Introduction
Athletes push their bodies to the limits in pursuit of excellence, striving for peak performance and achieving new personal bests. However, this intense physical exertion can sometimes lead to unintended consequences, including exertional rhabdomyolysis. This condition, characterized by the breakdown of muscle tissue and the release of harmful substances into the bloodstream, poses a significant risk to athletes if not properly understood and managed.
What Is Exertional Rhabdomyolysis?
Exertional rhabdomyolysis, a condition where muscles break down, is quite rare but can have serious consequences for athletes. In the United States, it is estimated that there are about 12,000 cases of this condition each year.
Exertional rhabdomyolysis is commonly seen in military recruits and athletes who push themselves too hard even when they are tired. Athletes who do movements that involve muscles both lengthening and contracting at the same time, like in programs such as CrossFit and Insanity, are more likely to experience this. Other sports that increase the risk include American football, track and field, swimming, and outdoor sports. On the other hand, endurance activities like marathon running, which mainly involve muscle contracting, have a lower risk.
Athletes are more likely to get exertional rhabdomyolysis if they are not in good shape to begin with and then suddenly start intense training or if they rapidly increase the difficulty of their workouts. Factors like hot weather, taking certain drugs or supplements, being sick, or not drinking enough water can also contribute to the risk.
What Is the Pathophysiology of Exertional Rhabdomyolysis?
Exertional rhabdomyolysis (ER) happens when exercising too hard hurts the muscle cells and messes up the balance of certain things inside them. This can occur because of direct damage or because the cells run out of energy. There are tiny pumps in the cells that usually keep the right levels of different things like calcium and sodium, and when these pumps get hurt, the balance gets messed up. This can cause some bad things to happen inside the cells, like the production of harmful substances that break the cell membranes.
When the cell membranes get damaged, stuff from inside the cells, like potassium, myoglobin, creatine kinase (CK), and LDH, leaks into the blood. This leakage can cause pain, swelling, and damage to important organs. The messed-up balance inside the cells also makes them contract more, which adds to the damage.
Myoglobin is a substance that is usually held in check in the blood. But when there is too much myoglobin because of the damaged cells, it can start to stick together in the kidneys and block them, which can lead to kidney problems. This is why the urine of someone with ER might look like tea.
ER can also mess up the levels of important things in the body, like calcium, phosphorus, potassium, and uric acid. These imbalances can cause heart problems. The stuff that leaks out of the cells can also cause problems with blood clotting and swelling in the body.
What Are the Symptoms of Exertional Rhabdomyolysis?
The signs of exertional rhabdomyolysis often include muscle pain and stiffness, along with weakness. This pain is more intense than the usual soreness that comes after a workout and usually appears about 12 to 36 hours after exercising. The muscles that help with posture and movement, such as those in the thighs, calves, and lower back, are usually the most affected. People might also feel tired, experience discomfort, and sometimes even vomit. Occasionally, there might be swelling, tenderness, or the skin over the muscles could change color, like turning purplish. Additionally, urine might take on a cola-like color due to a substance called myoglobin that comes from the damaged muscles.
How to Diagnose Exertional Rhabdomyolysis?
To diagnose this, doctors look for specific signs: muscle-related issues after exercise, high levels of a substance called CK within 12 to 36 hours (but not more than four days), and myoglobin in the blood or urine. However, myoglobin does not stay in the blood for long, so blood levels might seem normal after six hours. This makes blood tests less reliable for diagnosis. A urine test could show signs of blood even if there are no red blood cells present, which suggests myoglobin might be there instead.
The CK levels, a sign of muscle damage, go up within two to 12 hours after getting hurt, peak in one to three days, and then slowly go down by 39 percent each day. If the levels go down more slowly, it might mean there is still muscle damage happening. The higher the CK levels, the worse the muscle damage, but it is not a good way to tell if the kidneys are in danger. Generally, if the CK level is more than five times the usual limit, it is considered exertional rhabdomyolysis. However, some experts say that if the CK level is less than 50 times the limit, and the person does not feel sick, does not have myoglobin in the urine or kidney problems, then it might not be serious exertional rhabdomyolysis – it could be a normal response to exercise.
What Is the Treatment for Exertional Rhabdomyolysis?
If a doctor thinks the muscle problem is normal after exercising, they might suggest the person rest for 72 hours, avoid things that could cause this issue, and drink fluids. After resting, they will check the CK levels again. If the levels are back to being less than five times the normal limit, there is usually no need for more tests. But if the levels stay high for more than two weeks, it is a good idea to talk to an expert.
For those with serious exertional rhabdomyolysis, doctors might give fluids through a vein (IV) as soon as possible. The goal is to make sure the person pees a certain amount (200 to 400 cc) every hour for the first day, which might mean getting a lot of fluids at first.
The main goal of treatment is to stop the kidneys from getting hurt. If the CK levels keep going up, if the person is not peeing enough, or if they have problems with their blood being too acidic or having too much potassium, they might need to go to the intensive care unit (ICU) for dialysis. Doctors might also do a heart test (EKG) to check if the person's heart is affected because of the problems with the body's salts. If this has happened before, if the family has a history of this problem, or if the story does not match up (like if the exercise was not too intense), doctors might need to look into genetic reasons for this happening.
While checking the CK levels over time, if they suddenly go up again, it could mean there is a hidden problem called compartment syndrome. If the doctor thinks the rhabdomyolysis is serious and needs more treatment in the hospital, they should check if the person is at risk for acute kidney injury (ARF).
Conclusion
Exertional rhabdomyolysis is a condition where intense exercise can lead to muscle breakdown, potentially causing serious health issues, especially among athletes. Recognizing its symptoms, such as muscle pain, weakness, and dark urine, is vital for early intervention. Preventive measures like gradual training progression, hydration, and proper nutrition can mitigate risks. Timely medical attention and monitoring of CK levels are crucial to prevent kidney damage.
