Rhabdomyolysis facts for kids

Rhabdomyolysis (shortened as rhabdo) is a condition in which damaged skeletal muscle breaks down rapidly.

Etymology and pronunciation

The word rhabdomyolysis uses the combining forms rhabdo- + myo- + -lysis, yielding "striated muscle breakdown".

Symptoms

Symptoms may include muscle pains, weakness, vomiting, and confusion. There may be tea-colored urine or an irregular heartbeat. Some of the muscle breakdown products, such as the protein myoglobin, are harmful to the kidneys and can cause acute kidney injury.

Cause

The muscle damage is most usually caused by a crush injury, strenuous exercise, medications, or a substance use disorder. Other causes include infections, electrical injury, heat stroke, prolonged immobilization, lack of blood flow to a limb, or snake bites as well as intense or prolonged exercise, particularly in hot conditions. Statins (prescription drugs to lower cholesterol) are considered a small risk. Some people have inherited muscle conditions that increase the risk of rhabdomyolysis. The diagnosis is supported by a urine test strip which is positive for "blood" but the urine contains no red blood cells when examined with a microscope. Blood tests show a creatine kinase activity greater than 1,000 U/L, with severe disease being above 5,000-15,000 U/L.

Treatment

The mainstay of treatment is large quantities of intravenous fluids. Other treatments may include dialysis or hemofiltration in more severe cases. Once urine output is established, sodium bicarbonate and mannitol are commonly used but they are poorly supported by the evidence. Outcomes are generally good if treated early. Complications may include high blood potassium, low blood calcium, disseminated intravascular coagulation, and compartment syndrome.

Epidemiology

Rhabdomyolysis is reported about 26,000 times a year in the United States. While the condition has been commented on throughout history, the first modern description was following an earthquake in 1908. Important discoveries as to its mechanism were made during the Blitz of London in 1941. It is a significant problem for those injured in earthquakes, and relief efforts for such disasters often include medical teams equipped to treat survivors with rhabdomyolysis.

Other animals

Rhabdomyolysis is recognized in horses. Horses can develop a number of muscle disorders, many of which may progress to rhabdomyolysis. Of these, some cause isolated attacks of rhabdomyolysis (e.g., dietary deficiency in vitamin E and selenium, poisoning associated with pasture or agricultural poisons such as organophosphates), while others predispose to exertional rhabdomyolysis (e.g., the hereditary condition equine polysaccharide storage myopathy). 5–10% of thoroughbred horses and some standardbred horses have the condition equine exertional rhabdomyolysis; no specific cause has been identified, but an underlying muscle calcium regulation disorder is suspected.

Rhabdomyolysis affecting horses may also occur in outbreaks; these have been reported in many European countries, and later in Canada, Australia, and the United States. It has been referred to as "atypical myopathy" or "myoglobinuria of unknown etiology". No single cause has yet been found, but various mechanisms have been proposed, and a seasonal pattern has been observed. Very high creatine kinase levels are detected, and mortality from this condition is 89%.

Images for kids

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  Schematic diagram of myoglobin, a heme-containing protein that participates in oxygen storage in normal muscle but is responsible for kidney damage in rhabdomyolysis

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  The M-subunit of creatine kinase. In skeletal muscle, creatine kinase exists predominantly in dimers containing two M-subunits, also referred to as "CK-MM".

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  A hemofiltration machine

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  Investigations of people injured in collapsed buildings during the Blitz of London led to numerous discoveries in the mechanisms underlying kidney impairment in rhabdomyolysis.

See also

In Spanish: Rabdomiólisis para niños