Coma + PVS + Brain Death Flashcards
Difference between UMN & LMN facial palsy?
The upper face is supplied by fibres from both sides but via a common LMN.
Therefore damaging the UMN will result in weakness of the lower face, the upper face will be partially spared.
But damaging the LMN will cause weakness of the entire one side of the face (This type is Bells Palsy)
Define Coma
“State of unrousable psychologcial unresponsiveness”
Eyes closed & no perceivable response to external stimulus or inner needs.
Consciousness depends on what 2 things
Arousal:
Intact Asc Reticular Activating System to alert/awaken consciousness
Awareness:
Functional Cerebral Cortex to determine the content of your consciouness
What could cause your GCS to fall (alter consciousness)
- Toxic/Metabolic states such as intoxication, hypoxia/hypercapnia, sepsis, hypotension, hypoglycaemia, acidosis
- Seizures
- Damage to Reticular Activating System
- Raised ICP such as tumour, stroke, haematoma, SAH or hydrocephalus
Define a Persistant Vegetative State?
After reduced consciousness (mainly comas) the Brain stem recovers to a considerable extent but no recovery of coritcal function
High wakefulness but very low awareness
Define Locked in Syndrome?
Total Paralysis below III nuclei so:
- Can open and vertically move eyes
- But cant move horizontal
Diagnosis relies on spotting the patient can voluntarily open their eyes and signal by eye closure4
(Both high wakefullness and awareness)
What causes locked in syndrome?
Brainstem Strokes (e.g. Pontine Arteries)
Brainstem Lesions
Traumatic Brain Injury
Whats involved in resus for a patient with reduced consciousness?
ABCD
(Breathing patterns can indicate a specific condition)
Bloods (Glc, biochem, haematology, ABGs, toxicology)
BP/pulse/temp/IV acces
Stabilise neck in case of trauma
Look for evidence of meningitis
Neuro exam of coma?
GCS
Brainstem function
Motor function & reflexes
At what glasgow coma scale score do we call it Coma
GCS 8 or less, specifically:
Eye - 2 or less (pain or none)
Verbal - 2 or less (grunting)
Motor - 4 or less (weak flexion)
How do we assess brainstem function?
Brainstem reflexes:
- Pupill reflexes (2&3)
- Corneal Reflex (5 & 7)
- Spontaneous eye movement (3/4/6)
- Oculovestibular (Caloric Stimulation) (3/4/6/8)
- Resp Pattern (Medullary Centres)
- Oculocephalic (normal nystagmus) (3/4/6/8)
Causes of Coma without focal brainstem or lateralizing cerebral signs or meningism?
- Ischaemia
- Metabolic
- Intoxication
- Epilepsy
- Infection
- Hyper/Hypothermia
How would you investigate someone with coma without focal signs or meningism?
Toxicology Bloods Hepatic/renal function ABGs BP
Causes of Coma:
No focal signs or meningism = Toxic(Alcohol)/metabolic(hypoxia)/systemic
Meningism = SAH/meningitis/encephalitis
Focal brainstem or lateralizing signs = Tumour, infarct etc
How would you continue to care for a coma patient?
- Maintain their vital functions
- Care for their skin, particularly pressure sores
- Attend to bowel/bladder function
- Control seizures
- Prophylaxis for DVTs or Peptic ulcers
- Prevent Contractures
- Assess for Locked in Syndrome
