An Adult with Atrial Septal Defect Presenting with a Brain Abscess.

The common heart diseases resulting in a brain abscess are associated with a right to left shunt and include tetralogy of Fallot and transposition of great vessels. Atrial septal defect (ASD) is almost always associated with the left to right shunt and therefore is not a commonly considered risk factor for brain abscess. We report the case of a 29-year-old male, with no symptoms of cardiac disease, who presented with the left posterior frontal pyogenic abscess which led to the detection of a silent ASD. Our case emphasizes the need for a careful evaluation of the source of infection in patients with a brain abscess.