Chapter 14: traumatic brain injury Flashcards
Traumatic brain injury (TBI)
TBI occurs when external forces exert on the skull causing an insult to the brain that produces a loss of consciousness (LOC) and/or post-traumatic amnesia (PTA). There is a distinction made between low-energetic trauma, like a fall from standing height and high-energentic trauma, like a motor accident.
Post-traumatic amnesia (PTA)
A state of confusion where the patient is very disoriented, unable to remember new information and sometimes shows psychomotor and verbal agitation. Most of the time this is for a short duration, but mild or severe TBI can last up to several months with difficulty remembering things from before the accident.
Glasgow Coma Scale
Used to test the spontaneous reaction of a patient being addressed or having pain stimuli applied, and can thus be used to map the severity of impairments of consciousness.
Next to this it is important to assess pupil reactivity as an important early detection for increasing intracranial pressure.
The effect of TBI on the brain
The primary damage following a TBI occurs immediately during the insult. The biomechanical forces of the skull and the brain cause a chain of reaction at cell level. This causes an excessive relapse of excitatory neurotransmitters (especially glutamate), which leads to cell damage and death, plus a rapid activation of microglia. The secondary damage occurs in hours and days following the injury as a result of intracranial complications. this can be because of hemorrhages, cerebral oedema and extracranial issues.
Linear injuries
A straight lined force from when a moving skull suddenly hits a fixed object, which caused the brain to violently shift in the skull and hit its rough internal structures.
Focal damage
When direct impact on the skull causes damage directly under the point of impact.
Diffuse axonal injury
More common in energetic trauma. Grey-white matter axonal junctions are the most susceptible.
Moderate to severe TBI
1/5th of patients will suffer post-traumatic epilepsy. One of the most consistent consequences is a slowness of information processing, lack of attention, problems with planning, initiative taking, flexibility, problem-solving, organising and task regulation. A lot of patients also show anterograde amnesia. People can also become more egocentric and emotional indifferent, lack of initiative, disinhibited or inappropriate behaviour and aggression. Patients can have little control over emotions, theory of mind and recognition of facial expressions. But TBI does not really affect intelligence.
Mild brain injury
The post-traumatic scans show no or limited abnormalities. People can initially have physical and emotional complaints, but the majority makes a full recovery within 6 months. Psychological complaints and coping style are the most important predictors of suboptimal recovery. The cognitive deficits are subtle and temporary (3 months). People wild mild TBI report more complaints than people with moderate to severe TBI, which shows that other factors can play a role in the perception and reporting of cognitive complaints.
