A patient has an increased red count, hemoglobin, and hematocrit. ...

[Pea0909berry]

A patient has an increased red count, hemoglobin, and hematocrit. Which of the following features points to secondary polycythemia over polycythemia vera?
 
  a. Increased white count
  b. Increased red cell mass
  c. Bone marrow erythroid hyperplasia
  d. Decreased arterial oxygen saturation

Question 2

Which of the following is an expected finding in polycythemia vera?
 
  a. Thrombocytosis
  b. Anemia
  c. Low leukocyte alkaline phosphatase
  d. Normal white count

[Mochi]

Answer to Question 1

ANS: D
Decreased arterial oxygen saturation is characteristic of secondary polycythemia. Arterial oxygen saturation is normal in polycythemia vera. Decreased arterial oxygen saturation leads to hypoxia, resulting in increased production of erythropoietin. This stimulates the bone marrow to increase red cell production (erythroid hyperplasia), also found in polycythemia vera. This results in an increase in red cell mass, again also found in polycythemia vera, as is an increased white count.

Answer to Question 2

ANS: A
Thrombocytosis, or an elevated platelet count, is characteristically present in polycythemia vera. Polycythemia vera has an elevated red cell mass, so anemia is not present. The leukocyte alkaline phosphatase score and the white count are both elevated.