WBR0042

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Author PageAuthor::Gonzalo Romero (Reviewed by Rim Halaby)
Exam Type ExamType::USMLE Step 1
Main Category MainCategory::Pathology
Sub Category SubCategory::Cardiology
Prompt [[Prompt::A 21-year-old healthy male college student is playing in the soccer championship for his university when he suddenly falls on the ground while running. The player is unresponsive to athletic staff on the field. Emergency Medical Services arrive promptly, but CPR and resuscitation measures are unsuccessful. According to his family and friends, the patient has always been healthy and he has been playing soccer since high school. Autopsies are obtained in order to determine the cause of death. Which of the following cardiac macroscopic or microscopic changes is most likely present?]]
Answer A AnswerA::Symmetric left ventricular hypertrophy
Answer A Explanation [[AnswerAExp::Symmetric left ventricular hypertrophy is characteristically present in patients with increased afterload, such as aortic stenosis or hypertension. This leads to the increased synthesis of actin and myosin that are arranged in a "organized fashion". Ultimately, these patients develop diastolic dysfunction due to the inability of the heart to fill in with blood during diastole.]]
Answer B AnswerB::White appearance of the endocardium
Answer B Explanation [[AnswerBExp::A white appearance of the endocardium can be present in endocardial fibroelastosis, a rare restrictive cardiomyopathy present in young children less than 2 years old. It is caused by the excessive fibrosis of the endocardium that causes diastolic dysfunction. Shown below is an image depicting an autopsy of a heart affected with endocardial fibroelastosis.

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Answer C AnswerC::Cardiomyocyte hypertrophy in an organized fashion
Answer C Explanation [[AnswerCExp::Cardiomyocyte hypertrophy in an organized fashion is found among patients with increased afterload such as aortic stenosis or hypertension.]]
Answer D AnswerD::Prominent ventricular septum hypertrophy
Answer D Explanation [[AnswerDExp::Prominent ventricular septum hypertrophy is a characteristic finding of hypertrophic cardiomyopathy.]]
Answer E AnswerE::Fibrotic thickening of the endocardium and the valves of the right side of the heart
Answer E Explanation [[AnswerEExp::Fibrotic thickening of the endocardium and the valves of the right side of the heart is the macroscopic description of an endocardium affected by a carcinoid syndrome due to chronic serotonin exposure, which causes fibrosis of the tricuspid valve and pulmonary valve. Carcinoid syndrome occurs when the carcinoid tumor metastasizes to the liver, thereby bypassing the first-pass metabolism of the liver. These patients present with diarrhea, wheezing, telangiectasias, and flushing of the skin.]]
Right Answer RightAnswer::D
Explanation [[Explanation::This young athlete presents with sudden cardiac death during intense exercise due to ventricular arrhythmias, a typical clinical presentation of hypertrophic cardiomyopathy. Hypertrophic cardiomyopathy can be either autosomal dominant or idiopathic.
  1. Macroscopically the heart demonstrates hypertrophy more prominent in the ventricular septum, obstructing the outflow from the left ventricle. The ventricular cavity acquires a banana shape appearance.
  2. Histologically there are hypertrophied cardiomyocytes in disarray which alters the conduction system and subsequently predisposes to arrhythmias.

Educational Objective: Hypertrophic obstructive cardiomyopathy (HOCM) is a common cause of sudden death in young athletes during intense exercise. It is characterized by the presence of cardiac hypertrophy more prominent in the ventricular septum and hypertrophied cardiomyocytes in disarray.
References: First Aid 2014 page 290]]

Approved Approved::Yes
Keyword WBRKeyword::Cardiology, WBRKeyword::Pathology, WBRKeyword::Hypertrophic cardiomyopathy, WBRKeyword::HOCM, WBRKeyword::HCM, WBRKeyword::Ischemia, WBRKeyword::Sudden death, WBRKeyword::Cardiomyopathy
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