Ophthamology: Neuro-ophthamology Flashcards
What is the first thing to assess in a patient with diplopia?
If it’s monocular or binocular
-binocular is more serious because it indicates a neuro issue.
Most common cause of monocular diplopia.
Astigmatism
Direction the eye deviates in CN III palsy.
Down and Out
Why is a blown pupil more emergent than impaired extraocular muscles in CN III palsies?
Blown pupil usually means an aneuysm compressing the nerve which can lead to a stroke or more severe condition. (occurs at the junction of the posterior communicating artery and internal carotid).
Impaired EOM is usually a diabetic infarct
What should you do in a patient with CN III palsy and a blown pupil? Without a blown pupil?
w/: Order and MRI and angiogram
w/o: Check blood sugar and blood pressure
Main cause of CN VI palsy.
Increased intracranial pressure that stretches the nerve. It exits the pons and runs along the floor of the skull up towards the cavernous sinus.
What is pseudotumor cerebri?
A neurological disorder that is characterized by increased intracranial pressure in the absence of a tumor or other diseases. Can lead to CN VI palsy.
How do patient’s present with injury to CN IV?
Head tilt opposite the side of the injured nerve.
Common causes of trochlear nerve palsy.
Trauma, ischemia, congenital defect, tumor
What is the number one reason that a CN is damaged due to a vascular incident?
Diabetes
What condition is associated with:
“diplopia that does not map to a specific cranial nerve”?
Myasthenia Gravis
The Tensilon Test is used to diagnose myasthenia gravis and is a dose of Edrophonium (AChase inhibitor). How would you treat an overdose of this indirect cholinergic agonist?
Atropine (cholinergic antagonist)
If a patient is diagnosed with myasthenia gravis, what should you also test them for?
Thymoma: check thryoid hormone levels
What is a cardinal sign of optic neuritis and what is it associated with?
- Loss of color vision
- Usually a demyelinating disease that is associated with increased RISK of Multiple Sclerosis……..only increased RISK
How do you treat optic neuritis?
IV steroids
oral steroids might further increase RISK of MS
What must be ruled out in patients over 55 with unilateral vision loss?
Giant Cell Ateritis (temporal arteritis)
What two symtoms are indicative of Giant Cell Arteritis?
- Jaw Claudication
2. Scalp Tenderness
What is the procedure for treatment if a physician suspects Giant Cell arteritis?
- Order sed. rate and CRP
- Temporal Artery Biopsy
- Start on steroids immediately (even before test results are back)
Name and describe the 2 tests used to diagnose Horner Syndrome.
- Cocaine Test: block NE re-uptake. A Horner Syndrome patient will still show no effect on the bad eye but the normal eye will have mydriasis.
Paradrine Test: done after cocaine test. Inject hydroxyamphetamine, if the pupil doesn’t dilate it’s a lower motor neuron (3rd order) death.
If the pupil dilates, it’s a higher (1st or 2nd order) neuron issue.
What should you check for in a patient with Horner Syndrome and pain?
Internal carotid dissection. MRI or angiogram.
What is Adie’s Tonic Pupil?
Loss of parasympathetic innervation to the pupil. Pupil is dilated and won’t constrict.
