Reflex Sympathetic Dystrophy Support Group

Complex regional pain syndrome (CRPS) is a chronic condition characterized by severe pain following injury to bone and soft tissue. The International Association for the Study of Pain has divided CRPS into two types based on the presence of nerve lesion following the injury. Type I, also known as Reflex sympathetic dystrophy (RSD) or algoneurodystrophy, does not have demonstrable nerve lesions, while type II, also known as causalgia, has evidence of obvious nerve lesions. The cause of these syndromes is currently unknown.

The symptoms of CRPS usually occur near the site of an injury, either major or minor, and usually spreads beyond the original area. It may spread to involve the entire limb and, rarely, the opposite limb. The most common symptom is burning pain. The patient may also experience muscle spasms, local swelling, increased sweating, softening of bones, joint tenderness or stiffness, restricted or painful movement, and changes in the nails and skin.

Physicians use a variety of drugs to treat CRPS, including antidepressants, corticosteroids, vasodilators, gabapentin, and alpha- or beta-adrenergic-blocking compounds. Elevation of the extremity and physical therapy are also used to treat CRPS. Injection of a local anesthetic, such as lidocaine, is usually the first step in treatment. Injections are repeated as needed. TENS (transcutaneous electrical nerve stimulation), a procedure in which brief pulses of electricity are applied to nerve endings under the skin, has helped some patients in relieving chronic pain. Neurostimulation (spinal cord stimulators) may also be surgically implanted to diffuse the pain by replacing it with a tingling sensation. These devices place electrodes either in the epidural space (space above the spinal cord) or directly over nerves located outside the central nervous system. Implantable drug pumps may also be used to deliver pain medication directly to the cerebrospinal fluid which allows the use of powerful opioids to be used in a much smaller dose than when taken orally. Ketamine infusion to treat CRPS has been described (Correll et al, 2004).