Perifocal brain oedema in experimental brain abscess in rats.

An experimental cerebral abscess model in which staphylococcus aureus was inoculated into the brain parenchyma of rats was evaluated for perifocal brain oedema. Blood-brain barrier permeability was studied using various kinds of tracers; sodium fluorescein as a small molecule and Evans blue and HRP as macromolecular tracers. Brain abscess with clear delineation of fibrous capsule formation were found in all animals. Extravasation of tracers was demonstrated in the capsule (Evans blue), extracellular space (HRP) and white matter (sodium fluorescein). There were two types of oedema formation, so called vasogenic oedema and cytotoxic brain oedema.