Delayed extradural hematoma after mild head injury: report of three cases.

BACKGROUND: Extradural hematoma has been classically considered to be an acute complication of head injury whose maximum development takes place in the minutes following trauma. Delayed extradural hematoma (DEH) is defined on the basis of an exclusively radiologic criterion: epidural hematoma that is not present in the first neuroradiologic examination made after trauma but that appears in sequential neuroradiologic examinations during patient evolution. This is an infrequent complication that usually appears in hypotensive multiple trauma patients or is related to severe head injury with other intracranial lesions. CASE DESCRIPTION: We present three cases of DEH after mild head injury (GCS > 12) without associated intracranial or traumatic systemic lesions. Therefore, those usually considered to be "protective mechanisms" responsible for delayed development of an extradural hematoma were absent in our three patients. Diagnosis was attained by means of repetition of cranial computed tomography (CT) scan after neurologic impairment was noted. Surgical evacuation of DEH was immediately performed after diagnosis. Postoperative outcome was favorable in two patients who suffered DEH in the supratentorial compartment. One patient who presented a posterior fossa DEH died 3 days after surgery.
CONCLUSIONS: Early diagnosis and immediate treatment have proved to be essential for improving the prognosis of patients affected by DEH. Hospital admission under neurologic observation is recommended for patients who have sustained mild head injury associated with those factors that are related to the development of DEH, including GCS score under 15 or the detection of a skull fracture. Normality of a CT scan does not rule out subsequent appearance of delayed traumatic lesions.