Coma, Persistent Vegetative State and Brain Death Flashcards Preview

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Flashcards in Coma, Persistent Vegetative State and Brain Death Deck (46)
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1
Q

How is a coma neurologically assessed?

A

Glasgow coma scale
Brainstem function
Motor function and reflexes

2
Q

What does GCS stand for?

A

Glasgow coma scale

3
Q

What does the GCS look at?

A

Eye opening
Verbal response
Motor response

4
Q

Eye opening scores of the GCS

A

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

5
Q

Verbal response score of the GCS

A
Orientated - 5
Confused - 4
Inappropriate words - 3
Incomprehensible sounds - 2
None - 1
6
Q

Motor response scores of the GCS

A
Obeying commands - 6 
Localizing to pain - 5
Withdrawing from pain - 4
Flexing to pain - 3
Extending to pain - 2
None - 1
7
Q

Scores if a GCS score = 8 or under

A

Eye - 2 or less
Verbal - 2 or less
Motor - 4 or less

8
Q

What is a full score of the GCS?

A

15

9
Q

How do you test the brainstem function?

A
Pupillary reactions
Corneal responses
Spontaneous eye movements
Oculocephalic responses (dolls eye)
Oculovestibular responses
Resp pattern
10
Q

What CNs control pupillary reactions?

A

II and III

11
Q

What CNs control corneal responses?

A

V and VII

12
Q

What CNs control spontaneous eye movements?

A

III, IV and VI

13
Q

What CNs control oculocephalic responses?

A

III, IV, VI, VIII

14
Q

What CNs control oculovestibular responses?

A

III, IV, VI and VIII

15
Q

What controls the respiratory pattern?

A

Medullary centre

16
Q

How to test the motor function?

A

Motor response
Muscle tone
Tendon reflexes
Seizures

17
Q

What GCS score is needed to indicate a coma?

A

< 8

18
Q

Causes of a coma with no meningism and no focal brainstem or lateralising cerebral signs

A
Intoxications
Anoxic/ischaemic conditions
Metabolic disturbances
Systemic infections
Hyperthermia/hypothermia
Epilepsy
19
Q

Causes of a coma with meningism and no focal brainstem or lateralising cerebral signs

A

SAH
Meningitis
Encephalitis

20
Q

Causes of a coma with possible meningism with focal brainstem and lateralising cerebral signs

A

Focal cerebral e.g. tumour infarct

21
Q

Causes of coma with focal brainstem or lateralising cerebral signs

A

Cerebral tumour
Cerebral haemorrhage
Cerebral infarction
Cerebral abscess

22
Q

Medical causes of coma lasting more than 5 hours

A

40% due to drug ingestion +/- alcohol
25% due to hypoxia e.g. secondary to MI
20% due to cerebrovascular event, either haemorrhage or infarction
15% metabolic e.g. DM, Hepatic failure, renal failure, sepsis, hypercapnia/hypoxia

23
Q

Investigations of coma without focalising or lateralising signs and without meningism

A
Toxicology screen including alcohol level 
Blood sugar
Electrolytes
Hepatic and renal function 
Acid-base measurement and blood gases
Measure BP
Consider CO poisoning
24
Q

Investigations of a coma without focal or lateralising signs but with meningism

A

CT head scan

LP

25
Q

Investigations of coma with focal brainstem or lateralising cerebral signs

A
CT or MRI obligatory 
If CT/MRI not diagnostic, then investigate as far as can for other causes of coma e.g. 
- metabolic screens
- LP 
- EEG
26
Q

Causes of a patient in a coma with decreased respiration

A

Drug overdose

Metabolic disturbance

27
Q

Causes of a patient in a coma with increased respiration

A

Hypoxia
Hypercapnia
Acidosis

28
Q

Causes of a patient in a coma with fluctuating respiration

A

Brainstem lesion

29
Q

Factors affecting the outcome of a coma

A
Age
Cause of coma
Depth of coma
Duration of coma 
Certain clinical signs, most important of which are brainstem reflexes
30
Q

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

A

15%

31
Q

Continuing care of patients in a coma

A
Maintenance of vital functions
Care of skin, avoidance of pressure sores
Attention to bladder and bowel function 
Control of seizures
Prophylaxis of CVT, peptic ulceration 
Prevention of contractures
Consider the "locked in" syndrome
32
Q

Definition of coma

A

A state of unarousable psychological unresponsiveness in which the subjects lie with their eyes closed and show no psychologically understandable response to external stimulus or inner need

33
Q

What does consciousness depend on?

A

AROUSAL - An intact ascending reticular activating system to act as the alerting or awakening element of consciousness
AWARENESS OF THE ENVIRONMENT - A functioning cerebral cortex or both hemispheres which determines the content of that consciousness

34
Q

Definition of persistent vegetative state

A

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

35
Q

Causes of decreased GCS

A
Toxic/metabolic states
- hypoxia 
- hypercapnia
- sepsis
- hypotension 
- drug intoxication 
- renal or liver failure 
- hypoglycaemia 
- ketoacidosis
Seizures
Damage to the reticular activating system 
Causes of raised ICP
- Tumour
- Stroke
- EDH
- SDH
- SAH
- hydrocephalus
36
Q

Why do elderly patients have loads of space around their brain?

A

Their brain shrinks

37
Q

Does focal damage to part of the cortex affect the conscious level?

A

No

38
Q

Causes of diffuse hemisphere damage

A

Trauma
Ischaemia
Hypoglycaemia
Hepatic or renal failure

39
Q

Give an example of a condition that can cause bilateral thalamic involvement

A

Astrocytoma

40
Q

Causes of brain stem involvement

A

Ischaemia
Haemorrhage
Tumour
Drugs (sedatives, hypnotics)

41
Q

What is the “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 movements and no other voluntary eye movement. They can still breath. Usually fully aware

42
Q

What types of head injury can lead to focal neurological signs/epilepsy?

A
Diffuse axonal injury 
Contusion (bruise)
Intracerebral haematoma
Extracerebral haematoma 
- extra dural haematoma
- sub dural haematoma
43
Q

What does a subdural haematoma look like on CT?

A

Convex/convex

44
Q

What does a extradural haematoma look like on CT?

A

Concave/convex (lens)

45
Q

Treatment of head injury

A
Stabilize cervical spine
ABC
If GCS < 8 = intubation and ventilation 
Treat raised ICP
Cranial imaging - may need decompressive surgery or removal of haematoma
Neuro-observation
46
Q

Treatment of raised ICP

A
Surgery to relieve pressure 
- haematoma, ventricular shunt
Osmotic agents e.g. mannitol 
Head at 30-45% venous return 
Reduce pain 
Maintain good PO2, reduce PCO2
Reduce metabolism (reduce temp, barbituates)