Reflex sympathetic dystrophy syndrome (RSDS) is a severe, painful and long-lasting condition that usually involves one arm or leg. This condition has been called many other names, including algodystrophy, causalgia, shoulder-hand syndrome, Sudeck's atrophy and transient osteoporosis. In 1995, the name was changed officially to complex regional pain syndrome, or CRPS, although this name change has not been accepted universally.

The problem in RSDS is severe, constant, burning pain in the affected arm or leg.

The condition can be triggered by damage to nerve fibers in tissue that was injured in some way, but the cause of this syndrome remains unknown. Experts believe that in RSDS, nerves become overly sensitive. Painful signals become more painful, and common stimuli such as light touch and temperature changes also are experienced as pain.

This condition usually starts after an injury or other event, such as trauma, a fracture, an infection, surgery, a stroke or wearing a plaster cast. Often, the injury that triggers reflex sympathetic dystrophy syndrome is very mild compared with the pain that follows it. However, the condition also can follow more severe injury or paralysis. The pain often is not limited to the area that was injured. The earliest described cases were among Civil War soldiers in whom gunshot wounds that healed were followed over days to weeks by severe pain in arms or legs.

This condition can occur at any age and is relatively rare. It is most common in people between the ages of 40 and 60, but it is being diagnosed more frequently in children and adolescents. Researchers estimate that 12% to 21% of adults with paralysis on one side of the body and about 5% of adults with nerve injuries will develop RSDS.

In children with RSDS, girls are affected about two to four times more often than boys are affected.

Symptoms of RSDS can include:

• Intense pain, throbbing, burning and swelling, usually in the hand or foot
• Shiny, thin skin around the affected area
• Initially increased but later diminished hair over the affected area
• Brittle, thickened nails
• Dry and withered skin
• Skin that feels warmer or cooler than usual
• Skin that changes color
• Increased sweating

The condition can progress through three stages, although not everyone goes through every stage. In the earliest stage, days to weeks after an injury, the limb can become dry, hot, red and painful. Even the lightest touch or the slightest movement can cause excruciating pain. At this point, RSDS can be mistaken for rheumatoid arthritis, infection, gout or another disorder, and your doctor may not be able to identify the problem.

Over the next few weeks to months, the skin can become shiny, thin and cool. The limb becomes mottled and purplish. There is considerable swelling. Pain worsens. The nails become brittle and can grow faster. As the limb becomes difficult to move, you may have more pain further up the limb. This might be related to muscle stiffness and soreness.

Some people experience other movement problems, including weakness, spasm and tremor. An affected limb can become permanently flexed or bent, a condition called contractures. In some people, the skin can become tight, dry and shriveled. The bones can become brittle because they aren't being used. The skin, muscles and joints stiffen so that the affected area cannot be moved. Some patients have less pain at this point. Once the disease reaches this point, it is extremely difficult to treat.

Your doctor will ask questions about your medical history and will examine you. RSDS is diagnosed when all these symptoms are present: burning, spontaneous pain; hypersensitivity; swelling; temperature changes; and sweating. In the earliest stages, before many of these features develop, diagnosis is difficult or impossible.

In later stages, X-rays sometimes show bone loss, especially around the joints. A bone scan can help to confirm the diagnosis, but the condition cannot be diagnosed with a bone scan alone. Two tests that evaluate nerve function — electromyography and nerve conduction studies — may be ordered to look for nerve damage or another cause of your symptoms.

Your doctor also may order a test called a diagnostic sympathetic block. This is an injection in the neck or low back that reduces pain in some but not all people. If the block reduces or eliminates pain, this can help to confirm the diagnosis.

Some physicians use other specialized tests to help diagnose this condition. For example, the autonomic nerves that control sweating and skin temperature can be evaluated by measuring sweat output and skin temperature. A test called a thermogram maps the temperature in the skin at different sites in the body. This shows how well blood is flowing in different areas. Abnormal blood flow in the painful area is common in RSDS.

Some people with RSDS improve without treatment, but getting early treatment improves your chances of pain relief. About half of people with RSDS are still experiencing pain six months after treatment was started.

There is no way to prevent RSDS because the cause is not clear.

Physical or occupational therapy, together with supervised exercises, will be recommended. Maintaining movement is an important goal of treatment. Once a reasonable degree of movement is restored, an exercise routine will help to strengthen muscles and joints, and maintain functioning. It is important to get care from health care professionals who have expertise in the care of this condition, including an anesthesiologist, vascular surgeon, physical therapist and occupational therapist.

Medications can help to manage pain. Corticosteroids and physical therapy can help to ease pain during an acute episode, but long-term results are mixed. Medications that may help include:

• Nonsteroidal anti-inflammatory drugs (NSAIDs) and other pain relievers
• Capsaicin, a cream or ointment thought to interrupt pain signals
• Certain antidepressants and anticonvulsants used in nerve pain treatment, such as amitriptyline (Elavil) and gabapentin (Neurontin)
• Blood pressure medications that affect the sympathetic nervous system, including prazosin (Minipress), propranolol (Inderal), nifedipine (Procardia) and guanethidine (Ismelin)
• Bisphosphonates, such as alendronate (Fosamax), which are medications that reduce bone loss
• Pentoxifylline (Trental), a medication that helps to open constricted blood vessels
• Trigger-point injections, in which a corticosteroid and a long-acting anesthetic medication are injected just beneath the skin in painful areas

A small device called a transcutaneous electrical nerve stimulator (TENS) unit sometimes can help to relieve pain. The battery-operated device is thought to work by blocking nerve impulses. Biofeedback also can help to control pain, blood flow and skin temperature.

Simple measures such as applying heat or cold are controversial. Applying cold might relieve pain temporarily, but some experts suggest that ice worsens the symptoms of RSDS later on. The response to heat also varies.

When all else fails, your doctor may recommend an injection of a numbing agent near the affected nerves or alongside the spinal column to block the sympathetic nervous system. This procedure is called a nerve block. It usually is done as a series of 3 to 5 injections over 7 to 14 days. If the numbing is effective, a more permanent procedure called a sympathectomy may be done. In this procedure, the nerves are destroyed with chemicals or by surgery.

Newer treatments include implanting a device that stimulates the spinal cord, and infusing a medication called baclofen (Lioresal) into the spinal fluid. Baclofen usually is used for muscle spasms. These treatments do not always work and may be associated with complications. But for severe cases that have not responded to other treatments, the benefits may exceed the risks.

Contact your physician if you experience the symptoms of RSDS.

The earlier the condition is diagnosed, the better the prognosis. If treatment is started early, symptoms can disappear after as few as three months. Delayed treatment can lead to permanent bone and muscle changes. The overall response to treatment is poor. In about 50% of cases, people with RSDS are still in pain months and even years later.

American Chronic Pain Association
P.O. Box 850
Rocklin, CA 95677
Toll-Free: 1-800-533-3231
Fax: 916-632-3208
Email: ACPA@pacbell.net
http://www.theacpa.org/

National Institute of Neurological Disorders and Stroke
P.O. Box 5801
Bethesda, MD 20824
Phone: 301-496-5751
Toll-Free: 1-800-352-9424
TTY: 301-468-5981
http://www.ninds.nih.gov/