Enlarged Spleen (Splenomegaly)

Medically Reviewed on 6/21/2023

What is the spleen? What is its function?

An enlarged spleen can cause liver disease, lupus, and mono.

The spleen is an important organ in the body that has a variety of responsibilities, such as:

  • It is a major blood filter, which helps remove old and damaged red blood cells and bacteria.
  • It is part of the lymphatic system and produces lymphocytes (a type of white blood cell that is a part of the immune system that helps to prevent and fight infection).
  • It acts as a reservoir for red blood cells and platelets, should the body need them.

What type of pain does an enlarged spleen cause?

Because of its location, should it enlarge, the spleen can irritate the diaphragm and cause hiccups and perhaps some pain in the left upper quadrant of the abdomen. Additionally, due to its adjacent location to the diaphragm, pain from the spleen may radiate to the back and be felt in the shoulder blade.

If the enlarged spleen compresses the stomach, the person may feel full after eating a small amount and therefore be unable to eat large meals.

What causes an enlarged spleen?

Potential causes of an enlarged spleen include the following:

Blood disorders

The spleen will enlarge when it performs more of its duties to filter blood or manufacture blood cells. Therefore, any disease or condition that damages red blood cells, and requires them to be filtered and removed from the bloodstream, will cause the spleen to become larger.

Conditions such as hemolytic anemia, where red blood cells are damaged and broken down (hemolyzed) can cause the spleen to enlarge. Misshapen red blood cells, like those found in sickle cell disease, thalassemia, and spherocytosis, may be damaged when they try to squeeze through small capillary blood vessels. These damaged red blood cells need to be culled from the bloodstream and filtered out by the spleen.

Decreased blood flow

The spleen will enlarge if there is a decrease in blood flow through the splenic vein. This may cause spleen congestion and enlargement. This situation may be associated with liver disease and portal hypertension. Damage to liver cells makes it difficult for blood to flow normally, and as blood backs up in the portal vein system, it may affect the pressure in the splenic vein. The decreased ability of blood to drain from the spleen causes it to become congested and grow larger. People with congestive heart failure may have an enlarged liver and spleen because of poor blood flow to and from the heart.


Leukemia and lymphoma may be associated with abnormal white cells that can invade the spleen and increase its size.

Other cancers can spread or metastasize to the spleen and cause it to enlarge.

Metabolic diseases

Certain metabolic diseases may cause the spleen to enlarge, including Hurler Syndrome, Gaucher disease, and Niemann-Pick Disease.

In sarcoidosis and amyloidosis, the spleen can be involved and become enlarged with abnormal protein deposits.


Some infections may cause splenomegaly including:


Trauma, for example, from a car accident, can damage the spleen.


Symptoms of Mono: Infectious Mononucleosis Treatment See Slideshow

What are signs and symptoms of an enlarged spleen?

Often, an enlarged spleen causes no symptoms or signs itself, but they are due to an underlying illness that causes splenomegaly. However, those people who do have symptoms of an enlarged spleen may experience:

  • Indigestion and a feeling of fullness because the enlarged spleen can compress the stomach.
  • Hiccups because of diaphragm irritation.
  • Pain in the upper abdomen that may radiate to the back or shoulder blade.

Examples of illnesses that cause signs and symptoms may include:

What tests diagnose an enlarged spleen?

An enlarged spleen is most often found on physical examination. Either the health care practitioner is looking for an enlarged spleen because of a diagnosis that has already been made, or it is found incidentally when initially examining a patient (and it then serves as a clue to an underlying diagnosis).

With its location protected beneath the left lower ribs, a normal spleen is usually not felt on physical exam, except in some unusually thin individuals. As it enlarges, the spleen grows from the left upper quadrant of the abdomen towards the umbilicus (the belly button). Sometimes the doctor will ask the patient to roll on their right side to better attempt to feel the spleen. An enlarged spleen may not be felt in obese patients.

On occasion, an enlarged spleen may be diagnosed by plain X-ray, ultrasound, abdominal CT scan, or MRI (magnetic resonance imaging).

What is the treatment for an enlarged spleen?

Because splenomegaly is due to an underlying illness, treatment will depend upon the primary cause. In some situations, removal of the spleen (splenectomy) may be part of the treatment. For example, in hereditary spherocytosis, a condition in which red blood cells are abnormal and shaped like a sphere instead of a concave disk shape. These abnormal red blood cells are filtered from the bloodstream, which causes anemia and an enlarged spleen. Splenectomy limits the number of red blood cells destroyed and helps treat the disease.

There are no natural treatments for an enlarged spleen.

What is the prognosis for an enlarged spleen?

Often, the prognosis for an enlarged spleen depends entirely upon the underlying illness. For example, in patients with infectious mononucleosis, the spleen will return to its normal size once the infection resolves.

In some instances, the spleen may need to be removed and the risk of infection may increase. In other cases, the spleen will remain enlarged and leave the patient at an increased risk for bleeding, spleen rupture, and infection.

What complications are associated with an enlarged spleen?

Perhaps the most important worry with an enlarged spleen is the risk of injury as it grows beyond the protection of the rib cage. A minor injury may cause it to rupture and bleed. Spleen injuries are often treated by observation, but on occasion, the spleen can rupture causing life-threatening internal bleeding requiring surgery to remove the spleen. This is the reason that teenagers and young adults diagnosed with infectious mononucleosis need to wait until the spleen returns to its normal size, and is protected by the rib cage, before participating in activities where the enlarged spleen could be damaged.

All types of blood cells may become trapped in a large spleen. Anemia (low red blood cell count) may cause:

Low platelet count (thrombocytopenia) may be associated with an increased risk of bleeding.

Leukopenia (low white blood cell count) may be associated with an increased risk of infection.

Should the spleen need to be removed surgically (splenectomy), the risk of certain infections increases and the patient will need to make certain that their immunizations are up to date, especially against pneumococcus, meningococcus, and haemophilus influenzae.

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Can an enlarged spleen be prevented?

An enlarged spleen is the consequence of an underlying illness, many of which may not be anticipated or prevented.

Finally, certain infectious diseases such as HIV, malaria, tuberculosis, and anaplasmosis can be prevented if the appropriate measures are taken to minimize the risks of acquiring the disease.

Medically Reviewed on 6/21/2023

Hillman,R, et al. "Hematology in Clinical Practice." 5th edition. McGraw Hill Education. 2010

Rakel RE, Rakel DR. Textbook of Family Medicine. 9th edition. Saunders. 2015.