Recurrent Aseptic Meningitis Without Identifiable Pathogens: A Case Report.

Recurrent meningitis without an identifiable pathogen is an infrequent but taxing diagnostic dilemma, particularly when multiple systemic comorbidities obscure both the clinical picture and the laboratory data. A 66-year-old man with dyslipidemia, diabetes, hypertension, ischemic cardiomyopathy, and a left ventricular thrombus experienced five meningitic episodes over six years. Each event featured holocephalic headache radiating to the neck, neck stiffness, vomiting, transient dysarthria, and gait ataxia. The cerebrospinal fluid (CSF) consistently showed lymphocytic pleocytosis (6-48 cells/mm), elevated protein (75-142 mg/dL), and sterile cultures. Serial viral polymerase chain reaction (PCR) panels, bacterial and mycobacterial studies, fungal cultures, extended autoimmune screens, complement levels, and paraneoplastic panels were negative. Brain magnetic resonance imaging (MRI) revealed pachymeningeal enhancement without parenchymal lesions. Empiric antivirals and broad-spectrum antibiotics were commenced but discontinued once repeated microbiological testing remained negative. The patient received supportive care, namely, analgesia, hydration, and close neurological monitoring, under a multidisciplinary team comprising neurology, infectious disease, and cardiology specialists. Symptoms resolved within five days; inflammatory markers and CSF indices normalized, and he was discharged with outpatient follow‑up. When exhaustive investigations fail to reveal an infectious or systemic cause, idiopathic aseptic meningitis should be considered. Optimal care hinges on a structured diagnostic algorithm, early involvement of multiple specialties, and judicious avoidance of unnecessary antimicrobials. Documenting and sharing such cases refines clinical awareness and may eventually elucidate the still-obscure mechanisms driving idiopathic recurrent meningitis.