Cerebral edema is an excess of fluid in the brain, either within the cells or outside the cells. It has a number of causes including trauma, cancer, stroke, encephalitis and meningitis. It is usually accompanies by vomiting, nausea, fainting, blurred vision, seizure and even coma. It can be treated in a number of ways, including drugs that change the osmotic pressure between cells, the use of diuretics, steroids and surgery.