Consciousness

Question 1

What can be meant by consciousness?

Answer 1

A state of being aware/responsive to the environment - able to mentally/physically perceive surroundings

Question 2

Damage to what can alter consciousness?

Answer 2

Reticular formation
Bilateral lesions to intralaminar thalamic nuclei
Bilateral involvement of cerebral hemispheres
Major involvement of dominant hemisphere
Generalised depression of nervous system

Question 3

Outline the reticular formation

Answer 3

Medulla -> midrabin
Major role in sleep/wake cycle and modification of spinal tracts
Occupies significant portion of dorsal brainstem - very long dendrites radiate to all brainstem areas

Question 4

What’s the reticular activating system?

Answer 4

Network of structures including brainstem, thalamus and neural pathways that function together to maintain arousal (synapse with ascending descending spinal tracts) - play central role in bodily and behavioural alertness

Question 5

What are some causes of reduced consciousness?

Answer 5

Metabolic
Trauma
Tumour
Infection
Intoxication

Question 6

What are some metabolic causes for reduced consciousness?

Answer 6

Hypoxaemia/hypoperfusion (stroke, TIA, syncope)
Hypoglycaemia
Hyperglycaemia/diabetic ketoacidosis
Hypernatreamia, hypercalcaemia
Renal or liver failure
Hypothermia

Question 7

What are some trauma causes for reduced consciousness?

Answer 7

Minor concussion
Cerebral contusion
Intracranial haemorrhage

Question 8

What’s GCS used for? What’re its 3 components?

Answer 8

Measure of consciousness
Best eye response
Best verbal response
Best motor response

Question 9

What’s the best and worst GCS score?

Answer 9

15/15 or 3/15
E4
V5
M6

Question 10

How are different GCS scores classified?

Answer 10

Minor >13
Moderate head injury 9-12
Severe head injury <8

Question 11

What’s a persistent vegetative state?

Answer 11

Reticular formation in tact, but connection with cortex non-functional
Person is awake - eyes open and moving around
EEG shows sleep wake cycle rhythmic activity
Awareness is absent as no verbal or pain response

Question 12

What’s locked-in syndrome?

Answer 12

Sensation, reticular formation and cortical function are in tact
Person awake and fully aware
Eyes move vertically but no motor function

Question 13

What usually causes locked in syndrome?

Answer 13

Infarct in ventral pons -> corticobulbar and corticospinal tracts

Question 14

What are the 5 things you test in a peripheral neurological examination?

Answer 14

Tone
Power
Reflexes
Coordination
Sensation

Question 15

Name 1-6 of best motor response

Answer 15

6 obeys commands
5 localises to painful stimulus
4 withdraws from painful stimulus
3 flexes to pain
2 extends to pain
1 no motor response

Question 16

Name 1-5 of best verbal response

Answer 16

5 fully orientated
4 confused
3 inappropriate words
2 incomprehensible sounds
1 none

Question 17

Name 1-4 of best eye response

Answer 17

4 eyes open spontaneously
3 eyes open to speech
2 eyes open to painful stimulus
1 no eye opening