An enlarged spleen often causes no symptoms. Some people, however, may experience one or more of the following symptoms of enlarged spleen:

• Pain in the left upper abdomen that may spread to the left shoulder
• Feeling full without eating or after eating only a small amount — this can occur when an enlarged spleen presses on your stomach
• Anemia
• Fatigue
• Frequent infections
• Easy bleeding

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

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Your spleen is tucked under your rib cage next to your stomach on the left side of your abdomen. It's a soft, spongy organ that performs several critical jobs and can be easily damaged. Among other things, your spleen:

• Filters out and destroys old and damaged blood cells
• Plays a key role in preventing infection by producing white blood cells called lymphocytes and acting as a first line of defense against invading pathogens
• Stores blood and platelets, the cells that help your blood clot
• May act as an intermediary between your immune system and your brain, leading researchers to speculate that they may one day be able to trigger the spleen's infection-fighting abilities by manipulating the nervous system

An enlarged spleen affects each of these vital functions. For instance, as your spleen grows larger, it begins to filter normal red blood cells as well as abnormal ones, reducing the number of healthy cells in your bloodstream. It also traps too many platelets. Eventually, excess blood cells and platelets can clog your spleen, interfering with its normal functioning. An enlarged spleen may even outgrow its own blood supply, which can damage or destroy sections of the organ.

What causes it?
A number of infections and diseases can contribute to an enlarged spleen, including:

• 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 premature destruction of red blood cells
• Blood cancers, such as leukemia and Hodgkin's disease
• Metabolic disorders, such as Gaucher's disease and Niemann-Pick disease
• Pressure on the veins in the spleen or liver or a blood clot in these veins

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Although anyone can develop an enlarged spleen at any age, children with infections such as mononucleosis are at especially high risk. So are people of African descent, who may develop splenomegaly as a complication of sickle cell disease.

People of Ashkenazi Jewish ancestry are at higher risk of Gauchers disease and Niemann-Pick disease and are therefore more prone to develop an enlarged spleen. Travelers to areas where malaria is endemic also are potentially at higher risk.

©1998-2009 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.

Because an enlarged spleen can reduce the number of healthy red blood cells, platelets and white cells in your bloodstream, you may develop anemia, increased bleeding or frequent infections. More serious is the risk of a ruptured spleen. Even healthy spleens are soft and easily damaged, especially in car crashes. When your spleen is enlarged, the possibility of rupture is far greater. A ruptured spleen can cause life-threatening bleeding into your abdominal cavity.

©1998-2009 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.

An enlarged spleen is usually detected during a physical exam. Your doctor can often feel the enlargement by gently examining your left upper abdomen, just under your rib cage. Keep in mind that some people, especially those who are slender, may have healthy, normal-sized spleens that can be felt during an exam.

The diagnosis is usually confirmed with blood tests and an imaging study of your abdomen, such as an ultrasound or computerized tomography (CT) scan. These tests can help determine the size of your spleen and whether it's crowding other organs. Magnetic resonance imagining (MRI) may be used to trace blood flow through the spleen.

In general, you don't need any special preparation for an ultrasound or MRI. If you're having a CT scan, however, you may need to refrain from eating before the test. If you need to prepare, your doctor will let you know well in advance.

Finding the cause
Sometimes you may need further testing to identify what's causing an enlarged spleen, including liver function tests and a bone marrow exam, which can give more detailed information about your blood cells than can blood drawn from a vein.

In some cases, a sample of solid bone marrow is removed in a procedure called a bone marrow biopsy. Or, you may have a bone marrow aspiration, which removes the liquid portion of your marrow. In many cases, both procedures are performed at the same time (bone marrow exam).

Both the liquid and solid bone marrow samples are frequently taken from the same place on the back of one of your hipbones. A needle is inserted into the bone through an incision. Because bone marrow tests are painful, you'll receive either general or local anesthesia before the test.

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Treatment of an enlarged spleen is usually aimed at the underlying problem. Antibiotics may be used to treat infections, for instance, and chemotherapy or radiation may help bring Hodgkin's disease into remission.

If an enlarged spleen causes serious complications or the underlying problem can't be identified or treated, surgical removal of your spleen (splenectomy) may be an option. In fact, in chronic or critical cases, surgery may offer the best hope for recovery.

But elective spleen removal requires careful consideration. You can live an active life without a spleen, but you're more likely to contract serious or even life-threatening infections, including overwhelming post-splenectomy infection, which can occur soon after the operation. Sometimes, radiation can shrink your spleen so that you can avoid surgery.

Reducing infection risk after surgery
If you do have your spleen removed, certain steps can help reduce your risk of infection, including:

• A series of vaccinations both before and after the splenectomy. These include the pneumococcal (Pneumovax), haemophilus influenzae type b (Hib), and meningococcal vaccines, which protect against pneumonia, meningitis, and infections of the blood, bones and joints.
• Taking penicillin or other antibiotics after your operation — sometimes for life.
• Avoiding travel to parts of the world where diseases such as malaria are endemic.

©1998-2009 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.

If you have an enlarged spleen, avoid contact sports — such as soccer, football and hockey — and limit other activities as recommended by your doctor. Modifying your activities can reduce the risk of a ruptured spleen.

It's also important to wear a seat belt. If you're in an accident, a seat belt can help prevent injury to your spleen.

©1998-2009 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.