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
