Even with a course of antibiotics and even with a history of relevant vaccination, persons without a functional spleen are at risk for Overwhelming post-splenectomy infection.In an emergency room or hospital setting, appropriate evaluation and treatment for an asplenic febrile patient should include a complete blood count with differential, blood culture with Gram stain, arterial blood gas analysis, chest x-ray, and consideration for lumbar puncture with CSF studies. None of these evaluations should delay the initiation of appropriate broad-spectrum intravenous antibiotics. The Surviving Sepsis Campaign guidelines state that antibiotics should be administered to a patient suspected of sepsis within 1 hour of presentation. Delay in starting antibiotics for any reason is associated with a poor outcome. Vaccinations
It is suggested that splenectomized persons receive the following vaccinations, and ideally prior to planned splenectomy surgery:

Pneumococcal polysaccharide vaccine (not before 2 years of age). Children may first need one or more boosters of  pneumococcal conjugate vaccine if they did not complete the full childhood series. Haemophilus influenzae type b vaccine, especially if not received in childhood. For adults who have not been previously vaccinated,  two doses given two months apart was advised in the new 2006 UK vaccination guidelines (in the UK may be given as a combined Hib/MenC vaccine). Meningococcal conjugate vaccine, especially if not received in adolescence. Previously vaccinated adults require a single booster and non-immunised adults advised, in UK since 2006, to have two doses given two months apart. Children too young for the conjugate vaccine should receive meningococcal polysaccharide vaccine in the interim.
Influenza vaccine, every winter, to help prevent getting secondary bacterial infection. Travel measures
In addition to the normal immunizations advised for the countries to be visited, Group A meningococcus should be included if visiting countries of particular risk (e.g. sub-saharan Africa). The non-conjugated Meningitis A and C vaccines usually used for this purpose give only 3 years coverage and provide less-effective long-term cover for Meningitis C than the conjugated form already mentioned.Those lacking a functional spleen are at higher risk of contracting malaria, and succumbing to its effects. Travel to malarial areas will carry greater risks and is best avoided. Travellers should take the most appropriate anti-malarial prophylaxis medication and be extra vigilant over measures to prevent mosquito bites.The pneumococcal vaccinations may not cover some of the other strains of pneumococcal bacteria present in other countries. Likewise, their antibiotic resistance may also vary, requiring a different choice of stand-by antibiotic. Additional measures
Surgical and dental procedures - Antibiotic prophylaxis may be required before certain surgical or dental procedures. Animal bites - adequate antibiotic cover is required after even minor dog or other animal bites. Asplenic patients are particularly susceptible to infection by capnocytophaga canimorsus and should receive a five-day course of amoxicillin/clavulanate (erythromycin in patients allergic to penicillin). Tick bites - Babesiosis is a rare tickborne infection. Patients should check themselves or have themselves inspected for tick bites if they are in an at-risk situation.