Coma

Question 1

What does somnolent mean?

Answer 1

need external stimulation to get normal wakefulness

Question 2

What does obtunded mean?

Answer 2

with external stimulation, get abnormal wakefulness (never reach normal wakefulness)

Question 3

What does coma mean?

Answer 3

no wakefulness

Question 4

What is Cheyne Stokes respiration? What level drives it?

Answer 4

waxing and waning character, midbrain (below diencephalon)

Question 5

What is central neurogenic hyperventilation? What level drives it?

Answer 5

deep and fast inspiration, driven by reticular activating system in pons

Question 6

What is apneustic respiration? What level drives it?

Answer 6

inspiratory spasms that aren’t well organized, not purposeful breathing, driven by medulla

Question 7

What is ataxic respiration? What level is damaged?

Answer 7

complete irregularity of breathing with periods of apnea (will lead to complete apnea), damage to medulla

Question 8

What is the path of the pupillary light reflex?

Answer 8

optic nerve -> genu of superior colliculus -> tectum of midbrain -> synapses in pretectal area -> EW nuclei -> CN III parasympathetic -> ciliary ganglion -> ciliary muscle to constrict pupils

Question 9

What are metabolic pupils? Are they reactive to light?

Answer 9

from taking downers/barbituates
reactive to light because still have midbrain function
smaller because lost influence of cortex/diencephalon

Question 10

What are diencephalic pupils? Are they still reactive?

Answer 10

pupils smaller because lost sympathetics from hypothalamus that cause dilation
still reactive

Question 11

What are tectal pupils? Are they still reactive?

Answer 11

pupils midposition and dilated- fixed

non reactive, same as midbrain except not unconscious

Question 12

What are CNIII lesioned (uncal) pupils? Are they still reative?

Answer 12

dilated and fixed
will have consensual response in unaffected eye when testing affected eye
will only get direct response for testing unaffected eye
(the one eye is nonreactive)

Question 13

What are midbrain pupils? Are they reactive?

Answer 13

midposition, fixed
nonreactive
same as tectal, but person is in coma

Question 14

What are pontine pupils? Are they reactive?

Answer 14

pinpoint pupils, very small from loss of sympathetics

nonreactive

Question 15

What test can be used to test the integrity of portions of the pons and midbrain and connection between them?

Answer 15

VOR
turn head- eyes move opposite direction you turn
ice water in ear- eyes move towards that ear

Question 16

What do you get from a lesion above the red nucleus? Below it?

Answer 16

above red nucleus = decorticate

below red nucleus = decerebrate

Question 17

What does decorticate posturing look like?

Answer 17

abnormal flexor response of arm and adduction of upper extremity
abnormal extension and internal rotation and plantar flexion of legs

Question 18

what does decerebrate posturing look like?

Answer 18

abnormal extensor response of arms and legs

can get opisthotonos in full form (extension of trunk and neck, clenching of jaw, internal rotation of arms)

Question 19

What symptoms do you see in bilateral midbrain stage for respiratory pattern? pupillary size and reaction? VOR? motor?

Answer 19

• central neurogenic hyperventilation (driven by pons)
• midposition, fixed, nonreactive
• INO, discrepanices between eyes (since VI in pons still intact and CN III in midbrain isn’t)
• at rest motionless, can get decerebrate

Question 20

What symptoms do you see in bilateral diencephalic stage for respiratory pattern? Pupillary size and reaction? VOR? motor?

Answer 20

• cheyne stokes (driven by midbrain)
• small pupils because lost sympathetics, but reactive
• VOR intact
• at rest motionless, can get decorticate

Question 21

Where is the reticular activating system located? Do you need it to be bilaterally intact to maintain consciouness?

Answer 21

in midbrain, can have unilateral lesion and consciousness will still be intact

Question 22

Where do drugs act? Unilaterally or bilaterally?

Answer 22

bilateral cortex

Question 23

What symptoms do you see in bilateral pontine stage for respiratory pattern? pupillary size and reaction? VOR? motor?

Answer 23

• apneustic/ataxic respiration
• fixed, midposition, nonreactive
• no VOR response
• no motor response, + babinski

Question 24

What symptoms do you see in unilateral diencephalic for respiratory pattern? pupillary size and reaction? VOR? motor?

Answer 24

• Cheyne Stokes or normal with deep signs and yawns
• small because knocked out some sympathetics, reactive
• VOR normal because pons and midbrain fine
• asymmetric motor response

Question 25

When do you tend to get pinpoint pontine pupils?

Answer 25

with unilateral lesion of pons

Question 26

What symptoms do you see with late third nerve stage for respiratory pattern? pupillary size and reaction? VOR? motor?

Answer 26

• central neurogenic hyperventilation
• ipsilateral pupil large, dilated, fixed, nonreactive, do get consensual response though and direct response for unaffected eye
• VOR can be driven by pons but not midbrain, looks like INO
• decorticate or decerebrate

Question 27

What can cause late third nerve stage?

Answer 27

uncal herniation