TBI is caused by either a blow to the head or by the head being forced to move rapidly forwards or backwards. Brain tissue may be torn, stretched, penetrated, bruised or become swollen. Oxygen may not be able to get through to the brain cells, and there may be bleeding.
Common causes include motor vehicle accidents, assault, falls, sporting accidents and domestic domestic violence. The effects can be temporary or permanent, and range from mild injuries, such as being momentarily stunned, to a very severe injury that may cause prolonged loss of consciousness.
As well as injury to the brain caused by the initial trauma, there are secondary effects that can arise from bleeding, bruising, lack of oxygen and increased pressure within the skull.