[A case of primary interhemispheric subdural abscess].

A rare case of primary interhemispheric subdural abscess is reported. This 13 year old boy, who had had high fever for 2 days, was brought into the hospital by an ambulance. He was disoriented and mild stiffness of the neck was noted. A Jacksonian seizure that began in the left leg occurred immediately after admission. The initial CT scan showed no apparent abnormality. His clinical signs and spinal fluid findings showing slight monocytic response and normal sugar content suggested viral meningo-encephalitis. The patient was given steroid and glyceol to control the intracranial pressure and antibiotics was also given. The convulsions disappeared with anticonvulsants and the patient became afebrile on the 7th hospital day. He was discharged on the 53rd hospital day without any neurological deficit. But, he was re-admitted because of recurrence of the convulsion 29 days after the discharge. The CT scan revealed an interhemispheric (rt parafalcial) abscess and the drainage of abscess was performed through a craniotomy. The post-operative course was satisfactory and he was discharged on 33rd post-operative day. It is easy to diagnose the primary interhemispheric subdural abscess on CT scan at the advanced stage. However, it may be difficult to make definite diagnosis at its acute phase and it is important not to miss some characteristic clinical features of the interhemispheric abscess that can be safely cured by appropriate surgical treatment.