Polycythemia

Polycythemia refers to a condition where the number of red blood cells and hemoglobin content per unit volume of blood are higher than the upper limit of the reference range. Common symptoms include headache, dizziness, fatigue, blurred vision, and tinnitus. Polycythemia can be primarily classified into relative and absolute polycythemia. The latter can be further divided into primary and secondary types. Primary polycythemia can be congenital or acquired, with the acquired form typically referring to polycythemia vera.