Acute traumatic midbrain hemorrhage

Abstract
A syndrome resulting from traumatic midbrain hemorrhage is described in 5 patients, 3 of whom had intracranial pressure measurements and 2 of whom had pathological examinations. The major clinical signs, evident immediately after injury, are coma, dilated (4 to 8 mm diameter) pupils that are fixed to light and dark, diminished limb tone, and impaired horizontal eye movements. The hemorrhages are single and linear or oval‐shaped in the midsagittal rostral midbrain, extending several millimeters bilaterally. The appearance of the hematoma may be delayed on computed tomographic scanning, but early abnormalities of wave V of the brainstem auditory evoked potentials aid in diagnosis. Pathological features suggest that secondary brainstem distortion occurred soon after injury, perhaps resulting from a transiently raised intracranial pressure, but shearing injuries caused by acceleration–deceleration forces were also found.