Atherosclerosis Thrombosis - Part 1

1. A 56-year-old has not received any medical care nor seen a physician for years. He reports reduced exercise tolerance over the past 5 years. On occasion in the past year he has noted chest pain after ascending a flight of stairs. He smokes 2 packs of cigarettes per day. He is found to have a blood pressure of 155/95 mm Hg. His body mass index is 30. Laboratory findings include a total serum cholesterol of 245 mg/dL with an HDL cholesterol that is 22 mg/dL. Which of the following vascular abnormalities is most likely to be his most serious health risk?

Hyperplastic arteriolosclerosis

Lymphedema

Medial calcific sclerosis

Atherosclerosis

Deep venous thrombosis

Plexiform arteriopathy

(D) CORRECT. He has multiple risk factors for atherosclerosis, including his weight, smoking, hypertension, and high total cholesterol with low 'good' HDL cholesterol. His findings suggest coronary artery disease.
(A) Incorrect. Hyperplastic arteriolosclerosis can accompany malignant hypertension, which he does not have.
(C) Incorrect. Medical calcific sclerosis is a benign form of arteriosclerosis that does not often contribute to significant disease. It does not involve coronary arteries.
(F) Incorrect. Plexiform arteriopathy is seen in peripheral pulmonary arteries with pulmonary hypertension.

Explanation

(D) CORRECT. He has multiple risk factors for atherosclerosis, including his weight, smoking, hypertension, and high total cholesterol with low 'good' HDL cholesterol. His findings suggest coronary artery disease.
(A) Incorrect. Hyperplastic arteriolosclerosis can accompany malignant hypertension, which he does not have.
(C) Incorrect. Medical calcific sclerosis is a benign form of arteriosclerosis that does not often contribute to significant disease. It does not involve coronary arteries.
(F) Incorrect. Plexiform arteriopathy is seen in peripheral pulmonary arteries with pulmonary hypertension.

2. An autopsy study reveals that evidence for atheroma formation can begin even in children. The gross appearances of the aortas are recorded and compared with microscopic findings of atheroma formation. Which of the following is most likely to be the first visible gross evidence for the formation of an atheroma?

Thrombus

Fatty streak

Calcification

Hemorrhage

Exudate

Ulceration

(B) CORRECT. This is the first sign. It is benign and reversible, but it may be the precursor to more severe plaques.
(C) Incorrect. Calcification is a complication of an atheroma.
(E) Incorrect. Lymphocytes and macrophages play a role in atherogenesis, but their numbers are relatively small.
(F) Incorrect. Ulceration of an atheromatous plaque is an advanced lesion, not an early lesion. Ulceration or fissuring of the plaque increases the likelihood for overlying thrombosis.

Explanation

(B) CORRECT. This is the first sign. It is benign and reversible, but it may be the precursor to more severe plaques.
(C) Incorrect. Calcification is a complication of an atheroma.
(E) Incorrect. Lymphocytes and macrophages play a role in atherogenesis, but their numbers are relatively small.
(F) Incorrect. Ulceration of an atheromatous plaque is an advanced lesion, not an early lesion. Ulceration or fissuring of the plaque increases the likelihood for overlying thrombosis.

3. A 55-year-old previously healthy woman is hospitalized for pneumonia. On the 10th hospital day she is found to have swelling and tenderness of her right leg, which apparently has developed over the past 48 hours. Raising the leg elicits pain. An ultrasound examination reveals findings suggestive of femoral vein thrombosis. Which of the following conditions is most likely to have contributed the most to the appearance of these findings?

Trousseau syndrome

Protein C deficiency

Prolonged immobilization

Pregnancy

Chronic alcoholism

Hypertension

(C) CORRECT. The immobilization would predispose to thrombosis of leg veins. This is the most common cause for deep venous thrombosis.
(A) Incorrect. The hypercoagulable state of Trousseau syndrome with an underlying malignancy such as an adenocarcinoma predisposes to venous thrombosis, but her prior healthy condition makes malignancy less likely.
(B) Incorrect. Protein C deficiency is associated with venous thrombosis, but the onset of the disease is typically much earlier in life.
(F) Incorrect. Systemic hypertension increases the risk for atherosclerosis, which increases the risk for thrombosis in the arterial system, such as the coronary arteries or carotid arteries.

Explanation

(C) CORRECT. The immobilization would predispose to thrombosis of leg veins. This is the most common cause for deep venous thrombosis.
(A) Incorrect. The hypercoagulable state of Trousseau syndrome with an underlying malignancy such as an adenocarcinoma predisposes to venous thrombosis, but her prior healthy condition makes malignancy less likely.
(B) Incorrect. Protein C deficiency is associated with venous thrombosis, but the onset of the disease is typically much earlier in life.
(F) Incorrect. Systemic hypertension increases the risk for atherosclerosis, which increases the risk for thrombosis in the arterial system, such as the coronary arteries or carotid arteries.

4. A 63-year-old man has had increasing exercise intolerance for the past 5 years so that he now becomes short of breath upon climbing a single flight of stairs. Laboratory studies have shown fasting blood glucose measurements from 145 to 210 mg/dL for the past 25 years, but he has not sought medical treatment. If he dies suddenly, which of the following is most likely to be the immediate cause of death?

Myocardial infarction

Nodular glomerulosclerosis

Cerebral hemorrhage

Hyperosmolar coma

Right lower leg gangrene

(A) CORRECT. This is the most common cause of death in persons with diabetes mellitus, because of the high prevalence of coronary atherosclerosis.
(B) Incorrect. Although renal failure is a common complication of diabetes, it is not the major cause of death.
(C) Incorrect. Cerebrovascular disease in diabetes is common but is not the major cause of death.
(D) Incorrect. This complication may be life-threatening, but it is not frequent.
(E) Incorrect. This complication is usually treated before secondary sepsis becomes life-threatening

Explanation

(A) CORRECT. This is the most common cause of death in persons with diabetes mellitus, because of the high prevalence of coronary atherosclerosis.
(B) Incorrect. Although renal failure is a common complication of diabetes, it is not the major cause of death.
(C) Incorrect. Cerebrovascular disease in diabetes is common but is not the major cause of death.
(D) Incorrect. This complication may be life-threatening, but it is not frequent.
(E) Incorrect. This complication is usually treated before secondary sepsis becomes life-threatening

5. A 25-year-old man experiences chest pain on exercise when he attempts to climb three flights of stairs. This pain is relieved by sublingual nitroglycerin. He is 178 cm tall and weighs 101 kg. Laboratory studies show a total serum cholesterol of 550 mg/dL with an HDL cholesterol component of 25 mg/dL. He is worried about these findings because his brother died of a myocardial infarction at age 34. Which of the following conditions is this man most likely to have?

Diabetes mellitus, type II

Malignant hypertension

Familial hypercholesterolemia

Cushing syndrome

Morbid obesity

C) CORRECT. The very high cholesterol with symptoms of coronary artery disease at such a young age, coupled with the family history, are all consistent with familial hypercholesterolemia. In most persons with hypercholessterolemia from multifactorial causes, including diet and exercise patterns, the cholesterol rarely exceeds 400 mg/dL.
(A) Incorrect. Type II diabetes mellitus is most often a disease of middle aged to older adults.
(B) Incorrect. Malignant hypertension may, on occasion, complicate longstanding hypertension that is associated with development of atherosclerosis, but this is usually a complication seen in middle aged to older adults.
(D) Incorrect. The hypercortisolism of Cushing syndrome tends to promote diabetes mellitus, but the underlying conditions that lead to Cushing syndrome are unlikely to allow a long enough survival to develop severe atherosclerosis.
(E) Incorrect. Morbid obesity is a risk for type II diabetes mellitus, and decades are required to develop complications of atherosclerosis. It is unlikely that the cholesterol would be this high.

Explanation

C) CORRECT. The very high cholesterol with symptoms of coronary artery disease at such a young age, coupled with the family history, are all consistent with familial hypercholesterolemia. In most persons with hypercholessterolemia from multifactorial causes, including diet and exercise patterns, the cholesterol rarely exceeds 400 mg/dL.
(A) Incorrect. Type II diabetes mellitus is most often a disease of middle aged to older adults.
(B) Incorrect. Malignant hypertension may, on occasion, complicate longstanding hypertension that is associated with development of atherosclerosis, but this is usually a complication seen in middle aged to older adults.
(D) Incorrect. The hypercortisolism of Cushing syndrome tends to promote diabetes mellitus, but the underlying conditions that lead to Cushing syndrome are unlikely to allow a long enough survival to develop severe atherosclerosis.
(E) Incorrect. Morbid obesity is a risk for type II diabetes mellitus, and decades are required to develop complications of atherosclerosis. It is unlikely that the cholesterol would be this high.

6. A 66-year-old woman has the sudden loss of movement on part of the left side of her body. She has smoked a pack of cigarettes a day for the past 45 years. She has vital signs including T 37.1 C, P 80/minute, RR 16/minute, and BP 160/100 mm Hg. A cerebral angiogram reveals occlusion of a branch of her middle cerebral artery. Laboratory findings include a hemoglobin A1C of 9%. Which of the following components of blood lipids is most important in contributing to her disease?

Chylomicrons

Lipoprotein lipase

Oxidized LDL

VLDL

HDL cholesterol

(C) CORRECT. She has had a 'stroke' which is most often a consequence of cerebral atherosclerosis or embolic disease from the heart as a consequence of ischemic heart disease from atherosclerosis. LDL brings cholesterol to arterial walls, and when increased LDL is present or when there is hypertension, smoking, and diabetes, there is more degradation of LDL to oxidized LDL which is taken up into arterial walls via scavenger receptors in macrophages to help form atheromas.
(B) Incorrect. Endothelial lipoprotein lipase splits off fatty acids that are then used as a substrate in other metabolic pathways and not in atheroma formation.
(D) Incorrect. Both adipose tissue and muscle are areas where VLDL is transformed to LDL, and this does not directly promote atherogenesis.

Explanation

(C) CORRECT. She has had a 'stroke' which is most often a consequence of cerebral atherosclerosis or embolic disease from the heart as a consequence of ischemic heart disease from atherosclerosis. LDL brings cholesterol to arterial walls, and when increased LDL is present or when there is hypertension, smoking, and diabetes, there is more degradation of LDL to oxidized LDL which is taken up into arterial walls via scavenger receptors in macrophages to help form atheromas.
(B) Incorrect. Endothelial lipoprotein lipase splits off fatty acids that are then used as a substrate in other metabolic pathways and not in atheroma formation.
(D) Incorrect. Both adipose tissue and muscle are areas where VLDL is transformed to LDL, and this does not directly promote atherogenesis.

7. A 55-year-old woman has been treated in the hospital for pancreatitis for the past three weeks. She is examined one morning on rounds and found to have a swollen right leg. It is tender to palpation posteriorly but is not warm. This condition is most likely to be the result of which of the following vascular complications?

Venous thrombosis

Septic embolization

Congestive heart failure

Cellulitis

Infarction

(A) CORRECT. The signs point to thrombophlebitis.
(B) Incorrect. Septic emboli produce focal hemorrhage or infarction and are usually arterial.
(C) Incorrect. The peripheral edema that accompanies CHF would be symmetrical.
(D) Incorrect. Cellulitis would produce a warm, swollen, tender appearance from the subcutaneous inflammation.
(E) Incorrect. Infarction is a focal process from arterial occlusion.

Explanation

(A) CORRECT. The signs point to thrombophlebitis.
(B) Incorrect. Septic emboli produce focal hemorrhage or infarction and are usually arterial.
(C) Incorrect. The peripheral edema that accompanies CHF would be symmetrical.
(D) Incorrect. Cellulitis would produce a warm, swollen, tender appearance from the subcutaneous inflammation.
(E) Incorrect. Infarction is a focal process from arterial occlusion.

8. A 44-year-old woman has a family history of heart disease. Her father and mother both developed congestive heart failure and myocardial infarction as a result of extensive coronary atherosclerosis. A dietary modification to include consumption of which of the following is most likely to reduce her risk for ischemic heart disease?

40% of total caloric intake as fat

A diet high in saturated fat

Foods with cholesterol

Fish oil

Fat found in beef products

Trans-fats

(D) CORRECT. Fish oils diminish arachidonic acid metabolites and reduce platelet aggregation.
(F) Incorrect. Trans-fats are partially hydrogenated fats made commercially. Trans-fats tend to increase LDL cholesterol, decrease HDL cholesterol, and increase triglycerides - all of which are bad effects.

Explanation

(D) CORRECT. Fish oils diminish arachidonic acid metabolites and reduce platelet aggregation.
(F) Incorrect. Trans-fats are partially hydrogenated fats made commercially. Trans-fats tend to increase LDL cholesterol, decrease HDL cholesterol, and increase triglycerides - all of which are bad effects.

9. In an experiment, a glass bead is embolized to a branch of the renal artery. A day later there is a focal area in which the renal parenchymal cells in the distribution of the occluded artery show karyolysis and karyorrhexis. The outlines of the cells are still visible, but the nuclei have lost basophilic staining and the cytoplasm is eosinophilic but pale. Which of the following types of cellular necrosis is most likely present?

Caseous

Coagulative

Fatty

Gangrenous

Liquefactive

(B) CORRECT. A typical ischemic infarction with coagulative necrosis is described.
(A) Incorrect. Caseous necrosis is a mixture of liquefactive and coagulative necrosis, and is typical for inflammation caused by mycobacterial or fungal infections.
(C) Incorrect. Fat necrosis most often occurs in breast (with trauma) and in pancreas (with acute pancreatitis).
(D) Incorrect. Gangrene involves a whole organ or body part. There can be elements of coagulative necrosis ('dry' gangrene) and liquefactive necrosis ('wet' gangrene).
(E) Incorrect. Liquefactive necrosis is most typical for brain infarction and for abscesses with many neutrophils.

Explanation

(B) CORRECT. A typical ischemic infarction with coagulative necrosis is described.
(A) Incorrect. Caseous necrosis is a mixture of liquefactive and coagulative necrosis, and is typical for inflammation caused by mycobacterial or fungal infections.
(C) Incorrect. Fat necrosis most often occurs in breast (with trauma) and in pancreas (with acute pancreatitis).
(D) Incorrect. Gangrene involves a whole organ or body part. There can be elements of coagulative necrosis ('dry' gangrene) and liquefactive necrosis ('wet' gangrene).
(E) Incorrect. Liquefactive necrosis is most typical for brain infarction and for abscesses with many neutrophils.

10. A 61-year-old man has the sudden onset of severe chest pain. Vital signs include T 37 C, P 101/minute, RR 20/minute, and BP 80/40 mm Hg. An electrocardiogram demonstrates changes that are consistent with myocardial ischemia involving the left lateral ventricular free wall. He is given thrombolytic therapy with tissue plasminogen activator (tPA). However his serum creatinine kinase is found to be 450 U/L 3 hours after this therapy. Which of the following cellular events has most likely occurred?

Cellular regeneration

Drug-induced necrosis

Reperfusion injury

Increased synthesis of creatine kinase

Myofiber atrophy

(C) CORRECT. The restoration of blood flow is helpful if the existing cell damage is not great, so further damage can be prevented. However, the reperfusion of damaged cells results in generation of oxygen free radicals to produce a reperfusion injury.
(B) Incorrect. The tPA does not produce a chemical injury, but induces thrombolysis to help restore blood flow.
(D) Incorrect. Creatine kinase is released, but synthesis does not (cannot) increase from the injured cells.
(E) Incorrect. The elevation in creatine kinase is indicative of myocardial cell necrosis, not atrophy.

Explanation

(C) CORRECT. The restoration of blood flow is helpful if the existing cell damage is not great, so further damage can be prevented. However, the reperfusion of damaged cells results in generation of oxygen free radicals to produce a reperfusion injury.
(B) Incorrect. The tPA does not produce a chemical injury, but induces thrombolysis to help restore blood flow.
(D) Incorrect. Creatine kinase is released, but synthesis does not (cannot) increase from the injured cells.
(E) Incorrect. The elevation in creatine kinase is indicative of myocardial cell necrosis, not atrophy.

11. An autopsy study is conducted involving the gross appearance of the aorta of adults ranging in age from 60 to 90. In some of these patients, the aorta demonstrates atheromatous plaques covering from 70 to 95% of the intimal surface area, mainly in the abdominal portion, with ulceration and calcification. Which of the following contributing causes of death are these patients most likely to have?

Hyperparathyroidism

Hypertension

Marfan syndrome

Thrombophlebitis

Vasculitis

Colonic adenocarcinoma

Systemic lupus erythematosus

(B) CORRECT. HTN is a risk factor that accelerates atheromatous plaque formation.
(C) Incorrect. In Marfan syndrome, there is cystic medial necrosis of the aorta, but not atherosclerosis.
(D) Incorrect. Thrombophlebitis involves veins. Atherosclerosis does not involve veins.
(E) Incorrect. Various forms of vasculitis may produce vascular occlusion, but do not accelerate atherosclerosis.
(F) Incorrect. Cancer is a debilitating condition likely to result in reversal of atheroma formation. Hypercoagulable states from cancers are most likely to result in venous thrombosis, though arterial thrombi are possible, but not dependent upon prior arterial atheroma formation.
(G) Incorrect. SLE and autoimmune diseases in general are debilitating conditions in which atheromas may diminish in size. The antiphospholipid syndrome that can sometimes occur with SLE can lead to thrombosis, not atheroma formation.

Explanation

(B) CORRECT. HTN is a risk factor that accelerates atheromatous plaque formation.
(C) Incorrect. In Marfan syndrome, there is cystic medial necrosis of the aorta, but not atherosclerosis.
(D) Incorrect. Thrombophlebitis involves veins. Atherosclerosis does not involve veins.
(E) Incorrect. Various forms of vasculitis may produce vascular occlusion, but do not accelerate atherosclerosis.
(F) Incorrect. Cancer is a debilitating condition likely to result in reversal of atheroma formation. Hypercoagulable states from cancers are most likely to result in venous thrombosis, though arterial thrombi are possible, but not dependent upon prior arterial atheroma formation.
(G) Incorrect. SLE and autoimmune diseases in general are debilitating conditions in which atheromas may diminish in size. The antiphospholipid syndrome that can sometimes occur with SLE can lead to thrombosis, not atheroma formation.

12. A 63-year-old man has had insulin dependent diabetes mellitus for over two decades. The degree of control of his disease is characterized by the laboratory finding of a hemoglobin A1C of 10.1%. He has noted episodes of abdominal pain following meals. These episodes have worsened over the past year. On physical examination, there are no masses and no organomegaly of the abdomen, and he has no tenderness to palpation. Which of the following pathologic findings is most likely to be present in this man?

Ruptured aortic aneurysm

Hepatic infarction

Mesenteric artery occlusion

Acute pancreatitis

Chronic renal failure

(C) CORRECT. He has 'abdominal angina' from diminished blood flow to the bowel as a consequence of severe atherosclerosis. Persons with diabetes mellitus may have this finding, because all branches of major arteries to the bowel are affected by atherosclerosis.
(B) Incorrect. The liver has a dual blood supply (hepatic arterial plus portal venous circulations) and is difficult to infarct.
(D) Incorrect. Pancreatitis is a disease of the pancreatic acinar parenchyma, not the islets. Even in persons with pancreatitis, diabetes mellitus is a rare outcome.
(E) Incorrect. Nephrosclerosis can lead to renal failure. However, there is typically no pain associated with this process.

Explanation

(C) CORRECT. He has 'abdominal angina' from diminished blood flow to the bowel as a consequence of severe atherosclerosis. Persons with diabetes mellitus may have this finding, because all branches of major arteries to the bowel are affected by atherosclerosis.
(B) Incorrect. The liver has a dual blood supply (hepatic arterial plus portal venous circulations) and is difficult to infarct.
(D) Incorrect. Pancreatitis is a disease of the pancreatic acinar parenchyma, not the islets. Even in persons with pancreatitis, diabetes mellitus is a rare outcome.
(E) Incorrect. Nephrosclerosis can lead to renal failure. However, there is typically no pain associated with this process.

13. On sectioning of an organ from a 60-year-old man at the time of autopsy, a focal, wedge-shaped area that is firm is accompanied by extensive hemorrhage, giving it a red appearance. The lesion has a base on the surface of the organ. In which of the following situations will this lesion most likely occur?

Lung with pulmonary thromboembolism

Heart with coronary thrombosis

Liver with hypovolemic shock

Kidney with septic embolus

Spleen with embolized mural thrombus

Brain with cerebral arterial aneurysm

(A) CORRECT. The bronchial arterial supply to the lung does not provide enough oxygenation to prevent infarction, but does provide blood to make the infarct hemorrhagic.
(B) Incorrect. A myocardial infarction is predominantly ischemic, though the border may be hemorrhagic.
(C) Incorrect. The liver is hard to infarct because of its dual blood supply, but when infarcts occur, they are usually pale.
(D) Incorrect. Renal infarcts are usually ischemic and pale.
(E) Incorrect. Splenic infarcts are typically pale.
(F) Incorrect. A cerebral arterial aneurysm is most likely to rupture and produce subarachnoid hemorrhage. This hemorrhage may produce vasospasm with cerebral ischemia, which in the brain can produce liquefactive necrosis.

Explanation

(A) CORRECT. The bronchial arterial supply to the lung does not provide enough oxygenation to prevent infarction, but does provide blood to make the infarct hemorrhagic.
(B) Incorrect. A myocardial infarction is predominantly ischemic, though the border may be hemorrhagic.
(C) Incorrect. The liver is hard to infarct because of its dual blood supply, but when infarcts occur, they are usually pale.
(D) Incorrect. Renal infarcts are usually ischemic and pale.
(E) Incorrect. Splenic infarcts are typically pale.
(F) Incorrect. A cerebral arterial aneurysm is most likely to rupture and produce subarachnoid hemorrhage. This hemorrhage may produce vasospasm with cerebral ischemia, which in the brain can produce liquefactive necrosis.

14. A 62-year-old man has experienced substernal chest pain upon exertion with increasing frequency over the past 6 months. An electrocardiogram shows features consistent with ischemic heart disease. He has a total serum cholesterol of 262 mg/dL. By angiography, there is 75% narrowing of the left anterior descending artery. Which of the following vascular complications is most likely to occur in this patient?

A systemic artery embolus from thrombosis in a peripheral vein.

A systemic artery embolus from a left atrial mural thrombus.

Pulmonary embolism from a left ventricular mural thrombus.

A systemic artery embolus from a left ventricular mural thrombus.

Pulmonary embolism from thrombosis in a peripheral vein.

(D) CORRECT. Left ventricular mural thrombi are prone to embolize to the systemic arterial circulation. Such mural thrombi are likely to result from damage to the left ventricle from ischemic heart disease, either acutely with an underlying myocardial infarction, or with a left ventricular aneurysm formed following resolution of a large myocardial infarction.
(B) Incorrect. Left atrial thrombi are prone to embolize to the arterial circulation, but an enlarged left atrium is most likely to result from valvular heart disease, not ischemic heart disease.
(C) Incorrect. The left ventricular thrombi cannot get into the pulmonary circulation without a ventricular septal defect, and the VSD would probably lead to abnormal cardiac function.

Explanation

(D) CORRECT. Left ventricular mural thrombi are prone to embolize to the systemic arterial circulation. Such mural thrombi are likely to result from damage to the left ventricle from ischemic heart disease, either acutely with an underlying myocardial infarction, or with a left ventricular aneurysm formed following resolution of a large myocardial infarction.
(B) Incorrect. Left atrial thrombi are prone to embolize to the arterial circulation, but an enlarged left atrium is most likely to result from valvular heart disease, not ischemic heart disease.
(C) Incorrect. The left ventricular thrombi cannot get into the pulmonary circulation without a ventricular septal defect, and the VSD would probably lead to abnormal cardiac function.

15. A 10-year-old previously healthy child has been noted by her parents to be constantly thirsty. She is consuming large amounts of soft drinks. She is urinating often. Her diet and exercise patterns have not changed, except for an increased appetite, yet she appears cachectic and has lost 7 kg over the past 4 months. On physical examination there are no abnormal findings, other than peripheral muscle wasting and weakness. Which of the following laboratory findings would you most strongly suspect is present in this girl?

Increased blood insulin

Decreased blood glucagon

Ketonuria

Markedly increased serum osmolality

Decreased plasma hydrogen ion (alkalosis)

Decreased plasma cortisol

(C) CORRECT. Ketonuria is typical for type I diabetes mellitus.
(D) Incorrect. This finding is more typical of type II diabetes mellitus.
(E) Incorrect. The child probably has ketoacidosis.
(F) Incorrect. She is unlikely to have an acute Addison disease which would be characterized by hypotension and hypoglyccemia, and she is unlikely to present at this age with congenital adrenal hyperplasia.

Explanation

(C) CORRECT. Ketonuria is typical for type I diabetes mellitus.
(D) Incorrect. This finding is more typical of type II diabetes mellitus.
(E) Incorrect. The child probably has ketoacidosis.
(F) Incorrect. She is unlikely to have an acute Addison disease which would be characterized by hypotension and hypoglyccemia, and she is unlikely to present at this age with congenital adrenal hyperplasia.

16. An 81-year-old woman has the sudden onset of dyspnea and palpitations with chest pain. A pulmonary ventilation-perfusion scan is performed and indicates a high probability for a perfusion defect involving right segmental pulmonary arterial branch. Of the following findings or conditions, which is the most important factor favoring development of these findings?

An increased white blood cell count

Cirrhosis of the liver

Altered blood flow with stasis

An increased platelet count

Generalized atherosclerosis

(C) CORRECT. She has a pulmonary thromboembolus. Stasis predisposes to thrombosis, as is evidenced by the danger for thromboembolism in hospitalized patients.
(E) Incorrect. Atherosclerosis is seen in arteries, not veins.
(B) Incorrect. The cirrhotic liver functions poorly, usually causing an increase in prothrombin time. This makes it more difficult to form thrombi.

Explanation

(C) CORRECT. She has a pulmonary thromboembolus. Stasis predisposes to thrombosis, as is evidenced by the danger for thromboembolism in hospitalized patients.
(E) Incorrect. Atherosclerosis is seen in arteries, not veins.
(B) Incorrect. The cirrhotic liver functions poorly, usually causing an increase in prothrombin time. This makes it more difficult to form thrombi.

17. A 59-year-old woman has the sudden onset of severe dyspnea and goes into cardiac arrest, from which she cannot be resuscitated. At autopsy, she has the gross finding of a saddle pulmonary embolus. This event is most likely to be present as a consequence of which of the following?

Placement of a hip prosthesis

Marked thrombocytopenia

Chronic alcoholism

Infection with the human immunodeficiency virus

An autoimmune disease

(A) CORRECT. Immobilization is a major risk for the development of venous thrombosis and subsequent pulmonary embolization.
(C) Incorrect. Chronic alcoholics tend to have a coagulopathy due to their underlying liver disease which predisposes them to bleeding, not thrombosis.
(E) Incorrect. People with Autoimmune diseases generally do not have major problems with thrombosis, though some can develop an antiphospholipid syndrome with thrombosis.

Explanation

(A) CORRECT. Immobilization is a major risk for the development of venous thrombosis and subsequent pulmonary embolization.
(C) Incorrect. Chronic alcoholics tend to have a coagulopathy due to their underlying liver disease which predisposes them to bleeding, not thrombosis.
(E) Incorrect. People with Autoimmune diseases generally do not have major problems with thrombosis, though some can develop an antiphospholipid syndrome with thrombosis.

18. A 49-y/o woman has experienced marked pain in her lower extremities on ambulation more than 300 meters for the past 5 months. On physical examination, her lower extremities are cool and pale, without swelling or erythema. No dorsalis pedis or posterior tibial pulses are palpable. Her BMI is 32. She is a smoker. Which of the following abnormalities of the vasculature is most likely to account for these findings?

Lymphatic obstruction

Arteriolosclerosis

Atherosclerosis

Medial calcific sclerosis

Venous thrombosis

(C) CORRECT. She has claudication from severe peripheral arterial atherosclerosis, most likely from the iliac arteries down. She has risk factors for atherosclerosis.
(A) Incorrect. The result of lymphatic obstruction is lymphedema, with marked swelling from collection of interstitial fluid. Lymphatics normally scavenge the fluid and protein that escapes at the venule and capillary level and returns it to circulation.
(B) Incorrect. Arteriolosclerosis is more typically found in the kidneys and brain, not the extremities.
(D) Incorrect. Medial calcific sclerosis of Monckeberg is not typically a serious problem.
(E) Incorrect. Venous thrombosis should lead to a warm, tender, swollen extremity.

Explanation

(C) CORRECT. She has claudication from severe peripheral arterial atherosclerosis, most likely from the iliac arteries down. She has risk factors for atherosclerosis.
(A) Incorrect. The result of lymphatic obstruction is lymphedema, with marked swelling from collection of interstitial fluid. Lymphatics normally scavenge the fluid and protein that escapes at the venule and capillary level and returns it to circulation.
(B) Incorrect. Arteriolosclerosis is more typically found in the kidneys and brain, not the extremities.
(D) Incorrect. Medial calcific sclerosis of Monckeberg is not typically a serious problem.
(E) Incorrect. Venous thrombosis should lead to a warm, tender, swollen extremity.

19. A 73-year-old woman who exercises regularly falls down the stairs and injures her right hip. A radiograph is taken of the pelvis. There is no fracture but the radiograph reveals calcification of the small muscular arteries lateral to her uterus. What is the probable vascular lesion which accounts for this calcification?

Ulcerative atherosclerosis

Calcific medial sclerosis

Metastatic calcification

Trauma

Dystrophic calcification

(B) CORRECT. Monckeberg calcific medial sclerosis is a benign, incidental finding most often seen in the elderly. Small arteries in pelvis and extremities are typically involved. The vascular lumen is not compromised.
(E) Incorrect. Dystrophic calcification from tissue damage would probably not be so localized to arteries.
(A) Incorrect. Although calcification may complicate atheromas, this is typically seen in larger vessels.
(C) Incorrect. Metastatic calcification from hypercalcemia would involve other areas in lung, kidney and GI tract first.
(D) Incorrect. Dystrophic calcification following injury from trauma would be localized and would take weeks to form.

Explanation

(B) CORRECT. Monckeberg calcific medial sclerosis is a benign, incidental finding most often seen in the elderly. Small arteries in pelvis and extremities are typically involved. The vascular lumen is not compromised.
(E) Incorrect. Dystrophic calcification from tissue damage would probably not be so localized to arteries.
(A) Incorrect. Although calcification may complicate atheromas, this is typically seen in larger vessels.
(C) Incorrect. Metastatic calcification from hypercalcemia would involve other areas in lung, kidney and GI tract first.
(D) Incorrect. Dystrophic calcification following injury from trauma would be localized and would take weeks to form.

20. A 45-year-old man dies suddenly and unexpectedly. The immediate cause of death is found to be a hemorrhage in the right basal ganglia region. On microscopic examination his renal artery branches have concentric endothelial cell proliferation which markedly narrows the lumen, resulting in focal ischemia and hemorrhage of the renal parenchyma. An elevation in which of the following substances in his blood is most likely to be associated with these findings?

Ammonia

Calcium

Cholesterol

Renin

Troponin I

Triglyceride

C-reactive protein

(D) CORRECT. The findings suggest hyperplastic arteriolosclerosis, which accompanies malignant hypertension.
(B) Incorrect. Hypercalcemia can be associated with hyperparathyroidism.
(C) Incorrect. Increased cholesterol leads to atherosclerotic vascular changes.
(E) Incorrect. Myocardial injury increases the troponin I.
(G) Incorrect. An increased CRP can be a marker for an increased risk for atherosclerosis with atheroma formation, but not concentric endothelial proliferation.

Explanation

(D) CORRECT. The findings suggest hyperplastic arteriolosclerosis, which accompanies malignant hypertension.
(B) Incorrect. Hypercalcemia can be associated with hyperparathyroidism.
(C) Incorrect. Increased cholesterol leads to atherosclerotic vascular changes.
(E) Incorrect. Myocardial injury increases the troponin I.
(G) Incorrect. An increased CRP can be a marker for an increased risk for atherosclerosis with atheroma formation, but not concentric endothelial proliferation.

21. A 54-year-old man with diabetes mellitus has had 3 urinary tract infections during the past year. He now sees the physician for an ulceration on his right big toe which has not healed in 2 months. Laboratory studies on each of his doctor visits over the past year show blood glucose levels below 110 mg/dl. This situation could be best explained by which of the following laboratory findings?

Elevated hemoglobin A1C level

Increased urine ketones

Elevated serum osmolarity

Decreased plasma insulin

Elevated titer of anti-insulin antibodies

(A) CORRECT. Out-of-control diabetes over time can be better detected because the glycosylated RBCs will persist for months and the Hgb A1C increased.
(B) Incorrect. The ketones suggest ketoacidosis, but this could have been a recent development.
(C) Incorrect. Hyperosmolar coma is possible, but would be relatively recent in onset.
(D) Incorrect. This would be a likely finding with diabetes mellitus, but would tell you nothing about the course or the degree of control of hyperglycemia.
(E) Incorrect. In type I diabetes mellitus, elevated anti-insulin antibodies are often present, but tell you nothing about the course or the control of the hyperglycemia.

Explanation

(A) CORRECT. Out-of-control diabetes over time can be better detected because the glycosylated RBCs will persist for months and the Hgb A1C increased.
(B) Incorrect. The ketones suggest ketoacidosis, but this could have been a recent development.
(C) Incorrect. Hyperosmolar coma is possible, but would be relatively recent in onset.
(D) Incorrect. This would be a likely finding with diabetes mellitus, but would tell you nothing about the course or the degree of control of hyperglycemia.
(E) Incorrect. In type I diabetes mellitus, elevated anti-insulin antibodies are often present, but tell you nothing about the course or the control of the hyperglycemia.

22. A 52-year-old man has the sudden onset of chest pain. He is found to have a serum troponin I of 5 ng/mL. A year later he has reduced exercise tolerance. An echocardiogram reveals an akinetic segment of left ventricle, and he has reduced cardiac output, with an ejection fraction of 25%. He then experiences a transient ischemic attack (TIA). His serum troponin I is now <0.5 ng/mL. Thrombus formation involving which of the following locations is most likely to have put him at greatest risk for the TIA?

Cerebral vein

Vertebral artery

Superior vena cava

Left ventricle

Coronary artery

Saphenous vein

(E) Incorrect. Liquefactive necrosis is most typical for brain infarction and for abscesses with many neutrophils.
(A) Incorrect. The cerebral bridging veins cross the subdural space and rupture of them can produce a subdural hematoma. Cerebral venous thrombosis is far less common than cerebral arterial thrombosis or embolism.
(E) Incorrect. His original myocardial infarction may have been due to coronary thrombosis, but his last event was not, since the troponin I was not elevated.
(C) Incorrect. The superior vena cava may become occluded by thrombus when involved by a neoplasm in the chest. A thromboembolus from a leg vein may pass through the inferior vena cava on the way to the pulmonary arterial tree.

Explanation

(E) Incorrect. Liquefactive necrosis is most typical for brain infarction and for abscesses with many neutrophils.
(A) Incorrect. The cerebral bridging veins cross the subdural space and rupture of them can produce a subdural hematoma. Cerebral venous thrombosis is far less common than cerebral arterial thrombosis or embolism.
(E) Incorrect. His original myocardial infarction may have been due to coronary thrombosis, but his last event was not, since the troponin I was not elevated.
(C) Incorrect. The superior vena cava may become occluded by thrombus when involved by a neoplasm in the chest. A thromboembolus from a leg vein may pass through the inferior vena cava on the way to the pulmonary arterial tree.

23. A 29-year-old woman is involved in a motor vehicle accident that results in severe lacerations to her lower extremities, along with blunt abdominal trauma. In the emergency room she is noted to have cool, pallid skin. She has vital signs showing T 36.9 C, P 103/minute, RR 18/minute, and BP 70/30 mm Hg. She has decreased urine output. Which of the following laboratory findings on a blood sample from this patient is most likely to be present?

Hematocrit of 54%

Glucose of 181 mg/dL

PaO2 of 20 mm Hg

Lactic acid of 4.8 mmol/L

Troponin I of 4 ng/mL

(D) CORRECT. She has marked blood loss with shock. There will be vasoconstriction in skin in response to the hypovolemia. Decreased renal blood flow from shock can lead to acute tubular necrosis. The lack of tissue perfusion with shock leads to increased anaerobic glycolysis and lactic acidosis.
(B) Incorrect. Hyperglycemia is not a feature of blood loss with shock.
(C) Incorrect. She has had blood loss, but the oxygen carrying capacity of the remaining RBCs is not affected, and her ability to oxygenate is not completely lost.
(E) Incorrect. An elevated troponin I suggests myocardial ischemia. With good coronary blood flow in a young person, the myocardium is not seriously affected until the patient is near death.

Explanation

(D) CORRECT. She has marked blood loss with shock. There will be vasoconstriction in skin in response to the hypovolemia. Decreased renal blood flow from shock can lead to acute tubular necrosis. The lack of tissue perfusion with shock leads to increased anaerobic glycolysis and lactic acidosis.
(B) Incorrect. Hyperglycemia is not a feature of blood loss with shock.
(C) Incorrect. She has had blood loss, but the oxygen carrying capacity of the remaining RBCs is not affected, and her ability to oxygenate is not completely lost.
(E) Incorrect. An elevated troponin I suggests myocardial ischemia. With good coronary blood flow in a young person, the myocardium is not seriously affected until the patient is near death.

24. A 52-year-old woman has experienced marked substernal, crushing chest pain for the past 6 hours. Her vital signs show T 36.9 C, P 80/minute, RR 16/minute, and BP 100/60 mm Hg. Laboratory studies include a serum creatine kinase MB fraction of 10 microgm/L as well as a serum troponin I of 4.5 ng/mL. Which of the following findings is the best evidence for the presence of a coronary arterial thrombus as the etiology for her chest pain?

Total serum cholesterol of 300 mg/dL

Large size of the infarction by scintigraphic scanning

80% coronary occlusion by angiography

Response to thrombolytic therapy

Hemoglobin A1C of 10.1%

(E) Incorrect. The elevation in creatine kinase is indicative of myocardial cell necrosis, not atrophy.
(B) Incorrect. The size of the infarct gives no clue as to whether a thrombus was present or not.
(C) Incorrect. The severity of the atherosclerosis does not necessarily predict whether a thrombus will have formed.
(A) Incorrect. Though an increased total serum cholesterol suggests a risk for atherosclerosis and its complications, it does not predict acute events.

Explanation

(E) Incorrect. The elevation in creatine kinase is indicative of myocardial cell necrosis, not atrophy.
(B) Incorrect. The size of the infarct gives no clue as to whether a thrombus was present or not.
(C) Incorrect. The severity of the atherosclerosis does not necessarily predict whether a thrombus will have formed.
(A) Incorrect. Though an increased total serum cholesterol suggests a risk for atherosclerosis and its complications, it does not predict acute events.

25. A 25-year-old previously healthy primigravida is in the first trimester of pregnancy. During two successive prenatal visits, she has fasting serum glucose levels of 127 and 131 mg/dL. Prior to this pregnancy, her fasting serum glucose was 80 mg/dL. A hemoglobin A1C level is 8.1% at the last visit, at 18 weeks gestation. She feels well and has no major health problems. Which of the following problems is most likely to become apparent in the latter part of her pregnancy?

Intrauterine fetal growth retardation

Ketoacidosis

Hyperosmolar coma

Congenital anomalies

Placental insufficiency

(E) CORRECT. The big problem in gestational diabetes is eventual placental malfunction in later pregnancy (third trimester) with potential fetal demise.
(A) Incorrect. The babies of diabetic mothers tend to have macrosomia (increased size).
(B) Incorrect. This patient has gestational diabetes, not type 1 diabetes mellitus.
(C) Incorrect. This unlikely, given that hyperosmolar coma is more typical of older type 2 diabetics.
(D) Incorrect. The rate of fetal malformation is slightly increased in mothers with diabetes mellitus type 1 or 2, but not gestational diabetes.

Explanation

(E) CORRECT. The big problem in gestational diabetes is eventual placental malfunction in later pregnancy (third trimester) with potential fetal demise.
(A) Incorrect. The babies of diabetic mothers tend to have macrosomia (increased size).
(B) Incorrect. This patient has gestational diabetes, not type 1 diabetes mellitus.
(C) Incorrect. This unlikely, given that hyperosmolar coma is more typical of older type 2 diabetics.
(D) Incorrect. The rate of fetal malformation is slightly increased in mothers with diabetes mellitus type 1 or 2, but not gestational diabetes.

26. In a clinical study of patients with diabetes mellitus, a group of patients is found who had blood glucose measurements ranging from 140 to 180 mg/dL for at least 10 years. Rectal biopsies from these patients now show that there is a form of osmotic cellular injury present in arterioles. This form of injury is most likely to be manifested by which of the following complications?

Cerebral infarction

Colonic adenocarcinoma

Congestive heart failure

Impotence

Pyelonephritis

(D) CORRECT. The hyperglycemia leads to formation of sorbitol in tissues not requiring insulin for glucose uptake, resulting in osmotic cellular injury. This can occur in small vessels, retina, kidney, and nerves. The failure of erection and ejaculation results from diabetic neuropathy.
(A) Incorrect. Atherosclerotic cerebrovascular disease is more frequent with diabetes mellitus, but not findings related to osmotic vascular injury.
(B) Incorrect. The risk for cancer is not increased with diabetes mellitus.
(C) Incorrect. However, the major damage to the heart with diabetes mellitus is done via atherosclerotic coronary artery disease. Atherosclerosis affects muscular arteries by formation of intimal atheromatous plaques which occlude the lumen and lead to ischemic injury.
(E) Incorrect. Pyelonephritis with diabetes is related to diminished neutrophil function with hyperglycemia.

Explanation

(D) CORRECT. The hyperglycemia leads to formation of sorbitol in tissues not requiring insulin for glucose uptake, resulting in osmotic cellular injury. This can occur in small vessels, retina, kidney, and nerves. The failure of erection and ejaculation results from diabetic neuropathy.
(A) Incorrect. Atherosclerotic cerebrovascular disease is more frequent with diabetes mellitus, but not findings related to osmotic vascular injury.
(B) Incorrect. The risk for cancer is not increased with diabetes mellitus.
(C) Incorrect. However, the major damage to the heart with diabetes mellitus is done via atherosclerotic coronary artery disease. Atherosclerosis affects muscular arteries by formation of intimal atheromatous plaques which occlude the lumen and lead to ischemic injury.
(E) Incorrect. Pyelonephritis with diabetes is related to diminished neutrophil function with hyperglycemia.