Sympathetic Pain Syndrome

Complex Regional Pain Syndrome

The patient's arms or legs are usually involved, but CRPS may affect any part of the body, such as the face or trunk. In some patients, many different areas of the body are affected. CRPS can be progressive (meaning that it gets worse at one site or spreads to other sites), or it can stay the same for a long time or even improve on its own.

CRPS usually develops after an injury. The injury may be to the skin, bone, joints or tissue. This type of CRPS has been called reflex sympathetic dystrophy. CRPS can also develop after any type of injury to major nerves. This type has been called causalgia. The injury that leads to CRPS may be only minor, and sometimes a patient cannot remember any injury or event that caused CRPS to start.

Symptoms Needed to Make the Diagnosis of CRPS
These are the symptoms that doctors use to decide whether or not a patient has CRPS:

Pain that is constant or almost constant, with:

• pain caused by things that do not usually cause pain, such as clothing, wind, cold or a light touch to the skin (called "allodynia"), and/or
• severe pain when only a slight pain would be expected, such as when a doctor lightly pricks the skin with a pin (called "hyperalgesia")

Having some of the following in the painful area:

• swelling
• changes in skin color (mottled, purple-bluish, red)
• skin temperature that is not normal (either hotter or colder than other areas)
• either more or less sweating in the area

Reflex sympathetic dystrophy

Reflex sympathetic dystrophy syndrome (RSDS) is a condition that features a group of typical symptoms, including pain (often "burning" type), tenderness, and swelling of an extremity associated with varying degrees of sweating, warmth and/or coolness, flushing, discoloration, and shiny skin.

What causes reflex sympathetic dystrophy?

RSDS is also referred to as "the shoulder-hand syndrome," "causalgia," and "Sudeck's atrophy." The exact mechanism of how RSDS develops is poorly understood. The theories include irritation and abnormal excitation of nervous tissue, leading to abnormal impulses along nerves that affect blood vessels and skin. A variety of events can trigger the condition, including trauma, surgery, heart disease, degenerative arthritis of the neck, stroke or other brain diseases, nerve irritation by entrapment (such as carpal tunnel syndrome) or shingles, shoulder problems, breast cancer, and drugs for tuberculosis and barbiturates. There is no associated event in one-third of patients.

What are the symptoms of reflex sympathetic dystrophy?

The onset of the RSDS symptoms may be rapid on gradual. The condition may not display all features. It has been bilateral in up to half of the patients. There are several stages:

• Acute: (three to six months) burning, flushing, blanching, sweating, swelling, pain, and tenderness. This stage can show early x- ray changes of patchy bone thinning.
• Dystrophic: (three to six months) early skin changes of shiny, thickened skin and contracture with persistent pain, but diminished swelling and flushing.
• Atrophic: (may be long-standing) loss of motion and function of the involved hand or foot with contracture (flexed scarring process), thinning of the fatty layers under the skin. X-ray can show significant osteoporosis.