Brain abscess. Magnetic resonance imaging (MRI) scan of an axial section through the brain of a patient with a cerebral abscess (dark area at top). An abscess is a collection of pus in response to infection. It can exert pressure on the surrounding brain tissue causing symptoms such as headaches, drowsiness, confusion and seizures. Brain abscesses are usually linked to an underlying disease or a primary lesion elsewhere in the body, as they rarely occur by themselves. Treatment is by isolating the underlying cause and by taking antibiotics.