A 29-year-old woman has a history of frequent nosebleeds and increased menstrual flow. On physical examination, petechiae and purpura are present on the skin of her extremities. Laboratory studies show normal partial thromboplastin time, prothrombin time, and platelet count, and decreased von Willebrand factor activity. This patient most likely has a derangement in which of the following steps in hemostasis _ _
A. Vasoconstriction
B. Platelet adhesion
C. Platelet aggregation
D. Prothrombin generation
E. Prothrombin inhibition
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A 25-year-old woman who has had altered consciousness and slurred speech for the past 24 hours is brought to the emergency department. A head CT scan shows a right temporal hemorrhagic infarction. Cerebral angiography shows a distal right middle cerebral arterial occlusion. Within the past 3 years, she has had an episode of pulmonary embolism. A pregnancy 18 months ago ended in miscarriage. Laboratory studies show a false-positive serologic test for syphilis, normal prothrombin time, elevated partial thromboplastin time, and normal platelet count. Which of the following is the most likely cause of these findings _ _
A. Disseminated intravascular coagulation
B. Factor V mutation
C. Hypercholesterolemia
D. Lupus anticoagulant
E. Von Willebrand disease
A 66-year-old woman comes to the emergency department 3 hours after the onset of chest pain that radiates to her neck and left arm. She is diaphoretic and hypotensive; the serum troponin I level is elevated. Thrombolytic therapy is begun. Which of the following drugs is most likely to be administered _ _
A. Tissue plasminogen activator
B. Aspirin
C. Heparin
D. Nitric oxide
E. Vitamin K
A 49-year-old man is in stable condition after an infarction of the anterior left ventricular wall. He receives therapy with antiarrhythmic and pressor agents. Three days later, he develops severe breathlessness, and an echocardiogram shows markedly decreased ejection fraction. He dies 2 hours later. At autopsy, which of the following microscopic changes is most likely to be present in the lungs _ _
A. Congestion of alveolar capillaries with fibrin and neutrophils in alveoli
B. Congestion of alveolar capillaries with transudate in alveoli
C. Fibrosis of alveolar walls with hemosiderin-laden macrophages in alveoli
D. Multiple areas of subpleural hemorrhagic necrosis
E. Purulent exudate in the pleural space
F. Purulent exudate in the mainstem bronchi
A 27-year-old man is on a scuba diving trip to the Caribbean and descends to a depth of 50 m in the Blue Hole off the coast of Belize. After 30 minutes, he has a malfunction in his equipment and quickly returns to the boat on the surface. He soon experiences difficulty breathing, with dyspnea and substernal chest pain, followed by a severe headache and vertigo. About 1 hour later, he develops severe, painful myalgias and arthralgias. These symptoms abate within 24 hours. Which of the following mechanisms is the most likely cause of these symptoms_ _
A. Disseminated intravascular coagulation
B. Systemic vasodilation
C. Venous thrombosis
D. Tissue nitrogen emboli
E. Fat globules in arterioles