Causalgia

Reflex sympathetic dystrophy syndrome (RSDS) — also known as complex regional pain syndrome (CPRS)— 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. more...

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.

In ICD-10, it is listed as "Sympathetic reflex dystrophy", a form of algoneurodystrophy (M89.0), which has a distinct classification from causalgia (G56.4).

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. There are three variants of RSDS, previously thought of as stages. It is now believed that patients with RSDS do not progress through these stages sequentially and/or that these stages are not time limited. Instead, patients are likely to have one of the three following types of disease progression:

1. Type one 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. Type two is characterized by more intense pain. Swelling spreads, hair growth diminishes, nails become cracked, brittle, grooved, and spotty, osteoporosis becomes severe and diffuse, joints thicken, and muscles atrophy.
3. Type three is characterized by irreversible changes in the skin and bones, while the pain becomes unyielding and may 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.

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