1/18/2015

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The Efferent Visual System: Disorders of Cranial Nerves III, IV &

VI

James L. Fanelli, OD, FAAO Leonard V. Messner, OD, FAAO

Lorraine Lombardi, PhD

Course Goals • To Become Familiar with Presentations of CN III, IV

and VI Palsies

• To Understand the Relevant Neuro Anatomy

• To Understand the Neuro Imaging and Clinical Management

• To Obtain In Clinic Assessment Pearls

Course Format

• Case Presentation – Dr. Fanelli

• Relevant Neuro Anatomy – Dr. Lombardi

• Neuro Imaging and Management – Messner

• Clinical Take Home – Drs Fanelli, Lombardi and Messner

“THE FIRST 4 QUESTIONS”

• 1. WHO IS THE NEURO-OP ON CALL?

• 2. WHAT IS THEIR NUMBER?

• 3. HOW SOON CAN THE PATIENT BE SEEN?

• 4. WHAT IS THE DIAGNOSIS?

The Diplopic Patient

• Evaluation boils down to knowing the fields of action of the 6 EOM’s

• You know the actions, you can figure out the Palsy – Cerca Trova

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The Physiological “H”

• You are face to face with the patient

• Their EOM movements, as you view them, render the following “H” pattern:

EOM ACTIONS

SR

LR

IR

MR

IO

SO

4 Questions We Should Ask • 1-Is Double Vision Present with one eye

covered?

– “Yes” eliminates neurologic etiologies

– Usually a ‘windows’ problem

• Media opacities

4 Questions We Should Ask • 2-Does the Diplopia have a vertical

component or a horizontal component

EOM ACTIONS

SR

LR

IR

MR

IO

SO

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4 Questions We Should Ask • 3-In which direction (R or L) does the diplopia

worsen?

EOM ACTIONS

SR

LR

IR

MR

IO

SO

4 Questions We Should Ask • 4-Is the diplopia greater at distance or near?

EOM ACTIONS

SR

LR

IR

MR

IO

SO

Clinical Assessment of Diplopia • Begins with dissociating the presenting images

before each eye

• Maddox Rod

(PATIENT’S VIEW )

“LANGUAGE OF THE LIGHT”

R HYPER

L HYPER

EXO

ESO

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Third Nerve Palsies • CN III Innervates:

– SR

– IR

– MR

– IO

– Levator

– Parasympathetic Iris (constrictor)

So What is Presentation

• Go back to the Physiological H

• Assuming a RIGHT CN III Palsy:

EOM ACTIONS

SR

LR

IR

MR

IO

SO

EOM ACTIONS

SR

LR

IR

MR

IO

SO

“The Signature” of CN III Paresis

• Hyper deviation which increases in upgaze and reverses in downgaze

• Exo which increases across from the vertically-limited eye

Oculomotor nerve...

Its course and relationships

In the midbrain

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Midbrain

Oculomotor

nucleus CN III

Cerebral Hemisphere

Midbrain

III

Subarachnoid space

orbit

Midbrain

III

Posterior

Communicating

artery

Then CN III

can run into

trouble

BERRY

ANEURYSM

pcom can form aneurysms

III

pcom

Aneurysms

can rupture =

pressure

Compresses

Pupillary

Fibers of III…

Dilated pupil

III

Posterior

Communicating

Artery

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Extraocular

Muscle

Fibers of III

PUPILLARY

FIBERS of III

X-section

III

Posterior

communicating

artery

PUPILLARY

FIBERS of III

Extraocular

Muscle

Fibers of III

Posterior

communicating

artery

X-section

III

BRAIN BRAIN

Sub-

Arachnoid

space

Meningeal

Irritation…pain

meninges

dura

Subarachnoid

hemorrhage

III

Aneurysms can

rupture

Compression ( ie aneurysm)

vs

Vasculopathic (ie diabetes)

Lesion of CN III

PUPILLARY

FIBERS

III

Extraocular

Muscle

Fibers

Posterior

communicating

artery

Artery to the

IIIrd nerve

CN III is

peripheral nervous system

and it will regenerate

Sometimes to the wrong target organ…

Aberrant regeneration

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Degeneration and

regeneration

of the axon

Aberrant Regeneration

IR

“look down”

Lid up

Lev

CN III

•Two divisions

of III Ciliary ganglion

IO Constrictor;

Ciliary muscle

Levator SR

MR IR

•Superior

•Inferior

The Clinical Picture

• CN III Palsy

CRANIAL NERVE PALSY STRATEGY • IS THIS REALLY WHAT I THINK IT IS?

(imposters)

• DOES IT COME WITH ANYTHING ELSE? (anatomically guided exam)

• IF IT IS ISOLATED, WHAT DO I DO? (management)

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CN III palsy – pupil involved 52 y/o man with sudden onset/painful diplopia @

distance and near

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CN III – pupil spared 65 y/o diabetic man with recent onset diplopia @

distance and near

“Rule of the Pupil”

Pupil

Involved

Pupil Spared

Aneurysm 86% 14%

Ischemic /

Vascular

23% 77%

Kissel JT, et al. Ann Neurol 1983

Goldstein JE, et al. Arch Ophthalmol 1960

PCA

Aneurysm CN III

Pupil Fibers EOM Fibers

Vasonervorum

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Aberrant Regeneration of CN III

1. Pseudo-Graefe sign

2. Eyelid synkinesis

3. Light-gaze dissociated pupils

CN III aberrant regeneration 32 y/o woman with traumatic CN III palsy

Neuroimaging for CNIII Palsy

• MRI • MR Angiography • Intra-arterial

DSA • CT Angiography

Clinical Kernels: CN III

• EOM pattern of hyper deviation that switches on up and down gaze and increases on gaze away from paretic eye

• Aberrant regeneration does NOT occur in cases of microvascular (diabetic) CN III

• Pupil sparing is NOT always indicative of microvascular etiology

Fourth Nerve Palsies

4th N Innervation & Motility

• Innervation is easy:

– Superior Oblique

• Motility is more complex

– Both a horizontal AND vertical component

– AND……a TORSIONAL component

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EOM ACTIONS

SR

LR

IR

MR

IO

SO

EOM ACTIONS

SR

LR

IR

MR

IO

SO

4th N Palsy

• The paretic eye is hyper in primary

gaze

• The diplopia decreases on same gaze;

increases on opposite gaze

• But……..

Torsional Obliques

• Remember this:

• SUPERIOR muscles INTORT

• INFERIOR muscles EXTORT

4th N and SO Muscle

• The SO is primarily an INTORTER

– Compensating for a faulty intorter, one would

TILT your head in the opposite direction

Trochlear Nerve...

Its course and relationships

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IV

Trochlear

Nucleus

III

IV

Ambient cistern

Subarachnoid space

Subarachnoid space “Reality Neuro”—

Most Dangerous areas

for CN’s

pons

III

IV

AMBIENT

CISTERN

Trauma

IV

Ambient

Cistern

Trauma

The Clinical Picture

• CN IV Palsy

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“The Signature” of CN IV

Paresis

• A hypertropia that increases across from

the vertically-limited eye and on ipsilateral

head tilt

Evaluation of CN IV Palsy

• Which eye is higher in primary gaze?

• Hyper worse in right or left gaze?

• Which eye is higher on head tilt?

• Is there excyclotorsion?

Evaluation of CN IV Palsy

• Which eye is higher in primary gaze?

• Hyper worse in right or left gaze?

• Which eye is higher on head tilt?

• Is there excyclotorsion?

Evaluation of CN IV Palsy

• Which eye is higher in primary gaze?

• Hyper worse in right or left gaze?

• Which eye is higher on head tilt?

• Is there excyclotorsion?

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Evaluation of CN IV Palsy

• Which eye is higher in primary gaze?

• Hyper worse in right or left gaze?

• Which eye is higher on head tilt?

• Is there excyclotorsion?

SUPERIOR RECTUS

SUPERIOR OBLIQUE

INFERIOR RECTUS

INFERIOR OBLIQUE

reverse reverse

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Traumatic CN IV palsy

28 y/o woman s/p closed head trauma

Right hyper greater in left gaze and right head tilt Measuring Excyclotorsion

• Subjective

–Maddox rod

–Bagolini striated lenses

• Objective

–Fundus photos

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OBJECTIVE

ANGLE of

EXCYCLOTORSION

Objective vs. Subjective Excyclotorsion

• Objective = Subjective

• Objective > Subjective

• Objective without subjective

Recent onset

Long-standing

Infantile

Etiology of Adult Superior Oblique Palsies

(Mollan SP, et al. Eye 2009)

• N = 150

• 133 unilateral-isolated: – 38% congenital

– 29% trauma

– 23% vasculopathic

– 7% undetermined

• 10 bilateral: – 50% trauma

– 20% tumor

– 20% undetermined

• 7 unilateral – complicated – 71% trauma

– 14% tumor

– 14% undetermined

Isolate CN IV Palsy

Management • Observation (improvement within several months

for ischemic vascular)

• Prism (base-down over paretic eye/split between

both eyes) – Rx vertical prism as single vision/NVO

• Surgery – Wait for spontaneous improvement (at lest 6 months)

• Check for V-pattern eso in kids (indicator for

bilateral CN IV palsy)

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Clinical Kernels: CN IV

• ALL cranial nerves travel through the sub

arachnoid space, and as such they are

susceptible to compression

– Trauma and bleeds

– CN 4: Long intracranial/subarachnoid course

• SO is primarily an intorter, therefore

HEAD TILT will be an integral finding

Clinical Kernels: CN IV

• Assessment of excyclotortion is helpful

in determining onset of problem:

– Long standing, patients adapt, and objective

measure > subjective complaints

– Recent onset, patients haven’t ‘adapted’,

noticeable findings, noticeable complaints

Sixth Nerve Palsies

6th N Innervation and Motility

• Innervation is easy: – Lateral Rectus

• Motility is easy: – No vertical component

– Only horizontal component

EOM ACTIONS

SR

LR

IR

MR

IO

SO

EOM ACTIONS

SR

LR

IR

MR

IO

SO

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Motility Pattern

• Inability to Abduct, therefore paretic eye

has eso posture IN PRIMARY GAZE

• Eso increases on gaze TOWARD paretic

eye

Compensation for CN VI Palsy

• Since the paretic eye cannot Abduct and is

eso, the patient will TURN THEIR HEAD to

the SAME side

Abducens Nerve...

Its course and relationships

PONS

VI

pons

Subarachnoid space

prepontine cistern

Clivus…occipital bone

Petroclinoid

ligament

Prepontine

cistern Small posterior

cranial fossa

with Chiari cerebellum

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The brain and

its coverings (meninges)

Increased intracranial pressure

pons

Subarachnoid space

Papilledema and

Abduction deficit

The brain and

its coverings and

Subarachnoid space

..and optic

nerve

Petroclinoid

Ligament

Cavernous

Sinus with

III, IV…

clivus

Orbital

cavity

petroclinoid ligament

The Clinical Picture

• CN VI Palsy

“The Signature” of CN VI Paresis

• Eso which increases in the action of

the paretic eye

CNVI Palsy Motility Evaluation

• Duction > version

• “Glissades”

• Asymmetric OKN

• Negative forced duction

CN VI Motility Evaluation

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27 y/o AA Woman

• c/o horizontal diplopia (right gaze > left)

• h/o recurrent headaches (am > pm)

• BVA: – 20/20 OD

– 20/20 OS

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S/P Surgical Decompression Etiology of CN VI Palsy

Mayo Clinic Study of Olmstead Co. MN USA from 1978-1992

(n = 137)

• Undetermined: 26%

• Hypertension: 19%

• HTN & diabetes: 12%

• Trauma: 12%

• MS: 7%

• Neoplasm: 5% (complicated)

• Diabetes (alone): 4%

• CVA: 4%

• s/p neurosurgery: 3%

• Aneurysm: 2% (complicated)

• Other: 8%

Patel SV, et al. Ophthalmology 2004

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40 y/o woman

Acute horizontal diplopia greater at distance and on left gaze

Recent onset paresthesias R > L

FLAIR

T1 post

FLAIR T1 post

Clinical Kernels: CN VI

• Sudden onset unilateral, think small vessel

occlusive disease in vasculopathic population – But trauma is trauma

• Acquired bilateral: look at the optic nerves and

think about increased ICP – Long climb up the clivus in sub arachnoid space

• BO prism can optically correct

Poly Cranial Neuropathies

• Involvement of CN III, IV and/or VI can be

found simultaneously

• Investigation centers on locations in the

head where III, IV and VI travel together – Orbital apex

• Any associated proptosis???

– Cavernous sinus

• Can’t have a complete Neuro-op lecture without

mentioning the Cavernous Sinus

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