Coma, Persistent Vegetative State, Brain Death Flashcards
what are some features of a coma patient?
unrousable psychological unresponsiveness
eyes closed
no psychologically understandable response to external stimula or inner need
what does consciousness depend on?
intact ascending reticular activating system
functional cerebral cortex of BOTH hemispheres
what does the ascending reticular activating system do?
acts as the alerting or awakening element of consciousness
what does the cerebral cortex do with regards to consciousness?
determines the content of said consciousness
what can cause a decreased GCS score?
toxic/metabolic states
seizures
damage to reticular activating system
causes of raised ICP
what are examples of toxic/metabolic states?
hypoxia hypercapnia hypotension drug intoxication/renal or liver failure hypoglycaemia ketoacidosis
does focal damage to part of the cortex affect conscious level?
no
what is persistent vegetative state?
a state in which the brainstem recovers to a considerable extent but there is no evidence of recovery of cortical function
what are some features of persistent vegetative state?
arousal and wakefullness but no regaining of awareness of purposeful behaviour of any kind
what is “locked in” syndrome?
total paralysis below the level of the third nerve nuclei
what are some features of locked in syndrome?
patient able to open, elevate and depress eyes
no horizontal eye movement
no other voluntary eye movement
how is locked in syndrome diagnosed?
recognise that patient can open eyes voluntarily and signal numerically by eye closure
what can cause fluctuating respiration?
brainstem lesion
what can cause depressed respiration?
drug OD
metabolic disturbance
what can cause increased respiration
hypoxia
hypercapnia
acidosis
what infection should you examine for when attempting to resuscitate a patient?
meningitis - treat on suspicion
what should you establish when attempting to resuscitate a patient?
baseline BP pulse temperature IV access stabilise neck also
how is a coma neurologically assessed?
using:
GCS
brainstem function
motor function and reflexes
what GCS score would classify a patient as being in a coma?
less than or equal to 8
what can cause a coma without focal or lateralising signs and without meningism?
ischaemic conditions metabolic disturbance intoxications systemic infections epilepsy hyper/hypo thermia
what investigations are appropriate for assessing coma patients?
toxicology screen measure blood sugar and electrolytes assess hepatic and renal function measure BP acid - base assessment and blood gases CT head Lumbar puncture
what should you consider in a patient who is in a coma without focal or lateralising signs but with meningism?
subarachnoid haemorrhage
meningitis
encephalitis
what can cause a coma WITH focal brainstem or lateralising cerebral signs
cerebral tumour
cerebral haemorrhage
cerebral infarction
cerebral abscess
what investigations are obligatory in coma WITH focal brainstem or lateralising cerebral signs?
CT or MRI
if CT or MRI are not diagnostic in come WITH signs then what investigations can be used to try and determine the cause of the coma?
metabolic screens
lumbar puncture
EEG
what are the most common causes of coma lasting more than 5 hours?
40% drug ingestion with or without alchohol
25% due to hypoxia
20% due to cerebrovascular event
15% metabolic
what are some factors that can help predict the outcome of a coma?
age cause of coma depth of coma duration of coma certain clinical signs such as brain stem reflexes
what is important in continuing care of patients in a coma?
maintenance of vital functions care of skin attention to bladder and bowel function control of seizures prophylaxis of DVT and peptic ulceration prevention of contractures consider "locked in" syndrome
what shape does a subdural haematoma take on CT?
ellipse shape/convex
what shape does an extradural haematoma take on a CT?
concave
how do you manage a head inury?
stabilise C spine ABC if GCS < 8 intubation and ventilation treat raised ICP neuro obs
