Question

Jenny, a healthy young woman, had a battery of tests during a physical for a new job. Her RBC count was at the higher end of the normal range at that time, but four weeks later it was substantially elevated beyond that. When asked if any circumstances had changed in her life, she admitted to taking up smoking. How might her new habit explain her higher RBC count? Jenny, a healthy young woman, had a battery of tests during a physical for a new job. Her RBC count was at the higher end of the normal range at that time, but four weeks later it was substantially elevated beyond that. When asked if any circumstances had changed in her life, she admitted to taking up smoking. How might her new habit explain her higher RBC count? Several compounds found in cigarette smoke have been found to stimulate secretion of EPO, which is the main regulator of erythropoiesis. Cigarette smoke contains toxins that promote the proliferation and differentiation of proerythroblasts in red bone marrow. The frequent hypoxia resulting from inhalation of oxygen-poor smoke is causing secondary polycythemia. The nicotine contained in the cigarette smoke is causing polycythemia vera, which can result in a hematocrit as high as 80%.

Answer 1

The right answer is The third proposition (The frequent hypoxia...)

Polycythemia is characterized by an elevation of Hte and Hb due to an increase in total erythrocyte volume (TEV).

Polycythemia can be secondary to hypoxia (chronic respiratory insufficiency, heart disease, prolonged stay in altitude, smoking) or inappropriate secretion of EPO (kidney disease), or primitive (Vaquez disease).