Type A lmmunoglobulin Deficiency Presenting as a Mixed Polymicrobial Brain Abscess

OBIECTIVE AND IMPORTANCE: We pr€sent a case report of a patient wilh a left frontal brain abccess. Cultures obtained fiom the abecess at lhe time of suqgery were idenlified as dental flora knovm to establish a synergistic relationslrip in polymicrobial infections. Ihis type of synergistic relalionship nukes the clearance of an infeclion more difficult for an intact immune sydem. A serum immunoglobulin (lg) Type A deficiency was identified postoperatively, This immunodeficiency may have contrihrted to 0re development of the absces. CtlNlCAt PRESENTATION: The patient presented with headaches and photophobia. Computed tomography of the head performed with intravenously administered contrast demonstrated a left frontal brain abscess. INTERVENTION: The patient was operated on through a left frontal approach, carefully avoiding the frontal sinus. The abscess was aspirated, and the patient was treated with intravenous antibiotics for several weeks. Postoperatively, the patient did well. There were no signs of enhancement on follow-up computed tomographic scans at 7 and 12 months postoperalively. CONCLUSION: Through a comprehensive immunological workup, an lgA deficiency was identified postoperatively. Although the deficiency of a single type of lg may b€ asymptomatic/ complications from recurrent or chronic bacterial infections may occur. The deficiency of lgA. combined with a synergistic polymicrobial infection, contributed to the developmenl of an intracranial abscess. A patient presenting with a brain abscess without any predisposing medical history should be evaluated for an underf ying immune deficiency. (Neurosurgery 44:41 1 -41 4, 1 999)