I had minor surgery to remove a small but malignant tumor from my arm. Within a week I started having pain down my arm. My hand started going to sleep and sweating profusely. Now my fingers are starting to curl into a fist and I can’t stop it from happening. I’ve been told this is a hysterical reaction to the surgery. I’m not really a psycho kind of person. Could something else be causing it?

You may be describing a condition called complex regional pain syndrome (CRPS). CRPS occurs after trauma such as a soft tissue injury, fracture, or surgery. Pain, extreme sensitivity to touch, and increased skin sweating are common symptoms of CRPS.

In up to half the patients, additional symptoms of tremors or a movement disorder called dystonia may occur. Dystonia is a sustained muscle contraction causing abnormal postures. The flexion of your fingers, hand, and wrist may be the result of a movement disorder such as dystonia.

You may need some additional testing. It might be a good idea to ask for a referral to a neurologist for a more specific diagnosis. CRPS-related dystonia is not caused by a psychologic reaction to trauma.

Scientists believe this condition is most likely the result of a problem in the nervous system. The central circuits get turned on, but never turn off again or even down regulate once the traumatic event is over. The exact mechanism for this to happen is still unclear.