Type 2 CRPS is characterized by what feature?

• A. Diffused pain not limited to a single nerve
• B. Involves causalgia due to partial nerve injury
• C. Autoimmune mechanism
• D. Predominantly lower extremity involvement

Answer: (B)

CRPS type 2 is defined by a known injury to a peripheral nerve causing ongoing regional pain, aka causalgia. This distinguishes it from CRPS type 1, where no nerve lesion is demonstrable. The pain in type 2 typically follows a specific nerve distribution and is accompanied by sensory, autonomic, and trophic changes after the nerve injury.

So the best description is that CRPS type 2 involves causalgia due to partial nerve injury, reflecting the identifiable nerve damage underlying the pain syndrome. The other statements don’t capture this defining feature: CRPS type 1 can present with diffuse or map-like pain not confined to a single nerve, autoimmune mechanisms are not the defining cause, and the condition can affect either hand or foot rather than being predominantly one limb.