Monday, January 14, 2008

34 - CVS pathology mcqs - 31 to 35


Question 31

A 27-year-old man has become severely ill with fever and malaise over the past three days. On examination in the emergency room, he has a temperature of 38.8 C, heart rate of 105/minute, respiratory rate of 24, and blood pressure of 80/40 mm Hg. A grade IV/VI diastolic murmur is audible. He has small hemorrhages visible on nail beds. His spleen tip is palpable. Which of the following diseases is most likely to predispose him to this acute illness?
A Hypoplastic left heart syndrome
B Rheumatic heart disease
C Cardiac amyloidosis
D Coronary atherosclerosis
E Hypertrophic cardiomyopathy
---------------------------------------------------------

(B) CORRECT. This acquired condition can lead to valvular deformity that predisposes to infective endocarditis.
(A) Incorrect. This congenital condition is incompatible with life.
(C) Incorrect. Amyloidosis involves the myocardium, not the valves and is not a risk for infective endocarditis. It is imperative when infective endocarditis is suspected that an organism be identified and appropriate antibiotic therapy given to reduce the high mortality rate of this condition.
(D) Incorrect. Ischemic heart disease involves the myocardium and not the valves directly, so infection is not a typical complication.
(E) Incorrect. Cardiomyopathies are myocardial diseases that can lead to cardiac enlargement and/or hypertrophy with heart failure, but are typically not complicated by infection.
----------------------------------------------------------

Question 32
An epidemiologic study of eating habits is performed. Dietary patterns of adult patients are recorded and compared to risk for cardiovascular diseases. It is observed that persons who eat bacon for breakfast are more likely to have cardiovascular disease that persons who eat oat bran cereal. Which of the following conditions is the "bacon" group most likely to have?
A Mitral annulus calcification
B Ventricular aneurysm
C Left atrial dilation
D Thoracic aortic aneurysm
E Aortic valve stenosis
-----------------------------------------------------------

(B) CORRECT. This is a complication of myocardial infarction. The incidence of MI is increased with an atherogenic diet.
(A) Incorrect. Mitral ring calcification is rarely of functional consequence and is not related to an atherogenic diet.
(C) Incorrect. This is typically a complication of mitral stenosis with rheumatic heart disease.
(D) Incorrect. Most thoracic aortic aneurysms are a consequence of cardiovascular syphilis.
(E) Incorrect. Most aortic stenosis is a complication of bicuspid valves or senile calcific aortic stenosis unrelated to diet.
------------------------------------------------------------

Question 33
A 74-year-old man has had increasingly severe headaches for 2 months, centered on the right. He sees his physician, who records vital signs of T 36.9 C, P 82/minute, RR 15/minute, and BP 130/85 mm Hg. There is a palpable tender cord-like area over his right temple. His heart rate is regular with no murmurs, gallops, or rubs. Pulses are equal and full in all extremities. A biopsy of this lesion is obtained, and microscopic examination reveals a muscular artery with luminal narrowing and medial inflammation with lymphocytes, macrophages, and occasional giant cells. He improves with a course of high-dose corticosteroid therapy. Which of the following laboratory test findings is most likely to be present with this man's disease?
A Erythrocyte sedimentation rate of 110 mm/hr
B Rheumatoid factor titer of 80 IU/mL
C HDL cholesterol of 15 mg/dL
D Anti-double stranded DNA titer of 1:1024
E pANCA titer of 1:160
-----------------------------------------------------------------

(A) CORRECT. These are classic findings for temporal arteritis, the most typical involvement with giant cell arteritis. Corticosteroid therapy typically produces a diminution in the symptoms. Biopsy of the artery can remove the offending site of inflammation and relieve symptoms (don't worry--there are collateral branches). Not treating this condition puts the patient at risk for involvement of other branches of the external carotid artery, the worst of which would be the ophthalmic branch. The elevation of the sed rate is way out of proportion to the extent and amount of inflammation in this one arterial segment.
(B) Incorrect. Rheumatoid arthritis is not typically associated with an arteritis.
(C) Incorrect. A low HDL cholesterol is a risk for atherosclerosis, but atherosclerosis does not produce significant arterial inflammation. Instead, clinical problems result from narrowing of the lumen.
(D) Incorrect. Anti-ds-DNA is very specific for systemic lupus erythematosus, a condition that can be associated with vasculitis caused by antigen-antibody complexes. Vasculitis with SLE is more widespread than giant cell arteritis and typically involves smaller arteries.
(E) Incorrect. Anti-neutrophil cytoplasmic autoantibody can be seen most often with polyarteritis nodosa or Wegener granulomatosis. The pANCA is somewhat more common with polyarteritis.
------------------------------------------------------------------

Question 34
A 17-year-old girl "blacks out" while out running for exercise one afternoon, as she has done for many years. She is taken to the emergency room, where a physical examination, chest radiograph, head CT scan, CBC, and chemistry panel are all normal. Over the next year, she develops mild dyspnea and fatigue. She experiences several episodes of near-syncope. After another syncopal episode, she is referred to a cardiologist who orders an EKG that shows changes of left ventricular hypertrophy and broad Q waves. An echocardiogram reveals left ventricular and septal hypertrophy, small left ventricle, and reduced septal excursion. The septum has a "ground glass" appearance. She then dies suddenly and unexpectedly. The microscopic appearance of the septum with trichrome stain reveals myofiber disarray. Which of the following is the most likely diagnosis?
A Rheumatic heart disease
B Viral myocarditis
C Systemic lupus erythematosus
D Hypertrophic cardiomyopathy
E Diabetes mellitus
---------------------------------------------------------------------

(D) CORRECT. Myofiber disarray is the key feature of hypertrophic cardiomyopathy, an uncommon condition. The abnormal myocardium can be the focus for development of arrhythmias.
(A) Incorrect. Rheumatic heart disease is best known for causing valvular deformities, most often of the mitral valve, but sometimes the mitral and aortic, or just the aortic valve, and rarely the tricuspid valve.
(B) Incorrect. A viral myocarditis can be the cause for sudden death, but there is myocyte necrosis with interstitial infiltrates of lymphocytes in all chambers.
(C) Incorrect. SLE is best known to cause a Libman-Sacks endocarditis. Pericarditis with effusions is also possible with autoimmune diseases.
(E) Incorrect. Patients with diabetes mellitus are more likely to develop severe coronary atherosclerosis and subsequent myocardial ischemic damage.
----------------------------------------------------------------------

Question 35
A 35-year-old previously healthy woman dies suddenly and unexpectedly. At autopsy, one of her cardiac valves demonstrates attenuation of the chordae tendineae, with rupture of one of the chordae. On microscopic examination, one of the mitral leaflets show myxomatous change. Which of the following is the most likely cause for her death?
A Carcinoid heart syndrome
B Mitral valve prolapse
C Rheumatic heart disease
D Infective endocarditis
E Acute myocardial infarction
-------------------------------------------------------------------

(B) CORRECT. The valve leaflet can balloon upward. This condition can be associated with Marfan's syndrome.
(A) Incorrect. There is endocardial sclerosis of the right ventricular endocardium with carcinoid heart syndrome.
(C) Incorrect. Acute rheumatic fever produces small verrucous valvular vegetations. Chronic rheumatic changes include thickening and shortening of chordae tendineae.
(D) Incorrect. The large friable vegetations of infective endocarditis can lead to valvular destruction.
(E) Incorrect. There may be valve prolapse, but from rupture of a papillary muscle.
-------------------------------------------------------------------

No comments:

Subscribe Now: Feed

You are visitor number

Visitors currently online