CN III Palsy Flashcards
When can you only use the pupil as a guide when attempting to dx a CN III palsy?
- Only if complete CN III palsy
What are the 4 signature findings of a CN III palsy?
- Reversing Hyperdeviation
- Exo greater opposite of vertically limited eye
- Abduction still intact in vertically limited eye
- Horizontal and vertical diplopia = at distance and near
If the pupil is involved, 86% of the time it’s what?
An aneurysm
If the pupil is spared, 77% of the time it’s what?
Vasculopathic - diabetes
How long does it take for a vasculopathic CN III to resolve?
3 months (but can take up to 6 months to fully resolve)
When can you not use the pupil as a guide?
- Complicated CN III
- Incomplete CN III
- Relative sparing of pupil
- 20-50 years old
What are the 5 risk factors for an aneurysm?
- Smoking and alcohol
- HTN
- Women > 35 on BC
- Family Hx
- Polycystic Kidney Disease; Aortic Coarction; NF-1
In weber’s syndrome, where is the lesion localized and what are the main 2 findings?
- Localized to midbrain
- Ipsilateral CNIII palsy
- Contralateral Hemiparesis
In Benedict’s syndrome, where is the lesion localized and what are the main 2 findings?
- Lesion of cerebral peduncle and red nucleus
- Ipsilateral CN III palsy
- Contralateral hemiparesis and tremor
Contralateral hemiparesis and ipsilateral CN III palsy localizes where?
To the midbrain
Which is worse, a carotid cavernous fistula or a carotid cavernous thrombosis?
CCT - clot is pushing on vessel
What is a fistula?
arterial blood entering venous sinus, causing a back up of blood
What are the main 3 findings of a CCF?
- Pulsatile Exophthalmous
- Vein occlusion
- Blood in Schlemm’s Canal
In a cavernous sinus meningioma, what are we looking for on an MRI?
- homogenous enhancement
2. Dural tail
What are the 3 clinical findings of aberrant regeneration of CN III
- LND
- Pseudo-Graefe Sign
- Eyelid synkinesia
When the nerve that is used to innervate the IR goes to the levator, what is this called? What happens?
Pseudo-Graefe Sign
- when patient looks down, eyelid goes up
Can aberrant regen of CN II occur in diabetes (vasculoathic)?
NO!
When the nerve that used to innervate the MR and goes to the levator, what is this called? What happens?
- Eyelid Synkinesia
- when patient adducts, eyelie goes up
