WBR258

Author	PageAuthor::Mahmoud Sakr M.D.
Exam Type	ExamType::USMLE Step 2 CK
Main Category	MainCategory::Internal medicine
Sub Category	SubCategory::Cardiovascular
Prompt	[[Prompt::43 y/o female presents to her primary care physician for routine health examination. She denies any complaints and walks 2 miles 3 times a week. Initial evaluation reveals a Blood pressure is 127/77 mm Hg, Pulse is 82 /min, RR 14, oxygen saturation of 99% on room air. Physical examination is unremarkable except for a midsystolic click on cardiac auscultation. Which of the following mechanisms is likely responsible for this physical finding;]]
Answer A	AnswerA::Rupture of a papillary muscle due to an ischemic event
Answer A Explanation	AnswerAExp::This answer would relate an ischemic event.
Answer B	AnswerB::Myxomatous degeneration of a heart valve
Answer B Explanation	AnswerBExp::Correct answer. Mitral valve prolapse is due to of myxomatous degeneration of the mitral valve leading to a floppy mitral valve.
Answer C	AnswerC::Congenital bicuspid anomaly of valvular leaflets
Answer C Explanation	AnswerCExp::usually an abnormality of the aortic valve.
Answer D	AnswerD::Lipid deposition and plaque formation in the arterial walls
Answer D Explanation	AnswerDExp::This answer relates to an atherosclerotic process
Answer E	AnswerE::Rheumatic heart disease
Answer E Explanation	[[AnswerEExp::Rheumatic fever is an inflammatory disease that occurs following a Streptococcus pyogenes infection, such as streptococcal pharyngitis. Chronic rheumatic heart disease (RHD) is characterized by repeated inflammation with fibrinous resolution. It presents with polyarthritis, Carditis, subcutaneous nodules, erythema marginatum, fever, leukocytosis, ECG may show features of heart block, such as a prolonged PR interval.]]
Right Answer	RightAnswer::B
Explanation	[[Explanation::Mitral valve prolapse (aka primary form of myxomatous degeneration of the mitral valve aka floppy mitral valve syndrome) is a valvular heart disease characterized by the displacement of an abnormally thickened mitral valve leaflet into the left atrium during systole. Upon auscultation of an individual with mitral valve prolapse, a mid-systolic click, followed by a late systolic murmur heard best at the apex is common. Echocardiography is the most useful method of diagnosing a prolapsed mitral valve. Two- and three-dimensional echocardiography are particularly valuable as they allow visualization of the mitral leaflets relative to the mitral annulus. This allows measurement of the leaflet thickness and their displacement relative to the annulus. Thickening of the mitral leaflets >5 mm and leaflet displacement >2 mm indicates classic mitral valve prolapse. Educational Objective: References: ]]
Approved	Approved::Yes
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