Delayed Hydrocephalus Following Listeria monocytogenes Meningitis in an Immunocompetent Child.

Listeria monocytogenes meningitis in immunocompetent pediatric patients may present as a severe central nervous system infection and requires prompt recognition and appropriate antimicrobial therapy. We report the case of a previously healthy twelve-year-old boy who presented with acute-onset fever, severe holocranial headache, nausea, and recurrent vomiting consistent with bacterial meningitis. Given his stable neurological examination without focal deficits or signs of increased intracranial pressure, brain magnetic resonance imaging was performed as the initial neuroimaging study and demonstrated diffuse leptomeningeal enhancement without ventricular dilation, with radiologic findings compatible with ependymitis. Empiric intravenous ceftriaxone and vancomycin were initiated. Cerebrospinal fluid culture subsequently confirmed Listeria monocytogenes, and antimicrobial therapy was adjusted to targeted intravenous ampicillin, resulting in defervescence within 48 hours, complete resolution of headache and vomiting, and a progressive decrease in inflammatory markers. One week after hospital discharge, the patient returned with worsening headache, persistent vomiting, and anisocoria, consistent with acute increased intracranial pressure. A non-contrast head computed tomography scan performed at a secondary-level medical unit revealed obstructive hydrocephalus. Given the presence of neurological deterioration and radiological findings, repeat imaging was not performed, and the patient was transferred directly to the operating room for urgent ventriculoperitoneal shunt placement. The postoperative course was favorable, with resolution of anisocoria and progressive improvement in headache and vomiting. Neurological stability was maintained during follow-up. This case highlights the potential for delayed hydrocephalus following apparent clinical recovery from Listeria meningitis and underscores the importance of microbiological confirmation, timely antimicrobial adjustment, and structured neurological follow-up.