[Two cases of acute idiopathic subdural hematoma with delayed intracranial hypertension]

Two cases of acute idiopathic subdural hematoma with delayed intracranial hypertension were presented. The first case was a 68-year-old man admitted for vomiting following headache for eight days. There was no history of head trauma. A CT scan revealed a high-density mass that had a concave inner margin in the left temporo-parietal region with a slight midline shift. No vascular lesion was noted on the angiogram. The consciousness of the patient deteriorated suddenly on the 12th day. An operation was performed because of a marked midline shift on the CT. At operation, a subdural clot was removed. The postoperative recovery was good. The patient was discharged 7 days later without any neurological deficit. The second case was a 69-year-old man who was admitted with sudden onset of headache. There was no history of head trauma. A CT scan showed a high density mass in the right temporoparietal subdural space with a slight midline shift. The consciousness of the patient deteriorated suddenly on the 15th day. An operation was performed because of a marked midline shift on the CT. At operation, a subdural hematoma was removed. Two days later, suddenly his consciousness deteriorated. A CT scan showed his severe brain edema with a marked midline shift without increased hematoma. External decompression was performed immediately. The postoperative recovery was very good and 40 days after the second operation, the patient was discharged with no neurological deficit. The delayed intracranial hypertension appeared in these two cases about 10 days after the initial symptom. Two kinds of mechanisms are suspected: 1) swelling of the hematoma because of the adsorption of cerebrospinal fluid, 2) the occurrence of secondary brain edema. From our experience, a repeated CT scan is necessary for 2 to 3 weeks.(ABSTRACT TRUNCATED AT 250 WORDS)