An 18-year-old man suddenly collapses during a high school soccer game. There was no preceding collision or trauma. Immediate resuscitation is initiated but he dies before the emergency medical service arrives. The patient had recently experienced occasional exertion-related chest discomfort and dyspnea. Otherwise, he had no significant medical history. He took no medications and did not use tobacco, alcohol, or illicit drugs. Which of the following is most likely to be seen on autopsy?

Question

An 18-year-old man suddenly collapses during a high school soccer game.  There was no preceding collision or trauma.  Immediate resuscitation is initiated but he dies before the emergency medical service arrives.  The patient had recently experienced occasional exertion-related chest discomfort and dyspnea.  Otherwise, he had no significant medical history.  He took no medications and did not use tobacco, alcohol, or illicit drugs.  Which of the following is most likely to be seen on autopsy?

Quizplus · Accepted Answer

Sudden cardiac death (SCD) is most often precipitated by cardiac arrhythmia (eg, ventricular tachycardia/fibrillation) that leads to markedly decreased cardiac output and impaired coronary artery perfusion. In older adults (eg, age ≥35), myocardial ischemia due to atherosclerotic coronary artery disease (Choice A) is the most common cause of SCD. However, young adults who experience SCD usually have underlying structural heart disease; hypertrophic cardiomyopathy (HCM) is one of the most common precipitating diseases. Most patients with HCM are asymptomatic, but some may experience exertional dyspnea, fatigue, chest pain, or syncope. HCM is an autosomal dominant genetic disorder caused by mutation of one of several genes coding for cardiac sarcomere proteins. It is characterized by cardiomyocyte hypertrophy (predominantly affecting the septum) and myofiber disarray consisting of an irregular arrangement of abnormally shaped cardiomyocytes and increased interstitial fibrosis. This structural disarray leads to conduction abnormalities that predispose to ventricular arrhythmia and SCD. (Choice B) Dilated cardiac chambers and thin ventricular walls are consistent with dilated cardiomyopathy (DCM), a less common cause of SCD than HCM in young adults. A patient with DCM would likely have symptoms of heart failure (eg, lower extremity swelling, dyspnea, orthopnea) and would not be capable of participating in strenuous activities such as soccer. (Choice C) Extracellular deposits and stiff ventricular walls suggest restrictive cardiomyopathy due to amyloidosis or hemochromatosis. Although restrictive cardiomyopathy can cause SCD, there is usually a preceding course of progressive and symptomatic heart failure. (Choice E) Thrombus at the bifurcation of the main pulmonary artery (ie, saddle pulmonary embolism) is a potential cause of SCD; however, a preceding history of exertion-related dyspnea and chest discomfort would not be expected. Educational objective: Hypertrophic cardiomyopathy is a common cause of sudden cardiac death (SCD) in young adults. Histologic features include cardiomyocyte hypertrophy and myofiber disarray with increased interstitial fibrosis. The structural disarray creates a substrate for ventricular arrhythmia (eg, ventricular tachycardia, ventricular fibrillation) that can lead to SCD. __________ References: Sudden deaths in young competitive athletes: analysis of 1866 deaths in the United States, 1980-2006. (http://www.ncbi.nlm.nih.gov/pubmed/19221222)

An 18-Year-Old Man Suddenly Collapses During a High School Soccer