#may2020mccqe1
A 55-year-old man has a 1-year history of fatigue, chronic morning headache, daytime hypersomnolence, and frequent nighttime awakenings. The patient has hypertension
and a 48-pack-year smoking history. His only medication is lisinopril. His family history is noncontributory. On physical examination, temperature is normal, blood pressure is 135/85 mm Hg, pulse rate is 88/min, and respiration rate is 28/min. BMI is 35. The examination is otherwise unremarkable.
Hematocrit 53% (normal 5 years ago)
Leukocyte count 5700/μL (5.7 × 109/L)
Platelet count 345,000/μL (345 × 109/L)
Erythropoietin Elevated
Arterial oxygen saturation (on ambient air) 98%
Cytogenetic studies are negative for the JAK2 gene mutation. Which of the following is the most likely cause of the patient's elevated hematocrit?
(A) High-oxygen-affinity hemoglobin
(B) Polycythemia vera
(C) Sleep apnea
(D) Volume contraction
A 55-year-old man has a 1-year history of fatigue, chronic morning headache, daytime hypersomnolence, and frequent nighttime awakenings. The patient has hypertension
and a 48-pack-year smoking history. His only medication is lisinopril. His family history is noncontributory. On physical examination, temperature is normal, blood pressure is 135/85 mm Hg, pulse rate is 88/min, and respiration rate is 28/min. BMI is 35. The examination is otherwise unremarkable.
Hematocrit 53% (normal 5 years ago)
Leukocyte count 5700/μL (5.7 × 109/L)
Platelet count 345,000/μL (345 × 109/L)
Erythropoietin Elevated
Arterial oxygen saturation (on ambient air) 98%
Cytogenetic studies are negative for the JAK2 gene mutation. Which of the following is the most likely cause of the patient's elevated hematocrit?
(A) High-oxygen-affinity hemoglobin
(B) Polycythemia vera
(C) Sleep apnea
(D) Volume contraction
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