Seizures And Surgical Aspects Of TBI Flashcards
Types of diffuse TBI
Concussion
Diffuse axonal injury
Blast
Abusive head trauma/ shaken baby syndrome
Types of focal TBI
Contusion
Penetrating
Haematoma - EDH, SAG, SDH, intra ventricular, Intracerebral/intraparenchymal
Primary vs secondary TBI
Pri - caused at time of injury, vascular/neuronal
Sec - processes triggered by Pri brain injury
Secondary TBI examples
Hypotension
Hypoxia
Ischaemia
Pressure effects
Infection
Processes causing secondary TBI
Structural axonal injury
Excitotoxicity and calcium flux
Toxic proteins pathogens
Functional impairment
Cell autonomous death pathways
Neuro inflammation
Mitochondrial dysfunction
Autophagy, apoptosis, necrosis, pyroptosis
Cerebral bloodflow dysregulation
Cerebral oedema
Stroke
Aspects of focused neurological exam
ABCDE
Inspect for signs of craniofacial trauma or basal skull #
Eyes - acuity, pupils, fundoscopy, ocular movements
Moving 4 limbs
GCS
Breathing pattern
C SPINE
Possible Pupil abnormalities on examination
Anisocoria
RAPD
Mitosis
Mydriasis
Abnormal breathing patterns in TBI
Cheyne stokes (cerebral)
Apneustic (pons)
Ataxizpc (medullary)
What part of the brain is injured in a pt with cheyne stokes breathing
Cerebrum
What part of the brain is injured in a pt with apneusticbreathing
Pons
What part of the brain is injured in a pt with ataxic breathing
Medulla
Drawbacks of GCS
Skewed importance of motor score
Intubation
Facial/ocular trauma
Dysphasia
Inter-rated variability
Eyes scores in GCS
1 no opening
2 pain
3 voice
4 spontaneous
GCS verbal scores
1 none
2 incomprehensible
3 inappropriate words
4 confused
5 normal
GCS motor scores
1 none
2 extension (decerebrate)
3 abnormal flexion (decorticate)
4 withdraws from pain
5 localise to pain
6 obeys commands
GCS scores in mild mod and severe head injury
14/15 mild
9-13 mod
</=8 sev
Concussion
Alteration in consciousness without structural damage as a result of non penetrating TBI
Indications for head CT within 1 hour
GCS =/<8 on initial assessment
GCS <15 2 hrs after injury
Suspected open or depressed skull #
Any sign of basal skull #
Post traumatic seizure
Focus neuro deficit
More than 1 episode of vomiting
Indications for head CT within 8 hrs of injury (or within 1 hr if presenting >8hrs after injury)
LOC or amnesia since injury + 1 of:
- Age 65+
- any bleeding/clotting disorders or medications
- dangerous MOI (ped vs car, car ejection, fall from 1+m/5stairs, etc)
- >30mins retrograde amnesia of events immediately before injury
Consider if taking anticoagulants or anti platelets
Indications for immediate tube and vent in TBI
Coma / GCS<8
Loss of protective laryngeal reflexes
Ventilators insudpfficiency - hypoxaemia or hypercapnia
Irregular respirations
Indications for tube and vent before transfer to neurosurgery unit
Sig deteriorating consciousness level
Unstable facial skeleton #
Copious bleeding into mouth
Seizures
Which HI patients should be transferred to neurosurgery unit
Severe HI - GCS<8
Which HI pts should be admitted and observed
Clinically important abnormalities on imaging
GCS <15
Ongoing concerning sx (vomiting, headache, seizures)
Drug or alcohol use
Multiple injuries
No adult at home to supervise pt
Which HI pts should neurosurgery be involved
Sig abnormality on imaging
GCS </=8 after initial resus
Unexplained confusion >4hrs
Deterioration in GCS after admission
Progressive focal neuro signs
Seizure without full recovery
Definitive/suspected penetrating injury
CSF leak
Which type of brain injury is can have ‘talk and die’ presentation
EDH
Signs of brain herniation
Decr GCS
Anisocoria
Cushing’s reflex
Course of middle meningeal artery
Branches from maxillary artery -> passes through infra temporal fossa to foramen spinosum -> runs along squamous temporal bone -> anterior branch runs beneath pterion
Extradural haematoma locations
middle meningeal artery beneath pterion
Parietal
Convexity
Posterior fossa
EDH surgical mx
Craniotomy
Equation for estimating Intracerebral haemorrhage volume
(A x B x C) /2
A = greatest haemorrhage diameter on CT
B = haemorrgphage diameter at 90* to A
C = approx nbr CT slices w haemorrhage* slice thickness
Cause of DAI
Rotational acceleration or deceleration causing axonal and shearing stress
DAI
Microscopic white matter haemorrhage including brainstem/ CC
DAI signs on Ct
Usually normal
Which imaging is best for DAI
FLAIR or SWI MRI
DAI tx
Supporti e
DAI grades
1 - microscopic axonal damage in WM
2 - + focal lesion in CC
3 - + focal lesion in Cc and brainstem
Cerebral perfusion pressure equation
CPP = MAP - ICP
Cerebral bloodflow equation
CBF = CPP/CVR
ICP monitoring methods
Subarachnoid
Intra ventricular
Intraparenchymal
Epidural
Processes of compensation to ICP rise
Decr venous volume in brain
CSF egress into spinal column lumbar theca
Stretching of falx cerebri/tentorium cerebelli
What is causes by sustained uncompensated ICP rise
Brain Herniation
Herniation syndromes
Subfalcine herniation - ACA infarct, hydrocephalus
Uncal herniation - ipsilateral CN3 palsy, PCA infarction
Central herniation - decr consciousness dorsal midbrain pressure pressure on reticular formation, parinauds syndrome, basilar artery stretching
CN4 palsy
Cushing’s triad
Cushing’s triad
Hypertension
Bradycardia
Respiratory irregularity
Parinauds syndrome and durets haemorrhage causes
Perinauds - dorsal midbrain pressure
Durets - basilar artery stretching
Both caused by central herniation
Indication for ICP monitoring
Severe TBI
Hydrocephalus
Craniosynostosis
ICP monitoring contraindications
Intracranial haematoma
Extra axial location
What is shown by P1 P2 and P3 on ICP monitoring trace
P1 percussion wave
P2 tidal wave (brain compliance)
P3 dicrotic (aortic valve closure)
P2>p1 = non compliant brain
Conservative/1st line Raised ICP mx
Head up 30*
Straighten neck
Remove c spine collar
Normocarbia
Avoid temp rise
- AVP time cooling if 39*+
- paracetamol
Avoid coughing/straining
2nd and 3rd line raised ICP mx
2nd - optimise sedation (decr pain+agitation), neuromuscular blockade, Hyperosmolar therapy, intra ventricular drainage
3rd - barbituate coma (decr CMRO2), Decompressive craniectomy
Is normal brain electrical activity synchronous or non synchronous
Non synchronous
Main inhibitory and excitatory NT in the brain
Inhib GABA
Excite glutamate
What causes a seizure
Cortical neurones firing in a hypersynchronous manner
Paroxysmal depolarising shift causes spreading wave as neurones adjacent to abnormally firing neurones start firing abnormally
What process causes abnormal neurone firing to spread across the brain in a seizure
Paroxysmal depolarising shift
Fit
Colloquial term for seizure
3/4 fits are not epileptic
What causes post ictal periods
Neurotransmitter imbalance
Factors that lower seizure threshold
Alcohol
Electrolyte imbalance
Inter current illness
How long does a person need to be seizure free to be eligible to drive in the UK
12 months
Seizure subtypes
Tonic clonic
Atonic
Absence
Myoclonic
Which type of seizure pt often presents with a head injury sustained from sudden fall
Atonic seizure
Which type of seizure is characterised by repetitive movements
Myoclonic
Where do epileptic seizures (almost always) originate from
Supercentorial
Cerebellar epilepsy reported but very rare
Focal seizure onset
Onset within 1 hemisphere
Usually in temporal lobe
Focal seizure characteristics
Aura, motor, or autonomic
Awareness may be retained or altered
May stare blankly, automatisms, grunting
Often progresses to bilateral convulsive seizures in adults
Focal seizure characteristics
Aura, motor, or autonomic
Awareness may be retained or altered
May stare blankly, automatisms, grunting
Often progresses to bilateral convulsive seizures in adults
Do head versions turn towards or away from the lesion in a seizure
Away
Are eye movements and motor sx ipsi or Contralateral in a focal seizure
Contralateral
How can hyperventilation bring on a seizure
Hyperventilation -> hypercapnia -> cerebral vasoconstriction -> cerebral hypoperfusion -> brain cell dysfunction/transporter dysfunction -> seizure
Todd’s paresis
Unable to move 1/both sides after waking from seizure
Usually after focal seizure
No changes on imaging
What causes post traumatic epilepsy
Cortical irritation from SAH
