The spleen in the sickling disorders: an update.

In early life, patients with sickle cell disease (SCD) can have acute, life-threatening emergencies related to splenic hypofunction (overwhelming bacterial sepsis), as well as anemic crises from acute splenic sequestration because of sudden pooling of blood in the spleen. The landmark penicillin prophylaxis study in 1985 showed a remarkable decrease in mortality from sepsis in young children with SCD who were treated with oral penicillin prophylaxis compared to placebo. Since that study, newborns are screened for SCD and placed on oral penicillin prophylaxis in nearly all of the United States, as well as in other countries where the disease is highly prevalent. The previously described permanent, complete and nearly universal "autosplenectomy" emerging by late childhood or early adulthood is now challenged by recent findings of reversibility of splenic dysfunction by the antisickling drug hydroxyurea or by successful allogeneic stem cell transplantation, even in older patients. Imaging techniques for hypofunction of the spleen are the most commonly used modalities to guide the clinician in decisions regarding medical or surgical management.