Transcript Gaze palsy

Mahmood J Showail
 The
control of eye movement has three
components

The supranuclear pathway (from the cortex and
other control centers in the brain to the ocular
motor nuclei in the brainstem)

The ocular motor nuclei

The infranuclear pathway from the ocular motor
nuclei to the peripheral nerve, neuromuscular
junction, and extraocular muscles
 Supranuclear
structures coordinate the
action of extraocular muscles and muscle
groups and control two types of eye
movements:


conjugate version movements, in which both
eyes move in the same direction
vergence movements, in which both eyes move
in opposite directions, turning either in
(convergence) or out (divergence).
 What
A
does “Gaze Palsy” mean ??
gaze palsy is an eye movement abnormality
in which the two eyes move together but have
limited movement in one direction
Gaze palsies are caused by

malfunction of one of the "gaze centers"
(cortical and brainstem regions responsible for
conjugate gaze)


cortical gaze center
Brainstem gaze center
 interruption
of the pathways leading from
them.

Supranuclear gaze palsy
nuclear gaze palsy
( e.g isolated nerve palsy)
 The
patient with supranuclear palsy is unable
to move both eyes past the midline in one
direction, and the eyes usually are held fixed
and turned toward the opposite side by the
opposing extraocular muscles.
 It


involves gaze centers for the control of
Horizontal movments
Vertical movments
 The
patient with horizontal gaze palsy
typically is unable to move either eye beyond
the midline in one direction.
 The
eyes are deviated constantly to the
opposite side, and the patient must turn his
or her head toward the side with the gaze
palsy to fixate an object that is directly in
front of him or her

The signal for horizontal gaze originates in the
contralateral frontal lobe for fast eye movements
(saccades) and in the ipsilateral parieto-occipitotemporal region for smooth pursuit

For Horizontal gaze, impulses passes through the
pontine paramedian reticular formation (PPRF),
adjacent to 6th nerve nuclues.

The (PPRT) activates the ipsilateral 6th nerve nucleus
and therby innervates the lateral rectus.

The 6th nerve nucleus also communicate with the
contralateral medial rectus (occulomotor) subnucleus
via the medial longitudinal fasiculus (MLF).
Schematic representation of control of horozontal eye movment;
PPRF;pontine paramedial reticular formation, MLF;medial longitudinal fasiculus VN:
vestibular nucleus
(Horizontal gaze palsy usually is caused by
contralateral frontal or ipsilateral pontine
lesion ).
 A horizontal gaze palsy to the ipsilateral side
occurs in pontine lesions affecting the
abducens nucleus and/or the PPRF.
 Lesions of the MLF result in internuclear
ophthalmoplegia (INO)
 Lesions of the MLF plus the ipsilateral
abducens nucleus and/or PPRF result in the
one-and-a-half syndrome.

Frontal lobe lesions




Epileptogenic lesions in the frontal eye fields





Eye deviation to the side of the hemiparesis ("wrong way eyes")
Mesencephalic lesions



Contralateral selective saccadic palsy
Hemorrhages deep in a cerebral hemisphere, particularly the thalamus


Acquired ocular motor apraxia (inability to generate voluntary movements)
Lesions in the corona radiata adjacent to the genu of the internal
capsule


Unilateral or bilateral increased saccade latencies
Hypometria (shortened range) for contralateral saccades
Saccadic slowing
Bilateral parietal lesions


Transient deviation of the eyes and head to the contralateral side H
ead and eye movements toward the same side during a seizure
Unilateral parietal lesions


Defect in generating voluntary saccades
Transient ipsilateral horizontal gaze deviation acutely
Gaze palsy overcome with the oculocephalic (doll's eye) maneuver or caloric
stimulation
Paresis of contralateral saccades
Supranuclear contralateral gaze palsies associated with ipsilateral oculomotor palsies
Pontine lesions affecting the abducens nucleus and/or the PPRF



Ipsilateral conjugate gaze palsy
Doll's eye maneuver or cold caloric stimulation usually does not overcome gaze palsy
Bilateral horizontal gaze palsies with bilateral lesions


Patient with Lt gaze palsy and Lt 7th n palsy due to acute
pontine heamorrhage
he was able to minimally abduct the Rt eye but otherwise
was unable to look to the left because of involvment of
abducent nucleus on the left side .
 In
patients with pontine lesions involving the
PPRF or sixth nerve nucleus, the eyes may be
deviated away from the side of the lesion.
Thus, patients who are unable to move
either eye beyond the midline to the left
may have a left pontine lesion, and the eyes
are deviated to the right.

The patient may have partial horizontal gaze
movement if the damage to the pontine
structures is only partial
 pontine
lesions usually can be differentiated
from supranuclear lesions in the frontal lobe by
the oculocephalic or doll's eyes maneuver.
 Passive
horizontal rotation of the head directly
stimulates the sixth nerve nucleus via the
vestibulo-ocular reflex and will overcome gaze
palsies induced by frontal lobe lesions but will
not overcome gaze palsies caused by pontine
nuclear and infranuclear lesions
 Horizontal
gaze palsies are caused by
ischemia and infarction, hemorrhage,
vascular malformations, tumors,
demyelination, trauma, or infections
 MRI
should be performed with attention
given to the dorsal pons.
 EEG should be performed if sezuire disorder
is suspected
 INO
(medial longitudinal fasciculus
syndrome) is caused by MLF lesions
(demylination, vascular disease, trauma or
brainstem tumors )
 Such
lesions permit the horizontal gaze
center to communicate with the sixth nerve
nucleus but not the contralateral third nerve
nucleus.
 The


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features of right INO include:
Adduction deficit of Rt eye on attempted Lt gaze
Horozontal jerk nystagmus of abducting Lt eye
Normal Rt gaze
Upbeat & tortional nystagmus “may be present”
Convergence preserved
 Bilatral
INO is usually due to demylination,
with upbeat nystagmus on upgaze and down
beat nystagmus on down gaze a constant
feature.
Bilateral INO
a.Right gaze
b.Left gaze
 MRI

may help in the diagnosis of INO .
It may show abnormal high-signal intensity
in the mid pons corresponding to the right
medial longitudinal fasciculus.
 Myasthenia
gravis and a partial third nerve
palsy involving the medial rectus muscle
both can be mistaken for INO.

Patients with ptosis, variability, or fatigue
should be evaluated for myasthenia gravis
 Ptosis,
pupil involvement, involvement of
other extraocular muscles, and absence of
nystagmus in the abducting eye should
suggest the diagnosis of third nerve palsy
 Patients
with the one-and-a-half syndrome
have horizontal gaze palsy when looking to
one side (the "one") and impaired adduction
(INO) when looking to the other (the "and-ahalf")
 It
is caused by pontine paramedian reticular
formation (PPRF) lesion extending to the
medial longitudinal fasiculus (MLF).
 Features
of right sided one-and-a-half
syndrome include:



Gaze palsy on attempted Rt gaze
Adduction deficit on attempted Lt gaze
Abduction of the Lt eye is the only normal
horizontal movment
 Stroke
and multiple sclerosis are the main
causes of this rare syndrome, but it can be
caused by any structural lesion in the dorsal
pons.
 Vertical
eye movment are generated in the
rostral interstitial nucleus of the medial
longitudinal fasiculus(MLF) which consist of
paired nuclei


With lateral portion of each initiating upgaze
The medial portion initiating downgaze
 Vrtical
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

gaze palsy include the follwing:
Parinaud syndrome
Progressive supranuclear palsy
Skew deviation
 Paralysis
of upward vertical gaze is the most
common vertical gaze palsy, followed by
paralysis of both upward and downward
gaze, and finally paralysis of downward gaze
alone
 This
syndrome occures in dorsal midbrain
lesion that involve rostral interstitial nucleus
of the MLF & the 3ed nuclear complex.
 Causes





:
Demylination
Vascular disease
Aqueduct stenosis (hydrocephalus)
Arteriovenous malformation
tumors
 Features:
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
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Upgaze disturbance
Convergence-retraction nystagmus
Light-near dissociation
Lid retraction
Convergence paralysis
 This
is a progressive neurodegenerative
condition which affects the elderly.
 It
initially impairs downgaze, subsequently
upgaze become affected , followed by loss of
horozontal, then saccadic and pursuit eye
movements.
 Patients
may also develop pseudobulbar
palsy, parkinsonism and dementia.
 These
are usually small vertical tropias that
can occur following brainstem or cerebellar
lesion.
 The
vertical deviation is usually concomitent
and ipsilateral to the side of the lesion.
 They
are usually assocaiated with other
features that allow localization as


Unilateral INO “in pontine lesion”
Horner syndrome “”in medullary lesion”
 BCSC,
American Academy of Ophthalmology
2004-2005
 Training
in Ophthalmology- the essential
clinical curriculum,2009
 Up
to Date, Database
 www.emedicine.com