High Yield Overview
CRPS - HAND
The Suicide Disease
Vit CPrevention
PainDisproportionate
MoveTherapy
BlockDiagnostic
Types
CRPS Type I
PatternNo identifiable nerve injury (Reflex Sympathetic Dystrophy).
Treatment
CRPS Type II
PatternIdentifiable nerve injury (Causalgia).
Treatment
Warm vs Cold
PatternEarly (Warm) vs Late (Cold/Atrophic).
Treatment
Critical Must-Knows
- Diagnosis is CLINICAL, based on the Budapest Criteria.
- Pain is disproportionate to the inciting event.
- Vitamin C (500mg daily for 50 days) prevents CRPS after distal radius fractures.
- Surgery is CONTRAINDICATED in the active phase.
Examiner's Pearls
- "Triple Phase Bone Scan shows diffuse uptake in late phase.
- "Stellate Ganglion Block is both diagnostic and therapeutic.
- "Early mobilization is the cornerstone of treatment.
Clinical Imaging
Imaging Gallery
Click to expand
Click to expand
Do Not Operate
Surgical Trap
Active CRPS is a "No Fly Zone" Performing elective surgery (e.g. carpal tunnel release, trigger finger) on a hand with active CRPS will cause a massive flare-up. Delay all surgery until the CRPS is "quiescent" (usually greater than 12 months).
Tourniquet Risk
Reperfusion Injury Prolonged tourniquet time increases ischemia-reperfusion injury and free radical release, which drives CRPS. Minimize tourniquet time and use Vitamin C.
| Feature | CRPS Type I | CRPS Type II |
|---|---|---|
| Old Name | Reflex Sympathetic Dystrophy (RSD) | Causalgia |
| Nerve Injury | Absent (or minor) | Present (Major nerve) |
| Inciting Event | Fracture, Crush, Sprain | Nerve Transection/Injection |
| Symptoms | Identical | Identical |
Mnemonic
STAMPBudapest Clinical Categories
S
Sensory
Hyperalgesia, Allodynia.
T
Trophic/Motor
Weakness, Tremor, Hair/Nail changes.
A
Autonomic
Sweating (Sudomotor), Color (Vasomotor).
M
Motor
Reduced range of motion.
P
Pain
Disproportionate pain.
Memory Hook:STAMP out CRPS.
Mnemonic
VPT-SIMTreatment Ladder
V
Vitamin C
Prevention.
P
Physical Therapy
Desensitization, Stress Loading.
T
Topical
DMSO, Capsaicin.
S
Sympathetic
Blocks.
I
Implant
Spinal Cord Stimulator.
M
Meds
Gabapentin, Bisphosphonates.
Memory Hook:Very Painful Treatment SIMulation.
Mnemonic
FEMALERisk Factors
F
Female
3:1 ratio.
E
Event
Fracture or Trauma.
M
Middle age
50-70 years.
A
Anxious
Psychological predisposition.
L
Limb
Upper limb > Lower limb.
E
External
Tight casts.
Memory Hook:Female predispositon.
Overview
Definition
Complex Regional Pain Syndrome (CRPS): A chronic pain condition characterized by spontaneous or evoked pain that is disproportionate in time or degree to the usual course of any known trauma.
It typically affects one limb (usually upper) after an injury. The exact mechanism involves peripheral inflammation, sympathetic coupling, and central sensitization (neuroplasticity).
Pathophysiology
Peripheral Mechanisms
- Neurogenic Inflammation: Release of CGRP and Substance P leads to vasodilation ("Warm Phase") and plasma extravasation (Edema).
- Sympathetic Coupling: Alpha-adrenergic receptors are expressed on nociceptors. Circulating catecholamines (stress) trigger pain.
This explains why stress exacerbates the condition.
Classification
IASP Classification
- Type I (RSD): Developing after an initiating noxious event that is NOT limited to the distribution of a single peripheral nerve.
- Type II (Causalgia): Developing after a nerve injury.
- NOS (Not Otherwise Specified): Partially meets criteria.
This catch-all category allows for treatment without full diagnostic certainty.
Clinical Assessment
To diagnose CRPS, the patient must meet ALL of the following Budapest Criteria:
1. Continuing Pain: Disproportionate to inciting event. 2. Symptom Report: Must report at least ONE symptom in THREE of the four categories:
- Sensory: Hyperesthesia, Allodynia.
- Vasomotor: Temperature asymmetry, Skin color changes.
- Sudomotor/Edema: Sweating changes, Edema.
- Motor/Trophic: Decreased ROM, Weakness, Hair/Nail/Skin changes. 3. Examination Sign: Must display at least ONE sign in TWO of the four categories at time of evaluation. 4. Exclusion: No other diagnosis better explains the signs and symptoms.
Note: Specificity is 94 percent.
📊 Management Algorithm
Click to expand
Investigations
Triple Phase Bone Scan (Technetium-99)
- Phase 1 (Flow): Asymmetric blood flow (increased).
- Phase 2 (Pool): Soft tissue uptake.
- Phase 3 (Delayed): Diffuse peri-articular uptake in all joints of the hand/wrist.
- Sensitivity: High (greater than 90%) in Stage 1/2.
This is the gold standard for early diagnosis.
Management
📊 Management Algorithm
Click to expand
1. Prevention (The Best Cure)
- Vitamin C: 500mg daily for 50 days (Zollinger et al.) for all distal radius fractures.
- Pain Control: Aggressive acute pain management reduces central sensitization.
- No Tight Casts: Avoid constriction.
Every wrist fracture patient gets a verbal and written instruction for Vitamin C.
Surgical Interventions
Surgery is rarely indicated and often harmful.
Indications for Surgery
- Identifyable Nerve Lesion: E.g., neuroma or compression that is driving the CRPS (Type II).
- Contractures: Only in "Cold/Burned Out" phase (Stage 3).
A 'painful nerve' is different from 'CRPS'. Fixing the nerve may fix the CRPS.
Therapy Details
Stress Loading (Watson):
- Scrubbing: Patient moves a scrub brush back and forth on a table with weight bearing.
- Carrying: Patient carries a weighted bag in the hand throughout the day.
- Mechanism: Provides proprioceptive input without painful joint motion.
Mirror Therapy (Ramachandran):
- Place unaffected hand in front of mirror.
- Hide affected hand behind mirror.
- Move unaffected hand and watch reflection ("Tricks brain" into thinking the bad hand is moving pain-free).
Complications
Musculoskeletal Complications
| Complication | Frequency | Mechanism | Management |
|---|---|---|---|
| Joint Contractures | Very common | Disuse, fibrosis | Aggressive hand therapy, serial splinting |
| Finger Stiffness | 40-60% | Capsular fibrosis | ROM exercises, dynamic splinting |
| Wrist Ankylosis | 10-20% severe cases | Spontaneous fusion | May require salvage procedures |
| Osteoporosis | Nearly universal | Disuse atrophy | Weight bearing, bisphosphonates |
| Muscle Atrophy | Common | Disuse, neurogenic | Strengthening when pain controlled |
Trophic Changes
| Change | Features | Reversibility |
|---|---|---|
| Skin | Shiny, thin, atrophic | Partially reversible |
| Hair | Increased then decreased growth | Variable |
| Nails | Brittle, ridged, dystrophic | Usually improves |
| Subcutaneous Tissue | Oedema then atrophy | Often permanent changes |
Psychological Complications
- Depression: Affects 40-50% of CRPS patients. Screen and treat early.
- Anxiety: Very common with chronic pain. CBT beneficial.
- Sleep Disturbance: Pain disrupts sleep, worsening symptoms.
- Suicide Risk: CRPS called "The Suicide Disease" - actively assess and refer.
- Catastrophizing: Worsens outcomes. Address with psychological therapy.
Functional Disability
- Work Disability: 30-50% unable to return to previous work
- ADL Impairment: May affect dressing, eating, grooming
- Social Isolation: Pain and dysfunction lead to withdrawal
- Quality of Life: Significantly reduced without treatment
Postoperative Care
Acute Phase Management
- Pain Control: Multimodal analgesia, avoid opioid dependence
- Oedema Control: Elevation, compression, contrast baths
- Protected Motion: Early active ROM within pain tolerance
- Vitamin C: 500-1000mg daily for 50 days post any procedure
Rehabilitation Phases
Phase 1
- Identify and document triggers
- Desensitization techniques (textures, temperatures)
- Start Vitamin C immediately
- Refer to specialised Hand Therapy
- Mirror therapy initiation
Phase 2
- If pain controlled, aggressive active ROM
- Avoid passive stretching (provokes pain flares)
- Progressive loading and strengthening
- Stress loading program (scrub and carry)
- Continue mirror therapy
Phase 3
- Functional task training
- Work simulation activities
- Graded exposure to avoided tasks
- Vocational rehabilitation assessment
Long Term
- Life-long tendency for recurrence with new injuries
- Prophylactic Vitamin C for any future surgeries
- Self-management strategies
- Flare management plan
Red Flags Requiring Reassessment
- Increasing Pain Despite Treatment: Consider alternative diagnosis
- New Neurological Symptoms: May indicate central sensitisation
- Psychiatric Deterioration: Urgent mental health referral
- Spread of Symptoms: May indicate generalised CRPS
Prognosis
Prognostic Factors
| Factor | Better Prognosis | Worse Prognosis |
|---|---|---|
| Age | Children, young adults | Elderly |
| Duration at Treatment | Less than 3 months | Greater than 1 year |
| CRPS Type | Warm CRPS (early) | Cold CRPS (established) |
| Extent | Localised | Spreading to multiple limbs |
| Psychological Status | Minimal catastrophising | Depression, PTSD, anxiety |
| Treatment Response | Early response to therapy | Refractory to interventions |
Expected Outcomes
- Full Recovery: 10-30% (more in children)
- Significant Improvement: 40-60%
- Chronic Symptoms: 30-40%
- Severe Disability: 10-15%
Key Points for Outcome
- Early Diagnosis and Treatment: Single most important prognostic factor
- Children: Better prognosis than adults, higher recovery rates
- Warm CRPS: Better response to sympatholytics and early intervention
- Delayed Treatment: Poor prognosis - treatment started within 3 months has significantly better outcomes
- Multidisciplinary Approach: Improves outcomes across all patient groups
- Recurrence: Can recur in same or opposite limb.
Evidence Base
Vitamin C Prophylaxis
Zollinger et al. • JAMA (1999)
Key Findings:
- Randomized Control Trial
- 500mg Vitamin C for 50 days reduced CRPS risk from 22 percent to 7 percent
- Mechanism: Antioxidant, free radical scavenger
Clinical Implication: Standard of care for distal radius fractures.
Bisphosphonates
Varenna et al. • Rheumatology (2013)
Key Findings:
- Neridronate (Bisphosphonate) infusions
- Significant pain reduction and improvement in quality of life
- Effective in acute CRPS (less than 6 months)
Clinical Implication: Consider for active phase with bone changes.
Mirror Therapy
McCabe et al. • Rheumatology (2003)
Key Findings:
- Visual feedback reduced pain in localized CRPS
- Corrects the mismatch between motor output and sensory input
Clinical Implication: Low risk, high potential benefit intervention.
Stellate Ganglion Block
Price et al. • Pain Med (1998)
Key Findings:
- Retrospective review
- Provided relief in SMP (Sympathetically Maintained Pain)
- Less effective for Sympathetically Independent Pain (SIP)
Clinical Implication: Useful diagnostic and therapeutic tool.
Ketamine Infusions
Schwartzman et al. • Pain (2009)
Key Findings:
- Outpatient ketamine infusions for 10 days
- Significant reduction in pain scores
- NMDA receptor antagonist mechanism
Clinical Implication: Option for refractory cases.
Viva Scenarios
Practice these scenarios to excel in your viva examination
VIVA SCENARIOStandard
Scenario 1: The Swollen Hand
EXAMINER
"A 50-year-old female presents 6 weeks after a distal radius fracture (treated in a cast). She complains the cast was 'too tight'. The cast is off. Her hand is swollen, red, sweating, and she cannot make a fist due to pain."
EXCEPTIONAL ANSWER
This is classic CRPS Type 1 (Acute/Warm phase). My assessment would follow the Budapest Criteria (Sensory, Vasomotor, Sudomotor, Motor signs). I would rule out infection or unrecognized tendon rupture. Treatment is multidisciplinary: 1. Prevention (start Vit C 500mg). 2. Therapy (Desensitization, Edema control, Stress loading). 3. Pharmacotherapy (Gabapentin, NSAIDs, Prednisolone boost). 4. Referral to Pain Specialist for consideration of Stellate Ganglion Block. I would NOT operate.
KEY POINTS TO SCORE
Recognize Acute CRPS
Budapest Criteria
Multimodal treatment
Avoid Surgery
COMMON TRAPS
✗Operating (e.g. releasing a 'tight' carpal tunnel) - will manifest disaster
✗Dismissing as 'low pain threshold'
LIKELY FOLLOW-UPS
"What is the role of Bone Scan?"
"It supports the diagnosis. Phase 3 shows diffuse peri-articular uptake. Sensitivity greater than 90% in this stage."
VIVA SCENARIOStandard
Scenario 2: Chronic Neuropathic Pain
EXAMINER
"A patient with old nerve injury has a cold, stiff, blue hand with severe pain. It has been 2 years."
EXCEPTIONAL ANSWER
This represents Chronic/Cold phase CRPS (Stage 3). The prognosis is poorer. Treatment focuses on function and pain management rather than 'cure'. I would involve the chronic pain team for spinal cord stimulation or ketamine infusions. Therapy focuses on maintaining remaining ROM. Joint contractures may require release but only if the active CRPS is burned out, which is risky.
KEY POINTS TO SCORE
Stage 3 identification
Poorer prognosis
Spinal Cord Stimulation
COMMON TRAPS
✗Promising cure
✗Aggressive surgery
LIKELY FOLLOW-UPS
"Are Sympathectomies useful here?"
"Rarely. In the cold phase, the pain is often Sympathetically Independent (Centralized)."
VIVA SCENARIOStandard
Scenario 3: Prevention
EXAMINER
"You are fixing a distal radius fracture. The patient asks how to prevent 'that horrible pain syndrome'."
EXCEPTIONAL ANSWER
I would counsel her on three things: 1. Vitamin C (500mg daily for 50 days) - Level 1 evidence. 2. Early mobilization of fingers - 'Move it or lose it'. 3. Adequate pain control post-op to prevent central wind-up. I typically use a regional block (Axillary) which provides a 'pain holiday' and may reduce sympathetic drive acutely.
KEY POINTS TO SCORE
Vitamin C protocol
Early motion
Regional Anesthesia
COMMON TRAPS
✗Forgetting Vitamin C dose (500mg)
LIKELY FOLLOW-UPS
"Does the block prevent CRPS?"
"Evidence is mixed, but it facilitates early pain-free movement, which prevents CRPS."
MCQ Practice Points
Diagnosis
Q: What is the most sensitive imaging modality for early CRPS? A: Triple Phase Bone Scan (Phase 3 diffuse uptake).
Phases
Q: Is the hand warm or cold in acute CRPS? A: Warm (Vasodilation due to neurogenic inflammation). It becomes cold later.
Prevention
Q: What is the recommended dose of Vitamin C for prophylaxis? A: 500mg daily for 50 days.
Treatment
Q: What is the role of Stellate Ganglion Block in CRPS? A: Both diagnostic (confirms Sympathetically Maintained Pain if pain relieved) and therapeutic (series of 3-5 blocks may provide lasting relief).
Classification
Q: What is the difference between CRPS Type I and Type II? A: Type I (RSD) has no identifiable nerve injury. Type II (Causalgia) has an identifiable nerve injury.
Red Flag
Q: When is surgery contraindicated in CRPS? A: During the active phase - surgery will cause a massive flare-up. Wait until quiescent (usually over 12 months).
Australian Context
- Pain Clinics: Most major hospitals run dedicated chronic pain clinics (e.g. RNSH Pain Management Centre).
- Guidelines: ANZCA guidelines on Acute Pain Management specifically mention CRPS protocols.
- Workers Comp: Significant burden. Early reporting and intervention is incentivized.
High-Yield Exam Summary
Diagnostic Criteria (Budapest)
- •Continuing pain disproportionate to event
- •Sensory: Hyperalgesia/Allodynia
- •Vasomotor: Temp/Color asymmetry
- •Sudomotor/Edema: Sweating/Swelling
- •Motor/Trophic: Weakness/Nail changes
Management Hierarchy
- •1. Vitamin C & Physiotherapy (Stress Loading)
- •2. Pharmacotherapy (Gabapentin/Bisphosphonates)
- •3. Sympathetic Block (Stellate)
- •4. Neuromodulation (SCS)
Don't Forget
- •Vit C 500mg x 50 days (Prevention)
- •NO elective surgery during active CRPS
- •Bone Scan = Diffuse peri-articular uptake
- •Mirror Therapy for central desensitization
- •Horner's confirms stellate block worked