What Is Rhabdomyolysis?

Skeletal muscles are the ones you use voluntarily to move yourself. When some of this muscle is destroyed, it can lead to a condition known as rhabdomyolysis. The word is derived from the Greek words for “rod-like (skeletal)/muscle/breakdown.” Healthcare providers often call it simply “rhabdo.”

When skeletal muscle cells die, they can cause pain in the affected areas. They also leak their contents into the bloodstream. When released here, some of the muscle proteins and other components can be quite damaging to other parts of the body, especially the kidneys. 

In the United States, around 25,000 cases of rhabdomyolysis happen each year. Although it can occur in people of any age, people over 60 seem to have a higher risk.

Although most people with rhabdomyolysis fully recover with fluids and rest, people with more severe cases need hospitalization. Some even die from complications such as abnormal heart rhythms. That’s why it’s critical to get evaluated right away if you suspect you might have rhabdo. 

Rhabdomyolysis Symptoms

Some people with rhabdo have few to no symptoms, but others experience life-threatening complications. 

Classic Symptoms

There are three common symptoms of rhabdomyolysis:

• Unexplained severe muscle cramps or pain: This most often occurs in the calves or lower back.
• Weakness and fatigue: You might not be able to complete your normal tasks or workout.
• Urine the color of cola or tea: This might only happen for a limited time. 

A minority of people with rhabdo report all three of these symptoms, and some people don’t have any of them.

Symptoms From Electrolyte Abnormalities

Rhabdomyolysis can lead to too high or too low levels of electrolytes, which are small charged particles, in your bloodstream. For example, it might lead to:

• Elevated potassium (hyperkalemia)
• Elevated phosphorus (hyperphosphatemia)
• Lowered calcium (hypocalcemia)

If not corrected, these abnormalities can lead to many different symptoms such as heart palpitations, seizures, muscle cramps, weakness, or spasms.

Additional Symptoms

Rhabdomyolysis also sometimes causes additional symptoms, such as fever, a rapid heart rate, or nausea and vomiting. It can also sometimes cause symptoms from damage to different organ systems, especially the kidneys.

What Causes Rhabdomyolysis?

Many different situations can cause the skeletal muscle breakdown that leads to symptoms from rhabdomyolysis. 

Physical Trauma

Trauma is the most common cause of rhabdomyolysis.  Direct damage to the muscle cells leads to symptoms. Sometimes rhabdomyolysis is called “crush syndrome” in this context.

Strenuous Exercise

It might be surprising, but strenuous exercise is another important cause of rhabdo. This might happen if you jump into an intense workout program and you don’t give your muscles time to heal between sessions. 

Drugs

Drugs are another important group of causes. Some drugs that can sometimes cause it include:

• Statin drugs like Lipitor (atorvastatin) 
• Other non-statin drugs for high cholesterol, like Zetia (ezetimibe)
• Psychiatric drugs like Haldol (haloperidol) or Prozac (fluoxetine)
• Drugs for allergies like Benadryl (diphenhydramine)
• Alcohol and illicit drugs such as cocaine and heroin

Congenital Diseases

Another important category are certain genetic diseases. Although a wide variety of these can lead to rhabdo for different reasons, some important examples are sickle cell disease, mitochondrial diseases, inherited diseases of metabolism, and muscular dystrophies.

Other Causes

Some other causes of rhabdo include but are not limited to:

• Certain infections (including flu, strep, mono, and salmonella)
• Electrolyte disorders
• Prolonged immobilization
• Very high body temperature (e.g., from heat stroke or other medical situations)

Sometimes these causes work together to increase a person’s overall risk (e.g., a person with an infection who takes certain cold medicines). Underlying conditions like muscular dystrophy can increase your risk of rhabdo from exercise. Dehydration can also worsen rhabdo.

Diagnosis

Your healthcare provider starts by taking your medical history and performing an exam. Although these can’t definitively diagnose rhabdomyolysis, they can give clues that it’s a possibility. 

Tests

The most important test for diagnosing rhabdomyolysis is “creatine phosphokinase” or “CPK.” This is a protein present in your muscles, and more of it is released into your blood during rhabdomyolysis. If you are concerned you might have rhabdomyolysis, ask to have this blood test checked. 

When CPK is five times normal or more, it strongly points to rhabdomyolysis. However, it might not be high immediately after the muscle damage. Your healthcare provider will need to check this value more than once. People who have extremely high levels tend to have more complications compared to people whose levels are less elevated.

You might need other tests to rule out other conditions and get basic information about your health such as:

• Blood tests: Tests such as a complete blood count (CBC) and a complete metabolic panel (CMP) can give you some basic information about your health, including your electrolyte balance.
• Urine tests: These can be used to check for muscle protein (myoglobin) in the urine and help confirm rhabdomyolysis, although it is only helpful for a limited time.
• Electrocardiogram (ECG or EKG): This can tell you if the rhabdo is affecting your heart.

People who don’t have an obvious cause of rhabdo might also need further testing, such as genetic testing, to see if there are other less common contributors.

It’s important for rhabdo to be correctly diagnosed as quickly as possible so you can promptly start treatment.

Treatments for Rhabdomyolysis

Less severe cases of rhabdomyolysis may not require a lot in terms of treatment. After checking in with a healthcare provider, you’ll need to stay out of the heat, drink lots of fluids, and rest at home. However, if your condition is more severe, you’ll probably need treatment and monitoring at a hospital.

Intravenous (IV) fluids are key for flushing out the dead muscle cell components. Fluids also help protect your kidneys, and they can be used to adjust your electrolytes. 

If necessary, you’ll be treated for complications of rhabdo, such as kidney failure. Some people need temporary dialysis to perform the work of their kidneys. Some who are very ill from other complications of rhabdo might need additional treatments, like ventilator support and care in an intensive care unit (ICU).  

It’s also important to identify the potential cause of rhabdomyolysis and remove it if applicable (e.g., a statin drug that led to symptoms),

Prevention

Not all rhabdo cases can be prevented. However, you can take steps to help prevent rhabdo related to excess exercise and heat exposure, including:

• Don’t abruptly start an intense exercise program. Build up to it over time until you know what your body can handle. You might not be able to handle as much if it’s very hot. 
• If you need to exercise out in the heat, take frequent breaks.
• Stay hydrated when you are out working in the heat. Avoid alcohol and caffeine, which can dehydrate you further. 
• If you’ve been exercising heavily and you notice any potential signs of rhabdo, stop what you are doing right away. Cool down, get something to drink, and seek a healthcare provider right away.

Complications

Although it doesn’t always cause complications, especially when not very much muscle has been destroyed, rhabdomyolysis sometimes causes serious and life-threatening issues. 

Acute Kidney Injury

Damage to the kidneys, termed “acute kidney injury,” is the most common serious complication of rhabdo. The muscle proteins released into the blood are particularly damaging to the kidney. You might notice that you aren’t making any urine, or not as much as usual.

Less commonly, other organs such as the liver may also be damaged.

Compartment Syndrome 

Something called “compartment syndrome” is a rare but potentially very serious complication of rhabdomyolysis. Injury inside a muscle can cause swelling inside the muscle sheath, the fibrous portion that surrounds the muscle. That may cause the muscles in the sheath “compartment” not to get enough blood, leading to severe pain and muscle death. 

In some cases, a person might need an emergency procedure called a fasciotomy to decrease pressure inside the muscle and prevent permanent disability.

Disseminated Intravascular Coagulation (DIC)

Something called “disseminated intravascular coagulation” (DIC) is one of the most serious potential complications of rhabdomyolysis. In this situation, the blood can start to abnormally clot in multiple organs of the body, which may lead to death. It's much more likely if the CPK is extremely high.

Abnormal Heart Rhythms

The electrolyte imbalances caused by rhabdomyolysis can sometimes cause abnormal heart rhythms, because electrolytes are important for the way the heart electrically signals. In the most serious causes, this can cause a fatal heart rhythm. 

Prognosis

Most people treated early for rhabdomyolysis can return to their everyday life within a few days without any long-term effects. That being said, around 8% to 20% of people with rhabdomyolysis die.

However, this rate is much lower for people who don’t have injuries to organs like the kidneys. In people who have severe kidney damage and potentially damage to other organs, mortality may be up to 50%.

Most people who have kidney damage don’t suffer from long-term kidney problems, even if they need temporary dialysis. However, a significant minority develop chronic kidney disease from rhabdomyolysis, so their kidneys won’t work as effectively as before. But they may be able to eventually get off dialysis after their kidneys somewhat recover.