Rhabdomyolysis: What Is It?

Medically Reviewed by Jabeen Begum, MD on May 17, 2024
Written by Annie Stuart, Sarah Amandolare, Amy Gopal
6 min read

Rhabdomyolysis , called rhabdo for short, is a serious condition caused by a direct or indirect muscle injury. It happens when muscle fibers die and release their contents into your bloodstream. This can lead to serious complications such as renal (kidney) failure. This means your kidneys can't remove waste and concentrated urine.

In rare cases, rhabdomyolysis can even cause death. However, early treatment often brings a good outcome.

There are many traumatic and nontraumatic causes of rhabdomyolysis. In the first category, causes include:

  • A crush injury such as from an auto accident, fall, or building collapse
  • Long-lasting muscle compression such as that caused by prolonged immobilization after a fall or lying unconscious on a hard surface during illness or while under the influence of alcohol or medication
  • Electrical shock injury, lightning strike, or third-degree burn
  • Venom from a snake or insect bite

Nontraumatic causes of rhabdomyolysis include:

  • The use of alcohol or illegal drugs such as heroin, cocaine, or amphetamines
  • Extreme muscle strain, especially in those assigned male at birth who exercise regularly and have a body mass index (BMI) over 30, whether due to being overweight or extremely muscular. It can happen in elite athletes, too, and rhabdo can be more dangerous if there is more muscle mass to break down.
  • The use of medications such as antipsychotics or statins, especially when given in high doses
  • A very high body temperature (hyperthermia) or heat stroke. Those who work outside in hot weather or are exposed to high temperatures are at a higher risk, including construction workers, military service members, farmers, firefighters, and first responders.
  • Seizures or delirium tremens (alcohol withdrawal delirium)
  • A metabolic disorder such as diabetic ketoacidosis
  • Diseases of the muscles (myopathy) such as congenital muscle enzyme deficiency or Duchenne's muscular dystrophy
  • Viral infections such as the flu, COVID-19, HIV, or herpes simplex virus
  • Bacterial infections leading to toxins in tissues or the bloodstream (sepsis)

A previous history of rhabdomyolysis may also increase the risk of having rhabdomyolysis again.

Some doctors have seen an uptick in rhabdomyolysis cases, which they attribute to the rise of extreme exercise, such as high-intensity interval training, spinning, CrossFit, and ultrarunning.

Signs and symptoms of rhabdomyolysis may be hard to pinpoint. This is largely true because the course of rhabdomyolysis varies, depending on its cause. Also, its symptoms may affect the whole body or just one area and may occur in both early and later stages.

The “classic triad” of rhabdomyolysis symptoms are:

  • Muscle pain in the shoulders, thighs, or lower back
  • Muscle weakness or trouble moving arms and legs
  • Dark red or brown urine or decreased urination

Keep in mind that half of people with the condition may have no muscle-related symptoms.

Other common signs of rhabdo include:

If you experience rhabdo symptoms, see your doctor to get tested to confirm your diagnosis. 

Creatine kinase blood test

Blood tests for creatine kinase (CK), a product of muscle breakdown, are used to diagnose rhabdomyolysis. Your CK levels will be higher if you have rhabdomyolysis, and you may need multiple blood tests as you're treated to make sure levels go down.

Myoglobin urine test

Urine tests for myoglobin, a relative of hemoglobin that is released from damaged muscles, can also help diagnose rhabdomyolysis. However, these tests aren’t viewed as accurately as blood tests because myoglobin moves quickly through the body. You may get a negative urine test but still have rhabdo.

Other tests

Your doctor may use more tests to rule out other problems, confirm the cause of rhabdomyolysis, or check for complications. These include:

  • Liver function test
  • EKG
  • Chest X-ray

Early diagnosis and treatment of rhabdomyolysis and its causes are keys to a successful outcome. You can expect full recovery with prompt treatment. Doctors can even reverse kidney damage. However, if complications aren't identified and treated early enough, they may cause lasting damage.

Hospitalization

If you have rhabdomyolysis, you'll be admitted to the hospital to receive treatment for the cause. Treatment with IV fluids helps maintain urine production and prevent kidney failure. Rarely, dialysis treatment may be needed to help your kidneys filter waste products while they are recovering. Management of electrolyte abnormalities (potassium, calcium, and phosphorus) helps protect your heart and other organs.

You may also need a surgical procedure (fasciotomy) to ease tension or pressure and loss of circulation if compartment syndrome (when excessive pressure builds up inside an enclosed muscle space) threatens muscle death or nerve damage. In some cases, you may need to be in the intensive care unit (ICU) to allow close monitoring.

Most causes of rhabdomyolysis are reversible.

If rhabdomyolysis is related to a medical condition, such as diabetes or a thyroid disorder, appropriate treatment for the medical condition will be needed. And if your rhabdo is related to a medication or drug, its use will need to be stopped or replaced with an alternative.

After treatment, discuss with your doctor any needed limitations on diet or activity. And avoid any potential causes of rhabdomyolysis in the future.

Complications will vary depending on how long you’ve had rhabdomyolysis before treatment. Early complications include:

  • Very high levels of potassium in the blood (hyperkalemia)
  • Low levels of calcium in the blood (hypocalcemia)

Irregular heartbeat  or cardiac arrest

  • Kidney damage, which occurs in up to half of the people treated for rhabdo
  • Liver problems, like elevated liver enzymes
  • Abnormal blood clotting

Compartment syndrome, a serious compression of nerves, blood vessels, and muscles that can cause tissue damage and problems with blood flow

Later complications include:

  • Nerve damage related to compartment syndrome
  • Muscle contractures
  • Fatigue

It may take a few weeks before you feel back to normal after rhabdo, even if you haven’t had any complications. Rhabdomyolysis recovery tips include: 

  • Depending on the severity of your illness, your doctor may advise against exercising for several weeks to months. Your blood and urine tests, as well as hydration levels, should all be back to normal first. Most people can safely resume daily activities after muscle pain, weakness, and any fever or flu-like symptoms have resolved. 
  • Physical therapy can help strengthen your muscles after taking time off from exercise. 
  • Phase your return to exercise; start slowly, stay hydrated, and rest if you feel tired or sore to reduce your risk of having rhabdomyolysis again.

Early diagnosis and treatment of rhabdomyolysis can be essential to a full recovery. Most people begin to notice symptoms about 24-72 hours after exercise or an injury. However, it can be difficult to tell the difference between rhabdomyolysis and typical post-workout fatigue. Be alert to symptoms in a particular muscle or muscle group. If you notice extreme pain, weakness, swelling, or cramping in your muscles, and/or very dark urine, go to the hospital immediately.

Rhabdomyolysis is a serious, potentially life-threatening syndrome that occurs when muscle fibers die and release their contents into the bloodstream. It can result from exercise, a crush injury, or alcohol or illegal drug use, among other traumatic and nontraumatic causes. Signs of rhabdo often include very dark brown or red urine and severe muscular pain or weakness, but half of people may not experience muscle-related symptoms. You should go to the hospital immediately if you experience these symptoms to confirm it's rhabdomyolysis and receive treatment.

Can you fully recover from rhabdomyolysis? 

Yes, but it may take a few weeks to several months or longer. Complications can further delay your recovery.

Is rhabdomyolysis an emergency?

Yes, rhabdomyolysis can be life-threatening. Recovery may depend on how quickly you receive treatment.

How do you prevent rhabdomyolysis?

To prevent rhabdo:

  • Avoid strenuous exercise in the heat.
  • Stay hydrated.
  • Stop and rest if you feel fatigued or faint.