P0181 - Heart on Fire

Case: A 14 year old healthy male presents to the pediatric ED via EMS after becoming obtunded then collapsing during his first football practice of the summer. On arrival, vital signs showed temperature 107.8F, HR 180’s, BP 80/50 consistent with heat stroke and shock. He was diaphoretic with dry mucus membranes, bounding peripheral pulses, delayed capillary refill, without JVD or hepatomegaly. His labs were significant for multi-organ system dysfunction including AKI with rhabdomyolysis, liver injury, lactic acidosis and elevated troponin (2.34 ng/ml). After an initial GCS of 9, his mental status improved with IVF and aggressive cooling. However, his tachycardia (160’s) and hypotension (SBP 90’s) persisted despite 3.5L fluid resuscitation. A new systolic murmur, loudest at left sternal border, was noted on exam and cardiology was consulted as he was admitted to the PICU. His initial EKG showed sinus tachycardia, RAE, bifid p-wave notching (leads II, III, aVF), and biventricular hypertrophy with normal ST segments. Notably, he had never experienced symptoms like this before, nor has a history of syncope, palpitations, dyspnea, exercise intolerance, or chest pain during exercise. Family history is negative for CHD, arrhythmias, or sudden unexplained deaths. Prior to this incident, patient was a three-sport competitive athlete in football, wrestling and baseball attending an athletic magnet high school.
His initial echocardiogram showed asymmetric LVH and moderate hypertrophy of the interventricular septum with mildly depressed systolic function. After normalization of his labs and repeat echo demonstrated normal biventricular function, he was discharged from the hospital on a beta blocker given that underlying structural heart disease could not be ruled out. After a two-month period of activity restriction, cardiac MRI showed normal left ventricular systolic function with asymmetric septal hypertrophy (septal max thickness 1.8cm) and patchy fibrosis confirming the diagnosis of hypertrophic cardiomyopathy. Subsequent genetic testing was negative. He continued on long-term propranolol and an ICD was placed for ectopy (brief non-sustained ventricular tachycardia while hospitalized and isolated PVCs). After further discussion with his family using a risk-sharing approach, despite his increased risk for sudden cardiac death and knowing that the recommendations from both the 2011 ACCF/AHA Guidelines for HCM and 2015 AHA/ACC Statement on Eligibility for Competitive Athletes with Cardiovascular Disease advise against competitive football, he still plans to return to play.

Discussion: This is a rare case presentation of the leading cause of sudden cardiac death, hypertrophic cardiomyopathy, unmasked in a high school athlete critically ill with exertional heat stroke. It highlights the importance of investigating other causes of fluid-resistant shock and elevated troponin in a previously healthy adolescent presenting with heat-related illness. Additionally, the association between markers of cardiac injury and heat stroke has not been well characterized in the pediatric literature and warrants further investigation.