Hypersplenism is an overactive spleen. Your spleen is a fist-sized organ located behind your stomach and just under your left rib cage. It has two main functions: to store blood and to remove old or damaged blood cells from your bloodstream.

When your spleen’s overactive, or “hyper,” it removes too many blood cells, including healthy ones. Without enough healthy, mature blood cells, your body has a harder time fighting infections and you may become anemic. Anemia occurs when your blood doesn’t have the proper amount of oxygen, due to a low number of red blood cells.

There are two types of hypersplenism:

  • primary, in which there is no known cause
  • secondary, in which hypersplenism is related to another disorder

Essentially, any disorder that causes enlargement of the spleen (splenomegaly) can cause hypersplenism. That’s because as your spleen becomes enlarged, it holds more and more blood cells. This includes damaged and healthy blood cells. This stops your healthy blood cells from circulating and allowing your body to perform its functions and fight disease.

Conditions that can lead to an enlarged spleen and, thus, hypersplenism are:

  • Chronic liver diseases. These include hepatitis C, which causes inflammation of your liver, and cirrhosis, a liver disease in which scar tissue takes over healthy liver tissue. Cirrhosis caused by consuming too much alcohol as well as nonalcoholic cirrhosis can both cause hypersplenism.
  • Infections. This includes malaria, a flu-like illness carried by mosquitos, and tuberculosis, a bacterial lung disease.
  • Autoimmune diseases. These conditions, such as lupus and rheumatoid arthritis, cause widespread inflammation.
  • Gaucher disease. This inherited disease causes fats to build up in your spleen.
  • Cancer. One type of cancer that may cause enlargement is lymphoma, a cancer of your lymphatic system, which includes your spleen.

You may not be able to tell that your spleen is working overtime, but there are clues:

  • You have an enlarged spleen. In some cases, your spleen can become so large that you may feel pain or fullness in the left upper portion of your chest. You may also have no symptoms, although your doctor can feel an enlarged spleen when checking your abdomen.
  • You feel abnormal fullness, even after eating a small amount.
  • Your level of red blood cells (also called cytopenia) is reduced, as evidenced by a blood test.
  • Your likelihood of infections increases due to fewer disease-fighting blood cells circulating in your blood.
  • You have anemia, a condition in which you don’t have enough red blood cells or hemoglobin, a protein that carries oxygen in your blood. Symptoms can include headache, weakness, shortness of breath, and feeling cold.

Diagnosis is generally made based on:

  • a physical exam in which your doctor will check for an enlarged spleen
  • blood tests to examine your concentration of red and white blood cells
  • imaging tests, such as an ultrasound, to help visualize your spleen

Your doctor will also take into account your medical history. They’ll look for typical signs of hypersplenism, such as anemia and your body’s inability to fight off infections.

Treating hypersplenism involves treating the underlying condition causing it.

Those with cirrhosis may benefit from dietary changes. These changes may include avoiding alcohol and using diuretics to flush out excess fluids. Hepatitis C can be treated with antiviral medications. If you have tuberculosis, your doctor will prescribe antibiotics.

In some cases, your doctor may recommend radiation to shrink your spleen. In one study, low-dose radiation reduced the size of the spleen in 78 percent of participants and improved anemia in another 75 percent.

In severe cases of hypersplenism, removal of the spleen (called a splenectomy) may be necessary. In many cases this can be done laparoscopically, which involves passing a lighted instrument through small incisions to remove your spleen.

According to research, people who had their spleens removed laparoscopically due to cirrhosis and secondary hypersplenism had:

  • decreased blood loss
  • shorter hospitals stays
  • better postsurgical function of their livers

While people without a spleen do have a greater risk of developing infections than those who have their spleen intact, your other organs can usually compensate for the lost spleen and perform its necessary functions. It’s important, however, to keep up with vaccinations and receive a flu shot every year if appropriate. Your doctor can advise you on what’s necessary.

Hypersplenism can cause some significant health problems, including anemia and an increased risk of infection. However, unless your case is particularly severe or complicated, the underlying cause can be detected and successfully treated. Your spleen will then generally return to its normal size and take up its normal function.

If you recognize any of the symptoms of hypersplenism, see your doctor. As with most conditions, the earlier hypersplenism is treated, the better the outcome.