Assessing consciousness

Question 1

What damage to your nervous system can cause altered levels of consciousness?

Answer 1

Reticular Formation damage
Bilateral lesions to the intralaminar thalamic nuclei
Bilateral involvement of the cerebral hemispheres
Major involvement of the dominant hemisphere (usually left)
Generalised depression of the nervous system

Question 2

What is the role of the reticular formation?

Answer 2

Involved in the sleep-wake cycle

Question 3

Where is the reticular formation?

Answer 3

Dorsal brainstem - medulla to midbrain

Reticular fibres synapsing with ascending and descending tracts

Question 4

What are the main causes of decreased levels of consciousness?

Answer 4

Trauma
Infection 
Tumour
Metabolic
Intoxication

Question 5

What types of trauma can cause decreased levels of consciousness?

Answer 5

Minor concussion
Cerebral contusion (bruising)
Intracranial haemorrhage

Question 6

What types of infection can cause decreased levels of consciousness?

Answer 6

Meningitis
Encephalitis
Brain abscess
Subdural empyema (pus)

Question 7

What metabolic disorders can cause decreased levels of consciousness?

Answer 7

Hypoperfusion/ hypoxaemia 
Hypoglycaemia/ hyperglycaemia (e.g. DKA) 
Hypernatraemia/ Hyponatraemia 
Hypercalcaemia 
Renal/ liver failure
Hypothermia

Question 8

What 3 categories are assessed when using the Glasgow Coma Scale?

Answer 8

Best eye response
Best motor response
Best verbal response

Question 9

What is the scale used to assess best eye response (GCS)?

Answer 9

4 - eyes open spontaneously
3 - eyes open to speech
2 - eyes open to painful stimuli
1 - eyes do not open

Question 10

What is the scale used to assess best verbal response (GCS)?

Answer 10

5 - fully oriented (to person, place and time) 
4 - confused (disoriented) 
3 - inappropriate words
2 - incomprehensible sounds 
1 - none

Question 11

What is the scale used to assess best motor response (GCS)?

Answer 11

6 - obeys commands
5 - localises to painful stimuli 
4 - normal flexion 
3 - abnormal flexion 
2 - extension (to pain) 
1 - no motor response

Question 12

How is a GCS score classified in terms of severity of injury?

Answer 12

Severe head injury = GCS <8
Moderate head injury = GCS 9-12
Mild head injury = GCS >13

Question 13

What is a persistent vegetative state?

Answer 13

Reticular formation is intact but connection with cerebral cortex is non-functional meaning a person can be awake (and have sleep-wake cycles) but awareness is absent

Question 14

What is “locked-in” syndrome?

Answer 14

Sensation, reticular formation and cortical function is intact so person is fully awake and aware but has no motor function.
Usually due to an infarct in the ventral pons involving the corticobulbar and corticospinal tracts.

Question 15

List the cranial nerves

Answer 15

I - olfactory 
II - optic
III - occulomotor
IV - trochlear 
V - trigeminal 
VI - abducens
VII - facial 
VIII - auditory/ vestibulocochlear  
IX - glossopharyngeal 
X - vagus 
XI - accessory 
XII - hypoglossal

Question 16

What does a peripheral neurological examination test for?

Answer 16

Tone 
Power
Reflexes
Co-ordination 
Sensation

Question 17

What are the signs of decerebrate rigidity?

Answer 17

Extension of arms and legs and medial rotation of arms and legs

Question 18

What does the cold caloric test assess?

Answer 18

Vestibulo-ocular reflex
Looks for nystagmus towards side of cold water in EAM
Would indicate brainstem activity (i.e. not ‘brain dead’)

Question 19

What motor score would be given for a decerebrate or decorticate patient?

Answer 19

Decerebrate = 2 (extension)
Decorticate = 3 (abnormal flexion)