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NEURO > Coma, persistent vegetative state and brain death > Flashcards

Coma, persistent vegetative state and brain death Flashcards

1
Q

what is a coma

A

A state of unrousable psychological unresponsiveness

subjects lie with eyes closed and show no psychologically understandable response to external stimulus or inner need

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2
Q

what 2 components does consciousness depend on

A

AROUSAL
need an intact ascending reticular activating system
- acts as the alerting or awakening element of consciousness

ENVIRONMENTAL AWARENESS
need a functioning cerebral cortex of both hemispheres
- determines the content of that consciousness

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3
Q

what can cause your GCS to drop

A

Toxic/metabolic states

  • Hypoxia, hypercapnia, sepsis, hypotension
  • Drug intoxication/renal or liver failure
  • Hypoglycaemia, ketoacidosis

Seizures

Damage to reticular activating system

Causes of raised intracranial pressure
- tumour, stroke, EDH, SDH, SAH, hydrocephalus

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4
Q

what is a persistent vegetative state

A

the brain stem recovers to a considerable extent but there is no evidence of recovery of cortical function

arousal and wakefulness but no awareness or purposeful behaviour of any kind

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5
Q

what is locked in syndrome

A

total paralysis below the level of the third nerve nuclei

although able to open, elevate and depress the eyes, has no horizontal eye movements and no other voluntary eye movement

cognitive function unaffected, can still hear, see, have sleep-wake cycles

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6
Q

what does the diagnosis of locked in syndrome depend on

A

recognising that the patient can open their eyes voluntarily and signal numerically by eye closure

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7
Q

what can cause depressed respiration

A

drug overdose, metabolic disturbance

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8
Q

what can cause increased respiration

A

hypoxia, hypercapnia, acidosis

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9
Q

what can cause fluctuating respiration

A

brainstem lesion

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10
Q

what are the stabilising steps in presenting a coma

A

ABC

blood samples - glucose, biochemistry, haematology, blood gas, toxicology

establish BP, pulse, temp, IV access

stabilise neck

examine for meningitis

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11
Q

what should be continuously monitored in a coma

A 
Temperature
Heart rate, Blood Pressure, CVS
Respiration
Skin, breath
Abdomen
Meningism
Fundal examination
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12
Q

what from the history can give you an idea about what caused the coma

A

? Predictable progression of underlying illness

? Unpredictable event in patient with previously known disease

? Totally unexpected event
- Head injury, sudden collapse, limb twitching, previous history of drug or alcohol abuse

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13
Q

what comprises the neurological assessment of coma

A

GCS
brainstem function
motor function +reflexes

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14
Q

what are the three aspect of the GCS

A

eye opening
best verbal response
best motor response

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15
Q

how is eye opening scored in GCS

A

Spontaneous - 4
To speech - 3
To pain - 2
None - 1

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16
Q

how is the best verbal response scored in GCS

A 
Orientated - 5
Confused - 4
Inappropriate words - 3
Incomprehensible sounds - 2
None - 1
17
Q

how is the best motor response scored in GCS

A 
Obeying Commands - 6
Localising to pain - 5
Withdrawing from pain - 4		
Flexing to pain - 3
Extending to pain - 2
None - 1
18
Q

when does the GCS indicate a coma

A

<8
Eye opening - 2 or less
Verbal response - 2 or less
Motor response - 4 or less

*less than 8 = intubate

19
Q

what motor functions looked for in coma

A

motor response
muscle tone
tendon reflex
seizures

20
Q

what can cause coma without focal or lateralising signs and without meningism*

*neck stiffness, photophobia, headache

A 
Anoxic/ ischaemic conditions
Metabolic disturbances
Intoxications
Systemic infections
Hyperthermia/ Hypothermia
Epilepsy
21
Q

what investigations should be done for coma -f/l signs and

-meningism

A 
toxicology - alcohol 
blood sugar
electrolytes
assess hepatic/renal functions
acid/base assessment
BP
?CO poisoning
22
Q

what can cause coma without focal or lateralising signs with with meningism

A

subarachnoid haemorrhage
meningitis
encephalitis

23
Q

what investigations should be done for coma -f/l signs and +meningism

A

CT head scan

LP

  • appearance CSF
  • cell count
  • glucose
  • capsular antigen tests
24
Q

what can cause coma with focal brainstem or lateralising cerebral signs

A

Cerebral tumour

Cerebral haemorrhage

Cerebral infarction

Cerebral abscess

25
Q

what investigations should be done for coma +f/l signs

A

CT or MRI obligatory

if CT/MRI not diagnostic investigate for other causes

  • metabolic screen
  • LP
  • EEG
26
Q

what are common medical (non-truamtic) causes of coma that last more than 5 hours

A

drug ingestion +/- alcohol

hypoxia - secondary to MI

cerebrovascular event - haemorrhage/infarction

metabolic - diabetes, hepatic/renal failure, sepsis, hypercapnia/hypoxia

27
Q

what factors can affect the outcome of a coma

A 
Age
Cause of coma
Depth of coma
Duration of coma
Certain clinical signs - most importantly brain stem reflexes
28
Q

what % of patients in a non-truamtic coma >6 hours will make a good/moderate recovery

A

15%

other 85% will die, remain vegetative or reach a state of severe disability

29
Q

what must be considered in the continuing care of coma patients

A

Maintenance of vital functions

Care of skin, avoidance of pressure sores

Attention to bladder and bowel function

Control of seizures

Prophylaxis of DVT, peptic ulceration

Prevention of contractures

Consider the “Locked - in” Syndrome

30
Q

how can head injury lead to focal neurological signs/epilepsy

A

Diffuse axonal injury

Contusion - bruising, “haematoma of tissue”

Intracerebral haematoma

Extra-cerebral haematoma

  • Extra-dural haematoma
  • Sub-dural haematoma
31
Q

how does a subdural haematoma present on CT

A

both sides convex (follow curve of skull)

32
Q

how does an extradural haematoma present on CT

A

outside convex

inside concave

33
Q

what is the management of head injury

A

Stabilise cervical spine

ABC

GCS≤8 - intubation+ventilation

Treat raised ICP

Cranial imaging - may need decompressive surgery or removal of haematoma

Neuro observation

34
Q

how can raised ICP be treated

A

surgery to relieve pressure

osmotic agents - mannitol

nurse with head at 30-45%

reduce pain

maintain good PO2
reduce PCO2

reduce metabolism - reduce temp, barbiturates

35
Q

SUMMARY: how do you assess consciousness

A

GCS - for head injuries, help with communication between staff

Consider brainstem reflexes (+pupil size and reaction)

Focal vs non-focal CNS pathology

Consider general causes of depressed conscious level

NEURO (51 decks)

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