Ocular Motilities #13: Cerebellar Syndrome

Lateropulsion in the Cerebellum

ipsipulsion (hypermetric towards, hypometric away from lesion)

The most common type of cerebellar stroke

Superior cerebellar artery (SCA)

-due to gravity

Least common type of cerebellar stroke

anterior inferior cerebellar artery (AICA)

SCA stroke presentation

AICA stroke syndrome

Bell's Palsy and hearing loss (CN 7 and 8)

Posterior inferior cerebellar artery (PICA) is _________ most likely to stroke

in the middle for

PICA supplies the _______ and is often misdiagnosed as ______

medulla, lateral medullary syndrome

PICA syndrome looks like

dorsolateral medullary (Wallenberg) Syndrome so make a compare and contrast between Wallenberg vs PICA

Chiari Malformation

acquired hydrocephalus due to cerebellar tonsils protrude into foramen magnum, pinching the medulla, and blocking CSF flow

Eye movement problems with Chiari

a lot is possible due to high CSF pressure with occlusion of the foramen magnum, but downbeat nystagmus points to the problem often

Type I Chiari

not eligible for surgery, herniation of cerebellar vermis (symptoms occur is usually in adulthood), 2/3 of the cases

Chiari Type 1 is _______ onset and most symptoms are positional, particularly when the patient is __________

adult, reclined

Type II Chiari (Arnold-Chiari)

less common but can qualify for surgery!

-childhood onset, more severe symptoms

Type III Chiari

terrible birth defect where cerebellum herniates outside the skull, called a myelomeningocele

How to do surgery on chiari

Craniectomy, takes care of the syrinxes but leaves a soft spot that needs protection with helmets

Chiari Type 0

IIH, treat like Type 1 and give Diamox or loop diuretic -____-

Dandy-Walker Malformation

congenital brain malformation in which there is enlargement of the 4th ventricle, also results from absence of the corpus collosum and most or all of the cerebellar vermis

Dandy-Walker signs

hydrocephalus, slow/clumsy motor development, speech-language problems, EOM striated muscle motor issues

***Dandy-Walker can happen when mothers take ________ while pregnant

Warfarin

Walker-Warburg Syndrome

Causes micro OR megalo opthalmos, cerebellar malformation, hydrocephalus, coloboma, retinal dysplasia, congenital cataract, enlarged 4th ventricle

What kind of cataract is seen with Walker-Warburg?

It's not a PSC despite being congenital; persistent fetal vasculature from hyaloid turning fibrotic and obstructing vasculature

How to treat Walker-Warburg

Pars plana vitrectomy and cataract sx

*****A lesion of the flocculus / paraflocculus in the cerebellum impairs what two things?

fixation and smooth pursuits

-impaired smooth pursuits in all directions

-impaired eye-head tracking with VOR cancellation

****A lesion of the nodulus and uvula of the cerebellum cause what kind of nystagmus?

PAN

****A lesion of the dorsal vermis of the cerebellum causes what 4 eye movement issues?

saccadic undershooting

saccadic ipsipulsion

eso deviation

longer pursuit latency

-ipsilateral hypometria and mild contralateral hypermetria of saccades

-gaze is tonically deviated away from the lesion

-smooth pursuits are impaired for targets moving towards the side of the lesion

****A LESION of the fastigial nuclei of the cerebellum generally cause (hyper or hypo?) metria

hypermetria / overshooting

***REVIEW: What binocular vision problem do these lesions cause?

vermis lesion

fastigial lesion

vermis lesion causes DI

fastigial lesion causes CI

There are 3 fiber bundles for the cerebellar peduncles: inferior, middle, and superior. Which one talks to which part of the brain stem?

inferior peduncle -> medulla

middle peduncle -> pons

superior peduncle -> midbrain

This makes sense given the anatomy. of the brain stem being midbrian pons medulla from top to bottom.

Lateropulsion can happen with dorsolateral medullary syndrome, OR with ____

cerebellum

***Which of the arteries is the most common to receive a cerebellar stroke and why?

Superior cerebellar artery (SCA) due to gravity making it the least likely to retain blood since it's the highest of them all

Which of the arteries is the least common to receive a cerebellar stroke?

Anterior Inferior Cerebellar artery (AICA)

**Superior Cerebellar Artery (SCA) Syndrome signs

Very similar to dorsolateral medulla Wallenberg signs!

-ipsilateral ataxia

-dysarthria

-ipsilateral Horner's

-contralateral Pain and T loss

-vertigo

***Anterior inferior cerebellar artery (AICA) syndrome

-gaze evoked nystagmus

-horizontal gaze palsy

-ipsilateral Bell's palsy (CN7)

-deafness (CN8)

AICA patient video

black lady that looks like her left eye was gouged out, when they jerk her head side to side, she has to refixate with saccades

Compared to AICA and SCA, Posterior inferior cerebellar artery strokes are the ________

middle most common

Put these in order of which is most common to least common:

PICA

AICA

SCA

most common: SCA > PICA > AICA : least common

PICA supplies what part of the brain?

lateral medulla, inferior peduncle of the cerebellum, nodulus, and uvula

PICA strokes are often misdiagnosed as

lateral mediullary syndrome

AICA supplies what part of the brain?

pons

SCA supplies what part of the brain?

midbrain

***Label what part of the brain is supplied by these 3 arteries:

PICA

AICA

SCA

SCA midbrian

AICA pons

PICA medulla

******____________ syndrome looks like dorsolateral medullary (Wallenberg) Syndrome, so if you see lateropulsion on the final exam you will PICK THIS AS YOUR ANSWER NO MATTER WHAT

PICA

Name the 3 congenital abnormalities of the cerebellum

1) chiari malformation

2) Dandy-Walker Malformation

3) Walker-Warburg Syndrome

Chiari Malformation definition

Cerebellar tonsils protrude through the foramen magnum and pinch the medulla / block CSF