Med School Questions
A 66-year-old man with Parkinson disease develops pleuritic chest pain. On exam, he has guarding over the right lower lung with dullness to percussion. A chest CT scan shows a focal, wedge-shaped pleural based area of hemorrhage in the right lower lobe. Which of the following is the most likely cause for his pulmonary lesion?
(A) CORRECT. A pulmonary infarction is described. A thromboembolus from the venous circulation, usually arising in large leg veins, has lodged in a peripheral pulmonary arterial branch. The bronchial arterial supply to the lung does not provide enough oxygenation to prevent infarction, but does provide blood to make the infarct hemorrhagic. His neurodegenerative disorder with reduced movement is a risk for immobilization as a risk for phlebothrombosis. (B) Incorrect. Pulmonary atherosclerosis occurs with pulmonary hypertension, but is typically limited in extent, without significant arterial narrowing. (C) Incorrect. Vasculitis involving the lungs is likely to be diffuse. (D) Incorrect. Arteriolosclerosis does not involve pulmonary circulation. (E) Incorrect. Thrombosis within the lung likely occurs in areas of inflammation. In this case the localized lesion is unlikely to represent in situ vascular thormbosis.
A 57-year-old man has had blood pressure measurements in the range of 160/95 to 180/110 mm Hg for many years. He has taken no medications. A renal scan reveals kidneys of normal size for age. These findings with benign nephrosclerosis are most likely to occur with which of the following vascular changes? A Hyaline arteriolosclerosis B Monckeberg's medial calcific sclerosis C Complex calcified atherosclerosis D Arterial mural thrombosis E Hyperplastic arteriolosclerosis
(A) CORRECT. Hyaline arteriolosclerosis is a feature of long-standing hypertension and is part of benign nephrosclerosis which may go on for many years with no complications. The small arterioles are thickened with pink (hyaline) proteinaceous deposits. (B) Incorrect. Medial calcific sclerosis is a form of arteriolosclerosis without significant complications. The vascular lumen is not significantly compromised by the medial calcification. (C) Incorrect. Coronary artery disease is caused by atherosclerosis that can be accelerated by hypertension. Atheromatous plaques occur in medium to large sized arteries and can be complicated by calcification of the plaques. (D) Incorrect. Mural thrombosis typically occurs in the aorta and its branches when there is severe atherosclerosis. (E) Incorrect. Hyperplastic arteriolosclerosis is usually seen in the kidneys when there is severe hypertension.
A 58-year-old woman has the sudden onset of severe dyspnea with chest pain and diaphoresis. A chest CT scan shows areas of decreased attenuation within the main pulmonary arteries. Her D-dimer assay is elevated. Her acute event is most likely to be a consequence of which of the following? A Placement of a hip prosthesis B Marked thrombocytopenia C Chronic alcoholism D Infection with the human immunodeficiency virus E Rheumatoid arthritis
(A) CORRECT. Immobilization is a major risk for the development of venous thrombosis and subsequent pulmonary embolization (the areas of diminished attenuation). Immobilization occurs following surgery. The postoperative goal: get the patient mobile as soon as possible, and meanwhile employ methods to reduce the risk for thrombosis. (B) Incorrect. Thrombocytopenia leads to bleeding, not to thrombosis. (C) Incorrect. Chronic alcoholics tend to have a coagulopathy due to their underlying liver disease which predisposes them to bleeding, not thrombosis. (D) Incorrect. Some AIDS patients get an acquired protein S deficiency that predisposes to thrombosis, but this is not common. (E) Incorrect. Persons with autoimmune diseases generally do not have major problems with thrombosis, though some can develop an antiphospholipid syndrome with thrombosis.
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? A Elevated hemoglobin A1C level B Increased urine ketones C Elevated serum osmolarity D Decreased plasma insulin E 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. Single glucose values reflect the past few hours. His problems developed over years. (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.
A 57-year-old woman has had episodes of abdominal pain following meals for the past year. Her BMI is 31 kg/m2. She her blood pressure is 165/110 mg Hg. Her total serum cholesterol is 256 mg/dL. Which of the following types of blood vessel is the most likely location for the pathologic abnormality causing her pain? A Artery B Arteriole C Capillary D Venule E Vein
(A) CORRECT. She has abdominal angina from vascular insufficiency. She has multiple risk factors for atherosclerosis. Atherosclerosis occurs in muscular arteries, because the level of blood pressure in arteries predisposes to endothelial dysfunction. (B) Incorrect. The blood pressure is considerably lowered at the level of arterioles. Instead of atherogenesis, arteriolosclerosis occurs in arterioles. (C) Incorrect. Capillaries are not involved with atherogenesis. (D) Incorrect. Venules are not involved with atherogenesis. (E) Incorrect. Veins are not involved with atherogenesis.
A 63-year-old man has had increasing exercise intolerance for the past 6 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? A Myocardial infarction B Nodular glomerulosclerosis C Cerebral hemorrhage D Hyperosmolar coma E 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 advanced 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.
A 73-year-old healthy 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? A Ulcerative atherosclerosis B Calcific medial sclerosis C Metastatic calcification D Trauma E Dystrophic calcification
(A) Incorrect. Although calcification may complicate atheromas, this is typically seen in larger vessels. (B) CORRECT. Monckeberg calcific medial sclerosis can be a benign, incidental finding most commonly seen in the elderly. Small arteries in pelvis, breast, neck, and extremities are typically involved. The vascular lumen is often not compromised. (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. (E) Incorrect. Dystrophic calcification from tissue damage would probably not be so localized to arteries.
At autopsy, the kidneys of a 44-year-old woman who died suddenly are found to be of normal size. Their surfaces appear finely granular. There are small hemorrhages noted. The cortices appear pale. Microscopically, many small renal arteries and arterioles demonstrate concentric intimal thickening with marked luminal narrowing. These findings are most likely to be present as a result of which of the following underlying diseases? A Amyloidosis B Systemic lupus erythematosus C Scleroderma D Rheumatoid arthritis E Viral hepatitis F Diabetes mellitus
(A) Incorrect. Amyloid deposits can be seen in small arteries and glomeruli in the kidney, but do not produce a hyperplastic arteriolosclerosis. (B) Incorrect. Lupus nephritis may be accompanied by a vasculitis and by glomerular basement membrane thickening, but not hyperplastic arteriolosclerosis. (C) CORRECT. Hyperplastic arteriolosclerosis is typically seen in association with severe hypertension, which can complicate prior 'essential' hypertension or occur with progressive systemic sclerosis (scleroderma). (D) Incorrect. There are no prominent vascular changes with rheumatoid arthritis. (E) Incorrect. Cryoglobulinemic vasculitis may complicate some cases of hepatitis B or C infection. In general viral infections do not involve the vasculature. (F) Incorrect. Diabetes mellitus leads to accelerated atherosclerosis of medium to large arteries. There may also be hyaline arteriolosclerosis, but not hyperplastic arteriolosclerosis.
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? A Ammonia B Calcium C Cholesterol D Renin E Troponin I F Triglyceride G C-reactive protein
(A) Incorrect. An elevated blood ammonia is indicative of hepatocyte dysfunction and increasing hepatic failure. (B) Incorrect. Hypercalcemia can be associated with hyperparathyroidism. (C) Incorrect. Increased cholesterol leads to atherosclerotic vascular changes. (D) CORRECT. The findings suggest hyperplastic arteriolosclerosis, which accompanies hypertensive emergency (malignant hypertension) when systolic pressure is ≥180 and/or diastolic pressure ≥120 mmHg along with signs of acute or ongoing end-organ damage. Reduced renal blood flow increases renin, driving hypertension. (E) Incorrect. Myocardial injury increases the troponin I. (F) Incorrect. An elevated triglyceride increases the risk for atherosclerosis with atheroma formation, but not concentric endothelial proliferation. (G) Incorrect. An increased CRP can be a marker for an increased risk for atherosclerosis with atheroma formation, but not concentric endothelial proliferation.
A study of pathologic findings in the islets of Langerhans is performed. It is observed that insulitis may occur in the islets. The inflammatory infiltrate is predominantly composed of T lymphocytes. Which of the following complications is most likely to occur as a consequence of insulitis? A Neoplasia B Malabsorption C Ketoacidosis D Obesity E Sepsis
(A) Incorrect. An insulitis is typical for type I diabetes mellitus; there is no increased risk for neoplasia. (B) Incorrect. The insulitis involves just the endocrine portion of the pancreas, not the exocrine portion, so there is no loss of pancreatic enzymes for digestion. (C) CORRECT. An insulitis can precede the development of type I diabetes mellitus. Actually, it is rare to see it because by the time the patients present with overt diabetes mellitus, the islets are long gone. The presence of the T lymphocytes suggests an autoimmune component to the pathogenesis. (D) Incorrect. Obesity is typically associated with type II diabetes mellitus; with type I diabetes mellitus, there is a catabolic state with weight loss. (E) Incorrect. The lymphocytes in the islets are part of an autoimmune phenomenon, not an infectious process.
A 63-year-old man has had insulin dependent diabetes mellitus for over two decades. The degree of control of his disease is indicated by the laboratory finding of hemoglobin A1C 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? A Ruptured aortic aneurysm B Hepatic infarction C Mesenteric artery occlusion D Acute pancreatitis E Chronic renal failure
(A) Incorrect. Atherosclerotic aneurysms of the abdominal aorta can occur with the advanced atherosclerosis of diabetes mellitus, but there can be a pulsatile mass, and rupture is a medical emergency. (B) Incorrect. The liver has a dual blood supply (hepatic arterial plus portal venous circulations) and is difficult to infarct. 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. (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. Diabetes is not a risk for pancreatitis. (E) Incorrect. Nephrosclerosis can lead to renal failure. However, there is typically no pain associated with this process.
In a clinical study of patients with diabetes mellitus, a group of patients is found who have 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 elsewhere in the body by which of the following complications? A Cerebral infarction B Gastric adenocarcinoma C Congestive heart failure D Impotence E Pyelonephritis
(A) Incorrect. Atherosclerotic cerebrovascular disease is more frequent with diabetes mellitus, but is usually large vessel disease not directly related to osmotic vascular injury. (B) Incorrect. The risk for cancer is not increased with diabetes mellitus. (C) Incorrect. 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. (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. (E) Incorrect. Pyelonephritis with diabetes is related to diminished neutrophil function with hyperglycemia and risk for infection.
A 69-year-old woman has a history of atrial fibrillation. During the past day she has increasing right flank pain. Radiologic imaging reveals occlusion of a branch of the right 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?
(A) Incorrect. Caseous necrosis is a mixture of liquefactive and coagulative necrosis, and is typical for granulomatous inflammation caused by mycobacterial or fungal infections. (B) CORRECT. A typical ischemic infarction with coagulative necrosis is described. Coagulative necrosis is most likely to occur in solid internal organs with high metabolic demands. Cardiac arrhythmias, and a-fib in particular, predisposes to left atrial mural thrombosis, with risk for embolization into the systemic circulation. (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.
A 66-year-old woman has the sudden loss of movement on part of the left side of her body. 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%. She has smoked a pack of cigarettes a day for the past 45 years. Which of the following components of blood lipids is most important in contributing to her disease? A Chylomicrons B Lipoprotein lipase C Oxidized LDL D VLDL E HDL cholesterol
(A) Incorrect. Chylomicrons are formed by complexing lipids absorbed from the small intestine to transport apoproteins. They then travel to the liver. They do not directly produce atheromatous plaques. (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. (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. (D) Incorrect. Both adipose tissue and muscle are areas where VLDL is transformed to LDL, and this does not directly promote atherogenesis. (E) Incorrect. HDL cholesterol helps to transport lipid away from arterial walls to the liver, thus protecting against atheroma formation.
A 34-year-old previously healthy woman notes that she has pinpoint to larger red areas form spontaneously on her arms and legs. Physical examination reveals areas of purpura from 0.2 to 3 cm in size over her trunk and extremities, but no swelling, warmth, or erythema. Peripheral pulses are all palpable and full. Her blood pressure is 110/70 mm Hg. An ultrasound examination of her lower extremities with Doppler flow measurement reveals no evidence for thrombosis. Laboratory findings include serum urea nitrogen of 16 mg/dL, LDH 300 U/L, total protein 6.9 g/dL, albumin 5.3 g/dL, alkaline phosphatase 50 U/L, AST 40 U/L, and ALT 20 U/L. Which of the following additional laboratory findings is most likely to be present in this patient? A Hyperglycemia B Hypercholesterolemia C Lactic acidosis D Thrombocytopenia E Hypoprothrombinemia F Anemia
(A) Incorrect. Diabetes mellitus is a disease marked by hyperglycemia that leads to early and advanced atherosclerosis with peripheral vascular disease involving arteries, with reduced blood flow and reduced pulses. (B) Incorrect. Patients with hypercholesterolemia are at increased risk for accelerated atherosclerosis and peripheral vascular disease involving arteries. (C) Incorrect. Poor tissue perfusion leads to increased anaerobic glycolysis and lactic acidosis. However, her pulses are not reduced. (D) CORRECT. The platelets are responsible for dealing with small leaks in small vessels. Thrombocytopenia is marked by petechiae and purpura. She does not have evidence for peripheral vascular disease, since her circulation is good. Venous thrombosis should lead to swelling and tenderness. (E) Incorrect. She has no evidence for liver disease, which would reduce prothrombin production. The pattern of her bleeding fits best with lack of platelets, not coagulation factors. (F) Incorrect. The amount of bleeding into soft tissues is unlikely to lower the hematocrit significantly. Bone marrow injuries that lead to reduced platelet production, however, may also lead to anemia. With anemia, tissue appear pale.
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? A Hyperparathyroidism B Hypertension C Marfan syndrome D Thrombophlebitis E Vasculitis F Colonic adenocarcinoma G Systemic lupus erythematosus
(A) Incorrect. Hypercalcemia is not a risk factor for advanced atherosclerosis. (B) CORRECT. Hypertension 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 existing atheromas may diminish in size. The antiphospholipid syndrome that can sometimes occur with SLE can lead to thrombosis, not atheroma formation.
A 56-year-old man reports reduced exercise tolerance over the past 5 years. In the past year he has noted chest pain after ascending a flight of stairs. He smokes 2 packs of cigarettes per day. On examination he has a blood pressure of 155/95 mm Hg. His body mass index is 30 kg/m2. Laboratory findings include a total serum cholesterol of 245 mg/dL with HDL cholesterol of 22 mg/dL. Which of the following vascular abnormalities is he most likely to have? A Hyperplastic arteriolosclerosis B Lymphedema C Medial calcific sclerosis D Atherosclerosis E Deep venous thrombosis F Plexiform arteriopathy
(A) Incorrect. Hyperplastic arteriolosclerosis can accompany hypertensive emergency (malignant hypertension) when systolic pressure is ≥180 and/or diastolic pressure ≥120 mmHg along with signs of acute or ongoing end-organ damage, which he does not have. (B) Incorrect. Lymphedema is not related to the risk factors that he has, which are factors affecting muscular arteries. (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. (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 with risk for an acute coronary syndrome. (E) Incorrect. He does have an increased risk for thrombosis, but atherosclerosis is the worst risk, and his symptoms suggest coronary artery disease. F) Incorrect. Plexiform arteriopathy is seen in peripheral pulmonary arteries with pulmonary hypertension.
A 53-year-old woman is found on a routine physical examination to have vital signs with T 37°C, P 78/minute, RR 16/minute, and BP 165/110 mm Hg. There are no other significant findings. She has an abdominal ultrasound examination that shows the right kidney to be atrophic. Angiography reveals markedly reduced blood flow to the right renal artery from an occlusion at the orifice in the abdominal aorta. Which of the following laboratory findings is she most likely to have? A Serum sodium of 161 mmol/L B Serologic evidence of anti-cardiolipin antibody C Prothrombin time of 25 seconds D Plasma renin activity of 4.8 ng/mL/hr supine E Serum lactic acid of 5.5 mmol/L
(A) Incorrect. Marked dehydration or free water loss could lead to this degree of hypernatremia. Many persons with essential hypertension may have increased retention of sodium, but it is not marked by significant hypernatremia. (B) Incorrect. Anti-cardiolipin antibody is seen with the antiphospholipid syndrome, which is a cause for thrombosis. It is unlikely that the selective renal artery occlusion represents a hypercoagulable state. (C) Incorrect. An elevated prothrombin time predisposes to bleeding. (D) CORRECT. She has renal artery stenosis that is reducing renal blood flow on the right and simulating the JG cells to secrete renin to try and raise blood pressure to increase renal blood flow. (E) Incorrect. The decreased perfusion of the right kidney occurs over a long period of time, without a significant rise in lactate that would accompany more global hypoperfusion.
A longitudinal study is conducted to detect serum markers that predict risk for death from acute coronary syndromes. A marker is identified that is synthesized and released from the liver in response to formation of cytokines in atheromatous plaques. This marker increases endothelial adhesiveness to platelets. What is this marker most likely to be? A Prostacyclin B Immunoglobulin G C C-reative protein D Alpha-1-antitrypsin E Acetoacetate
(A) Incorrect. Prostacyclin is produced in the arachidonic acid pathway in endothelium to reduce platelet activation. (B) Incorrect. Immunoglobulins are not directly implicated in atherogenesis. (C) CORRECT. An increased CRP predicts a greater likelihood for adverse events from atherogenesis. One benefit of 'statin' drugs is their CRP lowering effect. (D) Incorrect. AAT is the major circulating anti-protease. It mitigates neutrophil proteases. However, atherogenesis is not related to neutrophil actions. (E) Incorrect. Free fatty acids, including acetoacetate, are released with lipolysis, but do not directly participate in atherogenesis.
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 110/minute, RR 26/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? A Hematocrit of 54% B Glucose of 181 mg/dL C PaO2 of 20 mm Hg D Lactic acid of 4.8 mmol/L E Troponin I of 4 ng/mL
(A) Incorrect. She has signs of marked blood loss, so her hematocrit should be low--probably in the 20's or lower. (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. She is compensating via increased cardiac output and respiratory rate. (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. She is compensating via increased cardiac output and respiratory rate. (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.
A 53-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? A Cerebral vein B Vertebral artery C Superior vena cava D Left ventricle E Coronary artery F Saphenous vein
(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. (B) Incorrect. Vertebral artery thrombi are rare and may be the result of local trauma. (C) Incorrect. The superior vena cava may become occluded by thrombus when involved by obstruction in the chest, such as mass effect from a neoplasm in the lung or medastinum. A thromboembolus from a leg vein may pass through the inferior vena cava on the way to the pulmonary arterial tree. (D) CORRECT. Mural thrombi can form over the damaged area of ventricular wall following myocardial infarction. This can happen acutely overlying the necrotic myocardium; it can occur remotely in a ventricular aneurysm. Portions of the mural thrombus can break off and embolize via the systemic arterial circulation to places such as the cerebral circulation. (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. (F) Incorrect. A thrombus in the saphenous vein may become a thromboembolus that travels to the pulmonary arterial tree of the lungs. The only way such a thromboembolus may reach the arterial circulation is through a patent foramen ovale--a rare event.
A 54-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 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?
(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. (C) CORRECT. The immobilization while in hopsital would predispose to thrombosis of leg veins. This is the most common cause for deep venous thrombosis. (D) Incorrect. The enlarged uterus obstructing venous return would predispose to thrombosis. However, her age is not in the childbearing years, and prior pregnancies do not significantly increase the risk for thrombosis. (E) Incorrect. The liver disease of chronic alcoholism predisposes to coagulopathy with hemorrhage, not thrombosis.
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? A Intrauterine growth restriction B Ketoacidosis C Hyperosmolar coma D Congenital anomalies E Placental insufficiency
(A) Incorrect. The infants of diabetic mothers tend to have macrosomia (increased size) due to hyperglycemia and its growth promoting effects. (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. (E) CORRECT. The big problem in gestational diabetes is eventual placental malfunction in later pregnancy (third trimester) with potential fetal demise.
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? A Increased blood insulin B Decreased blood glucagon C Ketonuria D Decreased serum osmolality E Decreased plasma H+ (alkalosis) F Decreased plasma cortisol
(A) Incorrect. The insulin is probably decreased. (B) Incorrect. The glucagon is probably increased. (C) CORRECT. Ketonuria is typical for type I diabetes mellitus. The findings of polydipsia, polyuria, and polyphagia are present in this case. The absolute decrease in insuling leads to a catabolic state, with underutilization of carbohydrates, and lipolysis with metabolism of fatty acids to produce ketone bodies. (D) Incorrect. Her frequent urination and thirst indicate a net loss of water, driving an increased osmolality. A very high osmolality can also be a finding typical of the complication of type II diabetes mellitus known as hyperosmolar coma. (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.
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 two major coronary arteries. In which of the following locations is a mural thrombus most likely to occur in this man? A Left atrium B Left ventricle C Right atrium D Right ventricle E Aorta F Vena cava
(A) Incorrect. The left atrium is unlikely to undergo infarction; it is most often affected by enlargement from valvular disease. B) CORRECT. The left ventricle is the major user of oxygen and nutrients and requires a good blood supply. A complication of ischemic heart disease with infarction is development of overlying mural thrombus. 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 (C) Incorrect. The right atrium is unlikely to be involved with ischemic heart disease. (D) Incorrect. The right ventricle is unlikely to be involved with ischemic heart disease. (E) Incorrect. The aorta may undergo atherosclerotic changes with aneurysm formation, in which mural thrombus may form. In this case, the likelihood of an acute coronary event is more likely. (F) Incorrect. The systemic venous system is not directly affected by atherosclerosis.
A study of atherogenesis is performed. There is a propensity for atheromas to form at muscular arterial branch points, such as the carotid and aortic bifurcations. Which of the following events in the arteries at these locations is most likely to initiate atherogenesis? A Collagen synthesis B Endothelial dysfunction C Lactic acidosis D Cholesterol breakdown E Hypoxemia
(A) Incorrect. There is collagen deposition as atheromatous plaques develop, but this is not the initiatig event. (B) CORRECT. A variety of stressors may affect endothelial cells, including the shear stress from turbulent flow at arterial branch points. Endothelial dysfunction is the initiating event that allows insudation of lipids to promote atherogenesis. (C) Incorrect. Lactic acid may build up in tissues with oxygen debt, such as muscle. The metabolic rate of arterial cells is not high, and direct diffusion provides oxygen and nutrients to endothelium. (D) Incorrect. Once endothelial injury has occurred, lipids begin to collect, but lipids are not the inciting factor at arterial branch points. (E) Incorrect. Hypoxemia does not affect muscular arteries directly, as the arterial cells do not have a high metabolic rate.
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? A Thrombus B Fatty streak C Calcification D Hemorrhage E Exudate F Ulceration
(A) Incorrect. Thrombosis is a complication of an atheroma. (B) CORRECT. A fatty streak on the arterial intimal surface is the first grossly visible sign of atheroma formation. It is benign and reversible, but it may be the precursor to more severe plaques. (C) Incorrect. Calcification is a complication of an atheroma. (D) Incorrect. Hemorrhage 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.
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. His blood pressure is 130/85 mm Hg. Laboratory studies show a total serum cholesterol of 550 mg/dL with an HDL cholesterol component of 25 mg/dL. The blood glucose is 120 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? A Diabetes mellitus, type II B Hypertensive emergency C Familial hypercholesterolemia D Cushing syndrome E Morbid obesity
(A) Incorrect. Type II diabetes mellitus is most often a disease of middle aged to older adults, taking years for complications to develop. His obesity is a risk for DM type II. (B) Incorrect. A hypertensive emergency (malignant hypertension) when systolic pressure is ≥180 and/or diastolic pressure ≥120 mmHg along with signs of acute or ongoing end-organ damage 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. (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. (D) Incorrect. The hypercortisolism of Cushing syndrome tends to promote secondary 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.
A 52-year-old woman has experienced marked substernal, crushing chest pain for the past 3 hours. Her vital signs show T 36.9°C, P 90/minute, RR 18/minute, and BP 100/60 mm Hg. Laboratory studies include a serum troponin I of 4.5 ng/mL. Which of the following findings is the best evidence for recent complete coronary arterial occlusion as the etiology for her chest pain? A Total serum cholesterol of 300 mg/dL B Large size of the infarction by scintigraphic scanning C 80% coronary occlusion by angiography D Response to thrombolytic therapy E Hemoglobin A1C of 10.1%
(D) CORRECT. The purpose of thrombolytic therapy is to lyse the thrombus and restore blood flow. Many acute coronary events are the result of thrombus formation on pre-existing atheromas. Low dose aspirin therapy helps prevent such events. (C) Incorrect. The severity of the atherosclerosis does not necessarily predict whether a thrombus will have formed. Narrowing may be produced by the atheroma formation alone. E) Incorrect. Atherosclerosis is accelerated and complications are more likely with diabetes mellitus, but this does not indicate that a thrombus is present.