pneumococci. Trimethoprim/sulfamethoxazole and the macrolides do not have consistent
activity against penicillin-resistant pneumococci (PRP). The decision to broaden the gram-
negative coverage to other gram negatives includingP. aeruginosashould be based on Gram
stain results. In patients with known or suspected central nervous system infections,
vancomycin with or without rifampin plus a third-generation cephalosporin is the most
optimal initial therapy. Intravenous immunoglobulin is another intervention that has been
shown to decrease mortality in asplenic animals (49,50). Granulocyte-macrophage colony–
stimulating factor has increased macrophage bactericidal activity in eusplenic and asplenic
mice. Treated animals have had improved survival after pneumococcal challenge (51).
Babesiosis in the asplenic host is best treated with a combination of clindamycin and quinine.
Exchange transfusions to lower high levels of parasitemia also have been used (52,53).
Intravascular volume deficits should be corrected aggressively. Other therapeutic
modalities, such as vasopressors, may be warranted in selected cases. The use of high-dose
steroid has not been demonstrated to be beneficial.
Prevention
Preventive strategies fall into three major categories: education, immunoprophylaxis, and
chemoprophylaxis (33,54).
Education
It represents a mandatory strategy in attempting to prevent OPSI. A low level of knowledge
regarding OPSI risk can exist at the patient, family, and even the health care worker level. Most
patients with asplenia (11% to 50%) remain unaware of their increased risk of serious infection
or the appropriate health precautions that should be undertaken (55,56). Asplenic patients
should be encouraged to wear a Medi-Alert bracelet or necklace and carry a wallet explaining
their lack of spleen and other medical details (33). Patients should be explained regarding the
potential seriousness of postsplenectomy sepsis and rapid time course of progression. Patients
should be instructed to notify their physician in the event of any acute febrile illness and
proceed to nearest emergency department. They should inform any new health care provider,
including their dentist, of their asplenic or hyposplenic status. Patients should also be educated
regarding travel-related infections such as malaria and babesiosis. Malaria chemoprophylaxis
relevant to the local pattern of infestation should be prescribed and preventive measures
implemented to reduce mosquito bites (33,54). They should also be educated regarding prompt
treatment of even minor dog or other animal bites.
Immunoprophylaxis
Vaccination is a very important strategy in preventing OPSI. Asplenia or hyposplenism itself is
not a contradiction for routine immunization including live vaccines. Vaccination significantly
reduces the risk of bacteremia of any cause beyond the postoperative period, and vaccinated
patients carry a lower risk of infection than non-vaccinated ones (57).
Pneumococcal Vaccine
Efficacy of pneumococcal polysaccharide vaccine in preventing postsplenectomy infections
has not been determined. Most virulent pneumococcal serotypes tend to be the least
immunogenic, and the efficacy of vaccine is poorest in younger patients who would be at the
highest risk (58,59). Studies indicate that 30% to 60% postsplenectomy patients never receive
the pneumococcal vaccine (55,56). Pneumococcal vaccination should be performed at least two
weeks before an elective splenectomy (60). If this could not be done then patients should be
vaccinated as soon as possible after surgical recovery and before discharge from hospital.
Unimmunized patients who are splenectomized should be immunized at the first opportunity.
The immunogenicity of the vaccine is reduced if it is given after splenectomy or while the
patient is receiving cancer therapy (58). For this reason the manufacturer recommends that the
immunization be delayed for at least six months following immunosuppressive chemotherapy
or radiotherapy. Revaccination is recommended for persons two years of age or older who are
at highest risk for serious pneumococcal infections. Revaccination in three years may be
354 Ahmed and Khardori