COMSAE - Comprehensive Osteopathic Medical Self-Assessment Examination Cardiovascular and Hematologic Systems Questions and Answers — Questions and Answers
Question 1: A 72-year-old male presents with exertional dyspnea and a harsh, crescendo-decrescendo systolic murmur best heard at the right upper sternal border. Which of the following physical exam findings would be most consistent with severe aortic stenosis?
- A brisk, collapsing carotid pulse
- A widely split S2 that increases with inspiration
- A low-amplitude and delayed carotid upstroke (Correct answer)
- A holosystolic murmur radiating to the axilla
Correct answer: A low-amplitude and delayed carotid upstroke
Severe aortic stenosis classically presents with a 'pulsus parvus et tardus,' which is a weak (parvus) and delayed (tardus) carotid upstroke, due to the obstruction of left ventricular outflow. A brisk, collapsing pulse is seen in aortic regurgitation. A widely split S2 is associated with conditions like pulmonic stenosis or right bundle branch block. A holosystolic murmur radiating to the axilla is characteristic of mitral regurgitation.
Question 2: A 55-year-old male with a history of ST-elevation myocardial infarction (STEMI) is being discharged. In addition to aspirin and a P2Y12 inhibitor, which of the following medication classes provides a mortality benefit and should be initiated prior to discharge for secondary prevention?
- Nitrates
- Calcium channel blockers
- Beta-blockers (Correct answer)
- Loop diuretics
Correct answer: Beta-blockers
For secondary prevention after an acute coronary syndrome, beta-blockers, ACE inhibitors/ARBs, and statins have been shown to provide a mortality benefit. Beta-blockers reduce myocardial oxygen demand, decrease the risk of ventricular arrhythmias, and have anti-hypertensive effects. Nitrates are used for symptom control of angina but do not offer a mortality benefit. Calcium channel blockers are second-line agents for symptom control if beta-blockers are contraindicated or not tolerated. Loop diuretics are used for managing symptoms of heart failure but do not have a primary role in secondary prevention of ACS unless heart failure is present.
Question 3: A 68-year-old female is diagnosed with multiple myeloma. Her initial lab work shows a hemoglobin of 9.2 g/dL, serum creatinine of 2.5 mg/dL, and serum calcium of 12.1 mg/dL. An X-ray reveals multiple lytic lesions in the vertebrae. Which of these findings is NOT part of the classic CRAB criteria for diagnosing symptomatic multiple myeloma?
- Hypercalcemia (Calcium > 11 mg/dL)
- Renal insufficiency (Creatinine > 2 mg/dL)
- Anemia (Hemoglobin < 10 g/dL)
- Thrombocytosis (Platelets > 450,000/µL) (Correct answer)
Correct answer: Thrombocytosis (Platelets > 450,000/µL)
The CRAB criteria are used to identify end-organ damage in multiple myeloma and are an indication to begin treatment. The acronym stands for: C - Calcium elevation (>11 mg/dL), R - Renal insufficiency (serum creatinine >2 mg/dL or creatinine clearance <40 mL/min), A - Anemia (hemoglobin <10 g/dL or >2 g/dL below the lower limit of normal), and B - Bone disease (one or more osteolytic lesions). Thrombocytosis is not part of the CRAB criteria; in fact, thrombocytopenia can sometimes be seen in advanced disease due to bone marrow infiltration.
Question 4: A patient is hospitalized and receives unfractionated heparin for a deep vein thrombosis. Five days later, their platelet count drops from 250,000/µL to 90,000/µL, and a new pulmonary embolism is suspected. What is the most likely underlying pathophysiology of this condition?
- Direct heparin-induced platelet aggregation
- Autoantibody formation against the heparin-platelet factor 4 (PF4) complex (Correct answer)
- Vitamin K antagonism leading to decreased platelet production
- Bone marrow suppression from a direct toxic effect of heparin
Correct answer: Autoantibody formation against the heparin-platelet factor 4 (PF4) complex
This clinical scenario is classic for Heparin-Induced Thrombocytopenia (HIT), specifically type II. The pathophysiology involves the formation of IgG antibodies against the complex formed by heparin and platelet factor 4 (PF4). This antibody-heparin-PF4 complex then binds to and activates platelets via their FcγIIa receptors, leading to platelet aggregation, thrombocytopenia, and a paradoxical prothrombotic state. Type I HIT is a non-immune, direct effect of heparin causing mild, transient thrombocytopenia without thrombosis.
Question 5: A 22-year-old male of Mediterranean descent presents with fatigue, jaundice, and dark urine after being treated with a sulfonamide antibiotic for a urinary tract infection. A complete blood count reveals normocytic anemia, and a peripheral smear shows Heinz bodies and bite cells. This presentation is most characteristic of a deficiency in which of the following enzymes?
- Pyruvate kinase
- Glucose-6-phosphate dehydrogenase (Correct answer)
- Fibrinogen
- Factor VIII
Correct answer: Glucose-6-phosphate dehydrogenase
This patient's presentation is classic for Glucose-6-phosphate dehydrogenase (G6PD) deficiency, an X-linked recessive disorder. G6PD is crucial for protecting red blood cells from oxidative stress. Exposure to triggers like certain drugs (e.g., sulfonamides, primaquine), infections, or fava beans causes oxidative damage to hemoglobin, leading to the formation of Heinz bodies and subsequent extravascular hemolysis by splenic macrophages, creating 'bite cells'. Pyruvate kinase deficiency also causes hemolytic anemia but is not typically triggered by oxidative stress in this manner. Fibrinogen and Factor VIII are clotting factors, and deficiencies would lead to bleeding disorders.
Question 6: Which of the following coagulation factors are dependent on Vitamin K for their synthesis and function?
- Factors V, VIII, and XI
- Factors I (Fibrinogen), V, and XIII
- Factors II, VII, IX, and X (Correct answer)
- Factors XI, XII, and prekallikrein
Correct answer: Factors II, VII, IX, and X
The synthesis of several crucial coagulation factors requires vitamin K as a cofactor for a post-translational modification called gamma-carboxylation. This modification allows the factors to bind calcium and interact with phospholipid surfaces. The vitamin K-dependent clotting factors are Factors II (prothrombin), VII, IX, and X, as well as the anticoagulant proteins C and S.
COMSAE - Comprehensive Osteopathic Medical Self-Assessment Examination Cardiovascular and Hematologic Systems Questions and Answers
A 72-year-old male presents with exertional dyspnea and a harsh, crescendo-decrescendo systolic murmur best heard at the right upper sternal border.
Which of the following physical exam findings would be most consistent with severe aortic stenosis?