Cranial Nerve Pathology and Disorders of Nervous System Development Flashcards
Why avoid irritants when testing olfactory nerve?
Irritation triggers trigeminal.
How to test for CSF rhinorrhea?
Look for glucose or beta 2 transferrin.
Spinal trigeminal nucleus senses?
Pain, temp, crude touch. Located at basal medulla.
Pontine Trigeminal/primary (V2) nucleus senses?
Discriminative touch
Mesencephalic nucleus of V senses?
Proprioception from muscles of mastication
Corneal reflex?
Sensory of V1.
What happens if tip of nose has zoster?
Get patient to optho, good chance of corneal involvement.
Most common location of trigeminal neuralgia?
In both V2 and V3.
How to treat trigeminal neuralgia
carbamazepine (stabilizes closed form of Na channels)
What type of myelin is most stable?
Peripheral (made by schwann cells)
Facial nerve nucleus located?
In pons.
Why is forehead not involved in stroke?
Because it’s dually innervated. Fibers from both sides of brain reach both nuclei.
Facial nerve sensation?
Behind the ear.
SSA fibers from VII?
Taste anterior 2/3 tongue (chorda tympani)
GVE fibers from VII?
Lacrimal and nasal glands, stapedius.
Bells palsy
Involves entire face on one side (including forehead), because its an infranuclear lesion. Also can include impaired taste and hyperacusis.
Trigeminal autonomic reflex
Reason
Ramsay Hunt Syndrome
Varicella rash around ear with VII involvement.
Hemifacial spasm
VII is compressed by a vertebral artery, treat with botox.
Nerve IX functions
Gag reflex, taste to posterior 1/3 tongue. Carries info from baroreceptors in head/neck to brainstem (with 10)
CN X functions
Gag reflex, palatal elevation
CN X lesion, effect on palatal elevation?
Lowering of palatal arch to the side of lesion.
Hypoglossal Nerve testing
Stick out tongue
Upper motor neuron lesion for CN XII
Weakness on contralateral side, so deviates opposite side of lesion. (This happens because it’s not completely dually innervated).
Pseudobulbar Palsy causes, symptoms, treatment.
Bilateral corticobulbar tracts involved (V, VII, IX, X, XI, XII). Inability to control facial movements, swallowing, spastic speech, emotional outbursts. Rx w/dextromethorphan.
