Angiostrongyliasis in an Infant Presenting as Lymphocytic Meningitis.

Angiostrongylus cantonensis meningitis is a parasitic disease of the central nervous system. Its diagnosis is challenging because it shows nonspecific clinical signs. In Mayotte, France, cases are reported annually, mainly in children. The key indicator is the presence of eosinophilic meningitis. We report the case of an 11-month-old infant seen in Mayotte with altered consciousness and fever. Lumbar puncture revealed an elevated white blood cell count in the cerebrospinal fluid (CSF) with a 100% lymphocytic formula. A brain computed tomography suggested tuberculosis but did not exclude parasitic infection. Blood tests showed significant eosinophilia. Empirical treatment of tuberculous meningitis was started. A second lumbar puncture showed 13% eosinophils, and the polymerase chain reaction for A. cantonensis was positive. This atypical case of lymphocytic meningitis could have caused a diagnostic error. In cases with strong clinical suspicion and absence of initial eosinophilic meningitis, it is essential to repeat CSF analysis and consider antiparasitic therapy.