hypersplenisme

Hypersplenism is a syndrome characterized by an enlarged spleen (splenomegaly) with excessive sequestration and destruction of blood cells, leading to cytopenias that are often greater than would be expected from the bone marrow study alone. The resulting anemia, leukopenia, and thrombocytopenia occur because red cells, white cells, and platelets are pooled and destroyed in the enlarged spleen.

Pathophysiology and presentation

An oversized spleen traps more blood cells, causing reduced circulating counts. The condition is usually associated with an underlying disease that enlarges the spleen, such as portal hypertension with cirrhosis, hematologic disorders (for example myeloproliferative diseases, leukemia, lymphoma), infections, inflammatory or autoimmune diseases, or hemolytic anemias. In hypersplenism, bone marrow function may be normal or hyperactive, and cytopenias improve if splenic sequestration is reduced or eliminated.

Causes

Common associations include portal hypertension and cirrhosis, chronic liver disease, myelofibrosis, leukemia, lymphoma, malaria, thalassemia, and autoimmune or inflammatory conditions. Hypersplenism is distinguished from splenomegaly alone by the presence of cytopenias attributable to splenic sequestration.

Diagnosis

Diagnosis rests on laboratory findings of cytopenias with a disproportionately enlarged spleen, often confirmed by imaging (ultrasound or CT). Bone marrow examination helps exclude marrow-intrinsic causes of cytopenias. Evaluation includes assessment for underlying etiologies such as liver disease, infection, or hematologic malignancy.

Management

Treating the underlying disease is primary. In cases with significant cytopenias or symptomatic splenomegaly, therapeutic splenectomy or partial splenectomy, or splenic embolization may be considered. Vaccination against encapsulated organisms is recommended before splenectomy, along with appropriate infection prophylaxis and monitoring for postsplenectomy sepsis. Supportive care might include transfusions and management of complications. Prognosis depends on the underlying condition and the severity of cytopenias.