Injury to the head can arise as a result of sports injuries, falls, assault, traffic accidents, accidents at work and at home or bullet wounds. The majority of people suffer a minor head injury at one point in their lives, but very rarely are the injuries bad enough to require medical treatment.
A head injury can damage the scalp, brain or skull. Minor injuries often cause no damage to the underlying brain. Even when there is a skull fracture, or the scalp has split, the brain may not always be damaged. However, a blow to the head can severely shake the brain, and this can sometimes even cause brain damage even when there are no visible signs of injury.
A blow usually bruises the brain tissue, creating the death of some of the brain cells in the injured area. When an object physically penetrates the skull, foreign materials and dirt can be impacted into the brain and cause infection. A penetrating injury or blow can also tear blood vessels creating brain haemorrhage (bleeding around or in the brain). Head injuries can cause swelling of the brain; this is especially apparent after bullet wounds due to their high velocity which creates extensive damage. When the skull has been fractured, bone can be pushed into the underlying brain.
Symptoms and signs
If the head injury is minor, there can be no other symptoms apart from a slight headache. In certain cases, there is concussion, which can create dizziness, confusion and blurred vision (sometimes persisting for a few days). More serious head injuries, particularly blows to the head, can result in unconsciousness that lasts longer than a few minutes, or coma, which can result in death.
Post-concussive amnesia (loss of memory of events that took place after an accident) can arise, particularly if the skull has been fractured. This amnesia often lasts more than an hour after consciousness is regained. There can also be pretraumatic amnesia (loss of memory of events that took place before the accident). The more grave the injury to the brain, the lengthier the unconsciousness and amnesia are expected to last.
After a severe brain injury, a person can suffer some muscular weakness or loss of sensation and paralysis.
Symptoms like double vision, pupils of an unequal size, persistent vomiting, or a deteriorating level of consciousness suggest progressive brain damage.
Investigations can include MRI or CT scanning and skull X-rays A blood clot within the skull can be fatal and needs surgical removal. Severe skull fractures can also require surgery.
Recovery from concussion can take a few days. There can be permanent mental or physical disability if the brain has been injured. Recovery from a major head injury can be very gradual and there may be signs of progressive improvement for many years after.