The spleen is a spongy organ about the size of a fist located in the upper left portion of the abdomen, towards the flank, behind the lower ribs. It is part of the lymphatic and immune system, helping the body fight off infections and clearing up the blood of waste products. Although people can live without a spleen, its absence can result in overwhelming bacterial infections if proper precautions are not taken.

Because of its role in the immune system, infections can affect the spleen, causing splenomegaly, or an enlarged spleen. Viral illnesses can cause splenomegaly. The most well-known one is mononucleosis, caused by the Epstein-Barr virus, which can cause splenomegaly and spleen fragility, to the point that the patient’s can sustain rupture of the spleen with severe trauma to the area. Other infections that can affect the spleen include hepatitis, malaria, and brucellosis (a rare bacterial infection caused by ingesting unsterilized milk or meat).

One of the functions of the spleen is to clear up the blood stream from cellular debris, particularly if there is breakdown of red blood cells. Therefore, conditions that result in the breakdown of red blood cells can affect the spleen, causing splenomegaly. One such condition is sickle cell disease, in which the red blood cells are fragile and break easily. The spleen stores these cells, becoming enlarged. Eventually the spleen can also trap normal red blood cells, leading to worsening anemia. Other blood conditions include hereditary spherocytosis and hereditary elliptocytosis, both conditions in which the red blood cells are abnormally shaped and fragile.

The spleen is a very vascular organ that can become engorged with blood, so rupture of the spleen can be potentially dangerous and life-threatening. Rupture of the spleen usually results from trauma, most notably car accidents. If the spleen ruptures, blood will seep into the abdominal cavity, causing pain. Patients with splenic rupture can become anemic quickly, resulting in cardiovascular compromise and the need for blood transfusions. The treatment for splenic rupture used to be removal of the spleen, but surgeons now try to salvage the spleen, as an absent spleen predisposes the body to serious bacterial infections.