Diagnosis can be difficult

## Anatomy nuggets

- Nucleus in the midbrain at the level of the superior colliculus
- Bilateral levator innervation
- Contralateral superior rectus innervation
- Ipsilateral innervation to the other EOMs
- Travels through the MLF and lateral to the posterior communicating artery
- Travels in the lateral wall of the cavernous sinus
- Superior and inferior branches enter the orbit within the annulus of Zinn
- Superior branch innervates the superior rectus and levator. Inferior branch does the rest
- Parasympathetic fibres from the Edinger-Westphal nucleus travel with the branch to inferior oblique to the ciliary ganglion then in the short ciliary nerves

## Aetiology

- Aneurysms, classically of the PCoA (most commonly at the junction of the PCoA and the ICA)
- Microvascular ischaemia: typically recover over 4 months
- Tumours
- Trauma
- Demyelination
- Vasculitis including GCA
- Congenital

## Subtypes

- Complete vs partial
- Pupil-sparing or involving
- Nuclear, fascicular or peripheral
    - Nuclear:
      - Unilateral palsy
      - Contralateral superior rectus paresis
      - Bilateral partial ptosis

    - Fascicular: ie. paramedial midbrain lesion eg. infarction of cerebral peduncle with involvement of third nerve fascicle
      - Ipsilateral palsy
      - Contralateral intention tremor, ataxia, anaesthesia (**Benedikt** syndrome)
      - Contralateral hemiparesis (**Weber** syndrome)

- Isolated vs complex (ie. associated with other deficits)

## Clinical features

- Diplopia with horizontal and/or vertical ophthalmoplegia

<HotTopic>
Vertical gaze palsy in third nerve lesions. Doll’s head manoeuvre can distinguish supranuclear from nuclear lesions:

- Eyes elevate on Doll’s head: supranuclear

- Eyes do not elevate on Doll’s head: nuclear

</HotTopic>

- Ptosis: bilateral in nuclear lesions
- Mydriasis
- Pain: may be severe and similar to the headache of a SAH
- Difficulty focussing due to pupil involvement

<HotTopic>
Check superior oblique and lateral rectus in third nerve palsy.

- The eye cannot adduct in third nerve palsies, so to assess function of SO, observe for**intorsion**(its primary action) in abduction and downgaze.

- Lateral rectus function can be assessed via saccadic velocity

</HotTopic>

## Aberrant regeneration

- Typically in longstanding**compressive**lesions or trauma (Note: does**not**occur in vasculopathic lesions)
- Lid-gaze dyskinesia:
    - Lid elevation on adduction (‘inverse Duanes’) or depression (pseudo Von Graefe’s sign)

- Pupil-gaze dyskinesia
    - Pupillary constriction on adduction (pseudo Argyll Robertson) or depression

## Tests
- Urgent neuroimaging with angiography (CTA/MRA)
    - Some would observe a pupil-sparing, non-traumatic palsy especially with vasculopathic risk factors/patient over 40 and undertake imaging if no recovery within 3 months.

- Lumbar puncture
- Assess vascular risk factors
- ESR/CRP if over 50
- Hess chart

## Posterior communicating artery aneurysms

- Rupture in 2/3rd
- If ruptures, 50% mortality

## Brainstem syndromes

- Raymond syndrome: 6th nerve palsy with contralateral hemiparesis
    - Lesion in the mid-pons (ventral pons) affecting 6th nerve fasciculus and corticospinal tract

- Weber syndrome: 3rd nerve equivalent of Raymond syndrome
    - Lesion in the midbrain causing fascicular 3rd nerve palsy and contralateral hemiparesis
    - Weber’s is “weak”

- Claude syndrome: ipsilateral 3rd nerve palsy with contralateral ataxia
    - Lesion in the dorsal midbrain affecting superior cerebellar peduncle and 3rd nerve fasciculus
    - Claude is “cerebellar”

- Benedikt syndrome: ipsilateral 3rd nerve palsy with contralateral ‘rubral’ tremor (slow tremor at rest and with movement)
    - Lesion in the midbrain (red nucleus) affecting the 3rd nerve fascicle and red nucleus

- Nothnagel: ipsilateral 3rd nerve palsy and ipsilateral cerebellar ataxia
    - Localises to midbrain

Neuro-ophthalmology

Third Nerve Palsies

Intro

FRCOphth Part 2 Study Notes

Tumours, masses and neoplasia

Tumours overview

Uveitis

Uveitis background

Anterior uveitis

Intermediate uveitis

Uveitis in JIA

Uveitis with JIA

Retinal vasculitis

Sarcoidosis

Behcet's disease

Toxoplasmosis

Strabismus

Overview

Viral uveitis

Esotropia

Fungal uveitis

Mycobacterial uveitis

Adnexal masses

Exotropia

Spirochaetal uveitis (including Syphilis)

Melanoma

Nematode uveitis

Retinoblastoma

Retinoblastoma (for Part 2)

Incomitent

Voyt-Koyanagi-Harada syndrome

Conjunctival intraepithelial neoplasia

Vertical deviations

Orbit and ocular adnexae

Orbit

Sympathetic ophthalmia

AV Malformations and hamartomas

Arteriovenous malformations and hamartomas

Restriction syndromes

Paediatrics

Leucocoria

Congenital Cataract

Paediatric Glaucoma

Retinopathy of prematurity

Retinopathy of Prematurity

ROP-like disorders

Congenital nasolacrimal duct obstruction

White dot syndromes

Aniridia: Short Arm 11 Deletion (11p13)

Choristomas

Management Of Amblyopia

Alphabet patterns

Iris Nodules

Scleritis

Meningioma

Strabismus surgery

Optic nerve glioma

Lymphoma

Extraocular Muscles

Rhabdomyosarcoma

Idiopathic orbital inflammation

Orbital neuroblastoma

Anterior Persistent Foetal Vasculature

Lacrimal system

Metastatic lesions

Surgical Retina

Retinal Detachment

Vitreoretinal Interface And Macular Hole

Epiretinal Membrane

Medical Retina

Diabetic Eye Disease

Orbital Blood Vessels

Retinal Vascular Disease

Macular Degeneration

Central Serous Chorioretinopathy (CSCR)

Sickle Cell Retinopathy

Retinitis Pigmentosa

Albinism

Retinal Telangiectasias

Miscellaneous Retinopathies

Atropine And Myopia Progression

Pharmacology

Side Effects Of Systemic Drugs

Foetal Alcohol Syndrome

Optic Neuropathy

Papilloedema

Idiopathic Intracranial Hypertension

Chiasmal Disorders

Retrochiasmal Disorders

Migraine

Paranasal Sinuses

Supranuclear Motility Disorders

Fourth Nerve Palsies

Sixth Nerve Palsies

Seventh Nerve Palsies

Anisocoria

Myasthenia Gravis

Myopathies

Blepharospasm

Functional Visual Loss

Lacrimal Glands

Phakomatoses

Developmental diseases

Tear Film

Eyelids

Blinking

Lid Malpositions

Anterior segment - ocular surface

Conjunctiva

Conjunctivitis

Sclera

Pigmented Conjunctival Lesions

Squamous Cell Carcinoma Of The Conjunctiva

Ocular Cicatricial Pemphigoid

Cornea

Corneal Structure And Development