An 18-year-old man is admitted to the emergency room following a motorcycle accident. He is alert and fully oriented, but witnesses to the accident report an interval of unresponsiveness following the injury. Skull films disclose a fracture of the left temporal bone. Following x-ray, the patient suddenly loses consciousness and dilation of the left pupil is noted. This patient should be considered to have

Epidural hematomas are typically caused by a tear of the middle meningeal artery or vein or a dural venous sinus. Ninety percent of epidural hematomas are associated with linear skull fractures, usually in the temporal region. Only 2% of patients admitted with craniocerebral trauma suffer epidural hematomas. The lesion appears as a hyperdense biconvex mass between the skull and brain on CT scan. Clinical presentation is highly variable and outcome largely depends on promptness of diagnosis and surgical evacuation. The typical history is one of head trauma followed by a momentary alteration in consciousness and then a lucid interval lasting for up to a few hours. This is followed by a loss of consciousness, dilation of the pupil on the side of the epidural hematoma, and then compromise of the brainstem and death. Treatment consists of temporal craniectomy, evaluation of the hemorrhage, and control of the bleeding vessel. The mortality of epidural hematoma is approximately 50%.