Rhabdomyolysis

Definition:

A disorder involving injury to the kidney caused by toxic effects of the contents of muscle cells.

Causes, incidence, and risk factors:

Myoglobin is an iron-containing pigment found in the skeletal muscle. When the skeletal muscle is damaged, the myoglobin is released into the bloodstream. It is filtered out of the bloodstream by the kidneys. Myoglobin may occlude the structures of the kidney, causing damage such as acute tubular necrosis or kidney failure. Myoglobin breaks down into potentially toxic compounds, which will also cause kidney failure. Necrotic (dead tissue) skeletal muscle may cause massive fluid shifts from the bloodstream into the muscle, reducing the relative fluid volume of the body and leading to shock and reduced blood flow to the kidneys.

The disorder affects about 1 out of 10,000 people of any age, sex, and race. It may be caused by any condition that results in damage to skeletal muscle, especially trauma.

Risk factors include:

• severe exertion such as marathon running or calisthenics
• ischemia or necrosis of the muscles (as may occur with arterial occlusion, deep venous thrombosis, or other conditions)
• seizures
• use or overdose of drugs-especially cocaine, amphetamines, heroin, or PCP
• trauma
• shaking chills
• heat intolerance and/or heatstroke
• alcoholism (with subsequent muscle tremors)