Autosplenectomy

An autosplenectomy (from 'auto-' self, '-splen-' spleen, '-ectomy' removal) occurs when a disease damages the spleen to such an extent that it becomes shrunken and non-functional.

Consequences

Main article: Asplenia

Absence of effective splenic function (asplenia) is associated with increased risks of overwhelming post splenectomy infection, especially by encapsulated organisms. Protocols involving vaccination and prophylactic antibiotics can reduce these risks.

Diseases that cause autosplenectomy

Sickle cell anemia

The most frequent cause of autosplenectomy is sickle cell anemia, the result of hypoxia and infarcts in the spleen. Since in the spleen blood flow is sluggish, the oxygen tension is low. When red blood cells with hemoglobin S are exposed to this low oxygen tension, they tend to aggregate and polymerize. Sickled cells also express more adhesion molecules and appear more sticky. The sickle cells arrest in the hypoxic vascular bed in the spleen, resulting in a vicious cycle: decrease in O2, sickling and vascular obstruction from thrombus formation. Initially the spleen is enlarged, then progressively becomes smaller. The stasis of flow in the spleen causes hypoxic damage, thrombosis, infarction and fibrosis. In the end, the spleen “disappears” completely.

Systemic lupus erythematosus

Systemic lupus erythematosus (SLE) — the most prevalent variety of an autoimmune disorder known as lupus — may also cause autosplenectomy.

Pneumococcal septicemia

Pneumococcal septicemia, or whole-body infection caused by the Streptococcus pneumoniae bacteria, has been reported to cause autosplenectomy.