There are genetic tests available for many of the hereditary muscle conditions that predispose to myoglobinuria and rhabdomyolysis.Muscle biopsy can be useful if an episode of rhabdomyolysis is thought to be the result of an underlying muscle disorder. A biopsy sample taken during an episode is often uninformative, as it will show only evidence of cell death or may appear normal. Taking the sample is therefore delayed for several weeks or months. The histopathological appearance on the biopsy indicates the nature of the underlying disorder. For instance, mitochondrial diseases are characterized by ragged red fibers. Biopsy sites may be identified by medical imaging, such as magnetic resonance imaging, as the muscles may not be uniformly affected. Treatment
The main goal of treatment is to treat shock and preserve kidney function. Initially this is done through the administration of generous amounts of intravenous fluids, usually isotonic saline (0.9% weight per volume sodium chloride solution). In victims of crush syndrome, it is recommended to administer intravenous fluids even before they are extracted from collapsed structures. This will ensure sufficient circulating volume to deal with the muscle cell swelling (which typically commences when blood supply is restored), and to prevent the deposition of myoglobin in the kidneys. Amounts of 6 to 12 liters over 24 hours are recommended.
Rhabdomyolysis is a condition in which damaged skeletal muscle breaks down rapidly. 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 may lead to kidney failure.The muscle damage is most often the result of 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. 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.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.Rhabdomyolysis occurs in about 26,000 people 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.