TABLE IV-114 Risk Factors for Active Tuberculosis Among Persons Who Have Been Infected With Tubercle Bacilli 11 page

V-53 and V-54. The answers are С and A, respectively.(Chap. 236) This patient has a coarctation of the aorta presenting with marked hypertension proximal to the lesion. The narrowing most commonly occurs distal to the origin of the left subclavian artery, explaining the equal pressure in the arms and reduced pressure in the legs. Coarctations account for approximately 7% of congenital cardiac abnormalities, occur more frequently (2x) in men than in women, and are associated with gonadal dysgenesis and bicuspid aortic valves. Adults will present with hypertension, manifestations of hypertension in the upper body (headache, epistaxis), or leg claudication. Physical examination reveals diminished and/or delayed lower extremity pulses, enlarged collateral vessels in the upper body, or reduced development of the lower extremities. Cardiac examination may reveal findings consistent with left ventricular (LV) hypertrophy. There may be no murmur, a midsystolic murmur over the anterior chest and back, or an aortic murmur with a bicuspid valve. Transthoracic (suprasternal/parasternal) or transesophageal echocardiography, contrast CT or MRI of the thorax, or cardiac catheterization can be diagnostic. MRI of the head would not be useful diagnostically. The clinical picture is not consistent with renal artery stenosis, pheochromocytoma, carcinoid, or Cushing's syndrome.

V-55. The answer is E.(Chap. 237) Mitral stenosis is one of the leading causes of pulmonary hypertension worldwide, particularly in developing countries where the treatment of streptococcal disease is less available. The primary determinants of pulmonary artery pressure are left atrial pressure, pulmonary vascular resistance, and flow. Mitral stenosis may restrict flow from the left atrium to the left ventricle, and thus is associated with left atrial hypertension and passive pulmonary hypertension (due to back pressure). Additionally, the pulmonary vascular bed may actively vasoconstrict in response to left atrial hypertension. Additional contributors to pulmonary hypertension in mitral stenosis include interstitial edema in the walls of small pulmonary vessels and, in end-stage disease, obliterative changes in the pulmonary vascular bed as may be seen in some forms of pulmonary arterial hypertension. Pulmonary hypertension related to mitral stenosis is generally reversible with correction of the valvular lesion.

V-56 and V-57. The answers are A and E, respectively.(Chap. 237) The patient presents with a relatively stable ST elevation myocardial infarction. He likely has extensive necrosis given the duration of symptoms and ECG findings, and thus is at risk for complication of myocardial infarction. In this case, his acute dyspnea, worsening oxygenation, and asymmetric edema on chest radiograph all point to acute mitral regurgitation from papillary muscle rupture. An allergic reaction to a medication should not cause severe hypoxemia. It may cause rather mild reversible hypoxemia, and should not cause an abnormal chest radiograph. The classic finding of acute mitral regurgitation is a relatively loud systolic murmur heard best at the apex and radiating to the axilla. The murmur is described as having a "cooing" or "seagull-like" quality. A fourth heart sound is also common. Management of acute mitral regurgitation includes afterload and preload reduction, if possible, often with intravenous nitroprusside.

If patients are unable to tolerate medical interventions to achieve this because of systemic hypotension, as in this patient, an intraaortic balloon pump is indicated. Albuterol and methylprednisolone are indicated for acute bronchospasm due to primary airways disease, but would not be helpful for the management of cardiogenic shock.

V-58. The answer is C.(Chap. 237) The patient has classic physical examination findings for mitral valve prolapse with a midsystolic click that may or may not be associated with a systolic murmur. Mitral valve prolapse is generally thought to be a benign lesion, with most patients never developing symptoms during their lifetimes. While many patients with heritable connective tissue disorders such as Marfan's syndrome have mitral valve prolapse, in the majority of cases, a cause is not identified. Mitral valve prolapse may be seen on echocardiography by systolic displacement of the mitral valve leaflets by at least 2 mm into the left atrium Doppler imaging may also be helpful to define the condition. Because the lesion is generally benign, endocarditis prophylaxis is generally not indicated unless the patient has a prior history of endocarditis. Although some patients develop atrial arrhythmias in conjunction with mitral valve prolapse, prophylactic antiplatelet agents or warfarin are not recommended, as most patients do not have complications.

V-59. The answer is B.(Chap. 237) The patient has aortic stenosis that presented late in life. While bicuspid aortic valve underlies nearly half of all aortic stenosis cases, this lesion typically presents earlier in life, and only 40% of patients greater than 70 years old with aortic stenosis who undergo surgery have a bicuspid valve. Rheumatic heart disease may cause aortic stenosis, but almost invariably mitral stenosis is also present. Underlying connective tissue disease is not known to be associated. Modern research on the development of aortic stenosis has shown that several traditional atherosclerotic risk factors are present such as diabetes mellitus, smoking, chronic kidney disease, and the metabolic syndrome. Polymorphisms of the vitamin D receptor have also been demonstrated in patients with symptomatic aortic stenosis.

V-60. The answer is C.(Chap. 237) Exertional syncope is a late finding in aortic stenosis (AS) and portends a poor prognosis. Patients with this symptom or with angina pectoris have an average time to death of 3 years. Patients with dyspnea have 2 years, and patients with heart failure have an average time to death of 1.5-2 years. Because of these data, patients with severe AS and symptoms should be strongly considered for surgical therapy.

V-61. The answer is A.(Chap. 237) Patients with severe aortic regurgitation will have a "water-hammer" pulse that collapses suddenly as arterial pressure rapidly falls during late systole and diastole, a so-called Corrigan's pulse. Capillary pulsations seen in the nail bed in severe aortic regurgitation are named Quincke's pulse. Traube's sign, or a pistol shot sound, may be heard over the femoral arteries and Duroziez's sign, with a to-and-fro murmur over the femoral artery, have also been described. Pulsus parvus et tardus is found in severe aortic stenosis. Pulsus bigeminus occurs when there is a shorter interval after a normal beat with a following low volume pulse, often with a premature ventricular beat. Pulsus paradoxus has been described with pericardial tamponade or severe obstructive lung disease. Pulsus alternans is alternating large and small volume pulses seen in severe heart failure.

V-62 and V-63. The answers are С and C, respectively.(Chap. 237) The patient presents with heart failure during her second trimester from a region with high rates of rheumatic fever. She is therefore at

risk for rheumatic mitral stenosis, which often presents during the second trimester of pregnancy as the cardiac output must rise to accommodate the fetus and intravascular volume expands substantially. The stenotic valve cannot accommodate the increased flow demands of pregnancy, and congestive heart failure ensues with secondary pulmonary venous hypertension. The patient has evidence of heart failure on examination with pulmonary hypertension. Her diastolic rumble is characteristic of mitral stenosis. Finally, hemoptysis is a not infrequent finding in severe mitral stenosis and may be due to the rupture of pulmonary-bronchial venous connections secondary to pulmonary venous hypertension. Occasionally, pink frothy sputum can be found in patients with frank alveolar hemorrhage related to elevated pulmonary capillary pressure. Mitral stenosis is readily demonstrated by echocardiography. While right heart catheterization may demonstrate pulmonary hypertension and an elevated pulmonary capillary wedge pressure, the etiology of these findings will remain unknown without imaging of the left heart. Short-term management of mitral stenosis with heart failure should include diuretics. As the patient does not have left ventricular failure, ACE inhibition and digoxin are not likely to alleviate her symptoms. Occasionally, beta blockade may improve symptoms, particularly in patients with symptomatic atrial arrhythmias. Anticoagulation is not indicated in mitral stenosis alone unless atrial arrhythmias or pulmonary embolism is present. As infection does not underlie the patient's hemoptysis, further antibiotics will not be helpful.

V-64. The answer is D.(Chap. 237) Indications for surgical repair of mitral regurgitation are dependent on left-ventricular function, ventricular size, and the presence of sequelae of chronic mitral regurgitation. The experience of the surgeon and the likelihood of successful mitral valve repair are also important considerations. The management strategy for chronic severe mitral regurgitation depends on the presence of symptoms, left-ventricular function, left-ventricular dimensions, and the presence of complicating factors such as pulmonary hypertension and atrial fibrillation. With very depressed left-ventricular function (<30% or end-systolic dimension >55 mm), the risk of surgery increases, left-ventricular recovery is often incomplete, and long-term survival is reduced. However, since medical therapy offers little for these patients, surgical repair should be considered if there is a high likelihood of success (>90%). When ejection fraction is between 30% and 60%, and end-systolic dimension rises above 40 mm, surgical repair is indicated even in the absence of symptoms, owing to the excellent long-term results achieved in this group. Waiting for worsening left-ventricular function leads to irreversible left-ventricular remodeling. Pulmonary hypertension and atrial fibrillation are important to consider as markers for worsening regurgitation. For asymptomatic patients with normal left-ventricular function and dimensions, the presence of new pulmonary hypertension or atrial fibrillation in patients with normal ejection fraction and end-systolic dimensions are class Ha indications for mitral valve repair.

V-65. The answer is F.(Chap. 237) Tricuspid regurgitation is most commonly caused by dilation of the tricuspid annulus due to right-ventricular enlargement of any cause. Any cause of left-ventricular failure that results in right-ventricular failure may lead to tricuspid regurgitation. Congenital heart diseases or pulmonary arterial hypertension leading to right-ventricular failure will dilate the tricuspid annulus. Inferior wall infarction may involve the right ventricle. Rheumatic heart disease may involve the tricuspid valve, although less commonly than the mitral valve. Infective endocarditis, particularly in IV drug users, will infect the tricuspid valve, causing vegetations and regurgitation. Other causes of tricuspid regurgitation include carcinoid heart disease, endomyocardial fibrosis, congenital defects of the atrioventricular canal, and right-ventricular pacemakers.

V-66. The answer is A.(Chap. 237) Bioprosthetic valves are made from human, porcine, or bovine tissue. The major advantage of a bioprosthetic valve is the low incidence of thromboembolic phenomena, particularly 3 months after implantation. Although in the immediate postoperative period some anticoagulation may occur, after 3 months there is no further need for anticoagulation or monitoring. The downside is the natural history and longevity of the bioprosthetic valve. Bioprosthetic valves tend to degenerate mechanically. Approximately 50% will need replacement at 15 years. Therefore, these valves are useful in patients with contraindications to anticoagulation, such as elderly patients with comorbidities and younger patients who desire to become pregnant. Elderly people may also be spared the need for repeat surgery, as their life span may be shorter than the natural history of the bioprosthesis. Mechanical valves offer superior durability. Hemodynamic parameters are improved with double-disk valves compared with single-disk or ball-and-chain valves. However, thrombogenicity is high and chronic anticoagulation is mandatory. Younger patients with no contraindications to anticoagulation may be better served by mechanical valve replacement.

V-67. The answer is E.(Chap. 238) Many infectious etiologies have been associated with the development of inflammatory myocarditis including viral agents (coxsackie, adenovirus, HTV, hepatitis C) and parasitic agents, with Chagas disease or T. cruzi being most prominent, but also toxoplasmosis. Additionally, bacterial etiologies like diphtheria, spirochetal disease like Borrelia burgdorferi, rickettsial disease, and fungal infections have been associated.

V-68. The answer is C.(Chap. 238) Peripartum cardiomyopathy is a rare complication of pregnancy and can occur during the last trimester or within the first 6 months postpartum. Risk factors include advanced age, increased parity, twin pregnancy, malnutrition, use of tocolytic therapy for premature labor, and preeclampsia.

V-69. The answer is A.(Chap. 238) Beriberi heart disease is a dilated cardiomyopathy due to thiamine deficiency. While uncommon in developed countries, this condition still occurs in patients who derive most of their calories from alcohol and has been reported in teenagers who eat only highly processed foods. This condition involves systemic vasodilation with a very high cardiac output in its early stages. In advanced disease, a low-output state can occur. Thiamine repletion can lead to a complete recovery. Patient A has evidence of heart failure with systemic vasodilation and elevated cardiac output, as would be found in beriberi. Alternatively, patient В has normal hemodynamics. Patient С has evidence of low-output heart failure with systemic vasoconstriction. Patient D has elevated pulmonary arterial pressures with right heart failure in conjunction with normal pulmonary capillary wedge pressure, consistent with primary pulmonary vascular disease, e.g., pulmonary arterial hypertension. Patient E has low right heart filling pressures, with somewhat low cardiac output and elevated systemic vascular resistance, as might be found in hypovolemic shock.

V-70. The answer is E.(Chap. 238) Hypertrophic cardiomyopathy usually presents between age 20 and 40 years, with the most common symptom being dyspnea. Many patients are, however, asymptomatic and the only clue to the presence of this potentially deadly disease is physical examination. Physical examination will show a harsh systolic murmur heard best at the left lower sternal border arising from both the outflow tract turbulence during ventricular ejection and the often concomitant mitral regurgitation. Maneuvers that decrease ventricular volume such as Valsalva or moving from squatting to standing will enhance the murmur. Conversely, maneuvers that increase left ventricular volume will

decrease the murmur's intensity. These include hand grip and squatting. Having the patient lie with the left side down and leaning forward may make the friction rub of pericarditis more audible.

V-71. The answer is E.(Chap. 238) A common diagnostic dilemma is differentiating constrictive pericarditis from a restrictive cardiomyopathy. Elevated jugular venous pressure is almost universally present in both. Kussmaul's sign (increase or no change in jugular venous pressure with inspiration) can be seen in both conditions. Other signs of heart failure do not reliably distinguish the two conditions. In restrictive cardiomyopathy, the apical impulse is usually easier to palpate than in constrictive pericarditis, and mitral regurgitation is more common. These clinical signs, however, are not reliable to differentiate the two entities. In conjunction with clinical information and additional imaging studies of the left ventricle and pericardium, certain pathognomic findings increase diagnostic certainly. A thickened or calcified pericardium increases the likelihood of constrictive pericarditis. Conduction abnormalities are more common in infiltrating diseases of the myocardium In constrictive pericarditis, measurements of diastolic pressures will show equilibrium between the ventricles, while unequal pressures and/or isolated elevated left ventricular pressures are more consistent with restrictive cardiomyopathy. The classic "square root sign" during right heart catheterization (deep, sharp drop in right ventricular pressure in early diastole, followed by a plateau during which there is no further increase in right ventricular pressure) can be seen in both restrictive cardiomyopathy and constrictive pericarditis. The presence of a paraprotein abnormality (MGUS, myeloma, amyloid) makes restrictive cardiomyopathy more common.

V-72. The answer is D.(Chap. 238) Cardiac involvement is common in many of the neuromuscular diseases. The ECG pattern of Duchenne's muscular dystrophy is unique and consists of tall R waves in the right precordial leads with an R/S ratio greater than 1.0, often with deep Q waves in the limb and precordial leads. These patients often have a variety of supraventricular and ventricular arrhythmias, and are at risk for sudden death due to the intrinsic cardiomyopathy as well as the low ejection fraction. Implantable cardioverter defibrillators should be considered in the appropriate patient. Global left ventricular dysfunction is a common finding in dilated cardiomyopathies, whereas focal wall motion abnormalities and angina are more common if there is ischemic myocardium This patient is at risk for venous thromboembolism; however, chronic thromboembolism would not account for the severity of the left heart failure and would present with findings consistent with pulmonary hypertension. Amyotrophic lateral sclerosis is a disease of motor neurons and does not involve the heart. This patient would be young for that diagnosis. An advanced atrial septal defect would present with cyanosis and heart failure (Eisenmenger's physiology).

V-73. The answer is D.(Chap. 239) The patient has a classic presentation for acute pericarditis with constant or pleuritic chest pain, exacerbated by lying flat and alleviated by sitting forward. Serum biomarkers may show mild evidence of myocardial injury from myocardial inflammation, but are generally not substantially elevated. Friction rub is frequently present, has three components, and is best heard while the patient is upright and leaning forward. In the acute stages, ECG classically shows ST-segment elevation with upward concavity in two or three standard limb leads and V₂ through V₆ with

reciprocal changes in aVR. Convex curvature is more commonly found in acute myocardial infarction. PR depression may be found. After several days, the ST changes resolve and T waves become inverted. After weeks to months, the ECG returns to normal.

V-74. The answer is B.(Chap. 239) Pulsus paradoxus is an exaggeration of the normal phenomenon in which systolic blood pressure declines 10 mmHg or less with inspiration. Pulsus paradoxus is typically seen in patients with pericardial tamponade and in patients with severe obstructive lung disease (COPD, asthma). In pulsus paradoxus due to pericardial tamponade, the inspiratory systolic blood pressure decline is greater due to the tight incompressible pericardial sac. The right ventricle distends with inspiration, compressing the left ventricle and resulting in decreased systolic pulse pressure in the systemic circulation. In severe obstructive lung disease, the inspiratory decline of systolic blood pressure may be due to the markedly negative pleural pressure either causing left ventricular compression (due to increased RV venous return) or increased LV impedance to ejection (increased afterload).

V-75. The answer is C.(Chap. 239) Beck's triad can be used to alert clinicians to the potential presence of cardiac tamponade. The principal features are hypotension, muffled or absent heart sounds, and elevated neck veins, often with prominent x-descent and absent y-descent. These are due to the failure of ventricular filling and limited cardiac output. Kussmaul's sign is seen in restrictive cardiomyopathy and pericardial constriction, not tamponade. Friction rub may be seen in any condition associated with pericardial inflammation.

V-76. The answer is D.(Chap. 239) This patient's presentation and physical examination are most consistent with the diagnosis of constrictive pericarditis. The most common cause of constrictive pericarditis worldwide is tuberculosis, but given the low incidence of tuberculosis in the United States, constrictive pericarditis is a rare condition in this country. With the increasing ability to cure Hodgkin's disease with mediastinal irradiation, many cases of constrictive pericarditis in the United States involve patients who received curative radiation therapy 10-20 years prior. These patients are also at risk for premature coronary artery disease. Risks for these complications include dose of radiation and radiation windows that include the heart. Other rare causes of constrictive pericarditis are recurrent acute pericarditis, hemorrhagic pericarditis, prior cardiac surgery, mediastinal irradiation, chronic infection, and neoplastic disease. Physiologically, constrictive pericarditis is characterized by the inability of the ventricles to fill because of the noncompliant pericardium. In early diastole, the ventricles fill rapidly, but filling stops abruptly when the elastic limit of the pericardium is reached. Clinically, patients present with generalized malaise, cachexia, and anasarca. Exertional dyspnea is common, and orthopnea is generally mild. Ascites and hepatomegaly occur because of increased venous pressure. In rare cases, cirrhosis may develop from chronic congestive hepatopathy. The jugular venous pressure is elevated, and the neck veins fail to collapse on inspiration (Kussmaul's sign). Heart sounds may be muffled. A pericardial knock is frequently heard. This is a third heart sound that occurs 0.09-0.12 seconds after aortic valve closure at the cardiac apex. Right heart catheterization would show the "square root sign" characterized by an abrupt y-descent followed by a gradual rise in ventricular pressure. This finding, however, is not pathognomonic of constrictive pericarditis and can be seen in restrictive cardiomyopathy of any cause. Echocardiogram shows a thickened pericardium, dilatation of the inferior vena cava and hepatic veins, and an abrupt cessation of ventricular filling in early diastole. Pericardial resection is the only definitive treatment of constrictive pericarditis. Diuresis and sodium restriction are useful in managing volume status preoperatively, and paracentesis may be necessary. Operative mortality ranges from 5-10%. Underlying cardiac function is normal; thus, cardiac transplantation is not indicated. Pericardiocentesis is indicated for the diagnostic removal of pericardial fluid and cardiac tamponade, which is not present on the patient's echocardiogram. Mitral

valve stenosis may present similarly with anasarca, congestive hepatic failure, and ascites. However, pulmonary edema and pleural effusions are also common. Examination would be expected to demonstrate a diastolic murmur, and echocardiogram should show a normal pericardium and a thickened immobile mitral valve. Mitral valve replacement would be indicated if mitral stenosis were the cause of the patient's symptoms.

V-77. The answer is C.(Chap. 240) Blunt, nonpenetrating trauma such as that described here can result in commotio cordis, which occurs when the trauma impacts the heart during the susceptible phase of repolarization just before the peak of the T wave and results in ventricular fibrillation. This syndrome is most common in young athletes who are playing hockey, football, baseball, or lacrosse, for example. Treatment is prompt defibrillation. While aortic rupture, myocardial rupture with cardiac tamponade, and tension pneumothorax may occur with chest wall trauma, their presentation should be less immediate after the trauma. Hypertrophic cardiomyopathy may present with sudden cardiac death, as in this case, but the preceding chest trauma makes commotio cordis more likely.

V-78. The answer is E.(Chap. 247) The patient presents with prehypertension, as evidenced by systolic blood pressure of 120-139 mmHg or diastolic blood pressure of 80-89 mmHg. Although at this blood pressure medication therapy is not indicated, the MRFIT trial clearly showed a graded influence of both systolic and diastolic blood pressure on cardiovascular mortality including down to within normal range at 120 mmHg systolic. Thus, lifestyle modification is in order for the patient described here. Alcohol consumption is recommended to be two or fewer drinks per day for men and one drink or less per day for women. NaCl consumption of less than 6 g per day has been shown to reduce blood pressure in patients with established hypertension and in certain ethnic groups. To reduce blood pressure, regular moderate to intense aerobic activity for 30 minutes 6-7 days per week is recommended. Finally, a weight loss of 9.2 kg has been shown to drop blood pressure on average 6/3 mmHg.

V-79. The answer is C.(Chap. 247) Several factors have been shown to confer an increased risk of complications from hypertension. In the patient described here there is only one: ongoing tobacco use. Epidemiologic factors that have poorer prognosis include African-American race, male sex, and onset of hypertension in youth. In addition, comorbid factors that independently increase the risk of atherosclerosis worsen the prognosis in patients with hypertension. These factors include hypercholesterolemia, obesity, diabetes mellitus, and tobacco use. Physical and laboratory examination showing evidence of end organ damage also may portend a poorer prognosis. This includes evidence of retinal damage or hypertensive heart disease with cardiac enlargement or congestive heart failure. Furthermore, electrocardiographic evidence of ischemia or left ventricular strain but not left ventricular hypertrophy alone may predict worse outcomes. A family history of hypertensive complications does not worsen the prognosis if diastolic blood pressure is maintained at less than 110 mmHg.

V-80 andV-81. The answers are D and E, respectively.(Chap. 247) This patient presents at a young age with hypertension that is difficult to control, raising the question of secondary causes of hypertension. The most likely diagnosis in this patient is primary hyperaldosteronism, also known as Conn's syndrome. The patient has no physical features that suggest congenital adrenal hyperplasia or Cushing's syndrome. In addition, there is no glucose intolerance, as is commonly seen in Cushing's syndrome. The lack of episodic symptoms and the labile hypertension make pheochromocytoma unlikely. The findings of hypokalemia and metabolic alkalosis in the presence of difficult to control

hypertension yield the likely diagnosis of Conn's syndrome. Diagnosis of the disease can be difficult, but the preferred test is the plasma aldosterone/renin ratio. This test should be performed at 8 a.m., and a ratio above 30 to 50 is diagnostic of primary hyperaldosteronism. Caution should be taken in interpreting this test while the patient is on ACE inhibitor therapy, as ACE inhibitors can falsely elevate plasma renin activity. However, a plasma renin level that is undetectable or an elevated aldosterone/renin ratio in the presence of ACE inhibitor therapy is highly suggestive of primary hyperaldosteronism. Selective adrenal vein renin sampling may be performed after the diagnosis to help determine if the process is unilateral or bilateral. Although fibromuscular dysplasia is a common secondary cause of hypertension in young females, the presence of hypokalemia and metabolic alkalosis should suggest Conn's syndrome. Thus, magnetic resonance imaging of the renal arteries is unnecessary in this case. Measurement of 24-hour urine collection for potassium wasting and aldosterone secretion can be useful in the diagnosis of Conn's syndrome. The measurement of metanephrines or cortisol is not indicated.

V-82. The answer is B.(Chap. 248) For all patients with aortic dissection or hematoma, appropriate management includes reduction of shear stress with beta blockade and management of systemic hypertension to reduce tension on the dissection. However, emergent or urgent surgical therapy is indicated to patients with ascending aortic dissection and intramural hematomas (type A), and for complicated type В dissections (distal aorta). Complications that would warrant surgical intervention include propagation despite medical therapy, compromise of major branches, impending rupture, or continued pain. Thus, patient В has a distal dissection without evidence of complications and is the best candidate for medical therapy.

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