Thrombocytopenia

Alternative names:

thrombocythemia

Definition:

Any of the bleeding disorders that result from a lack of functional platelets.

Causes, incidence, and risk factors:

Platelets are cells in the blood that are essential to blood clotting. Thrombocytopenia includes disorders where there are not enough platelets, and disorders where the platelets do not function properly.

These disorders include:

• idiopathic thrombocytopenic purpura (ITP)
• primary thrombocythemia
• thrombotic thrombocytopenic purpura
• drug-induced immune thrombocytopenia
• drug-induced nonimmune thrombocytopenia
• acquired platelet function defect
• congenital platelet function defects
• cyclic neutropenia