Nerve palsies Flashcards
If the pupil is involved in a 3rd nerve palsy, what is the likely cause?
Aneurysm
Which muscles are involved in a 3rd nerve palsy?
MR
SR
IR
IO
Ciliary muscle
Sphincter pupillae
Levator palpabrae superioris
How will a px with a 3rd nerve palsy likely present?
Affected eye down and out, ptosis and poss blown pupil
What will you see on motility on a px with a 3rd nerve palsy?
Limited adduction
Limited elevation in abduction and adduction
Limited depression in abduction
Why is muscle sequelae usually limited to the second stage for a 3rd nerve palsy?
Due to the amount of muscles involved
Why is an AHP unlikely in a 3rd nerve palsy?
Unlikely to be area of BSV due to amount of muscles involved
Which muscles are involved in a superior division 3rd nerve palsy?
SR
Levator palpebrae superioris
How will a px with a superior division 3rd nerve palsy likely present?
Hypotropia and ptosis
Poss chin up AHP
Which muscles are involved in a inferior division 3rd nerve palsy?
IO, IR, MR
Sphincter pupillae
Ciliary muscle
How will a px with a inferior division 3rd nerve palsy likely present?
No/small vertical deviation
Exotropia
Poss face turn towards unaffected eye
If an infant presents with a 3rd nerve palsy, what should you do?
Urgent referral
If an adult with a 3rd nerve palsy attends an appt, what should you do?
Urgent referral to eye casualty if new and undiagnosed
What can you do to make a px with a 3rd nerve palsy comfortable?
Occlude one eye if diplopia present
Only incorporate prism once stable
Fresnel prism unlikely to be helpful (due to multiple muscle involvement and incommitance)
What investigations will the HES do for a 3rd nerve palsy?
Work out aetiology (bloods, MRI/CT)
Occlude one eye until no diplopia
Surgery once stable if not full recovery - aiming for better cosmesis and reduced sxs in primary position
Which muscle is involved in a 4th nerve palsy?
SO
How will a px with a 4th nerve palsy likely present?
Hyper and esotropic
Poss excyclo
Deviation larger at near
What AHP is a px with a 4th nerve palsy likely to adopt?
Head tilt
Face turn
Chin depression
How does the Bielschowsky head tilt test work?
Determines which muscle is primary underacting when muscle sequelae present in 4th nerve palsy.
When head is titled towards affected eye, hypertropia increases in affected eye.
3m target used due to being neutral point for both SO and SR muscles.
How should a 4th nerve palsy be managed?
If acquired and not investigated previously, urgent referral to eye casualty.
If congenital - routine referral if HES intervention desired.
Fresnel prism
Temporary occlusion
Incorporate prism into specs once stable.
Surgery once stable if not full recovery (weakens overacting IO, brings eye down).
Treat amblyopia
Which muscle is involved in a 6th nerve palsy?
LR
What symptoms might a px with a 6th nerve palsy present with?
Horizontal diplopia which is better at near, worse on lateral gaze
What would you likely see on CT for a px with a 6th nerve palsy?
Esotropia at distance, poss smaller angle or phoria at near
What would you likely see on motility for a px with a 6th nerve palsy?
Limited abduction of affected eye
Possible A eso pattern (more eso on upgaze)
What should you do if you see a px with a 6th nerve palsy?
If acquired (most likely): urgent to HES
If infant, look for Duane’s characteristics
Temporary occlusion or fresnel to relieve diplopia
