Exertional rhabdomyolysis as a result of strenuous military training

A systematic review of hormone levels, biomarkers of cellular injury and oxidative stress in multi-stressor military field training exercises

The fundamental objective of military field training exercises (FTX) is to prepare military personnel for real-life operations through simulated scenarios. These training sessions often require extreme physical efforts with prolonged, high-intensity exercises that can be combined with food restrictions and partial, or total, sleep deprivation. Such conditions can compromise an individual's physical performance and cause tissue damage, thus affecting their health. This study aimed to perform a systematic review of the literature to identify studies that measured the changes in hormone levels and biomarkers of cellular injury and oxidative stress resulting from FTX with high levels of energy expenditure combined with food and sleep restrictions. PubMed and the Scopus database were searched for articles that combined physical effort/food restriction/sleep deprivation with military training. The initial database search identified 158 articles that were reduced to 18 after confirmation. Significant reductions were reported in thyroid hormones, T3, T4, and anabolic hormones such as testosterone, insulin and androstenedione. An exception for GH was found, which increased throughout FTX. Less distinct responses to FTX were observed with cortisol, TSH and LH. The presence of biomarkers for cellular damage (myoglobin, TNF, and CRP) and increased immune response activities were also described. The scarcity of information on oxidative stress, analyses of cellular injury and biomarkers of inflammatory responses warrants the future study of these topics, which could be helpful in facilitating the safe and effective physical preparations of the members of the armed forces.

Perspectives on Exertional Rhabdomyolysis

Exertional (exercise-induced) rhabdomyolysis is a potentially life threatening condition that has been the subject of research, intense discussion, and media attention. The causes of rhabdomyolysis are numerous and can include direct muscle injury, unaccustomed exercise, ischemia, extreme temperatures, electrolyte abnormalities, endocrinologic conditions, genetic disorders, autoimmune disorders, infections, drugs, toxins, and venoms. The objective of this article is to review the literature on exertional rhabdomyolysis, identify precipitating factors, and examine the role of the dietary supplement creatine monohydrate. PubMed and SPORTDiscus databases were searched using the terms rhabdomyolysis, muscle damage, creatine, creatine supplementation, creatine monohydrate, and phosphocreatine. Additionally, the references of papers identified through this search were examined for relevant studies. A meta-analysis was not performed. Although the prevalence of rhabdomyolysis is low, instances still occur where exercise is improperly prescribed or used as punishment, or incomplete medical history is taken, and exertional rhabdomyolysis occurs. Creatine monohydrate does not appear to be a precipitating factor for exertional rhabdomyolysis. Healthcare professionals should be able to recognize the basic signs of exertional rhabdomyolysis so prompt treatment can be administered. For the risk of rhabdomyolysis to remain low, exercise testing and prescription must be properly conducted based on professional standards.

Exercise-induced rhabdomyolysis mechanisms and prevention: A literature review

Exercise-induced rhabdomyolysis (exRML), a pathophysiological condition of skeletal muscle cell damage that may cause acute renal failure and in some cases death. Increased Ca²⁺ level in cells along with functional degradation of cell signaling system and cell matrix have been suggested as the major pathological mechanisms associated with exRML. The onset of exRML may be exhibited in athletes as well as in general population. Previous studies have reported that possible causes of exRML were associated with excessive eccentric contractions in high temperature, abnormal electrolytes balance, and nutritional deficiencies possible genetic defects. However, the underlying mechanisms of exRML have not been clearly established among health professionals or sports medicine personnel. Therefore, we reviewed the possible mechanisms and correlated prevention of exRML, while providing useful and practical information for the athlete and general exercising population.

Genetic polymorphisms associated with exertional rhabdomyolysis

Exertional rhabdomyolysis (ER) occurs in young, otherwise healthy, individuals principally during strenuous exercise, athletic, and military training. Although many risk factors have been offered, it is unclear why some individuals develop ER when participating in comparable levels of physical exertion under identical environmental conditions and others do not. This study investigated possible genetic polymorphisms that might help explain ER. DNA samples derived from a laboratory-based study of persons who had never experienced an episode of ER (controls) and clinical ER cases referred for testing over the past several years were analyzed for single nucleotide polymorphisms (SNPs) in candidate genes. These included angiotensin I converting enzyme (ACE), α-actinin-3 (ACTN3), creatine kinase muscle isoform (CKMM), heat shock protein A1B (HSPA1B), interleukin 6 (IL6), myosin light chain kinase (MYLK), adenosine monophosphate deaminase 1 (AMPD1), and sickle cell trait (HbS). Population included 134 controls and 47 ER cases. The majority of ER cases were men (n = 42/47, 89.4 %); the five women with ER were Caucasian. Eighteen African Americans (56.3 %) were ER cases. Three SNPs were associated with ER: CKMM Ncol, ACTN3 R577X, and MYLK C37885A. ER cases were 3.1 times more likely to have the GG genotype of CKMM (odds ratio/OR = 3.1, confidence interval/CI 1.33-7.10), 3.0 times for the XX genotype of ACTN3 SNP (OR = 2.97, CI 1.30-3.37), and 5.7 times for an A allele of MYLK (OR = 21.35, CI 2.60-12.30). All persons with HbS were also ER cases. Three distinct polymorphisms were associated with ER. Further work will be required to replicate these findings and determine the mechanism(s) whereby these variants might confer susceptibility.

Exertional rhabdomyolysis: a clinical review with a focus on genetic influences

In this review, the clinical and laboratory features of exertional rhabdomyolysis (ER) are discussed in detail, emphasizing the full clinical spectrum from physiological elevations of serum creatine kinase after exertion to life-threatening rhabdomyolysis with acute kidney injury and associated systemic complications. Laboratory markers used to diagnose both ER and rhabdomyolysis are very sensitive, but not very specific, and imperfectly distinguish "subclinical" or asymptomatic from severe, life-threatening illness. However, genetic factors, both recognized and yet to be discovered, likely influence this diverse clinical spectrum of disease and response to exercise. Genetic mutations causative for McArdle disease, carnitine palmitoyl transferase deficiency 2, myoadenylate deaminase deficiency, and malignant hyperthermia have all been associated with ER. Polymorphic variations in the myosin light chain kinase, α-actin 3, creatine kinase-muscle isoform, angiotensin I-converting enzyme, heat shock protein, and interleukin-6 genes have also been associated with either ER or exercise-induced serum creatine kinase elevations typical of ER. The prognosis for ER is significantly better than that for other etiologies of rhabdomyolysis, but the risk of recurrence after an initial episode is unknown. Guidelines for management are provided.

Rhabdomyolysis in the US Active Duty Army, 2004-2006

PURPOSE

Rhabdomyolysis (RM) is a skeletal muscle disorder resulting in severe cellular injury caused by vigorous physical activity and other systemic etiologies. RM is associated with significant morbidity, such as acute renal failure, and can be fatal. RM that occurs in the US Active Duty Army (ADA) results in time lost from training, deployment, and combat. We sought to systemically describe the epidemiology of ADA clinical RM by quantifying RM in terms of absolute numbers, examine rate trends, and identify soldiers at elevated risk.

METHODS

We used data from the Total Army Injury and Health Outcomes Database to calculate yearly RM rates in the overall ADA, as well as adjusted RM rates within soldier subpopulations for 2003-2006.

RESULTS

During this period, the absolute numbers of clinically diagnosed ADA RM ranged between 382 and 419 cases per year. Annual rates were 7-8 per 10,000, which is 300%-400% higher than the estimated US civilian population (2 per 10,000). In soldiers with a history of a prior heat injury, RM rates climbed to 52-86 per 10,000, a 7- to 11-fold increase. Increased RM rates were seen in soldiers who are male, African American, younger, less educated, and with a shorter length of service. Approximately 8% of yearly ADA RM cases resulted in acute renal failure, an estimate lower than that for the US civilian population.

CONCLUSIONS

Our findings suggest that rates of RM are higher in the ADA than in the US civilian population. Rates remained fairly stable; however, relative to other ADA soldiers, those with prior heat injury, who are African American, or who have a length of service of less than 90 d are at the highest risk for RM development.

Rhabdomyolysis in a collegiate football player

Rhabdomyolysis is a serious, potentially life threatening condition that can develop unexpectedly under supervised training conditions. Here we present a case of exertional rhabdomyolysis occurring in a healthy, fit 18-year-old placekicker following a supervised practice session led by the team's strength and conditioning coach. The day after this session, the player experienced extreme pain and dark urine and sought treatment at a local emergency department. Hospitalization resulted in a diagnosis of rhabdomyolysis based on myoglobinuria, muscle pain, and extremely elevated circulating creatine kinase values (>130,000 IU x L(-1)). Following eight days of hospitalization with intravenous fluids, the patient recovered without complications. This case illustrates that rhabdomyolysis can occur after strenuous exercise in the absence of dehydration in otherwise conditioned and healthy athletes.

Case Report of Exertional Rhabdomyolysis in a 12-Year-Old Boy

INTRODUCTION

Exertional rhabdomyolysis has been well characterized, and many case reports exist. No cases of exertional rhabdomyolysis in young healthy children (preteen) have been published.

CASE SUMMARY

Reviewed were the medical records of a 12-yr-old boy who participated in an indoor physical education class where excessive (>250) repetitive squat jumps were performed as punishment for talking in class. The boy, who reported intense muscle soreness in the thighs and dark urine 2 d postexercise, was brought to the emergency room by his parent. His serum creatine kinase (CK) was 92,115 U.L(-1) and urinalysis indicated the presence of blood and protein. He was transferred to another hospital that evening, admitted, and treated for 7 d. His serum CK rose to 244,006 U.L(-1) at 4 d postexercise.

CONCLUSION

Although exertional rhabdomyolysis is rare in young children, it can occur when excessive exercise is spurred on by an adult.

Pathophysiology and clinical presentations of rhabdomyolysis

Rhabdomyolysis has sparked new interest in recent years. The causes of rhabdomyolysis include drugs and other toxic agents, infections, physical exertion, crush injury, and muscle diseases (dystrophinopathies and metabolic myopathies). Prompt identification of the pathophysiological mechanism is the key to rapid control of the acute episode and to prevention of recurrences. In this update, we discuss the pathophysiological mechanisms and nosology of rhabdomyolysis, as well as diagnostic investigations, with special emphasis on noninvasive methods.

Adverse effects associated with physical restraint

OBJECTIVE

Restraint use is not monitored in the US, and only institutions that choose to do so collect statistics. In 1999, investigative journalists reported lethal consequences proximal to restraint use, making it a life-and-death matter that demands attention from professionals. This paper reviews the literature concerning actual and potential causes of deaths proximal to the use of physical restraint.

METHOD

Searching the electronic databases Medline, Cinahl, and PsycINFO, we reviewed the areas of forensics and pathology, nursing, cardiology, immunology, psychology, neurosciences, psychiatry, emergency medicine, and sports medicine.

CONCLUSIONS

Research is needed to provide clinicians with data on the risk factors and adverse effects associated with restraint use, as well as data on procedures that will lead to reduced use. Research is needed to determine what individual risk factors and combinations thereof contribute to injury and death.

Rhabdomyolysis following moderate exercise

Raised levels of serum muscle enzyme activity are frequently seen following unaccustomed or prolonged strenuous exercise. Following particularly severe exercise, muscle enzyme levels can be extremely high and are occasionally associated with rhabdomyolysis. A case of rhabdomyolysis following a moderate degree of accustomed exercise in a fit young soldier is reported and discussed.