Effect of dexamethasone on various stages of experimental brain abscess.

Rats were inoculated with staphylococcus aureus to produce cerebral abscesses and treated with either antibiotic or dexamethasone and with antibiotic plus dexamethasone at sequential stages of abscess formation. Antibiotic alone shortened the cerebritis stage, accelerated the encapsulation and affected the bacterial clearance in the abscess centre when it was started early in the course of cerebritis. Dexamethasone impaired the lymphocytic and fibroblastic responses and delayed the collagen deposition as well as suppressed the efficacy of antibiotic. However, it did not halt entirely the encapsulation and did reduce the associated cerebral oedema.