Brain injury Flashcards
What are the types of head trauma?
- Missile
- Non-missile (rotation forces, acceleration/deceleration)
- Focal (fractures, contusions, haemorrhage)
- Diffuse- (Diffuse axonal injury, diffuse vascular injury)
How does the Glasgow coma scale?
Assess eye, verbal, motor responses, obtain score/15.
13 or above: Mild injury
8 or less: Severe
Minimum score: 3.
What is primary injury?
Injury that has occurred and cannot be changed.
Depends on:
Type, location, age, drugs, pre existing disease, genetics.
What are some types of primary injury?
Skull fractures:
Base of skull fracture can cause CSF leakage-> Otorrhea, Rhinorrhea
This is breach of the subarachnoid space. (BAttle’s sign, racoon eyes)
Cerebral contusion:
Brain bruising when it collides with skull. (Coup/Contrecoup). Orbitofrontal cortex, occipital pole and temporal poles affected.
Intracranial haemorrhage:
Extradural, subdural, subarachnoid, intracerebral.
Diffuse axonal injury:
Sheer & Tensile forces on axons-> Retraction balls.
What is secondary injury and what are some types?
Treatment aims to prevent secondary damage.
Ischameia/Hypoxia
Cerebral swelling (Raised ICP, midline shift, herniation.) Herniation can be subfalcine, tentorial, tonsillar, coning. MOA unknown.
Infection
Seizure
What the grades of axonal injury, and what is primary vs secondary axotomy?
Grade 1: Parasagittal frontal, internal capsule.
Grade 2: + Corpus callosum
Grade 3: + Dorsal brainstem.
Primary: Axolemma tear-> Ca2+ influx->protease activation->cytoskeletal dysfunction->disconnnect
Secondary: Rupture->membrane sealing
Shearing forces->Axotomy->Stops normal axonal transport->buildup of toxic proteins
What causes cerebral swelling?
Unknown. Possible:
Vasodilation to aid perfusion, BBB breakdown, vasogenic oedema.
What is the inflammation in TBI?
Macrophage/microglia activation, neutrophil invasion. Oedema, cytokines, complement activation. Causes apoptosis, necrosis, repair and regneration.
What are the key features of boxer’s brains?
Tear in midline structures
Earlier cognitive changes
Tau tangles
AB plaques.
50% of boxers with dementia had CTE, other 50% did not have tau pathology.
What is found in CTE pathology, and what is the definition of pathology for CTE diagnosis?
Astrocytic tau.
- Foci of perivascular NFT & astrocytic tangles
- Irregular cortical distribution of NFT and tangles, predilection for depths of sulci.
- Clusters of subpial and periventricular astrocytic tangles in the cerebral cortex, diencephalon, basal ganglia and brainstem
- Neurofibrillary tangles in the cerebral cortex located preferentially in the superficial layers.
What are the symptoms of CTE?
Cognitive: Memory impairments, executive dysfunction, dementia
Mood: Suicide ideation, depression, mood swings.
Motor: Parkinsonism, dysarthria, ataxia
Behavioural and personality: Irritability, aggression ,substance abuse
What are some treatment possibilities for TBI?
Small therapeutic window: Minimise secondary damage with anti inflammatories, protease inhibitors, neuroprotection.
Hypothermia can slow degradation processes.
Hyperbaric treatment?
How can focal vs diffuse injury be imaged?
Focal : Fractures, contusions, haemorrhage: MRI, CT
Diffuse axonal injury, vascualr injury: Advanced MRI
How does CT scanning work, and what are its pros and cons?
3D reconstructino, differential attenutation of X-ray beams passed through an object from multiple directions.
Advantages: Fast, cheap, better than MRI for bony abnormalities.
DisadvantagesL Poor resolution, cannot see subtle changes in brain structure.
What are the types of MRI that can be used?
Large magnets aligns protons, 2nd RF misaligns proteons which relax to original position, releasing energy which is detected.
T1 weighted: Good tissue discrimination. Dark CSF, Bright fat, Dark lesions
T2: Sensitive to water. Dark fat, Bright CSF, bright lesions.
FLAIR: Sensitive to water. Dark CSF, dark fat, Bright lesions. (better jobs at delineating lesions near ventricles, edema, grey/white differentiation).
Gradient echo imaging (GRE): (metals dark) SWI. Useful for subtle injuries/microbleeds. Bleeds leave haemisiderin. Microbleeds have parafalcine distribution.
Diffusion tensor imaging:
Looking at specific tracts. Diffusion of water molecules is constrained by properties of the tissue. Measures how anisotrophic the water diffusion is.
