Snapshot A 35-year-old male is brought the ED following a motor vehicle accident in which his car struck a tree at high speeds. He is unconscious and remains in a vegetative coma over the next several weeks. His head MR is shown. Introduction Diffuse axonal injury (DAI) is a prolonged posttraumatic coma that is not due to ischemia or a mass lesion Most commonly follows deceleration injuries Damage characteristically occurs at grey-white junctions Presentation Physical exam decortication or decerebration (motor posturing) autonomic dysfunction (hypertension, hyperhidrosis, hyperpyrexia) Evaluation CT clinical features are often much worse than suggested by CT imaging MR test of choice for diagnosing DAI shows small punctate hemorrhages at grey-white junctions Treatment There is no treatment Prognosis, Prevention, and Complications Prognosis is poor