Clinical Neuro-Ophthalmology Surat Tanprawate, MD, MSc(London), FRCP(T)! Neurology Unit, Department of Medicine! Chiang Mai University
The scope of Neuro-Ophthalmology •
Oculomotor system!
Disconjugate eyes: diplopia
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conjugate eye movement!
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Saccadic system !
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Pursuit system!
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Vergence system!
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Visual perception system! Visual loss !
Counter rolling system: VOR, Ocular fixation Anisocoria system
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Eyelids! Pupils
Ptosis Anisocoria
Oculomotor pathway • Supranuclear(UMN)! • FEF: horizontal conjugate gaze! • Diffuse frontal and occipital: vertical conjugate gaze!
• Nuclear (LMN)! • Nerve III, IV, VI Nucleus! • Internuclear! • PPRF, abducen interneuron, MLF (Horizontal gaze)! • riMLF, INC, PC (Vertical gaze)!
• Infranuclear(LMN)! • • • •
Fasciculus! Cranial nerve! NMJ! Muscle
Frontal eye fields
Right frontal lobe infarct Frontal lobe lesion: no diplopia! - Destructive to FEF lesion: !
• eyes deviate to the lesion! - Destructive to Pontine lesion:!
• eyes deviate contralateral to the lesion! - Excitatory lesion: !
• eyes deviate contralateral to the lesion
Case
Dysconjugate eyes
Diplopia (double vision)
pic from wikipedia
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Diplopia is the simultaneous perception of the two images of a single object that may be displaced horizontally, vertically, diagonally!
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caused by impair EOMs functions
Diplopia Monocular diplopia
Repetitive images
- Cerebral polyopia! - Non-organic
Binocular diplopia
Ghosting image
- Retinal disease! - Refractive error
Misalignment of the eyes
Nuclear control
- CN III! - CN IV! - CN VI
Infranuclear control
- CN palsy! - NMJ disorder! - Muscle disorder
Internuclear control
Horizontal diplopia! - INO! - PPRF! Vertical diplopia! - INC, riMLF
Nuclear and Internuclear control
III
IV
VI
Nuclear control: Nucleus III, IV, VI Horizontal gaze internuclear control
Vertical gaze internuclear control
Infranuclear control
Muscle
Fasciculus Nerve NMJ
Key features Nuclear and fascicular lesion!
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Brain stem sign: long tract sign, other CN involvement!
Nerve lesion!
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Neighbourhood sign; other CN, other sign!
Internuclear lesion!
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Specific syndrome; Internuclear Ophthalmoplegia (INO), WEBINO, One and a half syndrome!
NMJ lesion!
• Fatiguability, not consistent with CN lesion, sign of myasthenia gravis!
Muscle lesion!
• Not consistent with CN lesion: not consistent with CN lesion, sign of myopathy
The action and nerve supply of the extraocular muscles is demonstrated
Nuclear and nerve lesion
CN III
The oculomotor nerve (cranial nerve III)
CN IV
The course of the trochlear nerve in the pons
CN VI
facial nerve wraps around the nucleus of cranial nerve VI within the pons
Isolated CN III palsy with sparing pupil
Cause of oculomotor nerve palsy • Common: vasculopathy (diabetes,
atherosclerosis, aneurysm), tumor!
• Less common: inflammation, cavernous sinus thrombosis
A woman with acute diplopia for 2 weeks
Right LR palsy; No other neurological sign, ! MRI brain-normal
“Pure Right CN VI palsy”
A 55 Y.O. with DM, HT presented with acute diplopia for 2 days
Left LR palsy Dx. “Left CN VI palsy from ischemic neuropathy”
Bilateral LR could be pseudo sixth nerve palsy from IICP
Cause of CN VI palsy
• Most common: vasculopathy (diabetes, hypertension, atheroscleosis), trauma, idiopathic, IICP!
• Less common: giant cell arteritis, cavernous sinus lesion, multiple sclerosis, vasculitis, stoke
Posterior communicating artery aneurysm causing CN III palsy
Multiple nerve involvement
• Cavernous sinus syndrome! • Superior orbital fissure syndrome
Cavernous sinus syndrome • Association with ! – other cranial nerve involvement: 4, 5, 6 CN ! – oculosympathetic paralysis! – Opthalmic branch of trigeminal nerve!
• Tend to be partial; alls muscles innervated are not equally involved
!29
Superior orbital fissure syndrome
CN 3, 4, 6, V1 !30
Superior orbital fissure syndrome • Involve CN 3, 4, 6 and V1 CN 5 distribution +/oculosympathetic paresis without anhydrosis! • May exopthalmos due to blockade of the opthalmic veins! • Blindness due to extension of the pathologic process to involve the optic canal
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A patient with diplopia for 1 week with gait ataxia and areflexia
2 weeks
2 months
Dx. Miller Fisher syndrome in a patient with polyneuropathy, all CN can be involved causing total ophthalmoplegia
Interneuclear lesion Horizontal
Interneuclear ophthalmoplegia (INO): MLF lesion! Bilateral INO : Bilateral MLF lesion! One and a half syndrome: PPRF lesion + MLF lesion
Unilateral MLF lesion • “ internuclear ophthalmoplegia “! • Ipsilateral MR weakness ipsilateral side! • Contralat. abducting nystagmus
Interneuclear ophthalmoplegia (INO)
a. Normal primary position
c. Normal left abduction on left gaze
b. Left impaired adduction on right gaze and horizontal nystagmus of the right eye
d. Normal convergence
Bilateral MLF lesion • Bilateral MLF lesion! – Bilateral adducting weakness! – Bilateral abducting nystagmus! – Impaired vertical vestibular and pursuit ! – Impaired vertical gaze holding! – Gaze evoked nystagmus!
• Wall eyed bilateral INO : WEBINO! – exotropia
A man with sudden diplopia
WIBINO
One and a half syndrome • Combined lesion : PPRF and MLF! • “ One and a half syndrome “! – Ipsilateral horizontal gaze palsy! – INO
Bilateral PPRF lesion • Bilateral horizontal gaze failure! • Sparing vertical gaze! • Sparing pupil! • May combine with other brain stem sign
A woman with diplopia and facial palsy
Interneuclear lesion Vertical
Upward and downward gaze failure
Vertical gaze control
Cause of internuclear lesion • Common: demyelination (multiple sclerosis), brainstem infarction!
• Less common: tumor, infection
Infranuclear lesion ; !
disease of NMJ ! disease of ocular muscle
Neuromuscular Junction
Features of NMJ disorder • Ophthalmoplegia is not consistent with nerve distribution!
• Fatigue! • Fluctuating course! • with other muscle weakness esp.
ptosis, proximal muscle weakness
A patient with diplopia and ptosis
Total ophthalmopathy in CPEO patient
TRIO with Bilateral ptosis (MG)
• Upper eyelid – Levator palpebral superioris(CN 3) – Muller muscle(sympathetic) – Frontalis muscle(CN 7)
• Lower eyelid – Capsulopalpebral fascia(inferior rectus) – Inferior tarsal muscle(sympathetic)
Ptosis Non-neurogenic(mechanical) ptosis
Neurologic ptosis Congenital ptosis
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•Uni-bilateral •Partial-complete
! Supranuclear lesion(cerebral ptosis) •Contralateral cerebral hemisphere
•Pupil involvement •EOM impairment
LMN •Neuropathic(N, fascicle, CN) •NMJ •Myopathic
Horner’s syndrome
Ptosis from Cranial nerve III lesion! - complete or near complete ptosis! - EOM involvement! - Pupil dilatation
MG with enhancing ptosis
Ptosis due to NMJ lesion: sign of fatiguability
Nystagmus
Nystagmus •
Ancient Greek (nustagmos (Ancient Greek, "nodding, be sleepy")!
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Involuntary biphasic rhythmic ocular oscillation in which one or both phase are slow!
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The slow phase is responsible for the initiation and generation of the nystagmus, whereas the fast (saccadic) phase i a corrective movement bringing the fovea back on target!
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Type: jerk (direction to fast phase) ; pendular nystagmus
Mechanism • Nystagmus may result from dysfunction
of the vestibular ending organ, vestibular nerve, brainstem, cerebellum, or cerebral centre for ocular pursuit
Peripheral vs Central nystagmus Peripheral nystagmus
Central nystagmus
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Severe vertigo
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None or mild vertigo
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Minute to Day to weeks duration
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Often chronic
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May be purely vertical or torsional
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Visual fixation usually has no effect
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Downbeat, upbeat, torsional
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Etiologies commonly vascular, demyelination, pharmacologic, toxic
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Hearing loss, tinnitus associated
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Usually horizontal with torsion
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Very rarely purely vertical or torsional
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Commonly peripheral vestibular organ dysfunction: labyrynthitis, meniere’s disease
A schematic illustration of nystagmus waveforms
(A) pendular nystagmus
(B) an accelerating velocity exponential slow phase jerk nystagmus (CN) (C) a decelerating exponential slow phase jerk nystagmus (MLN) (D) a linear or constant velocity slow phase jerk nystagmus (MLN) In (A) a slow phase is followed by a slow phase while in (B)–(D) a slow phase is followed by a fast phase
Mechanism •
Pendular nystagmus: is central (brainstem/ cerebellum)!
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Jerk nystagmus: !
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linear (constant velocity) slow phase: peripheral vestibular dysfunction!
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slow phase has decreasing velocity exponential: brainstem neural integrator, cerebellar!
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slow phase has increasing velocity exponential: central in origin (usual form of congenital nystagmus)
A woman with periodic vertigo occur when changing position
“vestibular nystagmus”
Case study: a boy with subacute dizziness
Conclusion •
Oculomotor system!
Disconjugate eyes: diplopia
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conjugate eye movement!
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Saccadic system !
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Pursuit system!
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Vergence system!
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Visual perception system! Visual loss !
Counter rolling system: VOR, Ocular fixation system
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Eyelids! Pupils
Ptosis Anisocoria
The Neurologist
CMU The Neurologist
CMU
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