Enlarged spleen (splenomegaly)

Overview

Your spleen is an organ that sits just below your left rib cage. Many conditions — including infections, liver disease and some cancers — can cause an enlarged spleen. An enlarged spleen is also known as splenomegaly (spleh-no-MEG-uh-lee).

An enlarged spleen usually doesn't cause symptoms. It's often discovered during a routine physical exam. A doctor usually can't feel the spleen in an adult unless it's enlarged. Imaging and blood tests can help identify the cause of an enlarged spleen.

Treatment for an enlarged spleen depends on what's causing it. Surgery to remove an enlarged spleen usually isn't needed, but sometimes it's recommended.

Symptoms

An enlarged spleen typically causes no signs or symptoms, but sometimes it causes:

• Pain or fullness in the left upper belly that can spread to the left shoulder
• A feeling of fullness without eating or after eating a small amount because the spleen is pressing on your stomach
• Low red blood cells (anemia)
• Frequent infections
• Bleeding easily

When to see a doctor

See your doctor promptly if you have pain in your left upper belly, especially if it's severe or the pain gets worse when you take a deep breath.

Causes

A number of infections and diseases can cause an enlarged spleen. The enlargement might be temporary, depending on treatment. Contributing factors include:

• Viral infections, such as mononucleosis
• Bacterial infections, such as syphilis or an infection of your heart's inner lining (endocarditis)
• Parasitic infections, such as malaria
• Cirrhosis and other diseases affecting the liver
• Various types of hemolytic anemia — a condition characterized by early destruction of red blood cells
• Blood cancers, such as leukemia and myeloproliferative neoplasms, and lymphomas, such as Hodgkin's disease
• Metabolic disorders, such as Gaucher disease and Niemann-Pick disease
• Pressure on the veins in the spleen or liver or a blood clot in these veins
• Autoimmune conditions, such as lupus or sarcoidosis

How the spleen works

Your spleen is tucked below your rib cage next to your stomach on the left side of your belly. Its size generally relates to your height, weight and sex.

This soft, spongy organ performs several critical jobs, such as:

• Filtering out and destroying old, damaged blood cells
• Preventing infection by producing white blood cells (lymphocytes) and acting as a first line of defense against disease-causing organisms
• Storing red blood cells and platelets, which help your blood clot

An enlarged spleen affects each of these jobs. When it's enlarged, your spleen may not function as usual.

Risk factors

Anyone can develop an enlarged spleen at any age, but certain groups are at higher risk, including:

• Children and young adults with infections, such as mononucleosis
• People who have Gaucher disease, Niemann-Pick disease, and several other inherited metabolic disorders affecting the liver and spleen
• People who live in or travel to areas where malaria is common

Complications

Potential complications of an enlarged spleen are:

• Infection. An enlarged spleen can reduce the number of healthy red blood cells, platelets and white cells in your bloodstream, leading to more frequent infections. Anemia and increased bleeding also are possible.
• Ruptured spleen. Even healthy spleens are soft and easily damaged, especially in car crashes. The possibility of rupture is much greater when your spleen is enlarged. A ruptured spleen can cause life-threatening bleeding in your belly.