31 - CVS pathology mcqs - 16 to 20

Question 16
A 21-year-old man has had increasing malaise over the past three weeks. On physical examination his vital signs show T 39.2 C, P 105/minute, RR 29/minute, and BP 80/40 mm Hg. The physician auscultates a loud systolic cardiac murmur. His lungs on auscultation have bibasilar crackles. Needle tracks are seen in his left antecubital fossa. He has splinter hemorrhages noted on fingernails, as well as painful erythematous nodules on palmar surfaces. A tender spleen tip is palpable. A chest radiograph shows pronounced pulmonary edema. Which of the following laboratory test findings is most likely to be present in this patient's peripheral blood?
A Creatine kinase-MB of 8% with a total CK 389 U/L
B Positive blood culture for Pseudomonas aeruginosa
C Total serum cholesterol of 374 mg/dL
D Blood urea nitrogen of 118 mg/dL
E Antinuclear antibody titer of 1:512
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(B) CORRECT. The history points to infectious endocarditis and acute congestive heart failure. Staphylococcus aureus and Pseudomonas aeruginosa are the most likely organisms to be found with a history of injection drug use.
(A) Incorrect. The CK-MB is typically elevated with ischemic heart disease, which would be unusual at his age.
(C) Incorrect. A cholesterol in this range could be seen with heterozygous familial hypercholesterolemia, which would be unlikely to manifest with ischemic heart disease at this age.
(D) Incorrect. His heart failure, if severe, could reduce cardiac output and lead to pre-renal azotemia if he survives.
(E) Incorrect. An autoimmune disease such as systemic lupus erythematosus can lead to non-infective endocarditis (Libman-Sacks endocarditis) in which there are small, non-destructive vegetations and no emboli.
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Question 17
A 2-year-old child has had failure to thrive for a year, becoming increasingly listless. On examination she is found to have a soft, rumbling systolic ejection murmur. An echocardiogram reveals a large membranous ventricular septal defect. Which of the following complications is she most likely to experience as an adult 2 decades later if this lesion remains untreated?
A Rib notching
B Mitral valve prolapse
C Pulmonary hypertension
D Myocardial infarction
E Cardiac tamponade
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(C) CORRECT. The left-to-right shunt eventually leads to pulmonary hypertension and reversal of the shunt (Eisenmenger complex).
(A) Incorrect. Rib notching is a rare finding that can be seen with post-ductal coarctation of the aorta.
(B) Incorrect. There is upward ballooning of a mitral leaflet with prolapse, due to attenuated chordae tendineae. (Note: a VSD sometimes becomes closed when a tricuspid leaflet adheres to the opening).
(D) Incorrect. Congenital heart disease is, in general, not a risk for ischemic heart disease.
(E) Incorrect. The defect is between the ventricular chambers and not connected to the pericardial sac.
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Question 18
A 42-year-old woman has noted increasing dyspnea for the past 6 years. On examination rales are auscultated in both lungs. She is afebrile. A chest radiograph shows an enlarged cardiac silhouette and bilateral pulmonary edema. Past history reveals that, as a child she suffered recurrent bouts of pharyngitis with group A beta hemolytic streptococcal infections. Which of the following cardiac valves are most likely to be abnormal in this woman?
A Aortic and tricuspid
B Mitral and pulmonic
C Aortic and pulmonic
D Tricuspid and pulmonic
E Mitral and aortic
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(E) CORRECT. She has chronic rheumatic valvulitis with scarring associated with rheumatic heart disease. If the tricuspid valve is involved, then the mitral and aortic are probably involved as well. The most common single valve involved is the mitral.
(A) Incorrect. The tricuspid valve is not often affected. When it is, the mitral and aortic valves are also affected, too.
(B) Incorrect. The mitral valve is the most common valve to be involved. The pulmonic valve is almost never involved.
(C) Incorrect. The aortic valve is the second most common valve to be involved. The pulmonic valve is almost never involved.
(D) Incorrect. The left side of the heart is involved far more commonly than the right with rheumatic heart disease.
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Question 19
A 25-year-old previously healthy woman has had worsening fatigue with dyspnea, palpitations, and fever over the past week. On physical examination her vital signs show T 38.9 C, P 103/minute, RR 30/minute, and BP 95/65 mm Hg. Her heart rate is slightly irregular. An ECG shows diffuse ST-T segment changes. A chest x-ray shows mild cardiomegaly. An echocardiogram shows slight mitral and tricuspid regurgitation but no valvular vegetations. Laboratory studies show a troponin I of 12 ng/mL. She recovers over the next two weeks with no apparent sequelae. Which of the following laboratory test findings best explains the underlying etiology for these events?
A Anti-streptolysin O titer of 1:512
B Total serum cholesterol of 537 mg/dL
C Coxsackie B serologic titer of 1:160
D Blood culture positive for Streptococcus, viridans group
E ANCA titer of 1:80
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(C) CORRECT. She has findings that suggest myocarditis, which can have features of cardiomyopathy. One of the most likely organisms is Coxsackie B virus.
(A) Incorrect. An elevation of the ASO titer suggests a recent streptococcal infection that might be associated with rheumatic fever. The infection, typically a pharyngitis, is gone by the time the ASO titer is elevated and the cardiac lesions, including myocarditis, are present.
(B) Incorrect. This level of cholesterol could be associated with familial hypercholesterolemia and risk for ischemic heart disease, even at a young age. This does not explain the fever.
(D) Incorrect. Viridans group of streptococcus is best known as a causative organism for subacute endocarditis, and valvular vegetations are present with forms of infective endocarditis.
(E) Incorrect. An antineutrophil cytoplasmic autoantibody can be detected with vasculitis, typically polyarteritis nodosa or Wegener granulomatosis.
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Question 20
A 44-year-old man has had no major medical problems throughout his life, except for arthritis pain involving all extremities for the past 5 years. He has had worsening orthopnea and pedal edema in the past 6 months. There is no chest pain. On examination he is afebrile. A chest radiograph shows cardiomegaly with both enlarged left and right heart borders, along with pulmonary edema. Laboratory studies show serum sodium 139 mmol/L, potassium 4.3 mmol/L, chloride 99 mmol/L, CO2 25 mmol/L, urea nitrogen 18 mg/dL, creatinine 1.3 mg/dL, and glucose 167 mg/dL. Which of the following additional laboratory test findings is he most likely to have?
A Spherocytes on his peripheral blood smear
B Hemoglobin of 10.7 g/dL with MCV of 72 fL
C Erythrocyte sedimentation rate of 79 mm/Hr
D Anti-centromere antibody titer of 1:320
E Serum ferritin of 8700 ng/mL
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(E) CORRECT. He has findings of a cardiomyopathy with right and left heart failure. Hereditary hemochromatosis can produce iron deposition in visceral organs, including the heart. The serum ferritin is a good indicator of body iron stores. Hemochromatosis affects the pancreas as well, leading to diabetes mellitus. Deposition of iron in joints leads to arthritis. The onset of disease is typically in the 40's in males and 60's in females.
(A) Incorrect. Spherocytosis can lead to a mild hemolytic anemia that stresses the heart somewhat to produce mild hypertrophy.
(B) Incorrect. An iron deficiency anemia in an adult could chronically lead to increased cardiac output. If severe enough, there could be a high-output cardiac failure. The heart will tend to enlarge somewhat. This does not explain his arthritis or hyperglycemia, though.
(C) Incorrect. An increased sed rate is a non-specific indicator of inflammation somewhere in the body.
(D) Incorrect. Anti-centromere antibody can be detected with sclerodema, which can produce cardiac findings resembling a cardiomyopathy, but hyperglycemia and joint problems are not part of scleroderma.
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