I was in a car accident and fractured my forearm in six places. I'm in a special splint with pins and wires. About two weeks ago I was diagnosed with complex regional pain syndrome, type 1. How many types are there and what's the difference?

Complex regional pain syndrome (CRPS) is a condition of nerve pain in the lower half of the arms or legs. It occurs most often after an injury or an operation. Type 1 was formerly known as reflex sympathetic dystrophy or RSD. Patients may or may not have pain with this type.

Type 2 is also known as "causalgia," a word that means a severe feeling of burning pain. The names were changed because doctors don't really know what causes the problem. The terms CRPS Type I and CRPS Type II are used to describe the conditions.

For the most part the symptoms of these two types of CRPS are the same. The main difference is that Type II occurs after a nerve has been injured. Type I occurs after an injury, but without any known nerve injury. So for example, if CRPS occurs after an ankle sprain or a fracture of the hand, it's Type I CRPS. If CRPS comes on following a gunshot wound that injures a nerve, then it's Type II CRPS.