Pain Medicine · Supplementary · from Pain Medicine

Case 1: Complex Regional Pain Syndrome

Patient Presentation

Demographics: 34-year-old female software engineer

Chief Complaint: "My left hand and wrist have been burning and swollen for 4 months after a simple fracture — the pain is unbearable and getting worse."

History of Present Illness: Ms. E.N. presents to the pain medicine clinic with a 4-month history of progressive, debilitating left upper extremity pain following a distal radius fracture sustained in a cycling accident. The fracture was non-displaced and managed conservatively with a short arm cast for 6 weeks. Upon cast removal, she noted immediate pain disproportionate to the injury, describing it as a constant burning, aching sensation rated 8-9/10 on the numeric pain scale. The pain has progressively worsened and now extends from the fingertips to the mid-forearm.

She reports that the affected hand has changed color, alternating between deep red/purple and pale/mottled, and that the skin temperature fluctuates dramatically — sometimes the hand feels burning hot, other times ice cold. She has noticed significant swelling in the dorsum of the hand and fingers. The skin has become shiny, thin, and hypersensitive; she cannot tolerate clothing touching the hand, water running over it, or even air currents from a fan (severe allodynia). She has stopped wearing her engagement ring due to edema and hypersensitivity.

Functionally, she is unable to type, grip objects, or use her left hand for activities of daily living. She has been on medical leave from work for 3 months. She reports sleep disruption (averaging 3 hours per night due to pain), depressed mood, anxiety, and social withdrawal. She has been referred by her orthopedic surgeon after failing 6 weeks of hand therapy and oral analgesics.

Past Medical History:

• Anxiety disorder (generalized)
• Migraine with aura (2-3 per month)
• No prior chronic pain conditions

Medications:

• Gabapentin 300 mg TID (started 6 weeks ago, minimal benefit)
• Oxycodone 5 mg Q6H PRN (taking regularly, reports 20% pain relief)
• Sertraline 50 mg daily
• Sumatriptan 100 mg PRN for migraines

Social History:

• Non-smoker
• Rare alcohol use
• Lives with fiancé; wedding planned in 6 months (considering postponement)
• Previously very active: rock climbing, cycling, yoga
• On medical leave from software engineering position

Family History:

• Mother: fibromyalgia, depression
• Maternal aunt: CRPS following knee surgery (3-year course)
• Father: healthy

Physical Examination

• Vital Signs: BP 138/86 mmHg (anxiety/pain), HR 96 bpm, RR 18, SpO2 99%, Temp 36.8°C
• Left upper extremity:
• Inspection: Dorsal hand and wrist edematous; skin erythematous with violaceous mottling; skin appears shiny, thin, and atrophic with loss of normal skin creases; excessive hair growth on dorsum of hand compared to right; nail changes — ridging and brittleness of all fingernails
• Temperature: Infrared thermometry reveals 3.2°C asymmetry (left hand 31.1°C vs. right hand 34.3°C — left hand cooler)
• Sweating: Increased sudomotor activity on left palm compared to right
• Allodynia: Severe mechanical allodynia — light brush stroke (cotton wisp) over dorsum of hand elicits 9/10 pain; thermal allodynia present to both warm and cool stimuli
• Hyperalgesia: Pinprick hyperalgesia extending from fingertips to mid-forearm (non-dermatomal distribution)
• ROM: Active wrist flexion 15° (normal 80°), extension 10° (normal 70°); finger flexion severely limited; unable to make a fist
• Motor: Grip strength not testable due to pain; difficulty initiating finger movements (motor neglect-like pattern); intermittent dystonic posturing of fingers noted
• Edema: 2+ pitting edema dorsum of hand; circumferential measurement 2.5 cm greater than right
• Right upper extremity: Normal examination throughout
• Psychological assessment: Pain Catastrophizing Scale: 38/52 (high); Tampa Scale of Kinesiophobia: 44/68 (moderate-high fear of movement)

Workup and Results

Laboratory Studies:

Imaging/Additional Studies:

• Triple-phase bone scan: Increased uptake in all three phases in the left hand and wrist — diffuse periarticular uptake in the delayed phase involving MCP, PIP, and DIP joints and distal radius/ulna (highly suggestive of CRPS)
• Plain radiographs (left hand/wrist): Healed distal radius fracture in anatomic alignment; diffuse patchy osteopenia of the carpals, metacarpals, and phalanges; periarticular osteoporosis (Sudeck atrophy)
• MRI left hand/wrist: Diffuse bone marrow edema in carpals and distal radius; soft tissue edema; thickening of palmar fascia; no evidence of fracture non-union or hardware complication; no mass or infection
• Quantitative sudomotor axon reflex test (QSART): Asymmetric sweat output — 3x increase on left forearm compared to right
• Autonomic testing: Resting skin temperature asymmetry confirmed (>1°C); laser Doppler flowmetry shows decreased blood flow in affected hand

Clinical Image

Illustration depicting the clinical features of CRPS Type I, showing the affected hand with edema, color changes, trophic skin changes, and a comparison of sympathetic nervous system dysregulation pathways. Source: Educational illustration.

Diagnosis

Complex Regional Pain Syndrome Type I (Reflex Sympathetic Dystrophy), Left Upper Extremity — Warm-to-Cold Transition Phase

Key Diagnostic Criteria (Budapest Criteria — all 4 met):

1. Continuing pain disproportionate to the inciting event (distal radius fracture)
2. At least one sign in 3 or more categories:

• Sensory: allodynia (mechanical and thermal), hyperalgesia
• Vasomotor: temperature asymmetry (>1°C), skin color changes
• Sudomotor/edema: edema, sweating asymmetry
• Motor/trophic: decreased ROM, motor dysfunction (weakness, dystonia), trophic changes (skin, nail, hair)

1. At least one symptom in all 4 categories (reported by patient)
2. No other diagnosis better explains the signs and symptoms

Treatment Plan

1. Interventional pain management:

• Stellate ganglion block (sympathetic block) — diagnostic and therapeutic; series of 3 blocks at weekly intervals with local anesthetic (bupivacaine 0.25%)
• If sympathetically maintained pain confirmed: consider pulsed radiofrequency of stellate ganglion or spinal cord stimulation trial if blocks provide temporary but non-sustained relief

1. Pharmacological optimization:

• Increase gabapentin to 600 mg TID (titrate to 900 mg TID as tolerated)
• Add low-dose naltrexone 4.5 mg nightly (emerging evidence for neuroinflammation)
• Topical compounded cream: ketamine 10% / gabapentin 6% / clonidine 0.2% — applied to affected area TID
• Taper oxycodone over 4 weeks (opioids may worsen CRPS through neuroinflammatory mechanisms and have limited evidence)
• Bisphosphonate: IV pamidronate 60 mg single infusion (evidence for CRPS-associated bone pain and osteopenia)
• Vitamin D3 2,000 IU daily

1. Rehabilitation (critical component):

• Graded motor imagery program: left/right discrimination training → imagined movements → mirror therapy (10 min, 3x daily)
• Pain exposure physical therapy (PEPT) with desensitization hierarchy
• Occupational therapy for functional restoration
• Aquatic therapy (warm water pool) for gentle ROM and desensitization

1. Psychological support:

• Cognitive behavioral therapy for chronic pain (pain catastrophizing reduction)
• Acceptance and Commitment Therapy (ACT) for pain-related anxiety
• Sleep hygiene optimization; consider trazodone 50 mg for sleep

1. Follow-up: Re-evaluate at 4 weeks; if inadequate response to sympathetic blocks, consider spinal cord stimulation trial (dorsal column or dorsal root ganglion stimulation)

Key Learning Points

• CRPS is diagnosed clinically using the Budapest Criteria; no single laboratory or imaging test is diagnostic, but triple-phase bone scan and MRI support the diagnosis. Normal inflammatory markers do not exclude CRPS
• The pathophysiology involves peripheral and central sensitization, neurogenic inflammation, sympathetic-afferent coupling, and maladaptive cortical reorganization — it is not primarily a psychological disorder
• Early aggressive treatment within the first 6-12 months offers the best prognosis; the condition becomes increasingly refractory with chronicity due to progressive central sensitization
• Mirror therapy and graded motor imagery are evidence-based rehabilitation strategies that target cortical body representation changes; they should be initiated early and performed consistently
• Opioids have limited efficacy in CRPS and may worsen outcomes through glial activation and neuroinflammation; a multimodal approach combining interventional, pharmacological, rehabilitative, and psychological strategies is essential

All cases for this lecture as Markdown