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CRPS and Dystonia: Unusual Co-existing Disorders

Complex regional pain syndrome (CRPS) and dystonia often occur together after a traumatic event. Does one cause the other? Or is it a coincident that they develop around the same time? In this review article, Dr. Schott from the National Hospital for Neurology and Neurosurgery in London, England looks at the data so far to find an answer.

CRPS is a collection of signs and symptoms including pain, skin temperature changes, and other sensory changes usually affecting the arm and/or hand. Loss of motion and function are common. The condition occurs after a traumatic injury.

Dystonia is a movement disorder. Weakness, stiffness, and clumsiness are the main features for some patients. In other cases, tremors, jerks, or twisting of the body part occur.

Not all patients with CRPS develop dystonia but many do. And the timing can be anywhere from a week to five years before the dystonia starts to show up. There are a few cases where dystonia occurs first, and then CRPS develops, but it's usually the other way around.

The symptoms of CRPS may even get better as the dystonia comes on. This suggests that separate mechanisms are at play. Scientists generally agree that both problems stem from a dysregulation of the central nervous system. But exactly what happens in each condition is still a mystery.

Doctors are looking for predisposing factors for the onset of dystonia. Does it only occur when there's a bone fracture? Or is it more likely to develop when the limb has been in a cast? Does surgery trigger it? Perhaps there are genetic or environmental factors.

Right now there are more questions than answers. The complex interaction of the nervous system with the immune system and the motor system are part of the picture. What are the biologic and mechanical pathways? This remains unknown and is still the focus of many studies.

References: G. D. Schott. Peripherally-Triggered CRPS and Dystonia. In Pain. August 2007. Vol. 130. No. 3. Pp. 203-207.

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