Potential complications of polycythemia vera is increased levels of circulating red blood cells, which increases the thickness or viscosity of the blood. This can be associated with higher risk of thrombus or clot formation leading to strokes, heart attacks, pulmonary embolism, and possibly death.
Another complication of polycythemia vera is the potential transformation into a blood cancer (leukemia), excessive bleeding (hemorrhage), or clotting problems.
Because of high turnover of blood cells in polycythemia, the excretion of the byproducts of red blood cell degradation may over burden the kidneys and result in kidney dysfunction, kidney stones, and gout.
Finally, there is the potential for myelofibrosis (spent marrow), in which the blood-forming marrow elements are eventually taken over by scar tissue resulting in anemia from marrow failure.
Complications of secondary polycythemia are typically related to those of the underlying disease. For example, chronic hypoxia from severe lung disease may be complicated by right sided heart failure and pulmonary hypertension. Chronic heart failure can lead to generalized swelling or edema (anasarca), low blood pressure, kidney dysfunction, and poor functional status.
In neonatal (infant) polycythemia, increased blood thickness or viscosity can affect several organs due to poor blood flow. As a result, kidney dysfunction, intestinal problems, increased blood pressure in the lungs, and hypoxia may ensue.