lancinating
• Distribution: Following nerve distribution (dermatomal pattern)
• Sensory changes: Allodynia (pain from non-painful stimulus), hyperalgesia (increased pain sensitivity)
• Motor changes: Weakness, atrophy, reflex changes in radiculopathy

Examples:

• Diabetic peripheral neuropathy
• Post-herpetic neuralgia
• Phantom limb pain
• Chronic low back pain with radiculopathy

3. Nociplastic Pain (Abnormal Pain Processing):

Mechanisms:

• Central sensitization: Increased excitability of central neurons (lowered threshold, expanded receptive fields)
• Impaired descending inhibition: Loss of endogenous inhibitory pathways
• Neuroplasticity: Reorganization of central pain pathways

Characteristics:

• Discordance: Pain severity disproportionate to tissue injury
• Distribution: Diffuse, may follow anatomical patterns but with atypical features
• Response: Poor response to conventional analgesics
• Psychological impact: High rates of depression, anxiety, catastrophizing

Examples:

• Fibromyalgia
• Complex regional pain syndrome (CRPS)
• Chronic low back pain without clear structural pathology
• Tension-type headache

4. Psychogenic Pain:

Definition: Pain primarily attributable to psychological factors rather than tissue injury

Mechanisms:

• Somaization: Expression of psychological distress as physical symptoms
• Psychophysiological: Muscle tension, autonomic dysfunction from anxiety/depression
• Conversion: Unconscious psychological conflict expressed as physical symptoms

Characteristics:

• Inconsistent with anatomical patterns
• May improve with psychotherapy, antidepressants
• Often accompanied by other somatic symptoms

Clinical Approach:

• Rule out organic causes first (comprehensive assessment, investigations)
• Recognize non-organic pain as diagnosis of exclusion
• Multidisciplinary approach (psychiatry, pain psychology)

Pain Classification Frameworks:

IASP Classification (1994):

Simplified Clinical Classification:

Chronic Pain Pathophysiology

Transition from Acute to Chronic Pain:

Peripheral Sensitization:

• Primary hyperalgesia: Increased sensitivity at site of injury
• Secondary hyperalgesia: Increased sensitivity in surrounding uninjured tissue
• Allodynia: Pain from normally non-painful stimuli (light touch, clothing)
• Mechanisms: Upregulated nociceptor expression, decreased threshold for activation
• Time course: Begins within hours-days of injury, may resolve or persist

Central Sensitization:

• Wind-up phenomenon: Progressive increase in neuronal response to repeated stimuli
• Expanded receptive fields: Larger brain areas responding to painful input
• Decreased threshold: Lowered activation threshold for pain neurons
• Impaired descending inhibition: Loss of brain's natural pain-inhibitory pathways
• Persistent: Becomes self-sustaining independent of peripheral input

Structural and Functional Brain Changes:

• Neuroplasticity: Reorganization of somatosensory cortex
• Gray matter changes: Reduced volume in pain-processing regions (prefrontal cortex, thalamus)
• White matter changes: Altered connectivity between pain networks
• Functional connectivity: Hyperconnectivity between default mode network and pain matrix

Neurotransmitter and Modulator Changes:

Excitatory Neurotransmitters (Upregulated):

• Glutamate: NMDA receptor upregulation → central sensitization
• Substance P: Potent vasodilator and algogen, sensitizes nociceptors
• Calcitonin gene-related peptide (CGRP): Migraine, vascular pain

Inhibitory Neurotransmitters (Downregulated):

• Serotonin: Descending inhibitory pathways
• Norepinephrine: Descending noradrenergic inhibition
• GABA: Central inhibitory neurotransmission
• Endogenous opioids: Enkephalins, endorphins (natural pain relievers)

Neuroimmune Interactions:

• Glia activation: Microglia and astrocytes activated by chronic pain
• Proinflammatory cytokines: IL-1β, IL-6, TNF-α sustain pain signaling
• Blood-brain barrier changes: Increased permeability allows inflammatory mediators into CNS
• Self-sustaining cycle: Pain → neuroinflammation → increased pain sensitivity

Specific Pain Types

Musculoskeletal Pain:

Pathophysiology:

• Nociceptive input: From muscles, ligaments, tendons, fascia, joints
• Peripheral sensitization: Injured tissues become hyperalgesic
• Motor dysfunction: Muscle weakness, atrophy, abnormal movement patterns
• Central sensitization: Chronicity leads to central changes

Characteristics:

• Localization: Well-defined, following anatomical distribution
• Aggravating factors: Movement, activity, weather changes
• Relieving factors: Rest, analgesics, some physical modalities

Common Conditions:

• Osteoarthritis
• Rheumatoid arthritis
• Low back pain (with/without radiculopathy)
• Fibromyalgia (nociplastic component)

Neuropathic Pain:

Peripheral Neuropathy Pathophysiology:

• Axonal degeneration: Distal "dying back" pattern
• Demyelination: Impaired nerve conduction (MS, GBS)
• Compression: Nerve root compression (spinal stenosis, herniated disc)
• Ischaemia: Microvascular nerve injury (diabetic neuropathy)

Clinical Features:

• Sensory: Numbness, tingling, burning, allodynia
• Motor: Weakness, atrophy, gait disturbance
• Autonomic: Dry skin, hair loss, colour changes
• Distribution: Dermatomal, peripheral nerve pattern

Central Neuropathy Pathophysiology:

• Stroke-related: Thalamic pain syndrome, central post-stroke pain
• Spinal cord injury: Below-level neuropathic pain
• Multiple sclerosis: Demyelination-related pain

Visceral Pain:

Pathophysiology:

• Organ-specific nociceptors: Different density and distribution
• Ischaemia: Referred pain patterns (e.g., cardiac ischaemia → left arm/jaw)
• Distension: Stretching of organ capsule (gastrointestinal, genitourinary)
• Inflammation: Chemical mediators (serotonin, bradykinin, histamine)

Characteristics:

• Poor localization: Often described as "deep," "pressure," "cramping"
• Referred patterns: Pain distant from source (e.g., right shoulder → gallbladder)
• Associated symptoms: Nausea, autonomic changes

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Clinical Presentation

Pain Assessment Framework

Comprehensive Pain Assessment Domains:

A systematic assessment should evaluate:

1. Pain Characteristics:

• Location
• Intensity
• Quality
• Temporal pattern
• Aggravating and relieving factors

2. Functional Impact:

• Activities of daily living
• Work capacity
• Sleep quality
• Social and recreational activities

3. Psychological Assessment:

• Mood (depression, anxiety)
• Catastrophizing
• Coping strategies
• Pain beliefs and attitudes

4. Social Assessment:

• Occupational impact
• Relationship and family effects
• Financial consequences
• Social isolation

5. Medication History:

• Current analgesics (type, dose, frequency, effectiveness)
• Past treatments
• Side effects
• Adherence

6. Red Flag Screening:

• Malignancy indicators
• Infection signs
• Fracture signs
• Cauda equina syndrome
• Systemic disease features

7. Physical Examination:

• Targeted examination based on pain presentation
• Identification of pain generators
• Neurological assessment
• Musculoskeletal assessment

Validated Assessment Tools

Pain Intensity Measures:

Numeric Rating Scale (NRS):

• Scale: 0-10 (0 = no pain, 10 = worst pain imaginable)
• Advantages: Simple, rapid, familiar to patients
• Use: Baseline and follow-up assessments
• Limitations: Unidimensional, doesn't capture pain quality or impact

Visual Analog Scale (VAS):

• Scale: 100-mm line (0 = no pain, 100 = worst pain)
• Advantages: Visual, continuous scale
• Use: Particularly for patients with language or cognitive barriers
• Limitations: Similar to NRS - unidimensional

Verbal Descriptor Scale (VDS):

• Scale: "No pain," "Mild," "Moderate," "Severe," "Worst possible"
• Advantages: Simple, qualitative descriptors
• Use: Patients with cognitive impairment, children
• Limitations: Limited categories, subjective interpretation

Pain Quality and Characteristics:

McGill Pain Questionnaire (MPQ):

• Assesses: Sensory (20 words), affective (4 words)
• Items: 78 pain descriptors grouped into subclasses
• Advantages: Captures pain quality, differentiates neuropathic vs. nociceptive
• Use: Patients with chronic pain to characterize quality
• Limitations: Complex, time-consuming

Short-Form MPQ (SF-MPQ):

• 15 sensory descriptors
• 4 affective descriptors
• Rapid administration (2-3 minutes)

Brief Pain Inventory (BPI):

• Assesses: Pain intensity (4 sites), interference (7 items)
• Scale: 0-10 for intensity, 0-10 for interference
• Advantages: Captures pain location and functional impact
• Use: Routine clinical assessment, research
• Limitations: Limited to 4 body areas

Pain Disability Index (PDI):

• Assesses: Interference with daily activities (7 items)
• Categories: Family/Home, Recreation, Social activity, Occupation, Sexual behavior, Self-care, Life-support activity
• Score: 0-70 (higher = greater disability)
• Advantages: Comprehensive functional assessment
• Use: Chronic pain rehabilitation planning, outcome measurement

Neuropathic Pain Specific Tools:

Neuropathic Pain Scale (DN4):

• Assesses: 10 items covering neuropathic pain qualities
• Items: Burning, tingling, electric shock, allodynia, hyperalgesia
• Score: 0-10 (higher = more severe)
• Advantages: Validated neuropathic pain assessment
• Use: Differentiating neuropathic from nociceptive pain
• Limitations: Developed in 1990s, may not capture all neuropathic qualities

Douleur Neuropathique 4 (DN4) Questions:

1. "Does the pain feel like burning?" (yes/no)
2. "Is the pain associated with tingling?" (yes/no)
3. "Is the pain associated with numbness?" (yes/no)
4. "Is the pain triggered by non-painful stimuli?" (yes/no)

PainDETECT Questionnaire:

• 9-item screening tool for neuropathic pain
• Developed for clinical use
• Quick administration (3-5 minutes)

Psychological Assessment:

Hospital Anxiety and Depression Scale (HADS):

• Assesses: Anxiety (7 items), Depression (7 items)
• Score: 0-21 per subscale (0-7 normal, 8-10 mild, 11-14 moderate, 15-21 severe)
• Advantages: Screens for anxiety and depression in medically ill
• Use: Chronic pain psychological assessment
• Limitations: Does not assess pain-specific coping

Pain Catastrophizing Scale (PCS):

• Assesses: Catastrophic thinking related to pain (13 items)
• Subscales: Rumination, Magnification, Helplessness
• Score: 0-52 (higher = greater catastrophizing)
• Advantages: Pain-specific, identifies maladaptive cognitions
• Use: Target cognitive-behavioral therapy

Tampa Scale for Kinesiophobia (TSK):

• Assesses: Fear of movement and re-injury (17 items)
• Score: 17-68 (higher = greater kinesiophobia)
• Advantages: Identifies fear-avoidance behaviors
• Use: Functional rehabilitation planning

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Assessment Content

SAQ Practice Question 1 (20 marks)

Question:

A 58-year-old woman (72 kg) presents with chronic low back pain of 8 years duration. She describes constant aching pain localized to lumbar region, rated 6/10 on NRS. Pain interferes with her ability to work as a cleaner and enjoy family activities. She reports low mood and poor sleep. No history of trauma. Examination reveals paraspinal muscle tenderness but normal neurological examination.

(a) What assessment domains would you evaluate? (5 marks)

(b) List validated pain assessment tools you would use and what they measure. (8 marks)

(c) What red flags would you screen for? (7 marks)

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Model Answer:

(a) Assessment Domains (5 marks)

1. Pain Characteristics [1 mark]

• Location: Lumbar region (well-localized)
• Intensity: 6/10 on NRS (moderate)
• Quality: "Constant aching" (somatic nociceptive)
• Temporal pattern: 8 years duration (chronic)
• Aggravating/relieving factors: Not yet characterized

2. Functional Impact [1 mark]

• Activities of daily living: Work as cleaner (requires lifting, bending, standing)
• Sleep quality: Poor (chronic pain disrupts sleep)
• Social/recreational: Interferes with family activities
• Need specific assessment: Pain Disability Index (PDI)

3. Psychological Assessment [1 mark]

• Mood: Low mood (suggests depression)
• Need formal assessment: Hospital Anxiety and Depression Scale (HADS)
• Coping: Not yet characterized (assess with Pain Catastrophizing Scale)
• Beliefs: Not yet assessed (pain beliefs questionnaire)

4. Social Assessment [0.5 marks]

• Occupational impact: Unable to work as cleaner
• Financial: Implication of lost income
• Family: Interferes with family activities
• Social isolation: Not yet characterized

5. Medication Review [0.5 marks]

• Current analgesics: Not yet obtained
• Past treatments: Not yet obtained
• Effectiveness and side effects: Not yet assessed
• Opioid use risk: Screen for misuse

6. Red Flag Screening [1 mark]

• Malignancy: Unexplained weight loss, night pain, systemic symptoms
• Infection: Fever, night sweats, IV drug use
• Fracture: Trauma history, steroid use, minor trauma in elderly
• Cauda equina: Bowel/bladder dysfunction, saddle anesthesia, progressive deficits
• Systemic disease: Features of rheumatoid arthritis, ankylosing spondylitis

(b) Validated Pain Assessment Tools (8 marks)

Pain Intensity Measurement [1.5 marks]

• Numeric Rating Scale (NRS): 0-10 scale (current rating 6/10)
• Visual Analog Scale (VAS): 100-mm line for baseline tracking
• Verbal Descriptor Scale (VDS): "Mild," "Moderate," "Severe," "Worst possible"

Pain Quality and Characteristics [2 marks]

• Brief Pain Inventory (BPI): Assesses pain at 4 body sites + interference with function
• McGill Pain Questionnaire (MPQ): 78 pain descriptors (sensory + affective)
• Short-Form MPQ: 15 sensory + 4 affective descriptors

Functional Impact [1.5 marks]

• Pain Disability Index (PDI): 7 categories (Family/Home, Recreation, Social, Occupation, Sexual, Self-care, Life-support)
• Score 0-70 (higher = greater disability)
• Brief Pain Inventory: Interference subscale (7 items, 0-10 each)

Neuropathic Pain Assessment [1.5 marks]

• Neuropathic Pain Scale (DN4): 10 items assessing burning, tingling, electric shock, allodynia, hyperalgesia
• PainDETECT: 9-item screening for neuropathic pain
• Differentiates neuropathic from nociceptive pain

Psychological Assessment [1.5 marks]

• Hospital Anxiety and Depression Scale (HADS): Anxiety (7 items) + Depression (7 items), scores 0-21 each
• Pain Catastrophizing Scale (PCS): 13 items, 3 subscales (Rumination, Magnification, Helplessness), score 0-52

Total: 8 marks

(c) Red Flag Screening (7 marks)

Malignancy Red Flags [1.5 marks]

• Unexplained weight loss: >10% body weight in 6 months
• Night pain: Pain worsens at night, disturbing sleep (beyond typical)
• Progressive pain: Increasing intensity or duration
• Age >50 with new pain
• Previous malignancy: History of cancer
• Systemic symptoms: Fatigue, anorexia, malaise

Infection Red Flags [1 mark]

• Fever: Temperature >38°C
• Night sweats: Drenching sweats at night
• Recent IV drug use: Risk of abscess or endocarditis
• Immunocompromise: Diabetes, HIV, steroid use
• Recent spinal procedure: Epidural, spinal injection

Fracture Red Flags [1 mark]

• Trauma: Recent falls, motor vehicle accident
• Minor trauma in elderly: Simple fall in >65 years
• Steroid use: Chronic steroid therapy (reduces bone density)
• Corticosteroid withdrawal: May cause bone pain

Cauda Equina Syndrome Red Flags [1.5 marks]

• Bowel dysfunction: Urinary retention or incontinence, fecal incontinence
• Bladder dysfunction: Inability to void or loss of sensation
• Saddle anesthesia: Loss of sensation in perineal region ("saddle" area)
• Bilateral leg symptoms: Both legs affected (suggests central pathology)
• Progressive neurological deficits: Worsening weakness, sensory loss over time

Systemic Disease Red Flags [1 mark]

• Morning stiffness: >1 hour (suggests inflammatory arthritis)
• Age <45 with chronic back pain + systemic symptoms (suggests ankylosing spondylitis)
• History of cancer: Metastatic disease to spine
• Unexplained constitutional symptoms: Fatigue, weight loss, malaise

Traumatic Red Flags [1 mark]

• Major trauma: Motor vehicle accident, fall from height
• Penetrating injury: Stab wound, gunshot
• Violence: Assault
• Recent surgery: Postoperative complication

Total: 20 marks

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Viva Scenario (25 marks)

Opening Stem:

You are conducting an initial pain clinic consultation for a 52-year-old man (80 kg) referred by his GP for chronic low back pain of 2 years duration following a workplace lifting injury. He reports constant aching pain in lumbar region rated 7/10 on NRS. Pain interferes with his work as a labourer and causes sleep disturbance. He appears frustrated and reports feeling "useless" due to pain. He takes paracetamol 1 g qds, ibuprofen 400 mg tds, but reports minimal benefit. No history of trauma (he was lifting heavy box, no fall). GP notes indicate normal blood tests and lumbar X-ray.

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Expected Viva Progression:

Examiner: What are your initial priorities in this assessment?

Candidate Response: [4 marks]

"My initial priorities for this initial chronic pain assessment are:

1. Therapeutic Alliance [1 mark]

• Establish rapport and trust
• Validate patient's pain experience
• Demonstrate empathy and understanding
• Ensure patient feels heard and believed

2. Comprehensive Assessment Planning [0.5 marks]

• Systematic approach to all domains (biopsychosocial)
• Clear explanation of assessment process
• Obtain informed consent for examination

3. Safety Screening (Red Flags) [1 mark]

• Critical priority: Screen for serious pathology before proceeding
• Malignancy red flags: Weight loss, night pain, systemic symptoms
• Infection red flags: Fever, night sweats, IV drug use
• Fracture red flags: Minor trauma, steroid use
• Cauda equina syndrome: Bowel/bladder dysfunction, saddle anesthesia, progressive deficits
• Traumatic red flags: Major trauma, penetrating injury
• Systemic disease: Morning stiffness, age <45 with inflammatory back pain

4. Current Medication Review [0.5 marks]

• Paracetamol 1 g qds (appropriate dose, regular use)
• Ibuprofen 400 mg tds (regular NSAID, assess renal/GI risks)
• Assess effectiveness: Minimal benefit reported
• Screen for opioid misuse (not currently taking opioids)

5. Functional Impact Assessment [0.5 marks]

• Work interference: Cannot work as labourer (heavy lifting required)
• Sleep disturbance: Pain disrupts sleep
• Social/recreational impact: Not specified
• Need formal assessment: Pain Disability Index (PDI)

6. Psychological Screening [0.5 marks]

• Mood: Patient reports feeling "useless" (suggests depression)
• Catastrophizing: Frustration, hopelessness
• Need formal assessment: HADS, PCS, TSK"

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Examiner: What red flags would you specifically screen for and what are your concerns?

Candidate Response: [3 marks]

"Red flag screening for this patient requires systematic approach:

Malignancy Red Flags [1 mark]

• Unexplained weight loss: >10% body weight
• Night pain: Pain significantly worsens at night (beyond typical mechanical pattern)
• Progressive pain: Increasing intensity or duration over time
• Systemic symptoms: Fatigue, anorexia, malaise
• Age: New-onset severe pain in >50 years warrants concern
• History of cancer: Previous malignancy increases risk

Infection Red Flags [0.5 marks]

• Fever: Temperature >38°C
• Night sweats: Drenching sweats, not environment-related
• Recent IV drug use: Risk of epidural abscess, endocarditis
• Immunocompromise: Diabetes, HIV, chronic steroid use

Fracture Red Flags [0.5 marks]

• Steroid use: Chronic steroid therapy reduces bone density
• Minor trauma in elderly: Simple fall can cause pathological fracture
• Osteoporosis risk factors: Age >65, female, smoking, low BMI

Cauda Equina Syndrome Red Flags [1 mark] This is critical to rule out:

Bowel/Bladder Dysfunction:

• Urinary retention or incontinence
• Fecal incontinence
• Loss of anal sphincter tone

Saddle Anesthesia:

• Loss of sensation in perineal region ("saddle" area)
• Numbness between genitals and anus

Bilateral Neurological Symptoms:

• Both legs affected (radiculopathy patterns)
• Progressive weakness
• Progressive sensory loss

My Concerns:

This patient has several concerning features:

1. Duration: 2 years (progressive symptoms would be expected)
2. Intensity: 7/10 (moderate-severe)
3. Work interference: Significant functional impact
4. Psychological distress: "Useless" suggests depression

However, no red flags clearly present:

• No weight loss reported
• No night pain (not specified)
• No fever or infection signs
• No bowel/bladder dysfunction (not mentioned)
• No saddle anesthesia (not mentioned)
• No bilateral leg symptoms (lumbar pain localized)

Conclusion: Red flag screening appears negative, but requires thorough examination to exclude serious pathology."

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Examiner: What validated pain assessment tools would you use?

Candidate Response: [4 marks]

"I would use a combination of tools to comprehensively assess this patient:

Pain Intensity and Characterization:

1. Numeric Rating Scale (NRS) [0.5 marks]

• Current pain rating: 7/10 (moderate-severe)
• Least and worst pain in past 24 hours
• Average pain over past week
• Pain at rest vs. with activity

2. Brief Pain Inventory (BPI) [0.5 marks]

• Assesses pain at 4 body sites
• Interference scale: General activity, Mood, Walking, Normal work, Relations, Sleep, Enjoyment of life
• Score 0-10 each (higher = greater interference)
• Captures functional impact of pain

3. Mcgill Pain Questionnaire (MPQ) [0.5 marks]

• 20 sensory descriptors (burning, tender, shooting, throbbing, etc.)
• 4 affective descriptors (exhausting, sickening, fearful, punishing)
• Differentiates neuropathic vs. nociceptive pain
• This patient's "constant aching" suggests somatic nociception

Functional Impact Assessment:

4. Pain Disability Index (PDI) [1 mark]

• 7 categories assessing interference with activities of daily living
• Categories: Family/home responsibilities, Recreation, Social activity, Occupation, Sexual behavior, Self-care, Life-support activity
• Score 0-70 each category (0-70 total)
• Higher scores indicate greater disability
• Particularly important given this patient's work interference

Psychological Assessment:

5. Hospital Anxiety and Depression Scale (HADS) [0.5 marks]

• 14 items: 7 anxiety, 7 depression
• Score 0-21 each subscale
• Screens for psychological distress in medically ill patients
• This patient reports feeling "useless" → screen for depression

6. Pain Catastrophizing Scale (PCS) [0.5 marks]

• 13 items assessing catastrophic thinking related to pain
• 3 subscales: Rumination, Magnification, Helplessness
• Score 0-52 (higher = greater catastrophizing)
• Identifies maladaptive cognitions to target with CBT

Neuropathic Pain Screening:

7. Douleur Neuropathique 4 Questions (DN4) [0.5 marks]

• 4 yes/no questions:
  1. Does the pain feel like burning?
  2. Is the pain associated with tingling?
  3. Is the pain associated with numbness?
  4. Is the pain triggered by non-painful stimuli?
• Screens for neuropathic qualities
• This patient's "constant aching" is NOT typical neuropathic quality → more likely nociceptive"

This combination provides:

• Comprehensive pain characterization
• Functional impact assessment
• Psychological screening
• Differentiation between neuropathic and nociceptive mechanisms"

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Examiner: How would you approach the physical examination?

Candidate Response: [4 marks]

"My physical examination approach is systematic and targeted:

1. Inspection [0.5 marks]

• General appearance: Look for distress, guarding, abnormal posture
• Gait assessment: Observe walking pattern, antalgic gait, ability to heel-walk, toe-walk
• Spinal alignment: Scoliosis, kyphosis, loss of lumbar lordosis
• Skin changes: Scars, signs of trauma, cellulitis, herpetic lesions

2. Palpation [1 mark]

• Spinous processes: Tenderness, step-off deformities
• Paraspinal muscles: Spasm, tenderness, trigger points
• Sacroiliac joints: Tenderness suggests sacroilitis (radicular pattern)
• Greater trochanter: Tenderness suggests trochanteric bursitis/hip pathology
• Facet joints: Deep tenderness over lumbar facets
• Trigger points: Localized hyperalgesic points

3. Range of Movement [0.5 marks]

• Lumbar flexion: Assess with finger-to-floor test (normal: can touch floor with knees straight)
• Lumbar extension: Assess arching back, assess pain
• Side flexion: Assess lateral bending
• Hip rotation: Assess internal and external rotation (excludes hip pathology)
• Straight leg raise (SLR): Assess for radiculopathy (positive: pain at 30-70°)

4. Neurological Examination [1 mark]

Motor Assessment:

• Myotomes: L4/L5 (knee extension, great toe extension), S1 (ankle plantar flexion)
• Strength: 0-5 grading for key muscle groups (quadriceps, hamstrings, gastrocnemius, tibialis anterior, extensor hallucis longus, foot intrinsics)
• Asymmetry: Compare left vs. right

Sensory Assessment:

• Dermatomes: L4 (medial knee, medial leg), L5 (lateral leg, dorsum foot, great toe), S1 (lateral foot, little toes)
• Light touch and pinprick: Assess sensory levels
• Vibration sense: 128 Hz tuning fork (posterior column function)

Reflex Assessment:

• Knee jerk (L3/L4): 0-4 grading (absent, diminished, normal, brisk)
• Ankle jerk (S1): 0-4 grading
• Babinski sign: Assess for upper motor neuron signs

5. Special Tests [0.5 marks]

• Femoral nerve stretch test: Assess L2-L4 radiculopathy
• Slump test: Assess for neural mechanosensitivity
• Patrick's (FABER) test: Assess sacroiliac joint pathology
• Heel walking/toe walking: Assess for functional overlay vs. organic pathology

6. Red Flag Examination Findings [0.5 marks]

Critical to assess for:

• Cauda equina:
  • Perineal sensation
  • Anal sphincter tone
  • Anal wink reflex
  • Bulbocavernosus reflex
• Upper motor neuron signs:
  • Hyperreflexia
  • Clonus
  • Extensor plantar response (Babinski)
  • Spasticity

Documentation:

• Record all findings systematically
• Note any red flag findings that require urgent imaging/referral
• Document functional limitations observed"

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Examiner: What imaging would you request and why?

Candidate Response: [3 marks]

"Given this patient's presentation and red flag screening, my imaging approach would be:

Initial Imaging: Lumbar X-ray [0.5 marks]

Indications:

• Patient already had lumbar X-ray (reportedly normal)
• Repeat X-ray NOT indicated if recent and adequate
• X-ray useful for: Fractures, dislocations, bony pathology

Advanced Imaging: Lumbar MRI [1.5 marks]

Strongly Indicated:

• Chronic pain >3 months (2 years duration)
• Progressive or severe symptoms (7/10, work interference)
• No clear mechanical diagnosis after examination
• Red flag features present (though screening negative)

What MRI Shows:

• Soft tissue structures: Discs, ligaments, nerves, muscles
• Disc pathology: Herniation, degeneration, bulging
• Nerve root compression: Stenosis, foraminal narrowing
• Inflammatory changes: Marrow edema
• Neoplasm: Primary or metastatic tumors
• Infection: Discitis, epidural abscess (if red flags positive)

Why MRI Over Other Modalities:

Additional Imaging Considerations:

If MRI contraindicated (e.g., pacemaker):

• CT myelography: Excellent for spinal canal and nerve root visualization
• Bone scan: If metastatic disease suspected

If Red Flags Present:

• Urgent MRI (within 24 hours)
• Consider CT if MRI not available or contraindicated"

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Examiner: The MRI shows L4/L5 disc herniation with mild L4 nerve root compression. How would you explain this to the patient?

Candidate Response: [3 marks]

"I would explain the findings in simple, clear language:

1. The Diagnosis: "Your MRI shows a disc herniation at the L4/L5 level in your lower back. This means one of the shock-absorbing discs between your vertebrae has bulged out and is pressing on the nerve that travels down your leg."

2. What This Means: "This disc herniation is causing:

• Nerve root compression: Irritation of the nerve that supplies sensation and movement to parts of your leg
• Inflammation: The area around the disc is swollen and irritated
• Pain generation: Both the disc itself and the compressed nerve can cause pain"

3. Relationship to Symptoms: "This likely explains:

• Your lower back pain: From the disc itself and surrounding inflammation
• Any leg symptoms: If you have shooting pain, tingling, or numbness going down your leg, this matches the L4/L5 nerve pattern"

4. What This Does NOT Mean: "This is not:

• A life-threatening condition
• A sign of permanent damage
• Something that will definitely require surgery
• Your fault (workplace injury is common trigger but not causative)"

5. Management Options: "Most people with similar findings improve with:

• Time and conservative management (6-12 weeks)
• Physiotherapy to strengthen core muscles and improve posture
• Medication adjustments (more effective pain relievers)
• Gradual return to activity

Surgery is only considered if:

• Pain remains severe and disabling despite conservative treatment
• Worsening neurological symptoms (increasing weakness, numbness)
• Your symptoms and MRI findings match
• You understand and agree with surgical approach"

6. Prognosis: "Many people with disc herniations recover fully, though it may take several months. The goal is to:

• Manage pain effectively
• Restore your ability to work and enjoy life
• Prevent the pain from becoming chronic
• Address the distress and frustration you're feeling"

7. Questions and Concerns: "Do you have any questions about what I've explained? Are you concerned about anything specific? What are your main priorities for getting back to work?"

8. Next Steps:

• Refer to physiotherapy for structured exercise program
• Adjust medications: Consider stronger analgesics, possibly neuropathic pain modifiers
• Refer to pain psychology: Address depression and catastrophizing thoughts
• Follow-up appointment: Review response to treatment in 4-6 weeks"

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Examiner: What multidisciplinary management would you recommend?

Candidate Response: [4 marks]

"Chronic low back pain with significant functional and psychological impact requires multidisciplinary approach:

1. Pain Medicine Specialist [1 mark]

• Comprehensive pain assessment and diagnosis
• Medication optimization:
  • First-line NSAID (if appropriate): Consider COX-2 inhibitor (celecoxib) with PPI cover for GI protection
  • Neuropathic pain modifiers: Consider gabapentin or pregabalin (even if pain primarily nociceptive, mixed mechanisms common)
  • Low-dose TCA (amitriptyline 10-25 mg nocte): Neuropathic pain modulation, sleep improvement
  • Consider weak opioid (tramadol, codeine) if NSAIDs ineffective
• Interventional options:
  • Epidural steroid injection: If radicular pain present
  • Facet joint injection: If facet joint tenderness
  • Radiofrequency ablation: For facet-mediated pain
  • Consider only if conservative management fails

2. Physiotherapy [1 mark]

• Manual therapy: Soft tissue mobilization, manipulation
• Exercise prescription:
  • Core strengthening (transversus abdominis, multifidus)
  • Lumbar stabilization exercises
  • Gradual return to normal movement patterns
• Education: Back care, posture, ergonomics for work activities
• Graded activity program: Pacing activities, avoid boom-bust cycles
• Work hardening program: Gradual return to work duties

3. Clinical Psychology [0.5 marks]

• Formal psychological assessment: HADS, PCS, TSK (Tampa Scale for Kinesiophobia)
• Cognitive-behavioral therapy (CBT):
  • Address catastrophizing thoughts ("I'm useless")
  • Challenge unhelpful beliefs about pain
  • Develop coping strategies
  • Gradual exposure to feared activities (graded activity)
• Depression treatment: Consider antidepressant (SSRI) if HADS indicates depression

4. Occupational Therapy [0.5 marks]

• Workplace assessment: Ergonomic evaluation of labourer duties
• Work modifications: Adjustments to reduce strain (mechanical aids, task rotation)
• Graded return to work: Structured program to build tolerance
• Disability support: If unable to return to previous work, identify alternative roles

5. Pain Management Program [0.5 marks]

• Multidisciplinary pain program: Combined sessions with all team members
• Group education sessions: Pain education, coping skills, exercise classes
• Goal setting: Functional goals rather than pain elimination
• Peer support: Opportunity to share experiences with others with chronic pain

6. Medical Specialist Referral (if indicated) [0.5 marks]

• Orthopaedic surgeon: If progressive neurological deficits or severe structural compression
• Neurosurgeon: If surgical intervention considered for disc herniation
• Rheumatologist: If inflammatory features or atypical presentation
• Occupational physician: If work-related injury compensation or return-to-work issues

Key Principles:

• Patient-centered goals: Focus on function and quality of life, not pain elimination
• Active management: Patient actively participates in recovery (exercises, pacing, cognitive strategies)
• Multimodal analgesia: Combinations of medications and interventions
• Avoid prolonged opioids: High risk of dependence, limited long-term efficacy
• Regular review: Assess progress, adjust management plan"

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Examiner: How would you address the patient's opioid risk?

Candidate Response: [2 marks]

"This patient is currently NOT taking opioids, but given chronic pain and potential future escalation, I would:

1. Document Baseline [0.5 marks]

• Current medications: Paracetamol 1 g qds, Ibuprofen 400 mg tds
• No opioids: Document this explicitly in notes
• Pain level: 7/10 despite regular analgesics

2. Opioid Risk Assessment [0.5 marks]

Screen for Risk Factors:

• Personal or family history of substance misuse
• Psychiatric history: Depression, anxiety, PTSD
• Previous long-term opioid use
• Age: Younger age (<30) associated with higher risk

Screening Tools:

• Opioid Risk Tool (ORT): 5-item screening (age, sex, history, mood, dose)
• Drug Abuse Screening Test (DAST): 10-item substance use screening
• Current medications: Review pharmacy records if concerns

3. Education and Agreement [0.5 marks]

Patient Education:

• Discuss opioid risks: Dependence, tolerance, hyperalgesia, endocrine dysfunction, respiratory depression
• Explain limited long-term efficacy: Opioids often less effective for chronic pain
• Discuss alternatives: Multimodal non-opioid approaches

Opioid Agreement:

• If opioids are prescribed:
  • Single prescriber: Prevent doctor shopping
  • Regular review: Frequent follow-up to assess efficacy and risk
  • Urine drug screening: Random monitoring
  • Dispensing limits: Controlled drug dispensing

4. Safe Prescribing Principles [0.5 marks]

If opioids become necessary:

• Start low, go slow: Begin with lowest effective dose
• Avoid long-acting opioids: Use immediate-release formulations
• Set time limits: Trial periods (e.g., 2-4 weeks) with clear review
• Avoid concurrent sedatives: Benzodiazepines + opioids increase respiratory depression risk
• Regular review: Ongoing risk-benefit assessment

5. Monitoring [0.5 marks]

• Prescription monitoring: Prescription monitoring program (if available)
• Pharmacy review: Check for multiple prescribers or early repeats
• Functional assessment: Monitor for pain control vs. impairment

6. Refer to Addiction Services [0.5 marks]

If concerns emerge:

• Pain medicine addiction specialist: For assessment and management
• Drug and alcohol services: For substance use treatment
• Psychiatry: For underlying mental health conditions"

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Total: 25 marks

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