Complex Regional Pain Syndromes (CRPS)

Modern Study Review (AI-Generated)

High-Yield Summary

Complex Regional Pain Syndrome (CRPS) is a debilitating chronic pain condition often triggered by trauma or surgery, characterized by disproportionate pain and autonomic dysregulation. It is classified into Type I (without confirmed nerve injury) and Type II (with confirmed nerve injury). Early diagnosis and multidisciplinary management are critical to improving pain control and functional outcomes, with evolving evidence supporting both pharmacologic and interventional therapies.

Key Diagnostic Findings

Current Gold Standard Treatment

• Non-Operative Indications:
• Early mobilization and physical therapy to prevent contractures and maintain function.
• Pharmacologic management: NSAIDs, corticosteroids (early phase), neuropathic agents (gabapentinoids, TCAs), bisphosphonates, and emerging use of ketamine or IVIG in refractory cases.
• Sympathetic nerve blocks for diagnostic and therapeutic purposes.
• Psychological support and pain coping strategies.

• Operative Indications:
• Reserved for refractory cases with clear nerve entrapment or neuroma amenable to surgical intervention (mostly Type II).
• Spinal cord stimulation or dorsal root ganglion stimulation for chronic, intractable pain unresponsive to conservative measures.

Modern Complications & Outcomes

• Complications:
• Chronic pain syndrome with potential for severe disability.
• Joint stiffness, muscle atrophy, contractures due to disuse.
• Psychological sequelae including depression and anxiety.
• Risk of progression to fixed dystonia or trophic skin changes.

• Outcomes:
• Early diagnosis and multidisciplinary treatment improve pain and function.
• Delayed treatment correlates with poorer prognosis.
• Functional recovery varies; some patients achieve remission, others develop chronic disability.
• Board exams emphasize recognition of diagnostic criteria, differentiation between Type I and II, and evidence-based treatment algorithms.

Classic Clinical Notes

Complex Regional Pain Syndromes (CRPS)

• The task force identified the problem that the term “reflex sympathetic dystrophy” was often used in cases that did not have sympathetically maintained pain, or a dystrophic component.

CRPS TYPE I: Reflex Sympathetic Dystrophy

• “CRPS Type I is a syndrome that usually develops after an initiating noxious event, is not limited to the distribution of a single peripheral nerve, and is apparently disproportionate to the inciting event. It is associated at some point with evidence of edema, changes in skin blood flow, abnormal sudomotor activity, in the region of pain, or allodynia or hyperalgesia.”

Diagnostic Criteria:

1. The presence of an initiating noxious event, or a cause of immobilization
2. Continuing pain, allodynia, or hyperalgesia with which the pain is disproportionate to any inciting event.
3. Evidence at some time of edema, changes in skin blood flow, or abnormal sudomotor activity in the region of the pain.
4. This diagnosis is excluded by the existence of conditions that would otherwise account for the degree of pain and dysfunction.

• Criteria 2, 3, and 4 must be satisfied.

CRPS TYPE II: Causalgia

• “Burning pain, allodynia, and hyperpathia usually in the hand or foot after partial injury of a nerve or one of its major branches.”

Diagnostic Criteria:

1. The presence of continuing pain, allodynia, or hyperalgesia after a nerve injury, not necessarily limited to the distribution of the injured nerve.
2. Evidence at some time of edema, changes in skin blood flow, or abnormal sudomotor activity in the region of the pain.
3. This diagnosis is excluded by the existence of conditions that would otherwise account for the degree of pain and dysfunction.

• All three criteria must be satisfied.

Last Updated on January 24, 2026 by orthonet