Fulminant Fusobacterium necrophorum Meningoencephalitis Secondary to Frontal Sinusitis in a Previously Healthy Young Adult: A Case Report.

BACKGROUND: Fusobacterium necrophorum is an anaerobic Gram-negative organism classically associated with severe head and neck infections and Lemierre syndrome. Central nervous system involvement is uncommon but may be rapidly progressive and fatal, particularly when associated with sinusitis, intracranial empyema, cerebritis, or brain abscess. CASE PRESENTATION: We report the case of a previously healthy 18-year-old male who presented after four days of high fever up to 41.5 °C, severe holocranial headache, vomiting, and acute hyperactive delirium. On admission, he had meningismus, markedly elevated inflammatory markers, and concomitant Influenza A infection. The initial cranial computer tomography showed a left frontal hypodense lesion with hemorrhagic transformation and perfusion deficit. The cranial magnetic resonance tomography demonstrated left frontopolar cerebritis, intracranial empyema along the falx and tentorium, intraspinal extension, and extensive bilateral frontal, maxillary, and ethmoidal sinusitis, suggesting sinogenic intracranial spread. The patient underwent emergency bilateral pansinus surgery, placement of an external ventricular drain, left hemicraniectomy with evacuation of empyema, repeat evacuation of subdural empyema and frontal abscess drainage, and posterior fossa decompression with C1 laminectomy. Fusobacterium necrophorum was detected in anaerobic blood cultures and the operative intracranial samples. Despite aggressive interdisciplinary management, the patient developed septic multiorgan failure and died on hospital day 4. CONCLUSIONS: This case illustrates a rare but potentially fatal sinogenic Fusobacterium necrophorum infection of the central nervous system in a young adult. By providing a detailed report, we intend to increase awareness of this rare yet fatal clinical presentation.