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Reflex sympathetic dystrophy syndrome

Reflex sympathetic dystrophy syndrome (RSDS) — also known as complex regional pain syndrome — is a chronic condition characterized by severe burning pain, pathological changes in bone and skin, excessive sweating, tissue swelling, and extreme sensitivity to touch. The syndrome, which is a variant of a condition known as causalgia[?], is a nerve disorder that occurs at the site of an injury (most often to the arms or legs). It occurs especially after injuries from high-velocity impacts such as those from bullets or shrapnel. However, it may occur without apparent injury. Causalgia was first documented in the 19th century by physicians concerned about pain Civil War veterans continued to experience after their wounds had healed. Doctors often called it "hot pain," after its primary symptom. Over the years, the syndrome was classified as one of the peripheral neuropathies, and later, as a chronic pain syndrome. RSDS is currently classified as a variant of causalgia, not necessarily caused by trauma.

Table of contents

Symptoms

The symptoms of RSDS usually occur near the site of an injury, either major or minor, and include: burning pain, muscle spasms, local swelling, increased sweating, softening of bones, joint tenderness or stiffness, restricted or painful movement, and changes in the nails and skin. One visible sign of RSDS near the site of injury is warm, shiny red skin that later becomes cool and bluish.

The pain that patients report is out of proportion to the severity of the injury and gets worse, rather than better, over time. It is frequently characterized as a burning, aching, searing pain, which may initially be localized to the site of injury or the area covered by an injured nerve but spreads over time, often involving an entire limb. It can sometimes even involve the opposite extremity. Pain is continuous and may be heightened by emotional stress. Moving or touching the limb is often intolerable. Eventually the joints become stiff from disuse, and the skin, muscles, and bone atrophy[?]. The symptoms of RSDS vary in severity and duration. However, there are usually three stages associated with RSDS, and each stage is marked by progressive changes in the skin, nails, muscles, joints, ligaments, and bones.

  1. Stage one lasts from 1 to 3 months and is characterized by severe, burning pain at the site of the injury. Muscle spasm, joint stiffness, restricted mobility, rapid hair and nail growth, and vasospasm[?] (a constriction of the blood vessels) that affects color and temperature of the skin can also occur.
  2. In stage two, which lasts from 3 to 6 months, the pain intensifies. Swelling spreads, hair growth diminishes, nails become cracked, brittle, grooved, and spotty, osteoporosis becomes severe and diffuse, joints thicken, and muscles atrophy.
  3. As the patient reaches stage three, changes in the skin and bones become irreversible, and pain becomes unyielding and may now involve the entire limb. There is marked muscle atrophy, severely limited mobility of the affected area, and flexor tendon contractions (contractions of the muscles and tendons that flex the joints). Occasionally the limb is displaced from its normal position, and marked bone softening is more dispersed.

Cause

The cause of RSDS is unknown. The syndrome is thought to be the result of damaged nerves of the sympathetic nervous system — the part of the nervous system responsible for controlling the diameter of blood vessels. These damaged nerves send inappropriate signals to the brain, interfering with normal information about sensations, temperature, and blood flow. Since RSDS is most often caused by trauma to the extremities, other conditions that can bring about RSDS include sprains, fractures, surgery, damage to blood vessels or nerves, and cerebral lesions. The disorder is unique in that it simultaneously affects the nerves, skin, muscles, blood vessels, and bones.

Susceptibility

RSDS can strike at any age, but is more common between the ages of 40 and 60. It affects both men and women, but is most frequently seen in women. Although it can occur at any age, the number of RSDS cases among adolescents and young adults is increasing.

Investigators estimate that two to five percent of those with peripheral nerve injury and 12 to 21 percent of those with hemiplegia (paralysis of one side of the body) will suffer from RSDS.

How is RSDS diagnosed?

RSDS is often misdiagnosed because it remains poorly understood. Diagnosis is complicated by the fact that some patients improve without treatment. A delay in diagnosis and/or treatment for this syndrome can result in severe physical and psychological problems. Early recognition and prompt treatment provide the greatest opportunity for recovery.RSDS is diagnosed primarily through observation of the symptoms. However, some physicians use thermography[?] — a diagnostic technique for measuring blood flow by determining the variations in heat emitted from the body — to detect changes in body temperature that are common in RSDS. A color-coded "thermogram" of a person in pain often shows an altered blood supply to the painful area, appearing as a different shade (abnormally pale or violet) than the surrounding areas of the corresponding part on the other side of the body. An abnormal thermogram in a patient who complains of pain may lead to a diagnosis of RSDS. X-rays may also show changes in the bone.

What is the prognosis?

Good progress can be made in treating RSDS if treatment is begun early, ideally within 3 months of the first symptoms. Early treatment often results in remission. If treatment is delayed, however, the disorder can quickly spread to the entire limb and changes in bone and muscle may become irreversible. In 50 percent of RSDS cases, pain persists longer than 6 months and sometimes for years.

Treatment

Physicians use a variety of drugs to treat RSDS, including corticosteroids, vasodilators, and alpha- or beta-adrenergic-blocking compounds. Elevation of the extremity and physical therapy are also used to treat RSDS. Injection of a local anesthetic, such as lidocaine, is usually the first step in treatment. Injections are repeated as needed. TENS (transcutaneous electrical 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. In some cases, surgical or chemical sympathectomy — interruption of the affected portion of the sympathetic nervous system — is necessary to relieve pain. Surgical sympathectomy involves cutting the nerve or nerves, destroying the pain almost instantly. But surgery may also destroy other sensations as well.

Similar disorders

RSDS has many of the same features as causalgia, such as severe burning pain that is aggravated by physical or emotional stimuli. However, causalgia usually affects the lower limbs, the palm of the hand or the sole of the foot; RSDS may strike any part of the body.

RSDS also has characteristics similar to those of other disorders, such as shoulder-hand syndrome, which sometimes occurs after a heart attack and is marked by pain and stiffness in the arm and shoulder; Sudeck's syndrome, which is prevalent in older people and in women and is characterized by bone changes and muscular atrophy, but is not always associated with trauma; and Steinbrocker's syndrome, which affects both sexes but is slightly more prevalent in females, and includes such symptoms as gradual stiffness, discomfort, and weakness in the shoulder and hand.

Current research

The National Institute of Neurological Disorders and Stroke (NINDS), a part of the National Institutes of Health (NIH), supports and conducts research on the brain and central nervous system, including research relevant to RSDS, through grants to major medical institutions across the country. NINDS-supported scientists are working to develop effective treatments for neurological conditions and, ultimately, to find ways of preventing them.Investigators are studying new approaches to treat RSDS and intervene more aggressively after traumatic injury to lower the patient's chances of developing the disorder. In addition, NINDS-supported scientists are studying how signals of the sympathetic nervous system cause pain in RSDS patients. Using a technique called microneurography, these investigators are able to record and measure neural activity in single nerve fibers[?] of affected patients. By testing various hypotheses, these researchers hope to discover the unique mechanism that causes the spontaneous pain of RSDS and that discovery may lead to new ways of blocking pain.Other studies to overcome chronic pain syndromes are discussed in the pamphlet "Chronic Pain: Hope Through Research," published by the NINDS.

Further information

Contact the RSDS Association: 116 Haddon Avenue, Suite D, Haddonfield, New Jersey 08033, (856) 795-8845, website: www.rsds.org

Based on http://www.ninds.nih.gov/health_and_medical/pubs/rsds_fact_sheet.htm (in the public domain)



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