Rhabdomyolysis is the breakdown of muscle fibers that leads to the release of muscle fiber contents (myoglobin) into the bloodstream. Myoglobin is harmful to the kidney and often causes kidney damage.A.D.A.M.

Causes, incidence, and risk factors

When muscle is damaged, a protein called myoglobin is released into the bloodstream. It is then filtered out of the body by the kidneys. Myoglobin breaks down into substances that can damage kidney cells.

Rhabdomyolysis may be caused by any condition that damages skeletal muscle, especially injury.

Risk factors include the following:

• Alcoholism (with muscle tremors)
• Crush injuries
• Drugs, especially cocaine, amphetamines, statins, heroin, or PCP
• Genetic muscle diseases
• Heatstroke
• Ischemia or necrosis of the muscles (which may occur with arterial occlusion, deep venous thrombosis, or other conditions)
• Low phosphate levels
• Seizures
• Severe exertion, such as marathon running or calisthenics
• Shaking chills
• Trauma

Symptoms

• Abnormal urine color (dark, red, or cola colored)
• Decreased urine production
• General weakness
• Muscle stiffness or aching (myalgia)
• Muscle tenderness
• Weakness of the affected muscles

Other symptoms that may occur with this disease:

• Fatigue
• Joint pain
• Seizures
• Weight gain (unintentional)

Signs and tests

An examination shows tender or damaged skeletal muscles.

The following tests may be done:

• Creatine kinase (CK) level
• Serum calcium
• Serum myoglobin
• Serum potassium
• Urinalysis
• Urine myoglobin test

This disease may also affect the results of the following tests:

• CK isoenzymes
• Serum creatinine
• Urine creatinine

Treatment

Getting fluids that contain bicarbonate may prevent kidney damage by quickly flushing myoglobin out of the kidneys. Fluids may need to be given through a vein (by IV). Some patients may need kidney dialysis.

Medicines that may be prescribed include diuretics and bicarbonate (if there is enough urine output).

Hyperkalemia and low blood calcium levels (hypocalcemia) should be treated right away, if present. Kidney failure should also be treated.

Expectations (prognosis)

The outcome depends on the amount of kidney damage. Acute kidney failure occurs in many patients. Getting treated soon after rhabdomyolysis begins will reduce the risk of permanent kidney damage.

People with milder cases may return to their normal activities within a few weeks to a month. However, some people continue to have problems with fatigue and muscle pain.

Complications

• Acute tubular necrosis
• Acute renal failure
• Harmful chemical imbalances in the blood
• Shock (low blood pressure)

Calling your health care provider

Call your health care provider if you have symptoms of rhabdomyolysis.

Prevention

Drink plenty of fluids after strenuous exercise to dilute your urine and flush any myoglobin that is released from your muscles out of your kidneys. Also drink a lot of fluids after any condition or event that may have damaged skeletal muscle.

References

1. O'Connor FG, Deuster PA. Rhabdomyolysis. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 114.
2. Remuzzi G, Perico N, DeBroe ME. Acute kidney injury. In: Brenner BM, ed. Brenner and Rector's the Kidney. 8th ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 29.

Review Date: 9/19/2011.

Reviewed by: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; and Herbert Y Lin, MD, PhD, Nephrologist, Massachusetts General Hospital; Associate Professor of Medicine, Harvard Medical School. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.