Infection associated with asplenia: risks, mechanisms, and prevention.

The risk of overwhelming sepsis in asplenic patients has been recognized increasingly over the past several decades, but the underlying mechanisms are not fully understood, and there is controversy over the true magnitude of risk and the value of specific interventions. Review of recent series indicates that postsplenectomy sepsis is more likely after splenectomy in childhood than after splenectomy in adulthood but may occur after splenectomy at any age. In some cases, sepsis has been documented many years after surgery. The pneumococcus remains the predominant organism, and the characteristic course is rapid progression to multisystem involvement with high morbidity and mortality. Predisposition to pneumococcal sepsis and to other infections reflects the role of the spleen in mechanical filtration of particulate material in the bloodstream, generation of opsonins and other soluble mediators of phagocytosis, and anatomic juxtaposition of different elements of the immune system. Whereas pneumococcal vaccine is indicated in asplenic patients, the value of other interventions requires further evaluation.