Amoxicillin-Induced Aseptic Meningitis

Amoxicillin is a semi-synthetic beta-lactam antibiotic that belongs to the penicillin family. It is the most prescribed antibiotic in the world. It has few side effects, even though hypersensitivity reactions may occur, with potential life-threatening effects. The authors present the case of a 63-year-old male admitted to the emergency department with a 2-week history of fever and occipital headache. The symptoms began after he started antibiotic prophylaxis with amoxicillin for a dental procedure. Cerebrospinal fluid analysis was suggestive of aseptic meningitis and the patient improved quickly after discontinuation of the drug. The patient’s previous medical history highlighted a similar episode after he had started taking amoxicillin as part of a scheme for the treatment of a Helicobacter pylori infection. Aseptic meningitis is an extremely rare adverse reaction of amoxicillin, with only 16 cases reported in the literature. LEARNING POINTS: Aseptic meningitis is a rare side effect of amoxicillin. It is a diagnosis of exclusion and establishing a chronological relationship between the administration of amoxicillin and the onset of clinical symptoms is a key element for the diagnosis. The physiopathology is not well defined, but the consensus is that it is most probably the result of an immunologic hypersensitivity reaction.