In which condition that cause polycythemia, is the serum erythropoietin extremely low?
A. Dehydration
B. Renal cell carcinomaC. Polycythemia vera
D. Cyanotic heart disease
Ans. C. Polycythemia vera
Polycythemia
vera is a neoplastic disorder of myeloid stem cells that tend to differentiate
predominantly along the erythroid lineage, giving rise to polycythemia. The
neoplastic erythroid progenitor cells require extremely small amounts of
erythropoietin for survival and proliferation, and hence the levels of
erythropoietin are virtually undetectable in polycythemia vera. In all other
conditions erythropoietin levels are elevated to produce excess red cells.
Erythropoietin secretion is triggered by anoxia in high-altitude dwellers and
persons with cyanotic heart disease. Renal tumors produce erythropoietin and
trigger a paraneoplastic erythrocytosis. In dehydration, transient polycythemia
is caused by hemoconcentration. This does not affect normal erythropoietin
secretion.
