The clinical challenge of recognizing infratentorial empyema

BACKGROUND: Infratentorial empyema is an uncommon complication of bacterial meningitis. Very little is known about its recognition and appropriate management. METHOD: We present a patient with infratentorial subdural empyema and compare findings with 41 cases with infratentorial empyema reported in the literature. RESULTS: Many patients with infratentorial empyema presented as subacute meningitis with neck stiffness and decreased consciousness. Diagnosis was often delayed. The minority had cerebellar findings and cranial nerve deficits. Clues to the diagnosis were presence of otitis, sinusitis, or mastoiditis and recent surgery for these disorders. The majority of patients underwent craniotomy; conservative treatment with antibiotics was associated with relapse of symptoms. The mortality rate was high especially in those with subdural empyema. CT failed to clearly visualize infratentorial subdural empyema in several reported cases. CONCLUSIONS: Infratentorial empyema is a life-threatening rare complication of bacterial meningitis. MRI, including diffusion-weighted imaging, is the preferred imaging technique in patients with suspected or proven bacterial meningitis and associated ear-nose-throat infection with deterioration in consciousness and neurologic signs that suggest a posterior fossa lesion. Neurosurgery should be regarded as first choice therapy.