CRPS etiology: Following what triggers is it most commonly seen?

• A. Trauma or surgery
• B. Viral infection
• C. Degenerative joint disease
• D. Autoimmune disease

Answer: (A)

CRPS is typically triggered by tissue injury, with trauma or surgical intervention to a limb being the most common precipitating event. After such an injury, a subset of people develop a disproportionate, persistent pain with sensory changes (like allodynia and hyperalgesia), along with autonomic signs (swelling, skin color or temperature changes) and sometimes motor dysfunction. This pattern reflects abnormal interactions between the peripheral nerves, the sympathetic nervous system, and inflammatory pathways that can become amplified after injury.

Viral infections can cause neuropathic pains but CRPS classically follows a physical injury rather than an infection. Degenerative joint disease causes pain from wear-and-tear changes in a joint rather than the autonomic and inflammatory dysregulation seen in CRPS. Autoimmune diseases involve systemic immune processes, but CRPS is defined by its post-injury sympathetic–nociceptive dysregulation rather than a primary autoimmune process.