The spleen is part of the lymphatic system and has a vital role in the body's immune system function. The spleen produces white blood cells (WBCs) that help fight infection; filters old, damaged blood cells from the circulatory system; and stores red blood cells (RBCs) and platelets. The spleen can be affected directly or indirectly as a result of trauma and disease. A diseased spleen may lead to anemia, frequent infections, bleeding disorders, and even rupture of the spleen.
Congestive Splenomegaly
Congestive splenomegaly is enlargement of the spleen caused by conditions that alter blood flow to and from the spleen or cause hypertrophy of the spleen (excessive spleen tissue production). These conditions interfere with the organ's ability to produce necessary WBCs and to effectively filter circulating blood. The spleen can literally become clogged, resulting in organ swelling. Causes include the following:
1. Hematopoietic diseases are those involving blood cell production and function. For example, blood disorders such as sickle cell disease (abnormal red blood cells) or polycythemia vera (production of too many RBCs), and hemolytic anemia (rapid destruction of RBCs) can clog the blood filtering system of the spleen.
2. Myeloid metaplasia of the spleen is overproduction of spleen tissue cells. The spleen hypertrophies (enlarges), allowing more blood cells and platelets to filter through.
3. Oncologic disorders (cancers) that affect the lymphatic and hematopoietic system such as Non Hodgkin's disease and leukemia affect the spleen.
4. Tumors, both benign and malignant, can impinge on normal spleen function, resulting in congestion and enlargement.
5. Splenitis is chronic or acute inflammation of the spleen caused by trauma or infections. Splenitis can lead to organ congestion and splenomegaly.
6. Felty's Syndrome is a condition associated with rheumatoid arthritis which causes splenomegaly, affecting production of infection fighting WBCs and platelets. This leads to neutropenia (decrease in a type of WBC) and thrombocytopenia (decreased platelets).
7. Banti's syndrome is a condition of the spleen that results secondary to complications of liver disease. Splenomegaly, anemia and thrombocytopenia occur.
Infectious Diseases
Viral, bacterial, and parasitic infections can alter spleen function. Mononucleosis is an acute viral infection that primarily affects lymphoid tissue. This infection causes the spleen to produce an abnormal number of certain WBCs. The spleen becomes enlarged.
Bacterial infections like syphilis cause splenomegaly and altered function. Parasitic infections such as malaria affect the spleen indirectly because the parasite attacks blood cells. High numbers of abnormal blood cells are filtered by the spleen. Simultaneously, the spleen must produce more infection fighting WBCs. Splenomegaly results.
Splenic Infarction
Arteries that feed the spleen can become blocked due to atherosclerosis or by blood clots or septic emboli from infections. Loss of blood supply to the organ leads to tissue death and subsequent loss of proper spleen function.
References
- Copstead, L. C., & Banasik, J. L. (2000). Pathophysiology: Biological and Behavioral Perspectives (2nd ed.). New York: Saunders.
- The Mayo Clinic
- Thomas, C. L. (1989). Taber's Cyclopedic Medical Dictionary (16th ed.). Philadelphia, PA: F. A. Davis Company.
