Rhabdomyolysis

Rhabdomyolysis is a term that refers to breakdown of muscle fibers of skeletal muscle. It is usually a result of various serious conditions with many consequences.

Causes

Excessive muscle strain

Extreme physical exercise, especially in untrained individuals, may lead to damage of overloaded muscles that can begin to break down.

Increased body temperature

High fever with temperatures over 40°C may cause muscle tremor and direct damage of the muscle tissue.

Acute arterial closure

Acute occlusion of an artery (that feeds muscle tissue) causes local muscle ischemia (lack of oxygen and nutrients). Typically, this occurs in the lower extremities. If the arterial closure is not solved, the affected tissues die and the muscles succumb to rhabdomyolysis.

Crush syndrome

This syndrome occurs in people who are buried under rubble or other objects. The prolonged compression of the tissues by external force causes muscle damage and rhabdomyolysis. The situation may be further worsened after the person is rescued due to reperfusion tissue damage.

Metabolic causes

Muscle damage can occur in mineral imbalance (for example the increased blood level of potassium or low calcium concentration) and overactive or underactive thyroid function.

Medications and other substances

Rhabdomyolysis is a severe side-effect of medications known as statins (commonly used medicines against high cholesterol). Neuroleptics (antipsychotics) can cause severe rhabdomyolysis as a part of feared neuroleptic malignant syndrome. Rhabdomyolysis has been also observed after ingestion of large amounts of alcohol and other addictive substances (cocaine, LSD, etc.).

Autoimmune diseases

Muscle damage occurs in polymyositis, dermatomyositis and similar diseases. The main symptoms include muscle weakness, but some forms of the disease may even manifest with rhabdomyolysis.

Symptoms

The muscle damage may manifest with muscle pain and muscle weakness. Decaying muscle fibers release a number of substances such as enzyme known as creatine kinase (CK) and myoglobin. The molecules of myoglobin get into the bloodstream and enter the kidneys, where they can cause acute renal failure.

Diagnosis

We should think about the rhabdomyolysis in risky patients. Blood tests are very important for proper diagnosis as we may find elevated creatine kinase and myoglobin blood levels. In case of kidney damage we find elevated renal parameters. The diagnosis can be confirmed also by urinalysis. The urine is dark and it contains large amounts of myoglobin.

Treatment

It is necessary to treat or eliminate the cause of rhabdomyolysis, if possible. Adequate hydration is necessary and at least temporary dialysis is indicated in case of acute kidney failure.