Definition
Complex regional pain syndrome is a chronic neuroinflammatory disorder usually affecting 1 or more extremities, characterized by continued regional pain disproportionate in time or degree to the usual course of any known trauma or lesion.
Usually, has a distal predominance of abnormal sensory, motor, sudomotor, or vasomotor edema, and/or trophic findings .
Classification
- By type
Complex regional pain syndrome, type I (previously called reflex sympathetic dystrophy): patients without confirmed nerve injury
Complex regional pain syndrome, type II (previously called causalgia): patients with confirmed nerve injury
- By stage
Stage 1 (lasts 1-3 months) : Changes in skin temperature, alternating between warm and cold, Rapid growth of nails and hair. Muscle spasms and joint pain. Severe burning, aching pain that worsens with slight touch or breeze. Skin slowly becomes: Blotchy, purple, pale, or red Thin and shiny, Moist with sweat.
Stage 2 (lasts 3-6 months) : Continued changes in skin temperature and colour. Nails become cracked and break more easily. Slower hair growth, Worsening pain, Stiff joints and weak muscles.
Stage 3 (irreversible changes) Limited movement in limb due to contracture. Muscle wasting, Pain throughout the entire limb.
Clear history of trauma in most cases; 10% of patients cannot recall any precipitating event.
Most common precipitating events : Fracture /Sprain /Surgery.
Less common precipitating events: Injection/ Local infection / Burn / Frostbite
Key symptom is prolonged pain that may be constant and severe Onset often occurs within a few days to a month but may be immediate in some cases
Pain may be described as burning, stabbing, dragging, pressing, throbbing, or constricting Augmentation of pain may occur during nonpainful touch, physical effort, heat, cold, or agitation Positive sensory abnormalities Spontaneous pain: Allodynia /Hyperesthesia Hyperalgesia : Mechanical/Thermal/ Deep somatic Vascular abnormalities: Vasodilation/ Vasoconstriction /Skin temperature asymmetry/ Skin color changes (blue, red, purple, blotchy, or pale; skin may appear shiny or thin) Edema and sweating abnormalities: Swelling in the affected area / Hyperhidrosis Motor or trophic changes: Abnormal hair or nail growth (unusually slow or fast growth patterns; brittle or grooved nails) / Tremor / Skin atrophy / Joint stiffness
Diagnosis
Clinical Evaluation
Imaging Imaging has low predictive value and is not routinely recommended
- MRI is unable to reliably differentiate between normal posttraumatic changes and changes due to complex regional pain syndrome
- Plain radiographs of the affected area may show osteopenia or fracture but no other specific findings
- Triple-phase bone scans (3-phase bone scintigraphy) can be helpful for patients in early stages to exclude other pain syndrome diagnoses, but test sensitivity is low.
Findings may show bone defects (eg, hyperperfusion) that are consistent with complex regional pain syndrome; however, absence of these findings does not exclude this diagnosis.
Functional testing: Nerve conduction study/electromyography: To rule out nerve injuries.
Differential Diagnosis
1. Deep vein thrombosis and thrombophlebitis
2. Peripheral neuropathy
3. Diabetic neuropathy
4. Infections: Herpes Zoster/ Lyme Disease
5. Autoimmune disorders: Rheumatoid/ reactive arthritis
6. Thoracic Outlet syndrome
Treatment
Goals
Regain normal limb function by:
Controlling edema
Restoring range of motion
Improving tolerance for stress-loading activities and exercise
Maximizing functional use
Improve circulation
Reduce and relieve pain
Improve pain coping skills
Strategies for selecting pharmacotherapy include the following:
For patients with mild to moderate pain: prescribe simple analgesics
For patients with excruciating pain: prescribe opioids or sympathetic nerve blocks
For patients with inflammation/swelling and edema: prescribe NSAIDs, steroids, or immune modulators
For patients with depression, anxiety, or insomnia: prescribe sedatives or analgesic antidepressants/anxiolytics
For patients with allodynia/hyperalgesia: prescribe anticonvulsants
For patients with osteopenia, immobility, and trophic changes: prescribe calcitonin or bisphosphonates
For patients with vasomotor disturbances: prescribe calcium channel blockers, sympatholytics, or sympathetic nerve blocks.
Non Pharmacological treatment: Psychotherapy, Physiotherapy and occupational therapy.
Summary
Complex regional pain syndrome is a chronic neuroinflammatory disorder usually affecting 1 or more extremities, characterized by continued regional pain
Soft tissue injuries or fractures, especially of the wrist or ankle, are common triggering events
Pain of greater severity than expected in injury healing phase is indicative and often first-noticed symptom
Clinical presentation is characterized by pain and tenderness of a distal extremity, usually accompanied by bone demineralization, trophic skin changes, and vasomotor instability
Diagnosis based largely on patient history and clinical findings, and may be assisted by utilizing the Budapest Consensus Group diagnostic criteria 1 A multidisciplinary management approach is most effective, including pain specialists, physical medicine and rehabilitation, neurology, anesthesiology, psychiatry/psychology, and neurosurgery
Treatment is centred on physical therapy and pain management strategies
Most patients with complex regional pain syndrome improve with a combination of medication and physical therapy; sympathectomy may be required in those whose symptoms are refractory to standard therapies
Recovery may be affected by secondary psychological effects of chronic pain, such as depression or anxiety
Early, aggressive treatment of pain may prevent chronic disease and later complications
Symptoms are variable and complex, and the timing of their onset after injury is variable, all of which complicate successful identification and treatment
No known cause; treatment is subject to a trial approach
Psychological features are important components to identify and aggressively treat; however, solely treating psychiatric aspects will lead to treatment failure Despite treatment, chronic pain and long-term disability may result .