Meningitis Penicillin Allergy — SCE Infectious Diseases MCQ

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ModerateCNS InfectionMeningitis Penicillin AllergySCE Infectious Diseases

A 70-year-old man develops acute bacterial meningitis. He has significant penicillin allergy (anaphylaxis). CSF shows Gram-positive cocci in pairs. What empirical regimen should be used?

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Correct answer: C — IV Chloramphenicol (or IV Meropenem — low cross-reactivity in anaphylaxis)

In true penicillin anaphylaxis where cephalosporins are also avoided (due to potential cross-reactivity concern — though carbapenem cross-reactivity is <1%), IV Chloramphenicol is the traditional alternative for bacterial meningitis. Meropenem is increasingly used in practice given the very low (<1%) cross-reactivity between penicillins and carbapenems, even in anaphylaxis. Chloramphenicol achieves excellent CSF penetration. Vancomycin has poor CSF penetration unless meninges are inflamed. Adjunctive Dexamethasone should also be given if pneumococcal meningitis is suspected.

Reference: NICE CG102 2010 – Bacterial meningitis; BSAC/BIA 2016 – Meningitis in penicillin allergy