• An enlarged spleen is not normal and occurs as a consequence of another underlying disease.
• An enlarged spleen is caused by
  • infections (mononucleosis, toxoplasmosis, endocarditis);
  • liver diseases (cirrhosis);
  • cancer;
  • inflammatory diseases (rheumatoid arthritis, sarcoidosis);
  • trauma; and
  • infiltrated diseases (Gaucher disease, amyloidosis).
• Signs of an enlarged spleen are usually due to underlying causes and may include
  • Weakness
  • Easy bruising and shortness of breath (anemia)
  • Weight loss (cancer)
  • Fever (infection)
  • Jaundice
  • Nausea and vomiting (liver disease)
• Symptoms of an enlarged spleen are usually due to the underlying disease or condition causing it; however, those individuals who do have symptoms 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.
• Diagnosis of an enlarged spleen is often made by physical examination or by X-rays, CT scan, MRI, or ultrasound
• Treatment for an enlarged spleen is directed to the care of the underlying condition.
• Enlarged spleen can be prevented by preventing the underlying illness as best as possible. An enlarged spleen is at risk for damage when it grows beyond the protection given to it by the lower ribs. Activity may need to be restricted to prevent any trauma or damage to the spleen when it is enlarged and vulnerable
• The prognosis of someone with an enlarged spleen depends upon the underlying condition.

The spleen is an important organ in the body that has a variety of responsibilities.

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

• 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.
• Because its location adjacent 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 are unable to eat large meals.

Often, it is not the enlarged spleen itself that causes symptoms, but rather it is the symptoms of the underlying illness that causes splenomegaly.

• Due to anemia, individuals may develop
  • weakness,
  • fatigue and
  • shortness of breath.
• Bleeding may occur spontaneously due to thrombocytopenia (low platelet count).
• Infections may occur more often because of ineffective white blood cell function.

The spleen is located in the left upper quadrant of the abdomen, just beneath the diaphragm and next to the stomach. It has a very rich blood supply since it is responsible for filtering blood, and it is protected by the 9th, 10th, and 11th ribs. Normally, it is the size of an orange or a small fist.

The spleen has two types of tissue; the red pulp is responsible for filtering blood, while the white pulp is responsible for its immune function.

Picture of the spleen

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

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 also affect 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.

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 the abnormal protein deposits.

Some infections may cause splenomegaly including:

• Infectious mononucleosis caused by the Epstein-Barr virus
• Cytomegalovirus
• HIV/AIDS
• Viral hepatitis
• Malaria
• Tuberculosis
• Anaplasmosis

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

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, misshapen red blood cells are filtered from the blood stream causing anemia and an enlarged spleen. Splenectomy limits the number of red blood cells destroyed and helps treat the disease.

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 for 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

• weakness,
• fatigue,
• dizziness,
• shortness of breath, and
• chest pain.

Thrombocytopenia (low platelet count) 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.

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

• Liver disease due to alcohol abuse, which causes cirrhosis and portal hypertension, can be prevented. With alcohol use, moderation is the key, and excessive drinking has very dangerous consequences both in the short and long term.
• Certain causes of viral hepatitis (for example, hepatitis B and hepatitis C), which can lead to cirrhosis also can be prevented by avoiding contact with body fluids from infected individuals. Hepatitis B can also be prevented through vaccination.

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.

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.