Sudden Onset Diplopia & CN Palsy Flashcards
What are the two types of defects in neuro-opthalmic disease
- Eye movement defects (double vision)
- Visual defects (visual acuity, field loss)
Define diplopia & tropia
What is sudden onset diplopia
Patient has changed from having binocular single vision, seeing one image only, to a sudden onset manifest squint and diplopia (double vision)
Sudden onset diplopia aetiology
Weakness of extra-ocular muscles due to cranial nerve palsy
Acute onset diplopia (less than 4 weeks) investigations
- Cover test
- Ocular motility test
- MRI imaging
Define
- esotropia
- exotropia
- hypertropia
- hypotropia
What does horizontal double vision suggest
What does vertical double vision suggest
Describe the cover test
Describe the ocular motility test
CN VI palsy aetiology
- microvascular disease (most common)
- raised intracranial pressure (most concerning)
- tumour pressing on nerve
- congenital
CN IV palsy aetiology
- Congenital decompensated (most common)
- Microvascular (most common in >60yrs)
- Tumour
- Blunt head trauma (characteristic - bilateral CN IV palsy)
CN III palsy aetiology
CN IV palsy presentation
- Vertical diplopia & hypertropia
- Eye looks up on adduction
- Compensatory head tilt
CN VI palsy presentation
- Horizontal diplopia & esotropia
- Eye cannot abduct and trying to do so worsens diplopia
- Compensatory head tilt
CN III palsy presentation
- down (SO) & out (LR) squint
- ptosis (LPS)
- miosis (sphincter papillae muscle) (if aneurysm)
- pain (if aneurysm)
What two reds flag signs alongside CN III palsy suggests aneurysm as the cause
Miosis & pain
