neuro-ophth

Question 1

where is the oculomotor nucleus located?

Answer 1

the dorsal midbrain at the level of the superior colliculus

Question 2

where does the oculomotor nerve exit the brainstem?

Answer 2

through the interpenduncular fossa -> cavernous sinus _> enters orbit via superior orbital fissure

Question 3

unique characteristics of the trochlear nerve

Answer 3

only cranial nerve that exits dorsally from the brainstem

smllest CN

longest intracranial course

Question 4

which foramen does trochlear nerve enter orbit through?

Answer 4

superior orbital fissure

Question 5

causes of horners syndrome

Answer 5

stroke (lateral medullary syndrome)
syringomyelia
pancoast tumour, carotid aneurysm
ICA aneurysm (painful)
cavernous sinus lesion

kids - trauma commonest

Question 6

lateral medullary syndrome

Answer 6

due to blockage of posterior inferior cerebellar artery or vertebral artery

Clinical features:
- Damage to the vestibular nucleus causing vertigo,vomiting and nystagmus.
- Damage to the descending sympathetic system causing ipsilateral Horner’s syndrome.
- Damage to the spinal trigeminal tract causing ipsilateral loss of pain/temperature and loss of corneal reflex.
- Damage to the spinothlalamic tract causing contralateral loss of pain/temperature in the trunk and limbs.
- Other symptoms include dysphagia and horseness.

Question 7

Adie’s pupil

Answer 7

large dilated “tonic” pupil which does not constrict to light

caused by idiopathic degeneration of ciliary ganglion

typically unilateral + affects young females

Question 8

Adie’s pupil clinical features

Answer 8

anisocoria = affected pupil is larger + blurring on near vision (slow constriciton on accom)

light reflex absent + near reflex is slow

diminished or absent deep tendon reflex of lower limbs + adie’s pupil +/- orthostatic hypotension = Holmes-Adie syndrome

Question 9

Adie’s pupil investigations

Answer 9

Slit lamp
0.125% (low dose) of topical pilocarpine into both eyes. –> Adie’s pupil constricts (due to denervation hypersensitivity) while normal pupil doesn’t.

Question 10

Argyll robertson pupil

Answer 10

is characterized by bilateral, irregular and small pupils. Both pupil do not react to light, however, they constrict normally on accommodation.

Question 11

Argyll robertson pupil cause

Answer 11

diabetes
use to be neurosyphilis

Question 12

0.1% pilocarpine affect in Argyll robertson pupil

Answer 12

NO effect

(effect in Adie’s pupil)

Question 13

what visual field defect will lesions on the temporal radiations have?

Answer 13

contralateral superior homonymous quadrantopia

Question 14

what visual field defect will lesions on the parietal radiations have?

Answer 14

contralateral inferior homonymous quadrantopia

pie in floor

Question 15

visual field defect from lesion in occipital cortex

Answer 15

homonymous hemianopia with macula sparing