Chemoprophylaxis

Data concerning the effects of longterm antibiotic therapy in asplenic patients is not conclusive.

There is good evidence that penicillin is effective in preventing pneumococcal infection in Jamaican children with sickle-cell anaemia.

Lifelong prophylactic antibiotics should be offered in all cases where a patient has an absent or dysfunctional spleen, especially in the first two years after splenectomy, for all children aged up to 16, and when there is underlying impaired immune function (3).

A first-line regimen is (3,4):

• amoxicillin 250-500 mg daily for adults
• amoxicillin 125mg daily for children 5-14 years old
• amoxicillin 10 mg/kg/d in children under 5 yr of age

Allergic patients should be given (3,4):

• in subjects allergic to beta-lactams, the use of a macrolide is frequently recommended
  • erythromycin 250-500 mg daily in adults and in children over 8 yr
  • erythromycin 250 mg daily in children aged 2-8 yr
  • erythromycin 125 mg daily in children aged under 2 yr
  • however some authors also suggest cotimoxazole as an alternative if allergic to beta-lactams

If chemoprophylaxis is terminated, the patient should be given a small supply of the antibiotics to start immediately if they experience flu-like symptoms.

Notes:

• the advantages of amoxicillin over penicillin in adults are that it is better absorbed as an oral preparation and it has a broader spectrum and a longer shelf life (3)
• phenoxymethylpenicillin does not cover H influenzae and neither does amoxicillin reliably (3)
• a more recent review notes that other authors suggest use of phenoxymethylpenicillin rather than amoxicillin (4):
  • penicillin V 250mg-500mg bd for adults
  • penicilling V 250mg bd for children 3-14 years old

Reference:

1. Editorial.BMJ 1993; 307: 1372-3.
2. Mayon-White, R.. Protection for the asplenic patient. Prescriber's Journal 1994; 34 (5): 165-166.
3. Working Party of the British Committee for Standards in Hematology Task Force. Guidelines for the prevention and treatment of infection in patients with an absent or disfunctional spleen. BMJ 1996;312:430-434.
4. Castagnola .E, Fioredda F. Prevention of life-threatening infections due to encapsulated bacteria in children with hyposplenia or asplenia: a brief review of current recommendations for practical purposes. European Journal Of Haematology 2003;71 (5): 319-326.