Primary brain injury occurs at the time of accident. In other words, it is the initial damage that occurs immediately as a result of trauma. The main causes of Primary brain injury are angular acceleration and deceleration forces. Secondary brain injury occurs subsequently to the brain. In other words, it is the result of neurophysiological and anatomical changes after minutes and days of trauma. The main causes are hypotension, hypoxia, hyperthermia, hypoglycemia, hyperglycemia, hyponatremia and sepsis.