3rd nerve palsy Flashcards
What is the 3rd nerve?
Oculomotor nerve
How many branches does the 3rd nerve have?
2- superior and inferior division
What does the superior division innervate?
Superior rectus and
Levator palpebrae superioris
What does the inferior division innervate?
Medial rectus
Inferior rectus
Inferior oblique
Branch to pupil sphincter
Branch to ciliary muscle
If there is a 3rd nerve palsy what will the affected eye look like?
Down and out (exo and hypo)
Why will the eye be down and out?
Because the lateral rectus and the SO muscles are spared as they are supplied by the 6th and 4th nerve respectfully
What is a congenital 3rd nerve palsy caused by?
Born with it - complete absence of the nerve and have other associated neurological deficits
Can be idiopathic
What 2 types of acquired 3rd nerve palsy are there?
Complete or partial
What are the symptoms of complete acquired 3rd nerve palsy
Pain around the eye of sudden onset, headache, ptosis, a dilated pupil and diplopia (if the ptosis is not fully covering the pupil)
Eye DOWN AND OUT
What are the symptoms of partial acquired 3rd nerve palsy
A partial third nerve palsy will have some, but not all, of the symptoms and the eye position will depend on which muscles have been affected
If pupil is affected, what will it look like?
Dilated
If pupil is involved what does this mean?
Aneurysm of the posterior communicating artery should be suspected;
If the pupil is spared what does this mean?
Normal pupil responses and the cause is more likely to be related to underlying vascular disorders such as diabetes or hypertension
How do you manage a suspect a third nerve palsy complete or partial?
Emergency referral to hospital to rule out a life-threatening aneurysm REGARDLESS of pupil involvement or not
What are other causes of acquired 3rd nerve palsy?
Trauma
Tumour
If cause is vascular what are chances of recovery?
Highly likely to recover
What can be done temporarily to help alleviate symptoms?
Occlusive contact lens or patch
Why are prisms not much help for 3rd nerve palsy?
Due to complexity of deviation
When is surgery considered
When the condition is stable and has not resolved with time,
What is surgery done for?
To correct the strabismus and any associated ptosis.
Surgery for third nerve palsy is complicated and is often performed for cosmetic reasons rather than for regaining any useful BSV
If the cause is Trauma or Tumour or aneurysm what are chances of recovery?
less likely to recover
