Neuroophthamology

Question 1

CNIII palsy

Answer 1

• eye deviates “down and out”
• severe ptosis
• blown pupil: EWN damage = emergency
• caused by ischemia: HTN or DM or can be from PCOM aneurysm (if blown pupil)

Question 2

CNVI palsy

Answer 2

• loss of eye abduction
• pt will be cross eyed so will turn head to compensate and prevent diplopia
• can be caused by increased ICP b/c of route in cavernous sinus

Question 3

CNIV palsy

Answer 3

• eyes will deviate upward and eye will have “cyclotorsion” = twisting of eye
• pts tilt their head AWAY from lesion
• caused by trauma, ischemic event, or congenital
• CNIV has longest course inside cranium; exits from the BACK of brainstem

Question 4

superior oblique m. inserts where?

Answer 4

• BACK of the eye

Question 5

myasthenia gravis (MG) - general info and eye problems

Answer 5

• autoimmune: body makes antibodies to nicotinic ACh receptors at the neuromuscular junction (NMJ)
• causes diplopia and ptosis in eyes if affected –> worse on prolonged gaze
• consider when there is a diplopia complaint that doesn’t map out to any particular CN

Question 6

MG - testing

Answer 6

• Tensilon test: give an AChE and look for symptom improvement
• for any adverse rxn to tensilon test you give atropine
• ice test commonly done in ophth office: hold icepack over closed eyes, remove it and look for symptom improvement
• neuro can also do an EMG

Question 7

MG: other associated issues

Answer 7

• problems w/ mastication, talking, drinking, and SWALLOWING = aspiration pneumonia and respiratory failure
• work up all MG pts for thymoma and check thyroid levels

Question 8

optic neuritis

Answer 8

• “inflammation” of the n. = demyelinating
• S&S = decreased vision (esp. color), pain w/ eye mvmt, optic n. edema, APD
• occurs in younger pts, usually women
• potential for pt to develop MS but NOT diagnostic of MS; just means pt is at higher risk
• get MRI and tx w/ IV steroids –> NEVER w/ oral steroids b/c you will increase the recurrence

Question 9

ischemic optic neuropathy (ION)

Answer 9

• usually causes altitudinal visual defect

Question 10

multiple sclerosis

Answer 10

• demyelinating disease of CNS
• “lesions occurring at different times and different places”
• young white women from northern climates
• 90% of MS pts will get optic neuritis

Question 11

temporal arteritis: what it is, S&S, pt presentation

Answer 11

• aka giant cell arteritis (GCA)
• need to r/o w/ any pt over age 55 presenting w/ unilateral vision loss
• result of vasculitis w/in medium and small arteries around head
• disease process similar to polymyalgia rheumatic
• pts present w/ sudden, painless vision loss
• other S&S = scalp tenderness, JAW CLAUDICATION, polymyalgias, weight loss

Question 12

temporal arteritis: labs, testing

Answer 12

• order ESR and CRP for labs
• labs aren’t definitive dx so you need a temporal artery biopsy
• start pt on steroids RIGHT AWAY

Question 13

Horner Syndrome: symptoms, tests

Answer 13

• pupil constricts and stays small
• mild ptosis
• anhydrosis on affected side
• testing = cocaine and paradrine

Question 14

cocaine test

Answer 14

• diagnostic for horner’s
• cocaine stimulates pupil sympathetics by decreasing norepi uptake
• if pt has horner’s =
  no effect on affected eye
  good eye will dilate

Question 15

paradrine test

Answer 15

• done after the cocaine test
• stimulates the 3rd order n.
• if the pupil still doesn’t dilate you know the final LMN is dead
• if the pupil does dilate then a higher order n. must be out

Question 16

what if pt present w/ a painful horner’s?

Answer 16

• r/o carotid dissection ASAP w/ imaging

Question 17

Adie’s tonic pupil

Answer 17

• opposite of Horner’s = parasymp pathway knocked out
• eye is dilated and doesn’t constrict to light b/w EWN parasymp path blocked
• pupil will constrict w/ near vision but very slowly (tonically slow hence name)