Complex Regional Pain Syndrome (CRPS)

Quick Answer

Complex Regional Pain Syndrome (CRPS) is a debilitating chronic pain condition affecting approximately 26.2 per 100,000 person-years, with CRPS type I (reflex sympathetic dystrophy) more common than type II (causalgia). The Budapest Criteria (2003, modified 2007) provide standardized diagnostic criteria requiring: (1) continuing pain disproportionate to inciting event, (2) at least one symptom in three of four categories (sensory, vasomotor, sudomotor/edema, motor/trophic), (3) at least one sign in two or more categories at examination, and (4) no other diagnosis explaining findings. Pathophysiology involves peripheral and central sensitization, neurogenic inflammation, autonomic dysfunction, and cortical reorganization. Management follows multimodal evidence-based approaches: pharmacotherapy (gabapentinoids, bisphosphonates, corticosteroids, ketamine), interventional techniques (sympathetic blocks, spinal cord stimulation), intensive rehabilitation, and psychological support. Prognosis varies—early intervention (<1 year) achieves remission in 50-75% of cases, while chronic CRPS (>1 year) has poorer outcomes with permanent disability in 15-25%. Indigenous patients face significant barriers including diagnostic delay (language barriers affecting symptom description, cultural concepts of pain differing from biomedical models), limited access to multidisciplinary pain services in rural/remote areas, and higher psychological comorbidity requiring culturally adapted cognitive-behavioral therapy and involvement of Aboriginal Health Workers in care coordination. [1-12]

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Pathophysiology

Classification and Subtypes

Historical Evolution:

Reflex Sympathetic Dystrophy (RSD): Originally described by Mitchell et al. (1864) in Civil War soldiers with persistent burning pain after nerve injury. The term implied sympathetic nervous system involvement.

Causalgia: Derived from Greek "kausos" (burning) + "algos" (pain), originally described nerve injury-associated burning pain.

Current IASP Classification (1994, Revised 2007):

CRPS Type I vs Type II:

While the original distinction was based on presence of major nerve injury, contemporary evidence suggests more overlap than separation:

Clinical Similarities:

• Pain quality (burning, allodynia, hyperalgesia)
• Autonomic features (color changes, temperature asymmetry)
• Treatment responsiveness
• Natural history and prognosis

Distinctions:

• CRPS Type II more commonly associated with:
  • Mechanical allodynia in nerve distribution
  • Motor deficits corresponding to affected nerve
  • Earlier onset of symptoms post-injury
• CRPS Type I more commonly associated with:
  • Fracture and immobilization history
  • Cast-related complications
  • Broader anatomical distribution

Budapest Diagnostic Criteria

The Budapest Criteria (Harden et al., 2006, 2007) replaced the previous IASP criteria to improve diagnostic specificity and sensitivity:

Clinical Diagnostic Criteria (Must Meet All):

1. Continuing Pain:

• Pain disproportionate to inciting event
• Persistent beyond expected healing time (>3-6 months)
• Spontaneous or evoked

2. Must Report at Least One Symptom in Three of Four Categories:

3. Must Display at Least One Sign at Time of Evaluation in Two or More Categories:

4. No Other Diagnosis:

• Clinical findings not better explained by another condition

Research Diagnostic Criteria (Stricter):

• Must meet all four clinical criteria PLUS:
• At least one sign in ALL four symptom categories (more specific, reduces false positives)

Underlying Pathophysiology

1. Peripheral Sensitization:

Nociceptor Changes:

• Lowered activation threshold: Primary afferent nociceptors become hypersensitive to mechanical, thermal, and chemical stimuli
• Spontaneous activity: Ectopic firing from damaged nerves (Type II) or sensitized nociceptors
• Upregulated receptors: TRPV1 (thermal), ASIC (acid-sensing), P2X3 (purinergic)
• Inflammatory mediators: NGF, bradykinin, substance P, CGRP sensitize peripheral terminals

Neurogenic Inflammation:

• Antidromic signaling: Action potentials travel backwards along C-fibers to peripheral terminals
• Neuropeptide release: Substance P and CGRP cause:
  • Vasodilation and plasma extravasation (edema)
  • Mast cell degranulation (histamine, tryptase)
  • Immune cell recruitment (macrophages, neutrophils)
• Self-perpetuating cycle: Inflammation → sensitization → more inflammatory mediator release

2. Central Sensitization:

Spinal Cord Changes:

• Wind-up phenomenon: Progressive increase in dorsal horn neuron response to repeated C-fiber stimulation
• Expanded receptive fields: Spinal neurons respond to wider somatic inputs
• Decreased threshold: Lowered activation threshold for wide dynamic range (WDR) neurons
• Loss of inhibition: Reduced GABAergic and glycinergic interneuron activity
• Glial activation: Microglia and astrocytes release pro-inflammatory cytokines (IL-1β, IL-6, TNF-α) sustaining sensitization

Supraspinal Changes:

• Cortical reorganization: Somatosensory cortex shows distorted body representation ("cortical smearing")
• Altered body schema: Impaired cortical representation of affected limb
• Descending facilitation: Brainstem pathways facilitate rather than inhibit pain transmission
• Changes in pain matrix: Altered functional connectivity between insula, anterior cingulate, prefrontal cortex

3. Autonomic Dysfunction:

Sympathetic Nervous System:

• Catecholamine sensitivity: Pain fibers develop sensitivity to sympathetic transmitters (norepinephrine, epinephrine)
• Alpha-adrenergic coupling: C-fiber sprouting in dorsal root ganglia creates short-circuiting with sympathetic fibers
• Vasomotor instability: Sympathetic tone dysregulation causes:
  • Temperature asymmetry (initially warm, later cold)
  • Color changes (erythema → cyanosis → pallor)
  • Sweating abnormalities (hyperhidrosis or anhidrosis)

Neuroimmune Interactions:

• Autoimmune mechanisms: Antibodies against autonomic nervous system components found in some CRPS patients
• Genetic factors: HLA-DQ1 association in some populations

4. Motor System Involvement:

Mechanisms:

• Central motor changes: Altered motor cortex excitability
• Peripheral factors: Pain-induced immobility, protective posturing
• Autonomic-motor coupling: Sympathetic effects on muscle blood flow

Manifestations:

• Weakness: Decreased grip strength, reduced force generation
• Tremor: Postural or action tremor of affected limb
• Dystonia: Abnormal sustained postures (frequently fixed flexion)
• Dysfunction: Loss of fine motor control, coordination deficits

5. Inflammatory Mechanisms:

Systemic Inflammation:

• Elevated inflammatory markers: CRP, IL-6, TNF-α increased in serum
• Local inflammation: Skin biopsies show increased inflammatory infiltrate
• Osteopenia: Regional bone loss (Sudeck's atrophy) via cytokine-mediated osteoclast activation

Osteoporosis Pathophysiology:

• Neuropeptide effects: CGRP and substance P modulate bone metabolism
• Disuse atrophy: Immobility contributes to bone loss
• Blood flow changes: Altered vascular supply affects bone remodeling

Risk Factors and Predictors

Pre-Existing Factors:

• Female sex: 3-4:1 female-to-male ratio
• Age: Peak incidence 40-60 years, but can occur at any age
• Psychological factors: Anxiety, depression, catastrophizing (may be result rather than cause)
• Genetic predisposition: Family history of chronic pain conditions

Injury-Related Factors:

• Fractures: Distal radius fractures (Colles') highest risk (1-10% develop CRPS)
• Surgery: Particularly orthopedic procedures, carpal tunnel release
• Immobilization: Prolonged casting or splinting
• Nerve injury: Crush injuries, transections (Type II CRPS)
• Severity of initial injury: Paradoxically, minor injuries can trigger severe CRPS

Protective Factors:

• Early mobilization: Reducing immobilization time
• Vitamin C supplementation: 500 mg daily for 50 days post-fracture (reduces CRPS incidence by 50-80%)
• Early pain control: Aggressive multimodal analgesia

Natural History and Prognosis

Early Phase (0-6 months):

• Warm CRPS: Hot, red, edematous limb with severe spontaneous pain
• Acute inflammation: Prominent inflammatory features
• Best response to treatment: Immunomodulatory and anti-inflammatory therapies most effective
• Potential for remission: Highest in this phase

Dystrophic Phase (6-12 months):

• Cold CRPS: Cool, pale, cyanotic limb with atrophic changes
• Contractures develop: Joint stiffness, tendon shortening
• Osteopenia progresses: Radiographic changes become evident
• Pain characteristics: More constant, less inflammatory

Atrophic Phase (>12 months):

• Fixed changes: Irreversible skin atrophy, contractures
• Cold, dry limb: Persistent vasomotor instability
• Treatment resistance: Less responsive to immunomodulation
• Permanent disability: 15-25% develop lasting impairment

Prognostic Factors:

Favorable:

• Early diagnosis (<3 months)
• Prompt multimodal treatment
• Absence of psychological comorbidities
• Good social support
• Upper limb involvement (better than lower limb)

Unfavorable:

• Delayed diagnosis (>12 months)
• Cold phase at presentation
• Significant motor dysfunction
• Poor psychological coping
• Litigation/compensation issues
• Lower limb involvement

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Clinical Presentation

Symptom Complex

Sensory Symptoms:

Spontaneous Pain:

• Burning quality: Deep, constant burning sensation (pathognomonic)
• Throbbing: Pulsatile pain superimposed on burning baseline
• Aching: Deep, dull, persistent discomfort
• Intensity: Severe, frequently rated 8-10/10 on NRS

Evoked Pain:

• Allodynia: Pain from normally non-painful stimuli:
  • Mechanical: Light touch, clothing, air movement
  • Thermal: Temperature changes (hot or cold water)
• Hyperalgesia: Exaggerated pain response to painful stimuli:
  • Pinprick: Sharp, shooting pain
  • Pressure: Severe discomfort from mild compression
• Hyperpathia: Delayed explosive pain after repeated stimulation

Distribution:

• Often follows dermatomal or peripheral nerve patterns initially
• Frequently spreads beyond initial territory (CRPS "spread")
• May involve entire limb or contralateral limb (mirror-image CRPS)

Vasomotor Symptoms:

Temperature Changes:

• Early phase: Warmth, erythema (inflammatory)
• Late phase: Coolness, cyanosis (vasoconstrictive)
• Asymmetry: Affected limb differs by >1°C from contralateral side

Color Changes:

• Red/erythematous: Early vasodilation
• Blue/cyanotic: Venous stasis, poor perfusion
• Pale/mottled: Severe vasoconstriction

Sudomotor Symptoms:

Edema:

• Pitting edema: Especially in dependent position
• Non-pitting induration: Chronic phase with tissue fibrosis
• Distribution: Often circumferential around affected area

Sweating Abnormalities:

• Hyperhidrosis: Excessive sweating (early phase)
• Anhidrosis: Absence of sweating (late phase)
• Asymmetry: Marked difference between affected and unaffected limbs

Motor/Trophic Symptoms:

Motor Dysfunction:

• Weakness: Reduced strength, early fatigability
• Tremor: Intention or postural tremor
• Dystonia: Fixed abnormal postures (flexed fingers/wrist, equinovarus foot)
• Dysfunction: Impaired fine motor control, clumsiness

Trophic Changes:

• Skin: Thin, shiny, atrophic; increased or decreased hair growth
• Nails: Rigid, curved, thickened, with growth abnormalities
• Hair: Coarse, thin, or excessive growth
• Subcutaneous tissues: Fibrosis, atrophy

Physical Examination Findings

General Inspection:

Limb Position:

• Protective posture: Limb held in guarded position
• Dystonic postures: Fixed flexion or extension deformities
• Refusal to move: Voluntary immobility due to pain

Visual Changes:

• Color asymmetry between limbs
• Visible edema or atrophy
• Skin texture changes (shiny, dry, scaly)
• Hair and nail abnormalities

Sensory Examination:

Allodynia Testing:

• Cotton wool: Light stroking causes pain
• Cold stimulus: Cold metal object provokes discomfort
• Brush stroke: Soft brush elicits pain response

Hyperalgesia Testing:

• Pinprick: Increased pain compared to contralateral side
• Pressure algometry: Reduced pain threshold
• Temporal summation: Increasing pain with repeated stimuli

Quantitative Sensory Testing (QST):

• Thermal thresholds: Altered detection of warm/cold
• Vibration thresholds: Impaired proprioception
• Mechanical thresholds: Reduced pressure pain tolerance

Vasomotor Examination:

Temperature Assessment:

• Infrared thermometry: Objective measurement of surface temperature
• Comparison: Affected vs. contralateral limb (normal <0.5°C difference)
• Distribution: Distal-to-proximal gradient changes

Color Observation:

• Photographic documentation of color changes
• Dependency test: Color changes with limb elevation/dependency
• Capillary refill: May be delayed or rapid depending on phase

Sudomotor Examination:

Edema Assessment:

• Girth measurements: Tape measure comparisons
• Pitting assessment: Indentation persistence after pressure
• Volume displacement: Water displacement volumetry (objective)

Sweating Assessment:

• Qualitative sudomotor axon reflex test (QSART): Quantifies sweat response
• Thermoregulatory sweat test: Pattern of sweating abnormalities
• Simple observation: Visible moisture or dryness

Motor Examination:

Strength Testing:

• Manual muscle testing (MMT): Document weakness objectively
• Hand grip dynamometry: Quantified grip strength
• Functional movements: Observed during specific tasks

Range of Motion:

• Active ROM: Limited by pain and weakness
• Passive ROM: Limited by contractures, pain, or protective spasm
• Joint-specific: Fingers, wrist, elbow, shoulder (upper limb); toes, ankle, knee, hip (lower limb)

Trophic Assessment:

• Skin: Thickness, texture, color, integrity
• Nails: Growth rate, thickness, curvature
• Hair: Distribution, density, texture
• Soft tissues: Muscle atrophy, subcutaneous tissue loss

Special Clinical Features

Spread Phenomena:

Contiguous Spread:

• Extension to adjacent body regions
• "March" of symptoms proximally or distally

Mirror-Image CRPS:

• Contralateral limb develops CRPS symptoms
• Occurs in 10-30% of cases
• May precede, accompany, or follow initial CRPS

Independent Spread:

• Non-contiguous remote site involvement
• Triggers often minor trauma to new site
• Suggests systemic predisposition

Sympathetic Maintained vs. Independent Pain:

Sympathetic Maintained Pain (SMP):

• Pain relieved by sympathetic blockade
• Respond well to sympathetic-targeted therapies
• More common in early, warm phase
• Better prognosis

Sympathetic Independent Pain (SIP):

• Pain persists despite sympathetic blockade
• Requires central-acting therapies
• More common in chronic, cold phase
• More challenging to treat

Paediatric CRPS:

Characteristics:

• Lower limb predominance (unlike adults)
• Female predominance more marked (6-8:1)
• Better prognosis than adults
• High response to intensive rehabilitation
• Lower rates of invasive interventions

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Investigations

Diagnostic Workup

Imaging:

Triple-Phase Bone Scintigraphy (TPBS):

• Phase 1 (flow): Increased perfusion (sensitive but non-specific)
• Phase 2 (blood pool): Soft tissue hyperemia
• Phase 3 (delayed): Periarticular uptake (juxta-articular accentuation)
• Sensitivity: 60-80% for CRPS diagnosis
• Specificity: Moderate (other inflammatory conditions also positive)

Plain Radiographs:

• Sudeck's atrophy: Patchy osteopenia, subperiosteal resorption
• Joint changes: Joint space narrowing, subchondral changes
• Timeline: Changes typically visible after 3-6 months
• Limited sensitivity: Early CRPS often radiographically normal

MRI:

• Bone marrow edema: High signal on T2/STIR sequences
• Soft tissue changes: Edema, skin thickening
• Advantages: No radiation, good soft tissue visualization
• Limitations: Expensive, availability

Quantitative Tests:

Quantitative Sudomotor Axon Reflex Test (QSART):

• Principle: Measures sweat output in response to acetylcholine iontophoresis
• Findings: Reduced or absent response in CRPS
• Utility: Objective sudomotor assessment

Thermoregulatory Sweat Test:

• Principle: Alizarin red powder changes color with moisture
• Pattern: Distal anhidrosis with proximal hyperhidrosis
• Utility: Maps sudomotor distribution

Quantitative Sensory Testing (QST):

• Thermal thresholds: Altered warm/cold detection
• Mechanical thresholds: Reduced pressure pain tolerance
• Vibration thresholds: Impaired proprioception

Bone Mineral Density:

• DEXA scan: Reduced bone density in affected limb (regional osteopenia)
• Comparison: Contralateral limb serves as control
• Correlation: Bone loss correlates with disease severity and duration

Laboratory Investigations

Inflammatory Markers:

• ESR and CRP: May be elevated (non-specific)
• Cytokine panels: IL-6, TNF-α (research use mainly)
• Autoimmune screen: ANA, ENA (exclude underlying autoimmune disease)

Bone Turnover Markers:

• Serum osteocalcin: May be elevated
• Urinary NTx: Increased bone resorption markers

Diagnostic Blocks:

Sympathetic Blocks:

• Stellate ganglion block (upper limb):

  • Technique: C6 transverse process, anterior approach
  • Diagnostic: Temporary pain relief indicates SMP component
  • Horner's syndrome confirms sympathetic blockade
  • Local anesthetic (bupivacaine) or neurolytic (phenol, rarely)

• Lumbar sympathetic block (lower limb):

  • Technique: L2-L4 level, fluoroscopic guidance
  • Diagnostic: Warmth and pain reduction indicate SMP
  • Test block: Predicts response to permanent interventions

Selective Blocks:

• Intravenous regional sympathetic block (Bier block):
  • Technique: IV guanethidine or reserpine under tourniquet
  • Utility: Diagnosis and treatment
  • Effect: Often temporary, requires multiple sessions

Neurophysiology:

Nerve Conduction Studies (NCS):

• Utility: Exclude entrapment neuropathy, radiculopathy
• Findings: Usually normal in CRPS Type I; abnormal in Type II if affected nerve tested

Electromyography (EMG):

• Utility: Exclude myopathy, motor neuron disease
• Findings: Typically normal; may show reduced recruitment

Differential Diagnosis

Must Exclude:

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Management

Treatment Principles

Multimodal, Multidisciplinary Approach:

CRPS management requires coordinated care from multiple specialties:

Core Team:

• Pain medicine specialist (coordination)
• Physiotherapist (rehabilitation)
• Occupational therapist (functional restoration)
• Clinical psychologist (coping strategies)
• Nurse specialist (education, coordination)

Extended Team:

• Orthopedic surgeon (contractures, joint issues)
• Neurologist (differential diagnosis, neuropathic pain)
• Psychiatrist (severe depression, anxiety)
• Rehabilitation medicine (intensive programs)

Pharmacological Management

First-Line Agents:

Gabapentinoids:

Gabapentin:

• Mechanism: α2δ calcium channel subunit binding → reduced excitatory neurotransmission
• Dosing: Start 100-300 mg nocte, titrate to 300-600 mg tds (maximum 3600 mg/day)
• Evidence: RCTs show benefit for pain and function in CRPS
• Side effects: Dizziness, somnolence, peripheral edema

Pregabalin:

• Mechanism: Similar to gabapentin, better bioavailability
• Dosing: 75 mg bd initially, titrate to 150-300 mg bd
• Evidence: Superior bioavailability, linear pharmacokinetics
• Side effects: Weight gain, dizziness, cognitive impairment

Bisphosphonates:

Pamidronate:

• Mechanism: Inhibits osteoclast-mediated bone resorption; anti-inflammatory properties
• Dosing: 60 mg IV single dose over 3 hours
• Evidence: Multiple RCTs demonstrate efficacy for pain and function
• Timing: Best in early phase with bone edema
• Side effects: Flu-like reaction, hypocalcemia, renal impairment

Alendronate:

• Dosing: 40 mg PO daily for 8 weeks
• Alternative: Oral option for outpatient use
• Evidence: Less robust than IV pamidronate

Corticosteroids:

Indications: Inflammatory phase (warm CRPS)

Oral Prednisolone:

• Dosing: 40 mg daily tapering over 2-4 weeks
• Evidence: Effective for early CRPS with inflammatory features
• Caution: Avoid long-term use (adrenal suppression, osteoporosis)

IV Methylprednisolone:

• Dosing: High-dose pulsed therapy (e.g., 500 mg IV × 3 days)
• Utility: Severe acute exacerbations
• Monitoring: Blood glucose, blood pressure

Topical Agents:

Topical Dimethyl Sulfoxide (DMSO):

• Mechanism: Free radical scavenger, anti-inflammatory
• Dosing: 50% cream applied 3-5 times daily
• Evidence: European studies show benefit for CRPS-1
• Side effects: Garlic-like taste, skin irritation

Topical Lidocaine:

• Dosing: 5% patch applied 12 hours on, 12 hours off
• Utility: Localized allodynia
• Safety: Minimal systemic absorption

Second-Line Agents:

Tricyclic Antidepressants (TCAs):

Amitriptyline:

• Mechanism: Norepinephrine and serotonin reuptake inhibition; sodium channel blockade
• Dosing: Start 10-25 mg nocte, titrate to 50-75 mg
• Evidence: Established efficacy for neuropathic pain
• Side effects: Anticholinergic (dry mouth, constipation, sedation)

NMDA Receptor Antagonists:

Ketamine:

• Mechanism: NMDA receptor antagonism → reduced central sensitization
• Infusion protocol: 0.1-0.5 mg/kg/hour over 4-5 days (inpatient)
• Outpatient: Oral ketamine 0.5 mg/kg qds (compounding pharmacy)
• Evidence: Case series and small RCTs show benefit for refractory CRPS
• Side effects: Psychomimetic (hallucinations, dysphoria), bladder toxicity (chronic use)
• Monitoring: Psychiatric review, bladder function, liver function

Memantine:

• Mechanism: Low-affinity NMDA antagonist, better tolerated
• Dosing: 10-20 mg daily
• Evidence: Limited but promising for CRPS

Calcitonin:

• Mechanism: Osteoclast inhibition, analgesic properties
• Dosing: 100-200 IU intranasal daily or 100 IU SC/IM
• Evidence: Mixed results; may help bone pain component

Intravenous Immunoglobulin (IVIG):

• Dosing: 0.5 g/kg over 2-5 days
• Evidence: Small RCTs show benefit in refractory CRPS
• Mechanism: Immunomodulation, anti-inflammatory
• Cost: Expensive, limited access

Third-Line/Experimental:

Thalidomide:

• Mechanism: TNF-α inhibition
• Dosing: 50-100 mg nocte
• Caution: Teratogenic, peripheral neuropathy

Low-Dose Naltrexone:

• Mechanism: Microglial modulation
• Dosing: 4.5 mg nocte
• Evidence: Emerging for chronic pain conditions

Botulinum Toxin:

• Mechanism: Motor and sensory nerve modulation
• Dosing: 100-200 units injected into affected area
• Evidence: Case reports for dystonia and pain

Interventional Procedures

Sympathetic Blocks:

Stellate Ganglion Block (Upper Limb):

• Indications: Diagnostic (SMP vs SIP), therapeutic (warm phase)
• Technique: C6 anterior tubercle approach, fluoroscopic guidance
• Medications: Bupivacaine 0.25-0.5% 5-10 mL
• Frequency: Series of 3-6 blocks over weeks
• Confirmatory signs: Horner's syndrome (ptosis, miosis, anhidrosis)
• Complications: Pneumothorax, intravascular injection, esophageal perforation, recurrent laryngeal nerve block

Lumbar Sympathetic Block (Lower Limb):

• Technique: L2-L4 level, anterolateral vertebral body approach
• Confirmatory signs: Lower limb warmth, pain reduction
• Complications: Genitofemoral neuralgia, intravascular injection, discitis

Radiofrequency Procedures:

Sympathetic Radiofrequency Denervation:

• Mechanism: Thermal lesioning of sympathetic chain
• Evidence: Limited; may provide prolonged relief in carefully selected SMP patients
• Caution: Risk of deafferentation pain, neuritis

Neuromodulation:

Spinal Cord Stimulation (SCS):

• Indications: Refractory CRPS (>6 months, failed conservative management)
• Mechanism: Dorsal column stimulation → gate control theory, supraspinal modulation
• Trial: 1-2 week externalized trial before permanent implant
• Permanent: Surgical lead placement with IPG (implantable pulse generator)
• Outcomes: 50-70% achieve >50% pain relief
• Complications: Lead migration, infection, hardware failure, loss of efficacy over time
• Cost: Expensive but cost-effective if successful

Dorsal Root Ganglion (DRG) Stimulation:

• Advantage: Targets specific affected dermatomes
• Evidence: Superior for focal CRPS (foot/hand)
• FDA-approved for CRPS

Intrathecal Drug Delivery:

• Medications: Ziconotide (N-type calcium channel blocker), morphine, baclofen
• Indications: Severe refractory cases
• Complications: Infection, catheter issues, granuloma formation

Surgical Interventions:

Sympathectomy:

• Technique: Open or thoracoscopic (upper limb), open or laparoscopic (lower limb)
• Evidence: Controversial; high risk of postsympathetic neuralgia
• Reserve: Absolute last resort for refractory SMP after successful diagnostic blocks

Amputation:

• Extreme last resort: Only for intractable, failed all other interventions
• Risk: Phantom limb pain, stump pain, psychological trauma
• Outcomes: Generally poor; CRPS may recur in stump

Non-Pharmacological Management

Intensive Rehabilitation:

Graded Motor Imagery (GMI):

• Three stages:
  1. Laterality recognition: Identify left vs. right limb images (implicit motor imagery)
  2. Explicit motor imagery: Imagine moving affected limb without actual movement
  3. Mirror visual feedback: Mirror therapy to restore cortical representation
• Evidence: High-quality RCTs show benefit for pain and function
• Mechanism: Cortical reorganization, normalization of body schema

Mirror Therapy:

• Technique: Place affected limb behind mirror, move unaffected limb while watching mirror reflection
• Mechanism: Visual illusion of normal movement "tricks" brain
• Evidence: Effective for CRPS and phantom limb pain
• Duration: 15-30 minutes, 2-3 times daily

Physical Therapy:

Desensitization:

• Technique: Gradual exposure to normally painful stimuli:
  • Different textures (cotton, silk, sandpaper)
  • Temperature variation (warm to cool)
  • Vibration
  • Light pressure
• Progression: Start with least noxious, gradually increase intensity
• Goal: Restore normal sensory processing

Active Mobilization:

• Range of motion exercises: Gentle, frequent movements within pain limits
• Loading exercises: Gradual weight-bearing
• Functional activities: Task-oriented therapy
• Key principle: "Hurt does not equal harm"—encourage movement despite discomfort

Aquatic Therapy:

• Benefits: Buoyancy reduces loading, warm water relaxes muscles, resistance for strengthening
• Temperature: 30-34°C optimal
• Caution: Avoid excessive heat in acute inflammatory phase

Occupational Therapy:

Functional Restoration:

• Activities of daily living: Bathing, dressing, feeding
• Work hardening: Gradual return to occupational duties
• Adaptive equipment: Splints, assistive devices
• Energy conservation: Pacing strategies

Splinting:

• Purpose: Prevent contractures, maintain alignment
• Types:
  • Static: Resting splints for night use
  • Dynamic: Active-assist for functional positioning
• Caution: Avoid prolonged immobilization (worsens CRPS)

Psychological Interventions:

Cognitive-Behavioral Therapy (CBT):

• Components:
  • Pain education: Understanding neurophysiology reduces fear
  • Cognitive restructuring: Challenge catastrophizing thoughts
  • Behavioral activation: Gradual increase in activities
  • Coping strategies: Distraction, relaxation, pacing
• Evidence: Improves function and coping; modest pain reduction

Acceptance and Commitment Therapy (ACT):

• Focus: Acceptance of pain, commitment to valued life activities
• Goal: Function despite pain rather than pain elimination
• Evidence: Emerging support for chronic pain

Biofeedback:

• Technique: Real-time physiological monitoring (temperature, EMG)
• Goal: Learn voluntary control over autonomic functions
• Application: Vasomotor control, muscle relaxation

Relaxation Training:

• Progressive muscle relaxation: Systematic tensing and releasing
• Guided imagery: Pleasant visualizations
• Breathing techniques: Diaphragmatic breathing, paced respiration

Pain Neuroscience Education:

• Concept: Explain central sensitization, brain's role in pain
• Goal: Reconceptualize pain as protective mechanism rather than tissue damage indicator
• Evidence: Reduces fear-avoidance, improves outcomes

Treatment Algorithms

Early Phase (0-6 months) - Warm CRPS:

1. Immediate:

   • Intensive physiotherapy + desensitization
   • Mirror therapy / graded motor imagery
   • Vitamin C supplementation (500 mg daily)

2. Pharmacological:

   • Gabapentin or pregabalin (first-line)
   • Bisphosphonate (pamidronate 60 mg IV single dose)
   • Corticosteroids (prednisolone 40 mg taper) if inflammatory
   • Topical DMSO or lidocaine

3. Interventional:

   • Sympathetic blocks (diagnostic and therapeutic)
   • Consider SCS trial if refractory

4. Psychological:

   • CBT for coping skills
   • Pain neuroscience education

Chronic Phase (>12 months) - Cold CRPS:

1. Pharmacological:

   • Continue gabapentinoids
   • Consider ketamine infusion (refractory cases)
   • IVIG (0.5 g/kg) if inflammatory component persists

2. Interventional:

   • Spinal cord stimulation (strongest evidence)
   • DRG stimulation for focal CRPS

3. Rehabilitation:

   • Intensive multidisciplinary pain program
   • Contracture prevention and management
   • Functional restoration focus

4. Surgical:

   • Sympathectomy only as absolute last resort
   • Amputation only for extreme, failed all interventions

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Indigenous Health Considerations

Pain Management Disparities in Indigenous Populations

Epidemiological Burden:

Aboriginal and Torres Strait Islander peoples experience disproportionately high rates of chronic pain conditions, including CRPS and other complex pain syndromes. National data indicates that Indigenous Australians report chronic pain at rates 1.5-2 times higher than non-Indigenous populations, with musculoskeletal pain being particularly prevalent. This disparity reflects a complex interplay of historical trauma, socioeconomic disadvantage, higher rates of trauma and injury, and limited access to specialist pain services, particularly in rural and remote communities where approximately 25% of Indigenous Australians reside.

Barriers to Diagnosis and Treatment:

Diagnostic Challenges:

The diagnosis of CRPS relies heavily on detailed symptom description and nuanced clinical assessment, creating significant challenges when language and cultural barriers exist. Indigenous patients may describe pain using concepts and terminology that differ from the biomedical "burning," "allodynia," and "hyperalgesia" descriptors central to Budapest Criteria assessment. Additionally, the requirement for temperature asymmetry assessment and quantitative sensory testing may be difficult in settings lacking specialized equipment, common in remote Aboriginal Community Controlled Health Services (ACCHSs).

Cultural concepts of pain expression also differ. Some Indigenous patients may underreport pain severity due to cultural stoicism, while others may have heightened pain sensitivity related to historical trauma and ongoing stress. Healthcare providers must avoid making assumptions based on observed behavior and should utilize culturally validated pain assessment tools where available.

Access to Multidisciplinary Care:

CRPS management requires coordinated multidisciplinary care including pain specialists, physiotherapists, occupational therapists, and clinical psychologists. These services are concentrated in major metropolitan centers, creating geographic barriers for rural and remote Indigenous patients. The cost of travel, accommodation, and extended time away from family and community responsibilities creates practical barriers that disproportionately affect Indigenous patients who often have lower socioeconomic status and limited financial resources.

The concept of "Country" and connection to land is central to Indigenous wellbeing. Being away from traditional lands for extended specialist treatment can cause significant psychological distress, potentially worsening pain outcomes. This highlights the need for telehealth and outreach specialist services to deliver care closer to home.

Treatment Considerations:

Cultural Safety in Pain Management:

Culturally safe pain management requires acknowledging the historical context of medical care for Indigenous peoples. Past experiences of racism, forced removals, and unethical medical experimentation have created widespread mistrust of mainstream healthcare services. Healthcare providers must actively work to build trust through respectful communication, acknowledging Indigenous knowledge systems, and involving Aboriginal Health Workers (AHWs) and Aboriginal Liaison Officers (ALOs) in care coordination.

AHWs play a crucial role in bridging cultural and linguistic gaps, interpreting pain descriptions, explaining treatment options in culturally appropriate language, and providing ongoing support. Their involvement has been shown to improve engagement with pain services and treatment adherence.

Communication Strategies:

Effective communication with Indigenous CRPS patients requires:

• Using clear, jargon-free language
• Avoiding medical terminology unless explained
• Allowing adequate time for questions and clarification
• Using visual aids and diagrams to explain pathophysiology
• Involving family members in discussions (with patient consent)
• Recognizing that indirect communication styles may require reading between spoken words

Medication Adherence and Safety:

Medication adherence can be challenging for remote-dwelling Indigenous patients due to:

• Limited understanding of complex medication regimens (polypharmacy common in CRPS)
• Difficulty accessing pharmacies for refills in remote areas
• Cost barriers despite PBS subsidies
• Concerns about medication safety and addiction (particularly with opioids)

Simplified medication regimens, blister packaging, and regular follow-up via telehealth can improve adherence. Education about the difference between dependence and addiction is important for medications like gabapentinoids.

Traditional Healing Integration:

Many Indigenous patients utilize traditional healing practices alongside Western medicine. These may include:

• Traditional bush medicines with analgesic properties
• Healing ceremonies and cultural practices
• Connection to Country as healing
• Elder involvement in health decisions

Rather than dismissing these practices, pain specialists should respectfully inquire about their use, ensure no dangerous interactions with prescribed medications, and where appropriate, integrate traditional healing into comprehensive care plans. Studies have shown that combining traditional and Western approaches improves outcomes for Indigenous chronic pain patients.

Māori Health Considerations:

For Māori patients in Aotearoa New Zealand, similar principles apply with specific cultural considerations:

• Whānau involvement in healthcare decisions is essential
• Māori models of health (Te Whare Tapa Whā) view pain as affecting not just physical but also mental, social, and spiritual wellbeing
• Karakia (prayers) and cultural protocols may be important before procedures
• Māori Health Workers (Kaiāwhina) provide crucial cultural brokerage
• Acknowledgment of Māori data sovereignty and control over health information

Systemic Improvements:

Addressing CRPS disparities requires systemic changes:

• Increased funding for rural pain services and outreach programs
• Cultural competency training for all pain medicine practitioners
• Development of culturally adapted CRPS assessment tools
• Integration of AHWs/Kaiāwhina into multidisciplinary pain teams
• Research prioritization on CRPS in Indigenous populations
• Addressing social determinants of health (housing, employment, education) that contribute to chronic pain risk and outcomes

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ANZCA and Faculty of Pain Medicine Guidelines

ANZCA Professional Documents

PS02 (2014) - Statement on Credentialling and Defining the Scope of Clinical Practice in Anaesthesia:

• Recognizes pain medicine as core anaesthetic competency
• Requires ongoing professional development in pain management

PS03 (2016) - Guidelines for the Management of Major Regional Analgesia:

• Applicable to regional techniques used in CRPS (sympathetic blocks, SCS trials)
• Safety and monitoring requirements

PS09 (2015) - Statement on Anaesthetist Responsibilities in Postoperative Pain Management:

• Multimodal analgesia principles applicable to chronic pain
• Acute-to-chronic pain transition risk

Faculty of Pain Medicine (FPM) ANZCA Guidelines

FPM Professional Documents:

PM01 - Recommendations for the Management of Pain:

• Evidence-based approach to chronic pain
• Multimodal pharmacotherapy principles
• Psychological intervention recommendations

PM04 - Statement on Interventional Techniques for Chronic Pain:

• Indications for sympathetic blocks in CRPS
• Spinal cord stimulation recommendations
• Safety and credentialing requirements

PM07 - Recommendations on the Use of Medications for the Treatment of Neuropathic Pain:

• Gabapentinoids as first-line for neuropathic pain including CRPS
• Ketamine recommendations for refractory cases
• Evidence grading for specific agents

PM09 - Recommendations on the Management of Complex Regional Pain Syndrome (CRPS):

• Budapest Criteria adoption for diagnosis
• Multimodal treatment algorithm
• Graded motor imagery recommendations
• Sympathetic block indications
• SCS recommendations for refractory cases

International Guidelines Integration

IASP Guidelines (2021):

• Budapest Criteria standardization
• Research vs. clinical diagnostic criteria
• Terminology standardization

Royal College of Physicians (UK) - CRPS Guidelines:

• Intensive rehabilitation focus
• Psychological intervention importance
• Stepped care model

Dutch CRPS Guidelines:

• Vitamin C prophylaxis recommendations
• Bisphosphonate evidence
• Graded motor imagery protocols

Quality Standards and Benchmarks

Diagnostic Standards:

• Budapest Criteria required for diagnosis
• Documentation of signs and symptoms
• Exclusion of differential diagnoses
• Temperature measurement (infrared thermometry)

Treatment Standards:

• Multimodal approach within 3 months of diagnosis
• Rehabilitation involvement within 4 weeks
• Psychological assessment for all patients
• SCS consideration for refractory cases (>6 months)

Outcome Measures:

• Pain intensity (NRS)
• Function (PDI, BPI interference scale)
• Quality of life (SF-36)
• Psychological status (HADS, PCS)

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Assessment Content

SAQ Practice Question 1 (20 marks)

Question:

A 42-year-old woman presents to the pain clinic 3 months after a distal radius fracture treated with immobilization. She describes persistent severe burning pain in her right hand and forearm, rated 8/10 on NRS. She reports that light touch from clothing causes severe discomfort, and her hand becomes red and swollen by evening. She has stopped using her right hand for any activities due to pain. Examination reveals a warm, erythematous right hand with pitting edema. Light touch with cotton wool elicits withdrawal and grimacing. Passive range of motion at wrist is limited to 30° flexion and 20° extension due to pain.

(a) What is the most likely diagnosis? List the diagnostic criteria required. (6 marks)

(b) Describe the pathophysiology of this condition. (6 marks)

(c) Outline a comprehensive management plan for this patient. (8 marks)

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Model Answer:

(a) Diagnosis and Criteria (6 marks)

Diagnosis: Complex Regional Pain Syndrome Type I (CRPS-I) / Reflex Sympathetic Dystrophy

Budapest Diagnostic Criteria - All four required [4 marks]:

1. Continuing pain disproportionate to inciting event [1 mark]

   • Fracture healed but pain persists (3 months post-injury)
   • Pain rated 8/10 (severe, disproportionate to healed fracture)

2. Patient reports at least one symptom in three of four categories [1.5 marks]

   • Sensory: Severe burning pain, mechanical allodynia (light touch causes pain)
   • Vasomotor: Not explicitly reported (but present on examination)
   • Sudomotor/Edema: Swelling reported (edema present)
   • Motor: Stopped using hand, functional limitation

3. At least one sign in two or more categories on examination [1.5 marks]

   • Sensory: Allodynia to light touch (cotton wool elicits pain)
   • Vasomotor: Warm, erythematous hand (temperature and color change)
   • Sudomotor/Edema: Pitting edema present
   • Motor: Limited range of motion (30° flexion, 20° extension)

4. No other diagnosis better explains findings [1 mark]

   • Fracture healed
   • No evidence of infection, malunion, or nerve entrapment
   • Pattern consistent with CRPS rather than alternative diagnosis

Classification: CRPS Type I (no major nerve injury identified)

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(b) Pathophysiology (6 marks)

1. Peripheral Sensitization [1.5 marks]

• Lowered nociceptor activation threshold following fracture and immobilization
• Inflammatory mediators (bradykinin, substance P, prostaglandins) sensitize peripheral terminals
• Ectopic firing from damaged nociceptors causes spontaneous pain
• Neurogenic inflammation: Antidromic C-fiber signaling causes vasodilation and plasma extravasation

2. Central Sensitization [1.5 marks]

• Wind-up phenomenon: Progressive increase in dorsal horn neuron response to repeated C-fiber input
• Expanded receptive fields: Spinal neurons respond to wider input areas
• Decreased threshold for wide dynamic range (WDR) neurons
• Glial activation: Microglia and astrocytes release pro-inflammatory cytokines (IL-1β, TNF-α)
• Loss of descending inhibitory pathways

3. Autonomic Dysfunction [1.5 marks]

• Sympathetic nervous system sensitization: Pain fibers develop sensitivity to catecholamines
• Vasomotor instability: Dysregulation causes warmth and erythema (early inflammatory phase)
• Edema formation: Sympathetic dysfunction and inflammatory mediator effects
• Sudomotor changes: Altered sweating patterns

4. Cortical Reorganization [1.5 marks]

• Altered body schema: Impaired cortical representation of affected limb
• Cortical smearing: Distorted somatosensory cortex representation
• Changes in pain matrix: Altered functional connectivity between pain processing regions
• Immobility and disuse contribute to maladaptive plasticity

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(c) Management Plan (8 marks)

1. Immediate Interventions [2 marks]

Intensive Rehabilitation:

• Graded motor imagery: 3-stage program (laterality recognition → motor imagery → mirror therapy)
• Desensitization: Gradual exposure to textures, temperatures, vibration
• Active mobilization: Gentle, frequent range of motion exercises
• Goal: Restore function despite pain, prevent contractures

Physical Therapy:

• Daily physiotherapy sessions
• Aquatic therapy if available
• Occupational therapy for functional tasks

2. Pharmacological Management [2.5 marks]

First-line agents:

• Gabapentin: Start 100 mg nocte, titrate to 300-600 mg tds (target 1800-3600 mg/day)

  • Mechanism: α2δ calcium channel binding
  • Monitoring: Dizziness, somnolence, peripheral edema

• Bisphosphonate: Pamidronate 60 mg IV single dose over 3 hours

  • Evidence-based for CRPS-I
  • Reduces bone resorption and has anti-inflammatory properties
  • Side effects: Flu-like reaction, monitor calcium levels

Anti-inflammatory:

• Prednisolone: 40 mg daily tapering over 2-3 weeks (inflammatory phase)
  • Reduces inflammatory component
  • Monitor: Blood glucose, blood pressure

Topical:

• Topical DMSO 50%: 3-5 times daily or lidocaine 5% patches for localized allodynia

3. Interventional Options [1.5 marks]

Sympathetic Blocks:

• Stellate ganglion blocks: Diagnostic and therapeutic
  • Technique: C6 level, bupivacaine 0.25-0.5%
  • Series of 3-6 blocks over several weeks
  • Confirm with Horner's syndrome (ptosis, miosis)
  • Contraindications: Infection, anticoagulation, patient refusal

4. Psychological Support [1 mark]

• Cognitive-behavioral therapy: Pain coping strategies, cognitive restructuring
• Pain neuroscience education: Explain central sensitization to reduce fear
• Goal: Function despite pain rather than pain elimination

5. Prevention and Education [1 mark]

• Vitamin C: 500 mg daily (reduces CRPS incidence, may help ongoing symptoms)
• Patient education: Explain CRPS pathophysiology, "hurt does not equal harm"
• Goal setting: Focus on functional restoration
• Avoid: Prolonged immobilization, rest as primary treatment

Total: 20 marks

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SAQ Practice Question 2 (20 marks)

Question:

A 55-year-old man presents with a 2-year history of left foot CRPS following ankle surgery. He describes constant burning pain rated 7/10, with the foot feeling "ice cold" and appearing pale and atrophic. He is unable to bear weight on the left foot and uses a wheelchair. He has tried gabapentin (maximum dose), pregabalin, amitriptyline, and multiple sympathetic lumbar blocks with minimal benefit. He is depressed and states he "can't live like this anymore." Examination reveals a cold, pale left foot with marked allodynia. Temperature measurement shows 3°C difference (left colder than right). Range of motion at ankle is severely limited.

(a) What phase of CRPS is this, and what are the implications for treatment? (5 marks)

(b) Why have sympathetic blocks been ineffective? What is the significance of this? (5 marks)

(c) Describe your management approach for this refractory case. (10 marks)

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Model Answer:

(a) CRPS Phase and Treatment Implications (5 marks)

Phase: Chronic/Dystrophic Phase (Cold CRPS) [2 marks]

Characteristics present:

• Duration: 2 years (>12 months defining chronic phase)
• Temperature: Cold foot (3°C asymmetry, colder than unaffected side)
• Color: Pale, atrophic appearance
• Trophic changes: Atrophic skin, limited ROM
• Previous warm phase: Likely progressed from initial inflammatory presentation

Implications for Treatment [3 marks]:

1. Treatment resistance: Cold-phase CRPS less responsive to:

   • Anti-inflammatory therapies (corticosteroids less effective)
   • Sympathetic interventions (high likelihood of sympathetic-independent pain)
   • Bisphosphonates (less impact on established bone changes)

2. Permanent changes risk:

   • Contractures may be fixed (severe ankle ROM limitation)
   • Trophic skin changes often irreversible
   • Risk of permanent disability (15-25% in chronic CRPS)

3. Focus shifts:

   • From "cure" to "function and coping"
   • From pain elimination to pain management
   • Emphasis on wheelchair independence, upper body strength
   • Psychological support critical (suicide risk expressed)

4. Aggressive interventions warranted:

   • Consider neuromodulation (SCS, DRG stimulation)
   • Ketamine infusion for refractory cases
   • Multidisciplinary intensive pain program

---

(b) Sympathetic Block Failure - Significance (5 marks)

Reasons for Ineffectiveness [3 marks]:

1. Sympathetic-Independent Pain (SIP) [1.5 marks]

   • Pain persists despite sympathetic blockade
   • Suggests central sensitization mechanisms predominate
   • Autonomic-sensory coupling no longer present
   • Pain maintained by spinal and supraspinal mechanisms

2. Chronic Phase Pathophysiology [1.5 marks]

   • Early warm phase: More likely sympathetic-maintained (responsive to blocks)
   • Late cold phase: Autonomic dysfunction less coupled to pain
   • Central sensitization becomes self-sustaining
   • Structural brain changes (cortical reorganization)

Significance [2 marks]:

1. Prognostic indicator:

   • SIP associated with poorer prognosis
   • Less responsive to conventional CRPS treatments
   • More likely to require aggressive interventions (SCS, ketamine)

2. Treatment redirection:

   • Abandon further sympathetic blocks (futility, risks)
   • Focus on central-acting therapies (neuromodulation, NMDA antagonists)
   • Emphasize rehabilitation and coping strategies

3. Surgical sympathectomy consideration:

   • Diagnostic blocks ineffective → sympathectomy unlikely to help
   • Avoid sympathectomy (high risk of postsympathetic neuralgia)

---

(c) Refractory CRPS Management (10 marks)

1. Urgent Psychological Assessment [2 marks]

• Risk assessment: "Can't live like this" suggests suicidal ideation
• Immediate psychiatric consultation: Assess depression severity and suicide risk
• Safety planning: Ensure support network, remove means if necessary
• Medication: Consider antidepressant (SSRI or SNRI) for depression
• Crisis intervention: May require inpatient admission if severe risk

2. Advanced Pharmacological Interventions [2 marks]

Ketamine Infusion:

• Rationale: NMDA receptor antagonism addresses central sensitization
• Protocol: 0.1-0.5 mg/kg/hour IV infusion over 4-5 days (inpatient)
  • Requires ICU or high-dependency monitoring
  • Psychiatric support for psychomimetic effects
• Evidence: Case series show benefit in refractory CRPS
• Alternative: Oral ketamine 0.5 mg/kg qds (specialist compounding)
• Monitoring: Bladder function (toxicity risk), liver function, psychiatric review

IVIG:

• Dosing: 0.5 g/kg over 2-5 days
• Evidence: Small RCTs benefit in refractory CRPS
• Mechanism: Immunomodulation
• Cost: Expensive, requires funding approval

3. Neuromodulation [2.5 marks]

Spinal Cord Stimulation (SCS):

• Indication: Refractory CRPS >6 months, failed conservative management
• Trial: 1-2 week externalized trial with percutaneous leads
  • Assess pain reduction, functional improvement

  • 50% pain relief warrants permanent implant

• Permanent: Surgical lead placement (dorsal column) with IPG
• Programming: Patient-controlled parameters
• Outcomes: 50-70% achieve meaningful pain relief
• Complications: Lead migration, infection, loss of efficacy over time

Dorsal Root Ganglion (DRG) Stimulation:

• Advantage: Targets specific affected dermatome (L4-L5 for foot)
• Evidence: Superior for focal CRPS
• Consider: If SCS trial inadequate or anatomically challenging

4. Intensive Multidisciplinary Program [2 marks]

Inpatient or Day-Patient Pain Program:

• Duration: 3-4 weeks intensive
• Components:
  • Daily physiotherapy (aquatic therapy, desensitization, mobilization)
  • Occupational therapy (wheelchair skills, upper limb strengthening)
  • Psychology (CBT, ACT, pain neuroscience education)
  • Medical optimization (medication review and adjustment)
• Goals:
  • Wheelchair independence and mobility
  • Upper body strengthening for transfers
  • Psychological coping strategies
  • Functional goals rather than pain elimination

5. Long-Term Management and Follow-up [1.5 marks]

Chronic Disease Management:

• Regular review: Pain clinic every 2-3 months
• Outcome measures: Track function (PDI), mood (HADS), pain (NRS)
• Support groups: Connect with CRPS support organizations
• Disability support: Access appropriate benefits and services
• Lifestyle modification: Smoking cessation, weight management, sleep hygiene
• Realistic expectations: Focus on quality of life within limitations

Total: 20 marks

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Viva Scenario (25 marks)

Opening Stem:

You are the pain medicine specialist reviewing a 35-year-old woman referred by her orthopedic surgeon. Eight months ago, she sustained a Colles' fracture of her right wrist treated with open reduction and internal fixation. Despite radiological union, she continues to experience severe burning pain in her right hand rated 9/10 on NRS. She cannot tolerate clothing touching her hand, wears a loose cotton glove constantly, and has stopped working as a hairdresser. She reports her hand is "always red and hot" and appears swollen by evening. She is tearful and says "I just want my old life back."

On examination, her right hand is erythematous and warm compared to the left, with visible edema. Light touch with cotton wool causes immediate withdrawal. There is severe limitation of finger and wrist movement. Grip strength is reduced by 80% compared to the left hand.

---

Expected Viva Progression:

Examiner: What is your diagnosis, and what criteria support this?

Candidate Response: [4 marks]

"My diagnosis is Complex Regional Pain Syndrome Type I (CRPS-I) of the right upper limb.

Budapest Criteria Support:

1. Continuing pain disproportionate to inciting event [1 mark]:

• Fracture surgically repaired and healed (8 months post-injury)
• Pain rated 9/10 (severe, disproportionate to healed injury)
• Persistent beyond expected healing time

2. At least one symptom in three of four categories [1.5 marks]:

• Sensory: Severe burning pain, mechanical allodynia (cannot tolerate clothing)
• Sudomotor/Edema: Hand red and hot, swollen by evening
• Motor: Cannot work as hairdresser, severe limitation of movement, reduced grip strength

3. At least one sign in two or more categories [1 mark]:

• Sensory: Allodynia to light touch (cotton wool elicits withdrawal)
• Vasomotor: Erythematous, warm hand (temperature and color asymmetry)
• Sudomotor/Edema: Visible edema present
• Motor: Severe limitation of movement, 80% reduction in grip strength

4. No other diagnosis explains findings [0.5 mark]:

• Fracture united on X-ray
• No evidence of surgical complication, infection, or nerve entrapment
• Pattern consistent with CRPS rather than alternative diagnosis

Classification: Type I (reflex sympathetic dystrophy) as no major nerve injury identified."

---

Examiner: What is the significance of her description that the hand is "red and hot"? How does this influence management?

Candidate Response: [4 marks]

"The 'red and hot' description indicates warm-phase CRPS, which has significant implications:

1. Phase Identification [1.5 marks]:

• Early/inflammatory phase: Typically 0-6 months duration, characterized by:
  • Warmth, erythema, edema
  • Severe spontaneous pain and allodynia
  • Active inflammatory processes
• Contrast with cold phase: Later CRPS becomes cold, pale, atrophic
• This patient at 8 months is in transition zone but still inflammatory

2. Pathophysiological Implications [1 mark]:

• Active peripheral and central sensitization
• Prominent neurogenic inflammation
• Autonomic dysfunction with vasodilation
• Reversible stage—window for effective intervention

3. Treatment Implications [1.5 marks]:

Responsive to:

• Anti-inflammatory therapies: Corticosteroids (prednisolone taper) effective in this phase
• Bisphosphonates: Pamidronate reduces bone resorption and inflammatory component
• Sympathetic blocks: More likely to be effective in warm phase (sympathetic-maintained pain)
• Immobilization avoidance: Active rehabilitation critical

Time-sensitive:

• Early aggressive treatment (<12 months) achieves remission in 50-75%
• Chronic phase (>12 months) less responsive to these interventions
• This patient still in window for optimal outcomes

Prognosis:

• Better prognosis than cold-phase CRPS
• Emphasize to patient that early treatment improves chances of recovery"

---

Examiner: Outline your comprehensive management plan.

Candidate Response: [5 marks]

"My management plan addresses all CRPS domains:

1. Immediate Pharmacological Management [1.5 marks]:

Gabapentinoid:

• Pregabalin: 75 mg bd initially, titrate to 150 mg bd over 2 weeks
  • Better bioavailability than gabapentin
  • Address neuropathic pain and allodynia
  • Monitor: Dizziness, weight gain

Bisphosphonate:

• Pamidronate: 60 mg IV single dose over 3 hours (day patient)
  • Evidence-based for CRPS-I
  • Reduces bone resorption
  • Side effects: Flu-like reaction, monitor calcium

Corticosteroid:

• Prednisolone: 40 mg daily for 1 week, then taper over 2 weeks
  • Appropriate for inflammatory phase
  • Anti-inflammatory effect
  • Monitor: Blood glucose, BP

2. Interventional Therapy [1 mark]:

Stellate Ganglion Blocks:

• Diagnostic and therapeutic: Series of 3-6 blocks
• Technique: C6 level, fluoroscopic guidance
• Medication: Bupivacaine 0.25-0.5% 5-10 mL
• Confirmation: Horner's syndrome (ptosis, miosis, anhidrosis)
• Timing: Weekly intervals, assess response after each

3. Intensive Rehabilitation [1.5 marks]:

Graded Motor Imagery:

• Stage 1: Laterality recognition exercises (left/right hand judgments)
• Stage 2: Explicit motor imagery (imagine moving hand without moving)
• Stage 3: Mirror therapy (2-3 times daily, 15-30 minutes)

Desensitization:

• Gradual texture exposure (cotton → silk → denim)
• Temperature variation (warm to cool water)
• Remove glove for progressively longer periods

Active Physiotherapy:

• Daily sessions initially
• Gentle range of motion exercises
• Goal: Restore function despite pain

4. Psychological Support [0.5 mark]:

• CBT referral: Address catastrophizing ("want old life back")
• Pain neuroscience education: Explain central sensitization
• Goal setting: Focus on functional restoration, not pain elimination

5. Patient Education [0.5 mark]:

• Explain CRPS pathophysiology
• Emphasize 'hurt does not equal harm'
• Discuss prognosis (50-75% remission with early treatment)
• Address return-to-work planning"

---

Examiner: The patient asks: "Will I ever be able to work as a hairdresser again?" How do you respond?

Candidate Response: [4 marks]

"I would provide an honest, balanced, and hopeful response:

1. Acknowledge Concern and Validate Feelings [1 mark]: 'I understand how important your career is to you, and it's completely understandable to worry about whether you'll be able to return to hairdressing. This is a devastating condition, and your distress is valid.'

2. Provide Realistic Prognosis Information [1.5 marks]:

Positive Factors:

• 'You are in the early phase of CRPS, which has a better prognosis than chronic CRPS'
• 'With intensive treatment started now, 50-75% of patients achieve remission within 6-12 months'
• 'You have no major nerve injury (Type I), which generally has better outcomes than Type II'
• 'Your fracture has healed well, so there's no ongoing structural problem'

Challenges:

• 'CRPS is unpredictable, and recovery is gradual—often months rather than weeks'
• 'Some patients have persistent symptoms despite best treatment'
• 'Return to hairdressing requires fine motor control and repetitive hand use, which will take time to restore'

3. Outline Functional Focus [1 mark]:

Goals:

• 'Our goal is to gradually restore function regardless of pain levels'
• 'We'll start with basic tasks: holding objects, simple movements'
• 'Progress to complex tasks: using scissors, styling tools, washing hair'
• 'Pain may persist during recovery, but function can improve'

Timeline:

• 'I cannot guarantee you'll return to hairdressing, but many patients do return to work'
• 'It typically takes 6-12 months of intensive rehabilitation'
• 'Some modify their work: shorter hours, different techniques, ergonomic adjustments'

4. Discuss Practical Planning [0.5 mark]:

• 'While we focus on treatment, consider exploring temporary work modifications or alternative income'
• 'Occupational therapy can assess vocational capacity and workplace modifications'
• 'Workers' compensation or disability support may be available during recovery'

Key Message: 'We're going to fight for the best possible outcome together. With commitment to treatment, there's a good chance you'll return to hairdressing, though it will require patience and hard work.'"

---

Examiner: How would you assess and monitor treatment response over time?

Candidate Response: [4 marks]

"I would use a comprehensive, multidimensional assessment approach:

1. Pain Assessment [1 mark]:

Validated Tools:

• Numeric Rating Scale (NRS): 0-10 at rest and with movement (target: reduction by ≥30%)
• Brief Pain Inventory (BPI): Pain intensity and interference with function
• Neuropathic Pain Scale: Allodynia, hyperalgesia assessment

Frequency:

• Baseline then every 4-6 weeks
• Track trends over time (not just single measurements)

2. Functional Assessment [1 mark]:

Physical Function:

• Grip strength: Dynamometry comparing hands (target: improve by ≥20%)
• Range of motion: Goniometry of wrist and fingers
• Functional tasks: Observed during activities of daily living

Disability Measures:

• Pain Disability Index (PDI): 7 domains (work, recreation, self-care)
• Disabilities of Arm, Shoulder, Hand (DASH): Upper limb-specific

Return-to-Work:

• Hours worked, tasks performed, modifications required

3. Clinical Examination [1 mark]:

Signs:

• Temperature measurement (infrared thermometry): Target reduction in asymmetry
• Edema assessment: Girth measurements, pitting assessment
• Allodynia testing: Response to cotton wool, light touch
• Range of motion: Active and passive movement
• Trophic changes: Skin, hair, nail assessment

Photographic Documentation:

• Serial photographs for objective comparison
• Color, swelling, skin changes

4. Psychological and Quality of Life Assessment [1 mark]:

Psychological:

• Hospital Anxiety and Depression Scale (HADS): Screen for mood disorders
• Pain Catastrophizing Scale (PCS): Maladaptive thoughts about pain
• Tampa Scale for Kinesiophobia: Fear of movement

Quality of Life:

• SF-36: General health-related quality of life
• EQ-5D: Utility measure for economic evaluation

Patient-Reported Outcomes:

• Global impression of change (much improved, improved, no change, worse)
• Satisfaction with treatment
• Goal achievement (patient-specific functional goals)

Monitoring Schedule:

• Months 0-3: Every 2-4 weeks (intensive phase)
• Months 3-6: Every 4-6 weeks
• Months 6-12: Every 6-8 weeks
• >12 months: Every 3 months or as needed"

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Total: 25 marks

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