Rhabdomyolysis explained: Hidden dangers of the rare muscle condition

NEW YORK CITY - Whether you are a seasoned endurance athlete, a casual gym-goer trying out a high-intensity bootcamp, or simply someone starting a new physical job, there is a rare but severe condition you need to be aware of: rhabdomyolysis.

What is rhabdomyolysis? 

What we know:

Often referred to simply as "rhabdo," this condition occurs when damaged muscle tissue releases its proteins and electrolytes into the bloodstream, which can quickly lead to heart arrhythmias and permanent kidney damage if left untreated.

When skeletal muscle is severely injured, either through extreme physical exertion, trauma, or toxic exposure, the muscle fibers rapidly break down and die. As these cells rupture, they leak their contents directly into your bloodstream. 

The most dangerous of these contents is a protein called myoglobin. While myoglobin is essential for storing oxygen inside your muscles, it is toxic to your kidneys. As your kidneys attempt to filter out the massive influx of myoglobin, the protein can crystallize and physically clog the kidneys' filtration system, potentially triggering acute renal failure.

Recent tragedy

Local perspective:

The devastating potential of rhabdomyolysis was recently brought to light during the New York City Marathon. 

Rachel Apa, a 24-year-old Pennsylvania native, was running her very first marathon and was reportedly in perfect health leading up to the race. She was pronounced dead later that evening after collapsing just two miles from the finish line, according to the New York Times, who confirmed with her family that the cause of death was rhabdomyolysis.

Symptoms, causes and triggers

Dig deeper:

Rhabdomyolysis can escalate quickly, making early detection critical. Medical professionals typically look for three hallmark symptoms:

• Severe muscle pain: This goes far beyond standard post-workout soreness. The affected muscles will feel intensely painful, tender to the touch, and severely stiff.
• Profound weakness: The damaged muscles may refuse to contract entirely, making it difficult or impossible to move the affected limbs.
• Dark urine: As myoglobin is filtered out of the blood, it turns urine a distinct tea, cola, or dark red color.

While rhabdo has gained recent media attention alongside extreme fitness trends, extreme exercise is just one cause for the condition.

• Extreme exertion: Pushing past exhaustion, particularly in high-intensity interval training, heavy weightlifting, or endurance running, especially when dehydrated or not being acclimated to the heat.
• Crush injuries: Prolonged pressure on muscles, such as being trapped under heavy debris in a car accident or a fall.
• Medications and toxins: High doses of certain statins (cholesterol-lowering drugs), substance abuse (like cocaine or amphetamines), and severe alcohol withdrawal.
• Medical emergencies: Heatstroke, severe burns, and prolonged seizures can all trigger massive muscle breakdown.

Diagnosis, treatment and prevention

What you can do:

If a doctor suspects rhabdo, they will order blood tests to check your levels of creatine kinase (CK), an enzyme released by damaged muscles. A normal CK level is typically under 200 U/L; in severe rhabdo cases, levels can skyrocket into the tens or hundreds of thousands.

Treatment requires immediate medical intervention, usually starting with aggressive intravenous (IV) fluids to flush the myoglobin out of the kidneys and stabilize dangerous electrolyte imbalances. In extreme cases where the kidneys have already shut down, temporary dialysis may be necessary.

How to stay safe

You do not need to avoid the gym, but you do need to respect your body's limits. Hydrate extensively before, during, and after strenuous activity. Gradually ramp up the intensity of new workout programs rather than jumping straight into extreme volume, and avoid pushing yourself to muscle failure in extreme heat.