Sinogenic intracranial infection in an older patient with absent meningeal signs: A case report and literature review

A 74-year-old male presenting with headache, high fever, and mental malaise was diagnosed with intracranial infection based on magnetic resonance imaging. The patient initially responded poorly to broad-spectrum antibiotic therapy. A multidisciplinary team review of imaging and dedicated sinus computed tomography results revealed pansinusitis and a right sphenoid bone wall defect, confirming a sinogenic origin. Functional endoscopic sinus surgery was performed followed by systemic antibiotics therapy and intrathecal injection, and the infection was eventually controlled. For intracranial infections with poor initial response, sinogenic sources should be investigated even in the absence of nasal symptoms. Meningeal irritation signs are often absent in older patients; the triad of headache, fever, and mental malaise warrants particular clinical attention. Source control and sustained anti-infective therapy under multidisciplinary collaboration are the key to successful treatment.