Which of the following is a hematologic symptom of polycythemia?

Polycythemia is characterized by an increased concentration of red blood cells in the blood, leading to increased blood viscosity. This condition often results in a variety of hematologic symptoms due to the elevated red blood cell mass.

Thrombocytopenia, or reduced platelet count, can be seen in cases of polycythemia, particularly in newborns. The increased blood viscosity can lead to complications that affect the bone marrow's ability to produce other blood components, resulting in thrombocytopenia. Moreover, in polycythemia, the higher red blood cell count may not always ensure a proportional increase in platelets, potentially causing a relative decrease in platelet numbers.

In contrast, lethargy, severe jaundice, and hyperglycemia are symptoms that can be associated with other conditions. Lethargy may arise due to various causes such as infection or nutritional deficiencies, severe jaundice is commonly linked to conditions like hemolytic disease of the newborn, and hyperglycemia is typically associated with metabolic issues unrelated to polycythemia itself. Therefore, recognizing thrombocytopenia as a hematologic symptom specifically highlights the inherent complications that can arise from an abnormal increase in red blood cell mass, such as polycythemia.