Causalgia of unspecified lower limb

This code represents a chronic pain syndrome characterized by severe, burning pain, allodynia, and hyperpathia, affecting an unspecified lower extremity. It is a form of complex regional pain syndrome (CRPS) type II, specifically resulting from a known nerve injury. The pain is typically disproportionate to the inciting event and often accompanied by vasomotor, sudomotor, and trophic changes.

Apply this code when documentation clearly indicates a diagnosis of causalgia (CRPS type II) in a lower limb, but the specific side (right or left) is not documented. This diagnosis is typically made based on clinical presentation following a peripheral nerve injury. Supporting documentation should detail the burning pain, sensory abnormalities, and objective signs of autonomic dysfunction.

• Ensure documentation specifies "causalgia" or "CRPS type II" and not CRPS type I (reflex sympathetic dystrophy).
• Avoid using this code if the laterality of the affected lower limb (right or left) is specified; instead, use the more specific codes.
• Query the provider for clarification if the documentation mentions causalgia but omits the specific nerve injury or laterality.