Cranial Nerve Pathology and Disorders of Nervous System Development

Question 1

Why avoid irritants when testing olfactory nerve?

Answer 1

Irritation triggers trigeminal.

Question 2

How to test for CSF rhinorrhea?

Answer 2

Look for glucose or beta 2 transferrin.

Question 3

Spinal trigeminal nucleus senses?

Answer 3

Pain, temp, crude touch. Located at basal medulla.

Question 4

Pontine Trigeminal/primary (V2) nucleus senses?

Answer 4

Discriminative touch

Question 5

Mesencephalic nucleus of V senses?

Answer 5

Proprioception from muscles of mastication

Question 6

Corneal reflex?

Answer 6

Sensory of V1.

Question 7

What happens if tip of nose has zoster?

Answer 7

Get patient to optho, good chance of corneal involvement.

Question 8

Most common location of trigeminal neuralgia?

Answer 8

In both V2 and V3.

Question 9

How to treat trigeminal neuralgia

Answer 9

carbamazepine (stabilizes closed form of Na channels)

Question 10

What type of myelin is most stable?

Answer 10

Peripheral (made by schwann cells)

Question 11

Facial nerve nucleus located?

Answer 11

In pons.

Question 12

Why is forehead not involved in stroke?

Answer 12

Because it’s dually innervated. Fibers from both sides of brain reach both nuclei.

Question 13

Facial nerve sensation?

Answer 13

Behind the ear.

Question 14

SSA fibers from VII?

Answer 14

Taste anterior 2/3 tongue (chorda tympani)

Question 15

GVE fibers from VII?

Answer 15

Lacrimal and nasal glands, stapedius.

Question 16

Bells palsy

Answer 16

Involves entire face on one side (including forehead), because its an infranuclear lesion. Also can include impaired taste and hyperacusis.

Question 17

Trigeminal autonomic reflex

Answer 17

Reason

Question 18

Ramsay Hunt Syndrome

Answer 18

Varicella rash around ear with VII involvement.

Question 19

Hemifacial spasm

Answer 19

VII is compressed by a vertebral artery, treat with botox.

Question 20

Nerve IX functions

Answer 20

Gag reflex, taste to posterior 1/3 tongue. Carries info from baroreceptors in head/neck to brainstem (with 10)

Question 21

CN X functions

Answer 21

Gag reflex, palatal elevation

Question 22

CN X lesion, effect on palatal elevation?

Answer 22

Lowering of palatal arch to the side of lesion.

Question 23

Hypoglossal Nerve testing

Answer 23

Stick out tongue

Question 24

Upper motor neuron lesion for CN XII

Answer 24

Weakness on contralateral side, so deviates opposite side of lesion. (This happens because it’s not completely dually innervated).

Question 25

Pseudobulbar Palsy causes, symptoms, treatment.

Answer 25

Bilateral corticobulbar tracts involved (V, VII, IX, X, XI, XII). Inability to control facial movements, swallowing, spastic speech, emotional outbursts. Rx w/dextromethorphan.