Epidemiology & Patho Of TBI

Question 1

What are the two types of brain injuries one can suffer?

Answer 1

1. Traumatic brain injury
2. Hypoxia/anoxic [low or lack of oxygen; near drowning, crush injuries to chest, respiratory chest]

TBI:

• leading cause of death and disability in adults and children
• age of onset is bimodal, 15-24 [motor vehicles] and 75+ [falls] age groups

Sudden trauma to the head causing brain damage [forcefully hits object, receives violent blow, excessive shaking, object pierces skull & brain]

Question 2

Define what a Coup injury is?

Define a Contracoup injury?

Answer 2

Initial impact of brain against cranium; knock or shock

It is the rebound impact; opposite

Question 3

What is the Primary damage in a TBI?

What is the Secondary damage in TBI?

Define Diffuse Axonal injury:

Answer 3

Primary damage at either side; includes bruising and/or tearing of neural tissue and rupture of arteries/veins

Secondary damage creates pressure from oedema/blood accumulation
- Brain herniation though rural reflections of foremen magnum.

Diffuse axonal injury = acceleration and torques cause shearing of nerves within myelin sheaths
- Only detectable by CT and MRI once cell death occurs.

Question 4

Diagnosis of TBI

Answer 4

Classified into 3 groups:
-mild [13-15], moderate [9-12], severe [<8]

Glasgow Coma Scale (GCS) is the most often used.

Sum of person’s eye-opening, verbal and motor responses
Typically obtained ASAP after injury and continually monitored

Mild head injury also called ‘concussion’.

Question 5

Diagnosis - How is a Mild head injury classified?

Answer 5

Loss of consciousness for <30min

Post traumatic amnesia [<24hrs] or retrograde amnesia

Altered mental state

GCS score 13-15 @ 30 mini post injury

Focal [e.g. Contusions] deficits expected to resolve within 3 months.

Question 6

Diagnosis : CT and MRI results

Haematoma
Cortical atrophy

Answer 6

MRI - associated with lower [nil] radiation, improved resolution and detecting of smaller injuries but more expensive

Blood from torn vessels may be seen immediately (epidural haematoma), especially if major injury to artery.
Oedema accumulation (subdural haematoma, hydrocephalus) seen over hours or days

Cortical atrophy needs longest time to be observable

Question 7

What does the Functional Consequences depend on?

• Diffuse Injury
• Focal Injury

Answer 7

It widely depending on site of injury and extent of legion

Diffuse injury due to:

• diffuse axonal injury
• hypoxic/anoxic events can cause widespread impairments/many body systems

Focal injuries depend on structures affected, and maybe unilateral.

Question 8

Functional Consequences: What might exercise be affected by?

Answer 8

• Deficits in judgement, memory/learning, apathy, easy frustration, loss of inhibition particularly if frontal lobe is affected]
• loss of selected, isolated movement patterns
• loss of synergy patterns to perform functional movements
• muscle weakness
• hypertonia or resistance to muscle stretch
• hyperactive deep tendon reflexes
• sensory/perceptual changes

Question 9

NB - MEDICAL SEQUELAE - NB

Define HETEROTOPIC OSSIFICATION:

Answer 9

-Often caused by surgery [e.g. Arthroplasty] or trauma to the hips and legs, but also seems to occur after neurological insult such as TBI or SCinjury

• Aetiology not clear, but associated with multiple traumas and internally fixed fractures: calcification due to immobility during recovery - bone rather than muscle deposition
• Calcium deposits in soft tissue structures in 11-76% of people with severe TBI
• May present heat, pain, swelling, and redness leading to contracture formations; but may lack signs/symptoms.
• May affects positioning, ROM & functional performance

Question 10

NB - MEDICAL SEQUELAE - NB

List Cardiopulmonary impairments:

Answer 10

• Prolonged hypertension and other cardiac impairments are unusual
• Lesser compliance of chest wall following limited mobility after severe head injury may reduce total lung capacity, vital capacity and force expiratory volume by 25-40%
• May be weak or non-coordinated actions of respiratory muscles

Question 11

NB - MEDICAL SEQUELAE - NB

What are some Medical/surgical treatments?

Answer 11

Psychotropic medication to minimise behaviour difficulties
-good to reduce agitation and help rehab process

Pharmacological intervention to reduce hypertonia [e.g. Baclofen, diazepam], which may reduce arousal and cognitive ability

Phenol blocks may alleviate hypertonia localised to smaller areas [denatures myelin sheath of nerves of hypertonic muscles] and botulinum toxin [botox] maybe be used.
- Phenol lasts 6 months, Botox lasts 2-6 months

Question 12

What is BACLOFEN?

Answer 12

It’s a muscle relaxer and an antispastic agent used to treat spasm, pain, and stiffness - reduces reflex activity

Used orally or intrathecally [auto release into cerebrospinal fluid] in brain/SC injury, CP, and MS. It’s use in people with stroke or Parkinson’s disease isn’t recommended

May impair thinking or reactions. Be careful if driving or need to be alert

Drinking alcohol can increase certain side effects of baclofen

Don’t use baclofen at a time when muscle tone is needed to assure safe balance and movement for certain activities

May have withdrawal symptoms such as seizures or hallucinations if stop using after a long period of time.

Question 13

What is Diazepam [e.g. Valium] and Lorazepam

Answer 13

In a group of drugs called benzodiazepines

Commonly used to treat anxiety, panic attacks, insomnia, seizures [including epilepsy; i.e. Anti convulsant], muscle spasm [such as in tetanus cases], restless legs syndrome.

Fast acting [half life- 10-20 hrs] so take 2-3x/day

Enhances the effect of the NT gammaamniobutyric acid [GABA] leading to CNS depression.
[GABA is inhibitory in the CNS]

Can’t drink alcohol while taking diazepam or lorazepam [increases effects of alcohol] and may be addictive. May affect the unborn baby.