Infratentorial empyema: analysis of 22 cases.

OBJECTIVE: Infratentorial empyema is an uncommon form of intracranial suppuration that is usually secondary to neglected otogenic infection. The diagnosis is frequently delayed and often confused with that of meningitis. The associated mortality is distressingly high, yet it has, as a clinical entity, received scant attention in the literature. We present a 13-year experience of this condition. PATIENTS AND METHODS: From a retrospective analysis of 3865 patients with intracranial suppuration during a 13-year period, 22 patients with infratentorial empyema were identified. The inpatient notes for these patients were analyzed with reference to clinical, radiological, bacteriological, operative, and outcome data.
RESULTS: Twenty-two patients with infratentorial empyema accounted for 0.6% of admissions caused by intracranial suppuration during the study period. Of these 22 empyemas, 13 were subdural and 9 epidural. Hydrocephalus was present in 17 (77.3%). Except for two epidural empyemas that did not warrant neurosurgical intervention, all patients underwent standard surgical management (wide posterior fossa craniectomy). Nineteen underwent mastoidectomy because the source of infection was otogenic. Concomitant and persistent hydrocephalus was treated aggressively. Five patients died (mortality rate of 22.7%). All fatalities had subdural empyemas, and all three patients with cerebellopontine angle extension of subdural purulent collections died.
CONCLUSION: Although rare, infratentorial empyema, especially when subdural, is a lethal disease. Cerebellopontine angle extension of pus was a particularly ominous sign in our experience. Early surgical drainage via wide posterior fossa craniectomy, aggressive treatment of associated hydrocephalus, eradication of the primary source of sepsis, and, finally, intravenous high dosage of appropriate antibiotics form the mainstay of treatment.