A Traumatic Brain Injury (TBI) is an injury to the brain caused by a trauma to the head by an outside force. The effects can be wide ranging and depend on a variety of factors such as type, location and severity of injury caused, but also depends on whether any complications develop e.g.lack of oxygen and swelling inside the brain.
A TBI can be viewed as a chain of events with three types of injury potentially being sustained.
The first injury is sustained in the first few seconds after an incident has occurred and the injury type can be categorised into one of three types:
Closed – The most common type of TBI and is so called because no break of the skin is visible. These often happen as a result of rapid acceleration or deceleration, for example when a car is hit at high speed from behind at traffic lights. The head is rocked back and forth and or rotated and the billions of nerve fibres which make up the brain can be twisted, stretched and even torn in the process.
Open or Penetrating – A less common injury, which sees the skull opened and the brain exposed and damaged. This injury could be sustained in a collision with a sharp object such as a motorcycle brake lever. If the damage is limited to one specific area, outcomes can be quite good but in many cases this type of injury is combined with an acceleration type injury leading to a poorer prognosis.
Crushing – In this type of injury, the head might be caught between two hard objects, such as the wheel of a car and the road. This is the least common type of injury, and often damages the base of the skull and nerves of the brain stem rather than the brain itself.
The second injury happens in the minutes and hours after the first injury whereby further injury is sustained if the brain is starved of oxygen as a consequence of the first injury. It can happen for several reasons, including choking on vomit after an accident or blood blocking a person's airway.
The third injury can take place at any time after the first and second injury, in the days and sometimes weeks which follow, and occurs as a result of bleeding, bruising or swelling in the brain crushing the soft brain tissue.
Traumatic brain injuries are generally organised into four categories. The table below gives a rough guide to how these measures affect the severity of the injury:-
Minor brain injury Loss of consciousness < 15 mins Post traumatic amnesia < 1 hour
Moderate brain injury Loss of consciousness 15 mins - 6 hours Post traumatic amnesia 1 hour - 24 hours
Severe brain injury Loss of consciousness 6 hours - 48 hours Post traumatic amnesia 24 hours - 7 days
Very severe brain injury Loss of consciousness > 48 hours Post traumatic amnesia > 7 days
Every person's injury is unique, so they may experience any number of the symptoms ranging from mild and temporary to severe and life changing.
A further EO QBE Rehabilitation blog will cover this in more detail in the near future.