Working Diagnosis:
Exercise collapse associated with sickle cell trait, rhabdomyolysis, and metabolic derangements

Treatment:
He was admitted to the intensive care unit for monitoring, cooling, and aggressive resuscitation with crystalloid. He required multiple antihypertensives to manage his blood pressure.

Outcome:
Total CPK rose to greater than 80,000 units/L within the first 24 hours. Troponin normalized and lactate gradually trended downward. Sensorimotor deficits in the lower extremities gradually improved, but he required bilateral ASO braces and a walking device at discharge. He enrolled in an intensive outpatient rehabilitation program and continues to work towards his goal of returning to military service.

Author's Comments:
Sickle cell trait (SCT) is a risk factor for exertional collapse, rhabdomyolysis, and sudden death. It is of particular interest to the National Collegiate Athletic Association (NCAA) and Department of Defense as approximately 9% of African Americans in the United States have SCT; it is not disqualifying for athletic participation or military service. The risk of exertional rhabdomyolysis and sudden death can be reduced by proper hydration, heat acclimatization, and training with paced progressions. It is important to recognize the differing presentations of typical muscle cramps and microvascular occlusion in SCT. Prompt diagnosis and management of the collapsed individual with SCT has a significant impact on survival and outcome.

Editor's Comments:
The collapsed athlete with seizure-like activity must be assumed to be in cardiac arrest until proven otherwise. Activation of emergency medical services and application of an automated external defibrillator (AED) is critical. In a responsive patient, assessment of mental status can help to determine benign from life-threatening conditions. Altered mental status warrants concern for conditions such as hypoglycemia, exercise-associated hyponatremia, and exertional heat stroke (EHS). Rectal temperature is essential to the diagnosis of EHS for which immediate cooling is a life-saving intervention. In this patient, a temperature less than 104 degrees Fahrenheit argues against EHS, noting however that axillary temperature is not a reliable measurement. History of SCT coupled with the clinical presentation above points toward a diagnosis of exercise collapse associated with sickle cell trait (ECAST) with concerns for exertional sickling and fulminant rhabdomyolysis.

The pathophysiology related to collapse and sudden death in ECAST remains unclear. However, knowledge of SCT status as a risk factor for exercise-related death allows for appropriate education and implementation of preventive measures, in addition to prompt recognition and treatment which can be life-saving.

References:
Eichner ER. Exertional Rhabdomyolysis. Curr Sports Med Rep 2008;7(1):3-4.

O'Connor FG, Franzos MA, Nye N, Nelson DA, Shell D, et al. Summit on exercise collapse associated with sickle cell trait: finding the "way ahead." Curr Sports Med Rep 2021;20(1):47-56.

Szczepanik ME, Heled Y, Capacchione J, Campbell W, Deuster P, O'Connor FG. Exertional rhabdomyolysis. Curr Sports Med Rep 2014;13(2):113-119.

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