An enlarged spleen is not a disease in itself but the result of an underlying disorder. Many disorders can make the spleen enlarge.
Many disorders, including infections, anemias, and cancers, can cause an enlarged spleen.
Symptoms are usually not very specific but can include fullness or pain in the upper left abdomen or back.
Usually doctors can feel an enlarged spleen, but ultrasonography and other imaging tests may be used to determine how large the spleen is.
Treating the disorder that is causing the spleen to enlarge usually takes care of the problem, but sometimes the spleen must be removed.
(See also Overview of the Spleen Overview of the Spleen The spleen, a spongy, soft organ about as big as a person’s fist, is located in the upper left part of the abdomen, just under the rib cage. The splenic artery brings blood to the spleen from... read more .)
To pinpoint the cause of an enlarged spleen, doctors must consider disorders ranging from chronic infections to blood cancers.
An enlarged spleen may outgrow its own blood supply. When parts of the spleen do not get enough blood, they may become damaged, causing them to bleed or die.
Hypersplenism
The spleen normally removes old and/or damaged red blood cells from the bloodstream. However, when the spleen enlarges, it traps and stores an excessive number of red blood cells, causing anemia Overview of Anemia Anemia is a condition in which the number of red blood cells is low. Red blood cells contain hemoglobin, a protein that enables them to carry oxygen from the lungs and deliver it to all parts... read more . Sometimes, the spleen also destroys white blood cells and/or platelets causing a low white blood cell count (leukopenia Overview of White Blood Cell Disorders White blood cells (leukocytes) are an important part of the body’s defense against infectious organisms and foreign substances ( the immune system). To defend the body adequately, a sufficient... read more 
) and a low platelet count (thrombocytopenia Overview of Thrombocytopenia Thrombocytopenia is a low number of platelets (thrombocytes) in the blood, which increases the risk of bleeding. Thrombocytopenia occurs when the bone marrow makes too few platelets or when... read more 
). This process creates a vicious circle: the more cells the spleen traps, the larger it grows, and the larger it grows, the more blood cells it traps and destroys.
Symptoms of an Enlarged Spleen
An enlarged spleen usually does not cause many symptoms, and the symptoms that it does cause may be mistaken for many other medical conditions. Because the enlarged spleen lies next to the stomach and sometimes presses against it, people may feel full after eating a small snack or even without eating. People may also have abdominal or back pain in the area of the spleen in the upper left part of the abdomen or the left side of the back. The pain may spread to the left shoulder, especially if parts of the spleen do not get enough blood and start to die.
If hypersplenism causes severe anemia, people may be tired and short of breath. People may also have frequent infections as a result of too few white blood cells, and the tendency to bleed as a result of too few platelets.
Diagnosis of an Enlarged Spleen
Imaging of the abdomen
Blood tests
Doctors may suspect that the spleen is enlarged when people complain of fullness or pain in the upper left portion of the abdomen or back. Usually, doctors can feel an enlarged spleen during a physical examination.
An x-ray of the abdomen done for other reasons may also show that the spleen is enlarged. Ultrasonography Ultrasonography Ultrasonography is a type of medical imaging that uses high-frequency sound (ultrasound) waves to produce images of internal organs and other tissues. During an ultrasound, a device called a... read more 
or computed tomography Computed Tomography (CT) Computed tomography (CT) is a type of medical imaging that combines a series of x-rays to create cross-sectional, detailed images of internal structures. In computed tomography (CT), which used... read more 
(CT) is usually needed to determine how large the spleen is and whether it is pressing on other organs. Magnetic resonance imaging Magnetic Resonance Imaging (MRI) Magnetic resonance imaging (MRI) is a type of medical imaging that uses a strong magnetic field and very high frequency radio waves to produce highly detailed images. During an MRI, a computer... read more 
(MRI) provides similar information and also traces blood flow through the spleen. Other specialized scanning techniques use mildly radioactive particles to assess the spleen’s size and function and to determine whether it is accumulating or destroying large numbers of blood cells.
Blood tests show decreased numbers of red blood cells, white blood cells, and platelets. When blood cells are examined under a microscope, their shape and size may provide clues to the cause of the spleen enlargement. An examination of bone marrow Bone Marrow Examination Red blood cells, most white blood cells, and platelets are produced in the bone marrow, the soft fatty tissue inside bone cavities. Sometimes a sample of bone marrow must be examined to determine... read more may show cancer of the blood cells (such as leukemia Overview of Leukemia Leukemias are cancers of white blood cells or of cells that develop into white blood cells. White blood cells develop from stem cells in the bone marrow. Sometimes the development goes awry... read more or lymphoma Overview of Lymphoma Lymphomas are cancers of lymphocytes, which reside in the lymphatic system and in blood-forming organs. Lymphomas are cancers of a specific type of white blood cells known as lymphocytes. These... read more 
) or an accumulation of unwanted substances (such as occurs in storage diseases). Blood protein measurement can suggest other conditions that can cause the spleen to enlarge, such as amyloidosis Amyloidosis Amyloidosis is a rare disease in which abnormally folded proteins form into collections called amyloid fibrils that accumulate in various tissues and organs, sometimes leading to organ dysfunction... read more 
, sarcoidosis Sarcoidosis Sarcoidosis is a disease in which abnormal collections of inflammatory cells (granulomas) form in many organs of the body. Sarcoidosis usually develops in people aged 20 to 40 years, most often... read more 
, malaria Malaria Malaria is infection of red blood cells with one of five species of the protozoa Plasmodium. Malaria causes fever, chills, sweating, a general feeling of illness (malaise), and sometimes... read more , visceral leishmaniasis Leishmaniasis Leishmaniasis is caused by 20 or more species of the protozoa Leishmania. Leishmaniasis includes several disorders that affect the skin, the mucous membranes of the nose, mouth, or throat... read more 
, brucellosis Brucellosis Brucellosis is an infection caused by several species of the gram-negative bacteria Brucella and characterized by fever and bodywide symptoms. Brucellosis is acquired mainly by having... read more , and tuberculosis Tuberculosis (TB) Tuberculosis is a chronic contagious infection caused by the airborne bacteria Mycobacterium tuberculosis. It usually affects the lungs, but almost any organ can be involved. Tuberculosis... read more 
. Liver tests Liver Blood Tests Liver tests are blood tests that represent a noninvasive way to screen for the presence of liver disease (for example, viral hepatitis in donated blood) and to measure the severity and progress... read more help determine whether the liver is also diseased.
Doctors cannot easily remove a sample of the spleen for examination because inserting a needle or cutting spleen tissue may cause uncontrollable bleeding. If an enlarged spleen is removed during surgery to diagnose or treat certain diseases, the spleen is sent to a laboratory, where the cause of enlargement can usually be determined.
Treatment of an Enlarged Spleen
Treatment of the underlying disorder
Sometimes removal of the spleen
When possible, doctors treat the underlying disorder that caused the enlarged spleen. People with an enlarged spleen should avoid contact sports and weight-lifting because an enlarged spleen is more likely to tear, causing uncontrollable bleeding.
The spleen may need to be surgically removed if hypersplenism causes severe problems. Surgical removal of the spleen (splenectomy) should be avoided whenever possible because it can cause problems, including an increased susceptibility to infections by certain bacteria. However, the risks are worth taking in certain critical situations:
When the spleen is severely damaged after an injury
When the spleen destroys red blood cells so rapidly that severe anemia develops
When the spleen so depletes stores of white blood cells that infection is likely
When the spleen so depletes stores of platelets that bleeding is likely
When the spleen is so large that it causes pain or puts pressure on other organs or causes early feelings of fullness after eating only a small amount
When the spleen is so large that parts of it bleed or die
As an alternative to surgery, radiation therapy can sometimes be used to shrink the spleen.
People who have had their spleen removed need to be vaccinated Overview of Immunization Immunization (vaccination) helps the body defend itself against diseases caused by certain bacteria or viruses. Immunity (the ability of the body to defend itself against diseases caused by... read more against infections caused by Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus influenzae. They should also make sure they receive the influenza vaccine Influenza Vaccine The influenza virus vaccine helps protect against influenza. Two types of influenza virus, type A and type B, regularly cause seasonal epidemics of influenza in the United States. There are... read more every year as well as the COVID-19 vaccine COVID-19 Vaccine Coronavirus disease 2019 (COVID-19) vaccines provide protection against COVID-19. COVID-19 is the disease caused by infection with the SARS-CoV-2 virus. There are multiple COVID-19 vaccines... read more .
After splenectomy, people are particularly susceptible to severe sepsis Sepsis and Septic Shock Sepsis is a serious bodywide response to bacteremia or another infection plus malfunction or failure of an essential system in the body. Septic shock is life-threatening low blood pressure ... read more , particularly if they regularly come into contact with children, and they may have to take antibiotics daily to prevent infections.
