Summary
Complex regional pain syndrome (CRPS) is characterized by pain, typically in a limb, that is more prolonged and/or severe than expected given the inciting event. The pain is accompanied by sensory abnormalities (e.g., hyperesthesia, allodynia), signs of autonomic dysfunction (e.g., changes in the temperature and color of the skin), and/or loss of motor function. The pathogenesis of CRPS is unclear. On physical examination, patients present with pain and signs of sensory and motor dysfunction on the affected side. Although osseous changes may occur in CRPS, diagnosis is based on the Budapest criteria rather than imaging. Physical and medical therapy (e.g., oral corticosteroids, biphosphonates), initiated in the early stages of CRPS, can lead to remission.
Epidemiology
Epidemiological data refers to the US, unless otherwise specified.
Etiology
- The pathogenesis of CRPS is unknown.
-
CRPS usually develops 4–6 weeks after an inciting event, e.g.: [1][2]
- Direct injury (e.g., fracture, sprain, crush injury surgery, frostbite, local infection)
- Cerebrovascular event (e.g., stroke, myocardial infarction)
- Pregnancy
- CRPS is idiopathic in ∼ 7% of patients. [3]
CRPS is most commonly incited by trauma, especially fractures and surgery. [1][2]
Clinical features
- Pain typically affects the extremities. [1][2]
-
Pain is excessive in duration or severity given the inciting event.
- Pain is regional (i.e., not dermatomal).
- May be described as burning, tingling, or shock-like
- May worsen with activity
- Pain is accompanied by sensory, motor, vasomotor, sudomotor, and/or trophic changes; see “Diagnostic criteria for CRPS” for details.
Symptoms usually develop within 4–6 weeks of an inciting event and can last years. [1]
Symptoms of CRPS may progress through several stages: acute or traumatic within weeks of injury (redness, swelling, burning) → dystrophic within months of injury (increase in pain beyond injury site, edema, increased hair and nail growth) → chronic or atrophic for years after injury (skin and muscle atrophy, cold skin, constant pain). [2]
Diagnosis
General principles [1][2]
- CRPS is a clinical diagnosis based on the diagnostic criteria.
- Additional studies may be required to rule out differential diagnoses.
- Consider early referral to specialists (e.g., neurology, pain specialists) for evaluation and management.
Diagnosing CRPS is challenging as the clinical presentation is heterogeneous and no confirmatory diagnostic studies exist. [4]
Diagnostic criteria [4]
| Diagnostic criteria for CRPS (Budapest criteria) [4] | |
|---|---|
| 1 |
|
| 2 |
|
| 3 |
|
| 4 |
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| All four criteria must be met. | |
Imaging [1][2]
- Consider as needed to rule out differential diagnoses.
- Supportive findings for CRPS include: [2]
- Bone demineralization
- Joint effusion, evidence of inflammation in the surrounding soft tissue, bone marrow edema (on MRI)
Imaging is not routinely performed in the diagnosis of CRPS, as visible changes (if present) are nonspecific. [1][2]
Additional diagnostics
The following studies are not routinely performed but can be considered on a case-by-case basis.
- Nerve conduction studies to evaluate for nerve involvement [1]
- Autonomic testing (e.g., thermography) as a supportive diagnostic tool [2]
- Laboratory studies (e.g., diagnostics for rheumatoid arthritis) to rule out differential diagnoses [1]
Differential diagnoses
- Infection (e.g., tenosynovitis, osteomyelitis)
- Compartment syndrome
- Peripheral vascular disease
- Deep vein thrombosis
- Peripheral neuropathy
- Stress fracture
- Thoracic outlet syndrome
- Rheumatoid arthritis
- Raynaud phenomenon
- Conversion disorder
- Factitious disorder
- Gout
- Charcot foot
The differential diagnoses listed here are not exhaustive.
Treatment
General principles [1][2][4]
- The main goal of treatment is functional restoration and pain management.
- Initiating treatment as soon as symptoms arise may prevent long-term sequelae.
- Multidisciplinary management is recommended with:
- Physical therapy and occupational therapy to restore function
- Medical management of pain
- Psychological support for concurrent mental health conditions [2][4]
Management of pain [1][2][4]
- Refer patients to a pain management specialist.
- Counsel patients.
- Provide patient education on chronic pain.
- Reassure patients that pain does not reflect ongoing tissue damage. [1]
- Offer nonpharmacological analgesia. [2]
- Options for early CRPS (≤ 6 months of symptoms) include:
- Oral corticosteroids: prednisone for 2–4 weeks [1]
- Bisphosphonates [1][2][5]
- Transdermal lidocaine or capsaicin [2][5]
- The following medications are often prescribed in CRPS, but studies show limited or no evidence of benefit. [1][2]
- Oral NSAIDs
- Adjuvant analgesics (e.g., gabapentin and amitriptyline)
- Calcitonin
- Sympatholytic drugs (e.g., clonidine)
Avoid opioids in CRPS, as use may worsen symptoms via opioid-induced hyperalgesia. [4]
There is limited evidence to support any of the treatment options for CRPS. Use shared decision-making, including a careful assessment of risks and benefits. [2][5]
Functional restoration [2][4]
The following treatments are usually overseen by physical and/or occupational therapy.
- Graded increase in sensorimotor stimuli
- Mirror visual feedback therapy [4]
- Graded motor imagery
- Desensitization therapy
- Contrast baths
- Gradual increase in physical movements, such as:
- Passive and active range of motion exercises
- Use of affected limb in daily tasks
- Graded weight-bearing exercises
- Aquatic therapy
- Recreational therapy
Management of limb edema [2]
- Exercise
- Limb elevation
- Compression garments
Refractory CRPS
Specialist treatments include: [1][2][4]
- Ketamine therapy
- Regional botulinum toxin injections
- Intrathecal pain management
- Spinal cord stimulation
- Nerve blocks [2]
- Surgery [2]
Prognosis
- Most individuals who develop CRPS experience resolution of their symptoms within 18 months. [1][4]
- CRPS becomes chronic in approximately 15% of patients. [4]