Rhabdomyolysis Symptoms and Causes

Dr. Wedro Weighs In On the University of Iowa's Football Players Hospitalization

Medical Author: Benjamin C. Wedro, MD, FACEP, FAAEM
Medical Editor: Melissa Conrad Stöppler, MD

They might be called the unlucky 13. At the end of a strenuous workout, a baker's dozen University of Iowa football players ended up in the hospital with rhabdomyolysis (rhabdo=skeleton +myo=muscle + lysis=breakdown), a condition in which muscles break down quickly and spill their contents into the blood stream. Myoglobin is a protein that is contained in muscle cells, and if enough is spilled into the blood stream, it can clog the kidney's filtering system and lead to kidney failure and a variety of other serious medical consequences and complications. While muscles routinely get sore after physical activity, rhabdomyolysis takes that muscle injury to a higher level.

For a muscle to contract or squeeze, it needs access to adequate water, electrolytes, glucose, and oxygen for aerobic metabolism. Then the muscle needs time to recover and remove lactic acid. But if the work that the muscle is asked to do overwhelms aerobic metabolism, muscle cells and fibers can be damaged, swell, and leak their chemicals into the blood stream. Mild injury happens routinely with normal activity, and body is able to recover without consequences, except perhaps for muscle soreness.

Rhabdomyolysis is the result of massive muscle destruction. Weight lifting in the gym is not the only cause.

It is often the major injury suffered by victims of a blast injury from an earthquake, bombing, or lightning strike.

It may be caused when a person falls and lies motionless for many hours and the weight of the body in effect crushes its own muscle. That scenario can happen in stroke victims or an intoxicated person who has fallen with no one around to assist, and then are found many hours later. Non-injury causes include side effects of certain medications such as statins used to treat high cholesterol and some psychiatric medications.

The most common symptoms of rhabdomyolysis include: 1) muscle weakness; 2) muscle aches; and 3) dark urine. The muscle damage causes inflammation leading to tenderness, swelling, and weakness of the affected muscles. The dark urine color is due to myoglobin being excreted in the urine by the kidney as it tries to rid the body of the muscle breakdown products.

Symptoms related to the expected complications of rhabdomyolysis include:

As mentioned previously, inflamed muscles hurt and the common symptoms include pain and swelling at the site of the overused or injured muscles, but the big issue is the myoglobin. It is a large protein and when it circulates in the blood can clog the filtering system in the kidneys causing kidney failure. Some of the protein passes into the urine and turns it brown, but some urinary function still decreases and nausea, vomiting, and weakness progress further. Confusion, coma, and seizures can occur if the body's electrolyte levels become unbalanced.

Aside from a high index of suspicion by the health care practitioner, the diagnosis is confirmed by an elevated CPK (creatine phosphokinase), another chemical that is leaked from muscle cells into the blood. While that test makes the diagnosis, the numbers that really matter are kidney function test (BUN and creatinine) and potassium levels.