Complex regional pain syndrome – Symptoms and causes – Mayo …

Complex regional pain syndrome (CRPS) is a form of chronic pain that usually affects an arm or a leg. CRPS typically develops after an injury, a surgery, a stroke or a heart attack. The pain is out of proportion to the severity of the initial injury. CRPS is uncommon, and its cause isn’t clearly understood.

https://www.mayoclinic.org/diseases-conditions/crps-complex-regional-pain-syndrome/symptoms-causes/syc-20371151