Attack regional pain syndrome with arsenal of medications

DEAR READER:

Complex regional pain syndrome (CRPS) is a long-lasting condition that causes severe, constant, burning pain in the affected arm or leg. As in your daughter's case, it usually starts after an injury or other trauma. In the last 20 years we've learned a lot about what goes wrong in the body with this condition, and about good treatments for it. But we still don't have a fundamental understanding of it, or perfect treatments.

What we know is that CRPS is triggered by nerve damage in injured tissue. The damaged nerves become overly sensitive. Pain signals become more painful. The brain experiences common stimuli, such as light touch, as being painful; stroking the skin with a feather hurts!

The skin in the affected arm or leg often becomes rough, thick and swollen, and the muscles lose bulk. Because of pain and weakness, the arm or leg is used less often, and this can weaken the underlying bones.

The earlier treatment begins, the better. Maintaining movement is an important goal. This is usually accomplished with physical therapy and, eventually, a regular exercise program.

Medications that may help manage pain include:

-- Nonsteroidal anti-inflammatory drugs (NSAIDs) and other pain relievers.

-- Capsaicin, a cream or ointment thought to interrupt or "distract" pain signals.

-- Certain antidepressants and anticonvulsants used in nerve pain treatment.

-- Certain blood pressure medications, such as prazosin or clonidine.

-- Bisphosphonates, medications that reduce bone loss.

-- Calcitonin, which may slow bone loss and provide pain relief.

-- Trigger-point injections of an anti-inflammatory medicine and a long-acting local anesthetic.

-- Baclofen, which may help relieve muscle spasms.

-- Tricyclic medicines, which are helpful with many unusual pain syndromes.

-- A transcutaneous electrical nerve stimulator (TENS) unit may help to relieve pain. Biofeedback can help to control pain, blood flow and skin temperature.

For severe pain that does not respond to other treatment, a nerve block may help. During this procedure, a numbing agent is used to block the nerves of the sympathetic nervous system, which are part of the pain pathways. If this is effective, a procedure may be done to permanently destroy those nerves.

A few newer treatments are available for severe cases. One entails implanting a device to stimulate the spinal cord or nearby nerves. The other involves injecting a drug that relaxes blood vessels into the space near the spinal cord. These treatments do not always work and may cause complications. But if nothing else has helped, the benefits may exceed the risks.

Unfortunately, about half of people with CRPS continue to experience pain despite treatment. It appears that smokers are at greater risk of getting CRPS if they have an injury. It has not been determined if stopping smoking improves the symptoms of CRPS, but most experts think it would.

(Dr. Komaroff is a physician and professor at Harvard Medical School. To send questions, go to AskDoctorK.com, or write: Ask Doctor K, 10 Shattuck St., Second Floor, Boston, MA 02115.)

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