Splenomegaly (Enlarged Spleen)

Overview

Splenomegaly means the spleen has become larger than normal. The spleen is a fist-sized organ tucked under the ribs in the upper left abdomen. It filters the blood, removes old or damaged blood cells, and helps the immune system fight infection. Normally it cannot be felt during an exam, so a spleen large enough to feel is a sign that something is going on in the body.

An enlarged spleen is not a disease in itself but a clue to an underlying cause, which ranges from common infections to liver disease and blood disorders. Many people have no symptoms and the enlargement is found during an exam or scan done for another reason. Because the spleen sits high under the left rib cage, a clinician can sometimes feel its lower edge when it grows large enough. An enlarged spleen is more fragile than a normal one and can rupture if injured, so people with splenomegaly are usually advised to avoid contact sports and heavy lifting until it resolves.

Common Causes

The spleen enlarges when it is working harder, holding more blood, or being infiltrated by abnormal cells. Common causes include:

• Infections: Mononucleosis (Epstein-Barr virus) is a classic cause; others include malaria, certain bacterial and parasitic infections, and hepatitis.
• Liver disease: Cirrhosis and portal hypertension cause blood to back up into the spleen.
• Blood disorders: Hemolytic anemias, thalassemia, and sickle cell disease.
• Blood cancers: Leukemia and lymphoma.
• Inflammatory conditions: Rheumatoid arthritis, lupus, and sarcoidosis.
• Congestion and clots: Blockage of veins draining the spleen.

Because the list of causes is broad, finding the reason for an enlarged spleen is an important part of the evaluation.

Associated Symptoms

Many people with splenomegaly feel nothing, but when symptoms occur they may include:

• Fullness or discomfort in the upper left abdomen, sometimes spreading to the left shoulder
• Feeling full quickly after eating only a little, because the spleen presses on the stomach
• Fatigue and frequent infections, if blood cells are being removed too quickly
• Easy bruising or bleeding
• Symptoms of the underlying cause, such as fever, night sweats, weight loss, or jaundice

Sudden, severe pain in the upper left abdomen can mean the spleen has ruptured, which is a life-threatening emergency requiring immediate care.

Diagnosis & Evaluation

An enlarged spleen may be found when a clinician feels it during a physical exam or sees it on imaging. Because the goal is to identify the cause, evaluation often includes:

• Blood tests, including a complete blood count to check red cells, white cells, and platelets.
• Imaging, usually ultrasound or CT, to confirm and measure the enlargement and examine the liver.
• Tests for infection, such as mononucleosis or malaria testing.
• Liver function tests to look for liver disease.
• Bone marrow examination if a blood disorder or cancer is suspected.

Treatment & Management

Treatment is directed at the underlying cause rather than the spleen itself. Examples include:

• Rest and supportive care for viral infections such as mononucleosis, which usually resolve on their own
• Specific medicines for malaria or other infections
• Treatment of liver disease or the condition causing portal hypertension
• Chemotherapy or other therapy for blood cancers
• Managing blood disorders that overload the spleen

When the spleen is very large, causes serious symptoms, or destroys too many blood cells, removing it (splenectomy) may be considered. People who have had their spleen removed or who have splenomegaly are advised on vaccinations and avoiding injury, since the spleen helps fight certain infections and an enlarged one can rupture. In most cases, treating the cause allows the spleen to gradually return to its normal size over weeks to months, and follow-up imaging or examination can confirm that it has settled.

When to See a Doctor

See a doctor if you have ongoing fullness or pain in the upper left abdomen, feel full quickly, or have fatigue, frequent infections, or easy bruising. Seek emergency care right away for:

• Sudden, sharp, severe pain in the upper left abdomen
• Pain spreading to the left shoulder, especially after an injury
• Signs of internal bleeding such as fainting, a racing heart, or pale clammy skin

If you have a known enlarged spleen, avoid contact sports and heavy lifting until your clinician says it is safe.

Related Topics

Frequently Asked Questions

References

1. Mayo Clinic. Enlarged spleen (splenomegaly) — Symptoms and causes.
2. MedlinePlus, U.S. National Library of Medicine. Enlarged spleen.
3. National Heart, Lung, and Blood Institute (NHLBI). Spleen Disorders.
4. Merck Manual Consumer Version. Enlarged Spleen.