PREVENTION OF OPSI
While mortality rates may be modestly reduced with prompt identification and treatment of a developing infection, the key to reducing the mortality associated with OPSI lies in preventing asplenia. Emergency care of patients with blunt abdominal trauma currently involves the use of selective criteria that discourage immediate removal of the spleen in favor of careful assessment and nonoperative management of splenic injuries.19 If the spleen must be removed because of excessive bleeding, surgeons frequently employ techniques for partial splenectomy, depending on the extent of the injury.20 Procedures involving autotransplantation of resected splenic tissue have also allowed the patient to preserve some immunologic function.21
When a total splenectomy becomes necessary, prevention of infection is the optimal goal. This is accomplished through the use of three effective strategies.
Immunization, the first of these strategies, is essential to prevent disease caused by the encapsulated bacteria S pneumoniae. The 23 serotypes of pneumococci covered by the polysaccharide vaccine are responsible for about 90% of pneumococcal infections in the United States.22 Updated guidelines put forth by the Working Party of the Haematology/Oncology Task Force of the British Committee for Standards in Haematology suggest that the vaccine should be given at least 2 weeks before an elective splenectomy, if possible. In situations involving emergent splenectomy, unimmunized patients should receive the vaccine shortly after surgery. Reimmunization is recommended every 5 to 10 years but may be required more frequently in patients with lymphoproliferative disorders or sickle cell anemia, as identified by declining antibody levels. Children younger than 2 years should receive vaccination with the conjugate heptavalent pneumococcal vaccine because of their reduced ability to mount an antibody response to the polysaccharide vaccine. Patients should also be immunized against disease caused by the two other encapsulated bacteria, H influenzae and N meningitidis, and a yearly influenza vaccine is recommended.23 The 2009 Recommended Adult Immunization Schedule put forth by the CDC's Advisory Committee on Immunization Practices suggests very similar guidelines.24 Patients who travel frequently may need additional immunizations.
The second strategy for prevention of infection is the use of daily prophylactic antibiotics. Prophylaxis is widely advocated for asplenic children younger than 5 years and is usually prescribed for a period of at least 2 years following splenectomy. The American Academy of Pediatrics Committee on Infectious Diseases recommends penicillin V potassium 125 mg twice a day for children younger than 3 years and 250 mg twice a day for children older than 3 years, with discontinuation at age 5 years in healthy immunized children.25 In asplenic adults, however, there is much controversy surrounding the use of prophylactic antibiotics. This is partly because the lifelong risk of sepsis in this group requires long-term use of maintenance doses. Continuous antibiotic use over an extended period can lead to poor compliance, which may increase the risk of developing antibiotic-resistant strains of bacteria. Chemoprophylaxis can also provide a false sense of security, which may be dangerous should symptoms of infection occur.26 A better alternative is to provide the adult patient with a 5-day supply of standby antibiotics, such as amoxicillin/clavulanate 500 mg/125 mg every 8 hours or cefuroxime axetil 250 mg every 12 hours, either of which can be self-administered at the first sign of infection. A fluoroquinolone with gram-positive activity, such as moxifloxacin 400 mg/d, is a viable alternative, especially for patients with a penicillin allergy.16 Patients who start standby antibiotics should be advised to seek professional medical care as soon as possible.
Education is the third component necessary for successful prevention of postsplenectomy infection. Patients should be made aware of their increased risk of developing lifethreatening sepsis through discussion and the provision of reading material appropriate to their educational level. Degree of patient understanding should be carefully assessed. The sample patient information sheet offers suggestions for educational material designed to enhance patients' knowledge and increase their confidence in their ability to manage any illnesses (see Figure 2). Asplenic patients should be urged to seek medical attention at the first sign of infection and to communicate their asplenic status to the person scheduling their appointment so they can be seen promptly. Patients should also be encouraged to wear an identification bracelet or carry a wallet card notifying others of their condition in emergency situations. Asplenic persons traveling to areas with a high incidence of B microti infection, such as Cape Cod and Nantucket Island in Massachusetts, or to areas where malaria is endemic should be counseled about their increased susceptibility to such infections.17
The life-threatening nature of OPSI has been recognized for many years. However, despite generalized knowledge of prophylactic measures, studies have shown that recommended guidelines are not being followed by a large percentage of providers and their patients.6,27 This may, in part, result from lack of a systematic approach to identifying and following atrisk patients.28 When treating patients with routine illnesses, primary care providers need to be aware of any past surgical procedures that may have included splenectomy. They also need to be aware of declining splenic function in their patients with hematologic diseases and to consider the possibility of asplenia in patients with other predisposing conditions. The charts of these individuals should be flagged, and checklists should be utilized to ensure that prophylactic recommendations are being followed (see Figure 3). This is especially important in patient populations whose poor access to health care is likely to result in low immunization rates. At future appointments, a flagged chart will serve as a visible reminder to assess the patient's presenting complaints for any similarities to the symptoms of OPSI, increasing the chances that an infection will be caught early and treated before fulminant sepsis develops.
CONCLUSION
While the risk of contracting OPSI is relatively low for many asplenic individuals, it is a lifetime risk. The mortality rate associated with this rapidly progressing infection is alarmingly high. Identification of those at risk and routine systematic administration of prophylactic measures for these patients can further reduce their incidence of infection and improve outcomes. Patients who are educated about their condition can learn to recognize warning symptoms and take the necessary steps to protect themselves from serious illness. For those who do develop sepsis, immediate empiric antibiotic treatment offers the best opportunity for survival and limits the associated complications. A committed partnership between patient and provider will assure the best outlook for the patient's continued good health. JAAPA
Sandra Moffett is a PA with Lancaster Neuroscience and Spine Associates in Lancaster, Pennsylvania. She has indicated no relationships to disclose relating to the content of this article.
DRUGS MENTIONED
Amoxicillin/clavulanate (Augmentin)
Ceftriaxone (Rocephin, generics)
Cefuroxime axetil (Ceftin, Zinacef)
Moxifloxacin (Avelox)
Penicillin
Penicillin V potassium
Vancomycin (Vancocin, generics)
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