CRPS - Hand (Complex Regional Pain Syndrome)

It typically affects one limb (usually upper) after an injury. The exact mechanism involves peripheral inflammation, sympathetic coupling, and central sensitization (neuroplasticity).

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: The Budapest clinical criteria are sensitive (0.99) with markedly improved specificity (0.68) over the older IASP criteria (0.41); the stricter Budapest research criteria reach specificity 0.79 (Harden et al., Pain 2010).

Algorithm

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Differential Diagnosis

CRPS is a diagnosis of exclusion (Budapest criterion 4). Actively rule out the following before committing to the label:

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Musculoskeletal Complications

Trophic 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

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

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

Prognostic Factors

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.

Global Epidemiology

• Incidence: Population-based estimates range from approximately 5 to 26 per 100,000 person-years, with the upper end from a Dutch cohort and the lower end from a US (Olmsted County) cohort.
• Demographics: Female predominance (roughly 3 to 4:1); peak onset in the post-menopausal range (around 50 to 70 years). Upper limb is affected more often than lower limb.
• Commonest trigger: Distal radius fracture is the single most frequent inciting event; CRPS may also follow crush, sprain, surgery or immobilisation.

Side-by-Side Guidance

Areas of Genuine Difference

• Vitamin C prophylaxis: Endorsed by several orthopaedic/trauma groups after distal radius fracture (Zollinger RCTs), but UK guidance treats it as optional given heterogeneous later evidence.
• Bisphosphonates: Increasingly recommended in early CRPS-I in European rheumatology practice (neridronate RCTs); used more selectively elsewhere.
• Spinal cord stimulation: Reserved for refractory disease; the Kemler RCT showed pain relief without functional gain, tempering enthusiasm.

High- vs Limited-Resource Practice

• Well-resourced settings: Access to specialist multidisciplinary pain teams, triple-phase bone scan, MRI, sympathetic blocks, neuromodulation and ketamine infusion.
• Limited-resource settings: Diagnosis remains clinical (Budapest criteria need no imaging), and the highest-yield, lowest-cost interventions - early mobilisation, desensitisation, mirror therapy, graded motor imagery, simple analgesia and vitamin C - are widely deliverable and remain the backbone of care.