General Medical Information

Brain Abscess

Frank E. Lucente
Samir Shah
Roger Kula

Brain abscess forms by means of direct extension, hematogenous spread from septic thrombophlebitis, and extension through congenital defects, traumatic fistulae, or tumors. Brain abscess begins as localized cerebritis consisting of leukocytic infiltration and microscopic necrosis. At this stage, it is difficult to diagnose. In 7 to 10 days, a capsule forms, and the abscess enlarges and causes edema in adjacent tissues, producing neurologic symptoms. Between 40% and 50% of brain abscesses are of otogenic origin. Sinus infection accounts for about 10%. General symptoms are lethargy, headache, and fever. Focal signs depend on the location of the abscesses. Frontal lobe abscesses, almost exclusively the result of paranasal sinus infection, rarely have localizing symptoms. Increased intracranial pressure, stupor, and papilledema are signs of abscesses in this area. Brain abscesses can cause brainstem herniation and can rupture into the ventricular system.