• Clinical science



Splenomegaly is enlargement of the spleen. The etiology is diverse and may result from increased splenic activity, decreased venous drainage, or infiltration of the spleen. Symptoms are seldom caused by the size of the spleen directly, but rather due to its hematologic effects on the different cell lines, which manifest as anemia, leucopenia, thrombocytopenia, or as a combination of these (i.e., pancytopenia). Diagnosis can be made by palpation of the spleen in the left upper quadrant, especially on deep inspiration. Imaging studies such as sonography and CT help detect subclinical splenomegaly. Refractory symptoms may necessitate a splenectomy. Vaccination against encapsulated pathogens is essential to reduce the incidence of overwhelming post-splenectomy infection (OPSI).


Cause Pathophysiology Associated diseases
Increased splenic activity
  • Increased degradation of defective or structurally abnormal blood cells (work hypertrophy)
Decreased venous drainage
Splenic infiltration
  • Suppression of splenic tissue


Massive splenomegaly

Myeloproliferative disorders are commonly accompanied by splenomegaly!



  • Definition: an overactive spleen
  • Causes: see “Increased splenic activity” in the table above
  • Pathomechanism: overactive spleen → cells are removed from the blood faster than normal → ↓ of a single or combination of cell lines, including possible cytopenia (pancytopenia; , leukopenia; , anemia, and thrombocytopenia) → reactive bone marrow hyperplasia (unless defective bone marrow is the cause of splenomegaly)
  • Clinical features
  • Treatment
    • Treatment of underlying disease
    • Splenectomy in case of symptomatic cytopenia
      • After splenectomy there is an increased risk of infection by encapsulated pathogens, possibly leading to overwhelming post-splenectomy infection (OPSI) → prevention with vaccinations against pneumococci, meningococci, and Haemophilus influenzae type B
      • Although not an encapsulated organism, a yearly influenza vaccine is also recommended