ABC | Volume 113, Nº2, August 2019

Case Report Exertional Rhabdomyolysis after Military Training Paralleled by Systemic Microvascular Dysfunction and Plasma Cytokine Increase: A Case Report Flavio Pereira, 1 Roger de Moraes, 2 Diogo Bavel, 1 A ndrea Rocha de Lorenzo, 1 E duardo Tibirica 1 Instituto Nacional de Cardiologia, 1 Rio de Janeiro, RJ – Brazil Universidade Estácio de Sá, 2 Rio de Janeiro, RJ – Brazil Mailing Address: Eduardo Tibirica • Instituto Nacional de Cardiologia - Rua da Laranjeiras, 374. Postal Code 22240-006, Rio de Janeiro, RJ – Brazil E-mail: etibi@uol.com.br Manuscript received June 16, 2018, revised manuscript September 06, 2018, accepted October 02, 2018 Keywords Rhabdomyolosis; Exercise; High-Intensity Interval Training; Myalgia; Cytokinase/blood; Creatine Kinase; Muscle, Skeletal. DOI: 10.5935/abc.20190165 Introduction Exertional rhabdomyolysis (ER) is diagnosed by the presence of intense muscular pain and sudden elevation of total plasma levels of the enzyme creatine kinase (CK), with or without myoglobinuria, 1 is closely associated with acute fatigue during exercise, 2 as well to the associated risk of acute renal injury, disseminated intravascular coagulation, cardiac arrhythmias, and electrolyte disturbances. 3 ER is highly prevalent in military training, particularly when performed in adverse climatic conditions, and many cases progress rapidly to acute, life-threatening renal failure. Moreover, it is estimated that about one-third of the cases of ER involve young male afro-descendants with low physical conditioning and extreme dehydration, occurring during summer military training courses. 4 In those situations, clinically healthy young subjects are submitted to strenuous exercise routines performed with combat uniforms and equipment and without adequate hydration possibilities. 4 The assessment of systemic endothelial microvascular reactivity has already been proven to be essential in the investigation of the pathophysiology of cardiovascular and metabolic diseases. 5 Additionally, the cutaneous microcirculation is now considered as an accessible and representative vascular bed for the assessment of systemic microcirculatory reactivity and density. 5 Considering that ER has already been shown to be related to decreased systemic endothelium-dependent vasodilation in the systemic circulation in the experimental setting, 6 it is reasonable to speculate that ER is also associated with significant systemic microcirculatory dysfunction. Moreover, there is no description in the specialized literature of the association of ER with microvascular endothelial function is humans. To the best of our knowledge, this is the first report on the detrimental outcomes of ER on endothelium-dependent systemic microvascular reactivity in human beings. Case report This case report is part of an observational research study without any intervention investigating the impact of special military training courses on cytokine profile and microvascular reactivity and the risk of developing ER in Brazilian Air Force military personnel who fully completed a five-week training period. This study was performed in accordance with the Declaration of Helsinki of 1975 (revised in 2013). The case report was approved by the Institutional Review Board (IRB) of the National Institute of Cardiology of the Ministry of Health, Rio de Janeiro, Brazil under protocol number # CAAE 49792515.6.0000.5272. The subject read and signed the informed consent form approved by the IRB. The patient was encouraged to share his perception of the clinical event that occurred during special military training with his colleagues. The patient was a 21-year-old and physically fit afro‑descendant Brazilian Air Force military trainee, who spontaneously applied for riot control military training. Themilitarywas considered tohave excellent aerobic endurance for his age range (20-29 years of age), using the Cooper run test (VO 2 max of 54.66 ml/kg/min). The patient presented no significant information on past personal or familial past medical history, including ER, and did not use any medication nor oral supplements during the period of military training. We tested the patient’s blood using hemoglobin electrophoresis, which showed the absence of hemoglobin S. Thus, we can consider that the patient did not present sickle-cell trait. He was diagnosed with ER on the second day of military training. He had performed running exercise in a combat uniform and transporting a 15 Kg kit including shield and gun, with a limited intake of water, and after being exposed to tear and pepper gases for 45 minutes. On the day before, he had run 2,400 meters in 12 minutes, and on both occasions, the running exercises were performed in warm (32 o C) and humid (86% relative humidity) conditions typical of the summer season in Rio de Janeiro, Brazil. The patient had vomiting, postural hypotension, myalgia and muscle weakness in the hip region and lower limbs and was promptly referred to the Air Force Hospital. He soon developed fever (41 o C axillary temperature), dark-colored urine, lower limb edema and gait difficulty. The evaluations of microvascular reactivity were performed one day before the beginning of military training and one day after hospital discharge, both in the morning between 8 and 12 AM and after a 12-hour fast. Microcirculatory tests were performed after a 20-minute rest in the supine position in a temperature-controlled room (23 ± 1°C). Microvascular reactivity was evaluated using a laser speckle contrast imaging 294