Increased splenic platelet sequestration can occur in various disorders that cause splenomegaly Splenomegaly Splenomegaly is abnormal enlargement of the spleen. (See also Overview of the Spleen.) Splenomegaly is almost always secondary to other disorders. Causes of splenomegaly are myriad, as are the... read more . However, thrombocytopenia that occurs in advanced cirrhosis Cirrhosis Cirrhosis is a late stage of hepatic fibrosis that has resulted in widespread distortion of normal hepatic architecture. Cirrhosis is characterized by regenerative nodules surrounded by dense... read more is mostly due to reduced thrombopoietin production by the liver (and consequent reduced platelet production) rather than splenic sequestration (1 General reference Increased splenic platelet sequestration can occur in various disorders that cause splenomegaly. However, thrombocytopenia that occurs in advanced cirrhosis is mostly due to reduced thrombopoietin... read more ). (See also Overview of Platelet Disorders Overview of Platelet Disorders Platelets are circulating cell fragments that function in the clotting system. Thrombopoietin helps control the number of circulating platelets by stimulating the bone marrow to produce megakaryocytes... read more .)
The platelet count usually is > 30,000/mcL (> 30 × 109/L) unless the disorder causing splenomegaly also impairs platelet production (eg, in myelofibrosis with myeloid metaplasia).
Sequestered platelets are released from the spleen at times of stress. Therefore, thrombocytopenia caused only by splenic sequestration rarely causes bleeding.
In patients with normal hepatic function, splenectomy corrects the thrombocytopenia; however, splenectomy is not indicated unless severe thrombocytopenia due to simultaneous bone marrow failure is present.
1. Peck-Radosavljevic M, Wichlas M, Zacherl J, et al: Thrombopoietin induces rapid resolution of thrombocytopenia after orthotopic liver transplantation through increased platelet production. Blood 95:795–801, 2009.