A 53-year-old man is brought to the emergency department because of wheezing and shortness of breath that began 1 hour after he took a new medication. Earlier in the day he was diagnosed with stable angina pectoris and prescribed a drug that irreversibly inhibits cyclooxygenase-1 and 2. He has chronic rhinosinusitis and asthma treated with inhaled β-adrenergic agonists and corticosteroids. His respirations are 26/min. Examination shows multiple small, erythematous nasal mucosal lesions. After the patient is stabilized, therapy for primary prevention of coronary artery disease should be switched to a drug with which of the following mechanisms of action?
ADirect inhibition of Factor Xa
BSequestration of Ca2+ ions
CPotentiation of antithrombin III
DBlockage of P2Y12 component of ADP receptors
EInhibition of vitamin K epoxide reductase
A 66-year-old woman presents to the emergency department complaining of palpitations. She says that she has been experiencing palpitations and lightheadedness for the past 6 months, but before this morning the episodes usually resolved on their own. The patient's medical history is significant for a transient ischemia attack 2 months ago, hypertension, and diabetes. She takes aspirin, metformin, and lisinopril. She states her grandfather died of a stroke, and her mom has a "blood disorder." An electrocardiogram is obtained that shows an irregularly irregular rhythm with rapid ventricular response, consistent with atrial fibrillation. She is given intravenous metoprolol, which resolves her symptoms. In addition to starting a beta-blocker for long-term management, the patient meets criteria for anticoagulation. Both unfractionated heparin and warfarin are started. Five days later, the patient begins complaining of pain and swelling of her left lower extremity. A Doppler ultrasound reveals thrombosis in her left popliteal and tibial veins. A complete blood count is obtained that shows a decrease in platelet count from 245,000/mm^3 to 90,000/mm^3. Coagulation studies are shown below: Prothrombin time (PT): 15 seconds Partial thromboplastin time (PTT): 37 seconds Bleeding time: 14 minutes Which of the following is the most likely diagnosis?
AThrombotic thrombocytopenic purpura
BType I heparin-induced thrombocytopenia
CWarfarin toxicity
DIdiopathic thrombocytopenia purpura
EType II heparin-induced thrombocytopenia
A 54-year-old man is brought to the emergency department 1 hour after the sudden onset of shortness of breath, severe chest pain, and sweating. He has hypertension and type 2 diabetes mellitus. He has smoked one pack and a half of cigarettes daily for 20 years. An ECG shows ST-segment elevations in leads II, III, and avF. The next hospital with a cardiac catheterization unit is more than 2 hours away. Reperfusion pharmacotherapy is initiated. Which of the following is the primary mechanism of action of this medication?
AConversion of plasminogen to plasmin
BInhibition of glutamic acid residue carboxylation
CBlocking of adenosine diphosphate receptors
DDirect inhibition of thrombin activity
EPrevention of thromboxane formation
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