Diagnosis of Acute Isolated Sphenoid Sinusitis Based on a Positive Kernig Sign in a Pediatric Patient.

Acute isolated sphenoid sinusitis in children is relatively rare, often presents with atypical symptoms, and may result in intracranial complications; therefore, early diagnosis is essential. We report the case of a 14-year-old girl who presented with a headache and a positive Kernig sign. Computed tomography (CT) demonstrated fluid retention in the sphenoid sinus, and lumbar puncture showed no abnormalities in the cerebrospinal fluid (CSF). Based on these findings, she was diagnosed with acute isolated sphenoid sinusitis without intracranial complications. However, the patient showed a poor response to antibiotic therapy, and magnetic resonance imaging (MRI) revealed dural thickening, necessitating surgical intervention. Intraoperatively, bony destruction and CSF leakage were identified, suggesting extension of inflammation into intracranial structures. Following treatment, the patient's Kernig sign resolved. To our knowledge, there have been no previous reports explicitly describing the appearance of the Kernig sign in sphenoid sinusitis. This case provides important insights into the clinical significance of this finding.