Platelets (thrombocytes) are small pieces of cells that play an important role in blood clotting by clumping and forming plugs when necessary. Thrombocytopenia (throm-boh-sigh-toe-PEE-nee-uh) is a condition in which blood has too few platelets. Causes of thrombocytopenia include increased breakdown and destruction of platelets (related to a problem with the immune system), reduced production of platelets or platelets trapped in the spleen.

Thrombocytopenia can occur as a result of a separate disorder, such as leukemia, bone marrow failure (aplastic anemia), an immune system problem or as a medication side effect. The most common reason for thrombocytopenia in children is idiopathic thrombocytopenic purpura (ITP). Idiopathic means unknown cause. ITP occurs when the immune system mistakenly attacks and destroys platelets. Recent viral infections can lead to short-term ITP in children. If ITP in children lasts longer than six months, it is known as chronic ITP.

Nov. 20, 2012