Closed head injuries involve trauma to the head without a break in the skull, states BrainInjuryInstitute.org. There are no lacerations present, adds MedicineNet. Although closed head injuries do not penetrate brain tissue, swelling or bruising of the brain may occur, according to Healthline.
Closed head injuries can occur as a result of sudden, violent movement that causes the brain to strike against the skull, notes BrainInjuryInstitute.org. Other potential causes include a direct blow to the head, a car crash, or slipping and falling. Symptoms of a closed head injury include headache, dizziness, loss of consciousness, convulsions, nausea and vomiting. Serious symptoms that may occur as a result of severe damage to the brain include postconcussion syndrome, seizures, personality changes, cognitive disabilities and coma.