The physiological mechanisms of rhabdomyolysis is diverse, but they fall into two discrete categories: ATPase malfunction and mechanical destruction. Mechanical destruction is primarily caused by blunt force trauma and other mechanisms that directly destroy the cell. ATPase dysfunction is the primary mechanism of ER and is caused by a high need for ATP and not enough ATP production. This in turn leads to an ion inbalance in the cell, which leads to osmotic swelling and ultimately cell death. The resulting cell death leads to the cellular contents being expelled into the extracellular space where they make their way into the bloodstream. The two major proteins in the bloodstream that characterize rhabdomyolysis are creatine kinase and myoglobin. These proteins, particularly myoglobin, precipitate in the nephrons in the kidney, causing obstructions, and thus renal failure. If left untreated, rhabdomyolysis can be fatal.
There is a particularly high incidence of ER in military personnel due to sudden increases in exercise during bootcamp, especially in new recruits who do not have much exercise experience. However, rhabdomyolysis is a disqualifying factor for joining the military, so there is a need to prevent it from happening in the first place. Ways to do this are to implement adaptive training strategies instead of having recruits jump right in. Other ways are to make sure that recruits are drinking plenty of water before, during, and after working out, as dehydration increases one's chance of developing ER. More research still has to be done on this topic because not much is known as to why ER occurs when it does, but because it is so rare, it is hard to study. However, it is a completely preventable disorder, so more must be done to better know how to prevent it from occurring in vulnerable populations.
References
Khan F. Y. (2009). Rhabdomyolysis: a review of the literature. The Netherlands journal of medicine, 67(9), 272–283.
Mao, H. D., Li, X., Liu, S. Y., Xing, L., Zhao, J. B., Tan, Z. J., Sun, H. L., & Song, Q. (2021). Exertional rhabdomyolysis in newly enrolled cadets of a military academy. Muscle & nerve, 64(3), 336–341. https://doi-org.dml.regis.edu/10.1002/mus.27355
As you stated, this is a more difficult disorder to study due to its rare occurrence. You mentioned how there is a higher rate of ER in new military personnel that do not have much experience exercising and can be affected by ER. It is interesting to note how if you build up to these immense hours of physical exertion, muscle breakdown, and prolonged exposure to heat that your body can adapt (assuming proper hydration). In my life, I have been around many ultra-marathon runners and those that run in 24-hour races. Many people know preparation is important, but for them, a focus is often proper training ahead of time for exactly these dangers. You stated that more research needs to be done to see how we can better prevent this disorder. What would be your approach to help prevent this in vulnerable populations? I think you are on the right track as this may come to affect more people in the near future. For example, I found an article on PubMed that states: “The worldwide increase in temperature has resulted in a marked increase in heat waves that carries a markedly increased risk for morbidity and mortality” (Johnson et al., 2019). It later states how the kidney plays a role in protecting the body from heat-associated disease. In these populations, CKD is an epidemic in labor-intensive jobs in the heat and rhabdomyolysis is one of the causes. How can we do research that will benefit these populations long-term instead of just athletes and military members that may just have acute effects?
ReplyDeleteJohnson, R. J., Sánchez-Lozada, L. G., Newman, L. S., Lanaspa, M. A., Diaz, H. F., Lemery, J., Rodriguez-Iturbe, B., Tolan, D. R., Butler-Dawson, J., Sato, Y., Garcia, G., Hernando, A. A., & Roncal-Jimenez, C. A. (2019). Climate Change and the Kidney. Annals of nutrition & metabolism, 74 Suppl 3, 38–44. https://doi.org/10.1159/000500344