Abstract
A hematoma is a mass of blood that collects in tissues. A hematoma within the skull puts pressure on the brain and is a well recognized risk factor for epileptic seizures. The strong, fibrous dura mater lines the skull and protects the brain; a hematoma within the dura is, of course, an intradural hematoma, and these possess a greater risk of seizures. However, extradural hematomas, which occur outside the dura mater, may also cause epileptic seizures. Previously, however, it has been hard to estimate the frequency with which extradural hematomas cause epileptic seizures, since it has often been difficult or impossible to determine with confidence whether an extradural hematoma coexisted with intradural damage as well. However, with the advent of modern imaging techniques, it has become possible to make this distinction, and determine the actual risk of seizures with extradural hematomas. Researchers examined the cases of 138 patients who suffered extradural hematomas as a result of trauma. Some patients were eliminated from the study because a preoperative computerized tomographic (CT) scan was not taken, they were lost to follow-up, or they died. Of the remaining 95 patients, 66 had extradural hematoma alone, and 29 had extradural hematoma with intradural damage as well. In three patients with extradural hematoma alone, epilepsy developed within a week of injury. In another patient, epilepsy developed more than one week after injury. In contrast, 5 of 29 patients with extradural hematoma and intradural damage developed epilepsy more than a week following injury. The results indicate that the overall risk of epilepsy from an extradural hematoma without additional intradural damage is about 6 percent, compared with 24 percent when extradural and intradural damage are present. This indicates the importance of accurate diagnosis and imaging in assessing the prognosis of extradural hematoma and deciding whether to administer anticonvulsant medication to these patients. (Consumer Summary produced by Reliance Medical Information, Inc.)