How Does Splenomegaly Cause Thrombocytopenia?

No platelets are stored in the bone marrow. If a condition causes the spleen to enlarge (splenomegaly), the spleen will function abnormally, sequestering up to 90% of the total platelet mass in the spleen. The result is a decrease in circulating platelets (thrombocytopenia).

Why does an enlarged spleen cause thrombocytopenia?

The spleen helps filter the blood. It also stores some blood cells, including platelets. If the spleen is enlarged, it can store too many platelets. This causes there to be fewer platelets in the blood than normal.

How does the spleen affect platelets?

The enlarged spleen traps platelets and other blood cells and prevents them from circulating in the blood stream.