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Neurology > Coma, Persistent Vegitative State, Brain Death > Flashcards

Coma, Persistent Vegitative State, Brain Death Flashcards

1
Q

Define coma

A

A state of unrousable physiological unresponsiveness (in which the subjects lie with eyes closed and show no physiologically understandable response to external stimulus or internal need)`

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2
Q

What are the two functions that consciousness relies on?

A

AROUSAL
An intact ascending reticular activating system - to act as the alerting or awakening element of consciousness

AWARENESS OF ENVIRONMENT
A functioning cerebral cortex of both hemispheres - which determines the content of the consciousness

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3
Q

What are some causes of a decreased GCS?

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 ICP
- tumour, stroke, EDH, SDH, SAH, hydrocephalus

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4
Q

Describe persistent vegetative state

A

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

There is arousal and wakefulness but the patient does not regain awareness or purposeful behaviour of any kind

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5
Q

What is ‘locked-in syndrome’?

A

The patient has total paralysis below the level of the third nerve nuclei and, although able to open, elevate and depress the eyes, has no horizontal eye movement and no other voluntary eye movements

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6
Q

What is the diagnosis of locked-in syndrome dependant upon?

A

The ability of the patient to open their eyes voluntarily and signal numerically by eye closure

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7
Q

Outline resuscitation in a comatose patient

A

Airway

Breathing

  • Depressed respiration = drug overdose, metabolic disturbance
  • Increased respiration = hypoxia, hypercapnia, acidosis
  • Fluctuating respiration = brainstem lesion

Circulation

Blood Samples

Establish baseline BP, pulse, temperature, IV access and stabilise neck

Examine for meningitis - TREAT ON SUSPICION

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8
Q

What should be considered when obtaining a history pertaining to a comatose patient?

A

Predictable progression of underlying illness?
Unpredictable event in patient with previously unknown disease?
Totally unexpected event? - head injury, collapse, twitching? Previous history or drug or alcohol abuse?

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9
Q

What should be examined (and monitored) in a comatose patient?

A 
Temperature
HR, BP, CVS
Respiration
Skin, breath
Abdo
Meningism
Fundal exam
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10
Q

What neurological assessments can be made to asses coma?

A

GCS

Brainstem function

Motor function and refelxes

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11
Q

What GCS score is considered to classify the patient as comatose?

A

=/

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12
Q

What nerves control pupillary reactions?

A

III, IV

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13
Q

What nerves control corneal responses?

A

V, VII

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14
Q

What nerves control spontaneous eye movement?

A

III, IV, VI

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15
Q

What nerves control oculocephalic responses?

A

III, IV, VI, VIII

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16
Q

What nerves control oculovestibular responses?

A

III, IV, VI, VIII

17
Q

What controls the respiratory pattern?

A

Medullary centre

18
Q

What four things indicate the motor function?

A

Motor response
Motor tone
Tendon reflexes
Seizures

19
Q

If there are focal brainstem or lateralising cerebral signs in coma what may this indicate?

A

Meningism

BUT - Meningism may still present with no lateralising signs

20
Q

What are some causes of coma without lateralising signs i.e. without Meningism?

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

What are the Ix for coma without lateralising signs or Meningism?

A 
Toxicology screen including alcohol level
Blood sugar and U&Es
RFTs LFTs
Acid tests
BP
CO poisoning?
22
Q

What are some causes of coma without lateralising signs but with Meningism?

A

SAH
Meningitis
Encephalitis

23
Q

What are the Ix for coma without lateralising signs but with Meningism?

A

CT head

LP - if CT is normal

24
Q

What are some causes for coma with lateralising signs and Meningism?

A

Cerebral tumour
Cerebral haemorrhage
Cerebral infarction
Cerebral abscess

25
Q

What are the Ix for coma with lateralising signs and Meningism?

A

CT or MRI - OBLIGATORY

If not diagnostic, use metabolic screens, LP, EEG to look for other causes of coma

26
Q

Folow through the table of causes for coma with and without lateralising signs, amd with and without meningism

A

Lateralising sings NO, Meningism NO = Toxic/Metabolic/Systemic

Lateralising signs NO, Meningism Yes = SAH/Meningitis/Encephalitis

Lateralising signs YES, Meningism YES = Focal cerebral e.g. tumour, infarct

27
Q

Outline the major medical causes of coma lasting for more than 5 hours

A

40% due to alcohol or drugs

25% due to hypoxia e.g. secondary to MI

20% due to cerebrovascular event, either haemorrhage or infarction

15% metabolic e.g. diabetes, hepatic failure, renal failure, sepsis, hypercapnia/hypoxia

28
Q

What factors influence the outcome of coma?

A 
Age
Cause
Depth
Length
Clinical signs, most importantly the brainstem reflexes
29
Q

What proportion of patients in a non-traumatic coma for more than 6 hours will make a moderate or good recovery?

A

15%

30
Q

What are the foundations of 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/PE, peptic ulceration
Prevention of contractures
Consider locked-in syndrome
31
Q

What brain insults that are caused by head injury can lead to neurological signs/epilepsy?

A 
DAI
Contusion
Intracerebral haematoma
Extra-cerebral haematoma
-Extra-dural haematoma
-Sub-dural haematoma
32
Q

How does a subdural haematoma appear on CT?

A

Convex ellipse

33
Q

How does an extradural haematoma appear on CT?

A

Concave lens

34
Q

What os the management for head injury?

A

Stabilise c-spine
CABC
If GCS =/

35
Q

How is raised ICP treated?

A 
Surgery to relieve pressure 
Osmotic agents e.g. mannitol
Nurse with head at 30-45%
Reduce pain
Maintain good PO2, reduce PCO2
Reduce metabolism, reduce temperature with barbiturates

Neurology (42 decks)

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