The spleen is an organ tucked away behind the stomach, on the left side of the abdomen. It has several immune and hematologic functions. Enlargement of the spleen is called splenomegaly. In the vast majority of cases, splenomegaly is secondary to other disorders because of its role in many metabolic processes.
Symptoms of Splenomegaly
In some cases, the presence of an enlarged spleen is asymptomatic. For this reason, splenomegaly may not be detected until very late, or until the spleen is ruptured by some accidental trauma.
When symptoms do occur, they include:
- Pain and feeling of abdominal fulness which may produce early satiety, produced by the pressure of the spleen on the stomach
- Persistent feeling of fulness of the stomach
- Hiccups
- Anemia
- Fatigue
- Recurrent infections
- Frequent hemorrhages
The last four symptoms are due to hypersplenism, which is often a sequel to splenomegaly. This causes cytopenia because of increased consumption of blood cells by the overactive spleen.
Causes
The spleen is enlarged in many conditions and splenomegaly may occur at any age. The etiology thus includes:
- Myeloproliferative diseases such as chronic lymphocytic leukemia, chronic myelogenous leukemia, large granular cell leukemia, polycythemia vera
- Lymphoproliferative diseases such as lymphoma especially of the hairy cell variety
- Lipid storage disorders such as Gaucher’s or Niemann-Pick disease
- Connective tissue disorders such as systemic lupus erythematosus
- Inflammatory disorders such as amyloidosis and sarcoidosis
- Viral infections such as cytomegalovirus or infectious mononucleosis
- Acute bacterial infections such as bacterial endocarditis
- Chronic bacterial infections including malaria, syphilis, brucellosis and miliary tuberculosis
- Liver diseases such as cirrhosis, or thrombosis of the portal or splenic veins, causing obstruction to hepatic blood flow and backing it up to the spleen
- Hemolytic anemia including those due to a hemoglobinopathy, such as thalassemia, with increased destruction of blood cells in the spleen; or abnormal red cell fragility, such as hereditary spherocytosis
- Splenic cysts such as those which follow an episode of hemorrhage into the spleen
Tropical splenomegaly is often due to chronic infections such as malaria, or kala-azar. Massive splenomegaly, where the spleen extends 8 cm or more below the left costal margin, is typically caused by a myeloproliferative disease, such as chronic lymphocytic or myelogenous leukemia, or polycythemia vera.
Risk Factors
Risk factors for splenomegaly include:
- Young people who acquire certain infections
- Those who have inherited metabolic disorders involving the spleen
- People who live in or travel in areas with endemic malaria
References
Further Reading
Avian flu crosses species, infecting cats and cattle in Texas and Kansas