Coma

Question 1

Vestibulo-Ocular Reflex

Answer 1

Cold water: normally eyes deviate to water ear
If brainstem intact this will happen
If brainstem not intact eyes will stay in place

Dolls Eye: Rotate head- normally eyes will stay straight ahead, if they ‘stick’ with the head this is a sign of brainstem dysfunction

Question 2

What are the causes of coma?

Answer 2

1. Diffuse bihemospheric: vascular, infectious, toxic/metabolic, raised ICP, traima
2. Cortical structural: mass on one side or mass in both
3. ARAS/Brainstem- direct injury or secondary to herniation

Question 3

Uncal brain herniation

Answer 3

Temporal lobe coming down, squishes CN 3 + motor tracts
Blown pupil
Contralateral babinski

Question 4

Central brain herniation

Answer 4

Central brain hernaites through tentorium
Obtunded, small equal pupils,
Bilateral babinksi
Decorticate posturing

Question 5

What is the difference between obtunded and coma?

Answer 5

Obtunded: loss of interest and some loss of responsiveness but still communicative
Coma: Unrousable unresponsiveness, reflexes

Question 6

What comprises the ARAS?

Answer 6

Thalamus, posterior hypothalamus, basal forebrain, upper brainstem

Question 7

Locked In Syndrome

Answer 7

Complete paralysis (usually bilateral pontine lesion)
Maintenance of conciousness

Question 8

Persistant Vegetative state

Answer 8

Massive cortical damage but brainstem intact

Question 9

Ipsilateral paralysis and eye deviation

Answer 9

Lesion in pontine reticular formation (eyes deviate away from lesion)

Question 10

Contralateral paralysis and eye deviation

Answer 10

Lesion in frontal eye fields (eyes deviate towards lesion)