by Bob Albright, D.O.
Looking at the title, you might think this is about a Vietnam-era special forces dude who’s been wronged, but it’s actually about what can be a life-threatening medical condition. There has been a lot of interest in this condition recently in the mainstream media. Are endurance athletes at risk?
Rhabdomyolysis (aka Rhabdo) is the medical term for the destruction of muscle tissue. This is not your average delayed onset muscle soreness (DOMS), nor is that nagging pain you feel in your quads after a huge load of eccentric stress. This is the actual death of muscle cells (myocytes) causing the release of the compound myoglobin and other muscle cell constituents into the circulation.
Muscles are bundled together and encased in connective tissue sheaths. When cell death occurs, the muscle units will swell, which is a dangerous situation, leading to high pressure within the muscle sheaths. This high compartment pressure may lead to even more damage due to ischemia as the high pressure exceeds blood pressure and more destruction ensues. This situation requires attention immediately, as with a surgical procedure the muscles can often be saved.
Elevated amounts of myoglobin in the blood (myoglobinemia) will lead to high amounts of myoglobin being filtered through the kidneys and into the urine (myoglobinuria). Herein lays one of the major dangers: sudden kidney shutdown, known as acute kidney injury (AKI).
AKI leads to metabolic derangements which range from mild to immediately life threatening. High potassium level (hyperkalemia) represents the worst complication, as it may lead to cardiac standstill.
Causes of rhabdomyolysis are myriad, and can be grouped into ischemic (insufficient blood flow), traumatic (crush injury), inherited, infectious and toxic/metabolic.
As endurance athletes I think it’s worth focusing on a few issues.
- Heat or cold stress: Both extremes of temperature can be deadly to our muscles. Heat stroke is just as dangerous as frostbite. Please read Gordo’s accounts from Day 23 of his training across America for inspiration.
- Trauma: Not only do we need to keep the rubber side down and stay away from collapsing buildings, but do not forget the infamous scene from Caddyshack where the clergyman is having the best golf game of his life… in the thunderstorm…
- Toxins/Drugs: This is not a big one among the clean-living types reading this, but excess alcohol, cocaine, amphetamines and snake/scorpion bites (rattlers mainly) all have colorful associations with athletes and rhabdomyolysis. Very rarely, high dose statin therapy has caused rhabdomyolysis. This risk is increased with certain drug combinations (gemfibrozil, amlodipine and a statin as examples).
- Metabolic: The nemesis of the endurance athlete -- hyponatremia, low phosphorus levels (rare, but typically due to nutritional disorders along with alcohol abuse), and low potassium levels have been associated with rhabdomyolysis. Do not forget the major cause of hyponatremia is the body’s excess production of antidiuretic hormone, which is in turn stimulated by extreme stress and inhibited by prostaglandins. ADH leads to the kidneys saving water and diluting the body’s sodium level…
Blah, blah, blah… so what? Well, NSAIDs block prostaglandins, so, NSAIDs increase your risk for hyponatremia. When low sodium is caused by extreme dehydration, NSAIDs also prevent the body from opening up critical vascular beds, perhaps taking a muscle injury right past nagging ache to muscle cell death. There are many other metabolic issues one can explore with the wonders of the interwebs as well.
- Inherited: Some folks inherit unusual changes in how cells use oxygen and fatty acids (mitochondrial defects) which manifest themselves as muscle cell death with exertion. This is not usually subtle, but depending on the person’s prior activity level, an unusual effort may lead to a rhabdomyolysis episode. Those with sickle cell disease (a blood disorder) need also to be cautious with exertion associated with possible dehydration, as these stresses lead to sickle crisis.
How do we prevent this?
Prevention is clearly the usual answer to most medical conditions. Dialing in your training, nutrition and fluid strategy is critical as well. So, as I’m mentioned in past columns, NO NSAIDS and be sensible about training in extreme weather.
How is it treated?
Much depends upon the severity and any complications that develop. Oral or IV fluids may be sufficient, but occasionally, hospitalization and even surgery may be required.
How will I know if I have it?
Keep an eye on your urine character and quantity. Cola-colored urine is never normal. This should prompt rest, fluids and a call to your provider if your urine does not clear within hours. Severe muscle pain accompanied by swelling of the extremity or discoloration of the painful area or signs of poor blood supply to the limb downstream should prompt you to go to the ER or med tent ASAP! Many times these situations are associated with feeling extremely ill in general as well. Get help! Dehydration and low blood pressure can make this bad situation worse.
Bob Albright, D.O., is a Nephrologist and Assistant Professor of Medicine at the Mayo Clinic in Rochester, Minn. You can contact him at firstname.lastname@example.org.