Musculofacial anomalies & Ocular Myopathies

MUSCULOFACIAL
ANOMALIES
Moderator- Dr. (Prof) M. I. MAGDUM
Presenter- Dr. Devanshu Arora
February 18, 2015 Department of Ophthalmology, JNMC, Belagavi 1

INTRODUCTION
• MUSCULOFACIAL ANOMALIES refers to a group of
congenital disorders in which there are errors in the
innervation of Ocular & Facial muscles.
• These conditions are now referred to as-
CONGENITAL CRANIAL DYSINNERVATION DISORDERS

OVERVIEW
1. Relevant Anatomy & Physiology
2. Musculofacial Anomalies (congenital cranial
dysinnervation disorders):
• Duane Retraction Syndrome
• Brown Syndrome
• Congenital Fibrosis of Extraocular Muscles
• Mobius Syndrome
• Marcus Gunn Jaw-winking Syndrome
3. Ocular Myopathies:
• Myasthenia Gravis
• Myotonic Dystrophy
• Chronic Progressive External Ophthalmoplegia
• Lambert-Eaton Myasthenic Syndrome

ANATOMY OF EXTRAOCULAR MUSCLES
• Visual axis (line of vision) is the line passing from the
fovea, through the nodal point of the eye, which is located
at the posterior capsule of the lens, to the point of fixation
(object of regard).
• Anatomical axis (Optic Axis) is a line passing from the
posterior pole through the centre of the cornea.
• Primary Position of Gaze: When
the eye is looking straight ahead at
a fixed point on the horizon with the
head erect. In this position the
visual axis forms an angle of 23°
with the orbital axis

MUSCLE ORIGIN INSERTION INNERVATION
MEDIAL RECTUS Annulus of Zinn
5.5 mm behind medial
limbus
Cranial Nerve III
LATERAL RECTUS Annulus of Zinn
6.9 mm behind lateral
limbus
Cranial Nerve VI
SUPERIOR RECTUS Annulus of Zinn
7.7 mm behind
superior limbus
Cranial Nerve III
INFERIOR RECTUS Annulus of Zinn
6.5mm behind inferior
limbus
Cranial Nerve III
SUPERIOR OBLIQUE
Orbital apex above
the Annulus of Zinn
Posterior Upper
temporal quadrant of
Globe
Cranial Nerve IV
INFERIOR OBLIQUE
Anteriorly from orbital
wall lateral to lacrimal
fossa
Posterior Lower
temporal quadrant of
Globe
Cranial Nerve III
LEVATOR
PALPEBRAE
SUPERIORIS (LPS)
Orbital apex above
the Annulus of Zinn
Skin of the upper
eyelid & superior
tarsal Plate
Cranial Nerve III

MUSCLE PRIMARY ACTION SUBSIDIARY ACTION
Medial Rectus Adduction --
Lateral Rectus Abduction --
Superior Rectus
Elevation (best when eye is
in abducted position)
Intorsion & Adduction
Inferior Rectus
Depression (best when eye
is in abducted position)
Extorsion & Adduction
Superior Oblique Intorsion
Depression (best when eye
is in adducted position)
& Abduction
Inferior Oblique Extorsion
Elevation (best when eye is
in adducted position)
& Abduction
ACTIONS OF EXTRAOCULAR MUSCLES

• Agonist–antagonist pairs are muscles of the same eye
that move the eye in opposite directions. The agonist is
the primary muscle moving the eye in a given direction.
The antagonist acts in the opposite direction to the
agonist.
• Sherrington law of reciprocal innervation states that
increased innervation to an extraocular muscle is
accompanied by a reciprocal decrease in innervation to its
antagonist.
For example- As the right eye abducts, the Right Lateral
Rectus muscle receives innervation & contracts while the Right Medial
Rectus receives decreased innervation & automatically relaxes.
EXTRAOCULAR MUSCLE PHYSIOLOGY

• Yoke Muscles: 2 Muscles (1 in each eye) that are the
prime movers of their respective eyes in a given position
of gaze
For Example- when the eyes move into right gaze
(dextroversion), the right lateral rectus muscle & the left
medial rectus muscle are yoke muscles.

• Hering Law of Equal Innervation states that during any
conjugate eye movement, equal and simultaneous
innervation flows to the yoke muscles concerned with the
desired direction of gaze.

CONGENITAL CRANIAL
DYSINNERVATION
DISORDERS
A number of well defined syndromes characterized by
congenital limitation of eye movements were found to
be resulting from aberrant innervation of the ocular &
facial musculature.

DUANE RETRACTION SYNDROME
(DRS)
• Duane’s Syndrome also known as Stilling-Turk syndrome
• Congenital non progressive ocular motility defect
• There are Type I,II & III – the common characteristic
feature being retraction of the globe on adduction or
attempted adduction.
• There is limitation or total absence of abduction & partial
restriction of adduction may also be present

• Most cases are sporadic but 5%-10% show Autosomal
Dominant Inheritance
• There is failure of innervation of the Lateral Rectus by the
6th nerve, with anomalous innervation of the lateral rectus
by fibers from the 3rd nerve
• Anatomical and imaging studies have shown that in most
cases there is aplasia of the sixth cranial nerve nucleus,
and an aberrant branch of oculomotor nerve has
innervated the lateral rectus.
PATHOGENESIS of Duane’s Syndrome

• So on attempted adduction because of innervation by the
oculomotor nerve there is co-contraction of the medial &
lateral recti (referred to as synkinesis phenomenon) which
results in retraction of the globe.
• Additionally, an association of DRS is seen with Marcus
Gunn jaw-winking, also a synkinesis phenomena (which
occurs due to aberrant trigeminal nerve innervation of
levator palpebrae superioris)

• Usually Unilateral
• About 15% case are Bilateral (in which also one side
involvement is usually subtle)
• In Primary Position the eyes look straight or there may be
slight Eso or Exotropia depending on the type, but
Binocular Single Vision is usually maintained.
• A Face turn is often noted which the patient uses for their
lateral rectus weakness to allow them to use both eyes
together
• Restricted Abduction (complete or partial)
• Restricted Adduction (usually partial)
• Retraction of the Globe on adduction
Narrowing of palpebral fissure
CLINICAL FEATURES of Duane’s Syndrome

• An up-shoot or down-shoot in adduction may be
present.
• It has been suggested that this is a ‘Leash’ phenomenon,
that because of co-contraction of medial & lateral rectus,
the tight lateral rectus muscle slips over or under the
globe and produces an anomalous vertical movement of
the eye.

• Type I , the most common, is characterized by:
 Marked restriction or total absence of abduction
 Normal or mildly limited adduction
 In the primary position, straight or slight esotropia
• Type II, the least common, is characterized by:
 Limitation of adduction
 Normal or mildly limited abduction
 In primary position, straight or slight exotropia
• Type III, is characterized by:
 Limited adduction and abduction.
 In the primary position, straight, slight esotropia or
slight exotropia
TYPES OF DRS: HUBER CLASSIFICATION

• Associated Ocular Anomalies-
Pupillary abnormalities (anisocoria), Cataract,
Choroidal colobomas
• Non Ocular Anomalies-
Perceptive Deafness with associated speech
disorders
Cervical spina bifida
Goldenhar’s Syndrome (hemifacial microsomia,
ocular dermoids, ear anomalies, preauricular skin
tags & upper eyelid colobomas)
ASSOCIATIONS OF DRS

• Most patients do not need surgical intervention
• Surgery is reserved for cases with primary position
deviations & marked globe retraction or for cosmetic
reasons- abnormal head posture
• For DRS with esotropia- Recession of Medial Rectus on
the involved side has been the most often used procedure
• For DRS with exotropia- Recession of Lateral Rectus on
the involved side.
• Patients with type III DRS, having severe globe retraction
may be helped by recession of both medial & lateral
rectus muscles which may also help in reducing the
vertical excursions.
MANAGEMENT of Duane’s

BROWN SYNDROME
• Described by Harold W. Brown in 1950 as the Superior
Oblique Sheath Syndrome
• Characteristic restriction of elevation in adduction that
improves in abduction
• Caused by restriction of superior oblique tendon at the
trochlear pulley.
• Usually congenital but occasionally acquired

ETIOLOGY of Brown’s Syndrome :
1. Congenital
• Idiopathic.
• ‘Congenital click syndrome’ where there is
impaired movement of the superior oblique tendon
through the trochlea.
2. Acquired
• Trauma to the trochlea or superior oblique
tendon.
• Inflammation of the tendon, which may be caused
by Systemic Inflammatory Diseases (Rheumatoid
arthritis), pan sinusitis or scleritis.

• Usually sporadic, some cases show Autosomal Dominant
Inheritance
• In mild forms, eyes are usually straight in primary position
& there is no hypotropia
• Sever forms show a primary gaze hypotropia, usually
accompanied by a chin-up head posture.
• Limited elevation in adduction
• Limited elevation on upgaze is common
• Normal elevation in abduction
• Down shoot in adduction may be seen
• Positive forced duction test on elevating the globe in
adduction is a major sign essential for the Diagnosis
CLINICAL FEATURES of Brown Syndrome

• How to differentiate Brown Syndrome from Inferior
Oblique Muscle Palsy?
Forced duction test is negative (no resistance to
elevation in adduction) in Inferior Oblique Palsy
No depression on adduction
• Orbital Floor fracture:
Restriction of elevation not only in adduction, but also
in direct elevation in primary gaze

• Observation alone remains the most common form of
management
• Treatment of the underlying cause is indicated in acquired
cases.
• Systemic treatment should be started in rheumatoid
arthritis or other systemic inflammatory diseases &
resolution is observed. Corticosteroids injections can also
be injected near the trochlea.
• Surgery is indicated in sever cases (having hypotropia &
AHP):
Superior Oblique Tenontomy is now the procedure of
choice
MANAGEMENT of Brown Syndrome

CONGENITAL FIBROSIS OF
EXTRAOCULAR MUSCLES (CFEOM)
• Congenital fibrosis Syndrome, is a group of congenital
disorders characterized by restriction of the extraocular
muscles and replacement of the muscles by fibrous
tissue.
• It can be unilateral or bilateral, with the bilateral form
being more common
• The spectrum ranges from isolated fibrosis of a single
muscle to B/L involvement of all EOMs
• Familial disorder showing AutosomalDominant Inheritance

• Congenital fibrosis syndrome has traditionally been
considered a primary muscle disorder
• Recently, CFEOM has been accepted to be of neurogenic
origin similar to that of DRS but involving the III cranial
nerve complex.
• Co-contraction phenomenon resulting in globe retraction
has also been described in patients with CFEOM
• But the exact mechanism & cause is unknown

• Congenital non-progressive bilateral external
ophthalmoplegia
• Congenital non-progressive bilateral ptosis
• In the primary position each eye is fixed below the
horizontal by about 10°.
• The hypotropic eye may be secondarily exotropic,
esotropic or neutral.
• The degree of residual horizontal movement varies from
full to absent.
• Vertical movements are always severely restricted with
inability to elevate the eyes above the horizontal plane.
CLINICAL FEATURES of CFEOM

• A subset of cases show unilateral fibrosis with
enophthalmos and ptosis
• These are non familial
• Systemic associations-
 Mental retardation
 Facial palsy
 Dental anomalies
 Spina bifida
 Prader-willi syndrome

MANAGEMENT of CFEOM :
• Surgery is difficult and requires release of the restricted
muscles (weakening procedures)
• Fibrosis of adjacent tissue may be present as well.
• A good surgical result aligns the eyes in primary position,
but full ocular movements cannot be restored
• Outcome of such surgeries is always unpredictable

MÖBIUS SYNDROME
• Heterogeneous clinical disorder, which includes
congenital facial palsy with impairment of ocular
abduction due to sixth nerve palsy
• Developmental disorder of the brainstem rather than an
isolated cranial nerve disorder
• The ocular motility disturbances in Mobius syndrome are
frequently bizarre and asymmetrical, resembling more of
a congenital fibrosis pattern than cranial nerve palsies
• Most cases are sporadic

• Neural Imaging studies have shown:
Brain stem hypoplasia in the region of the sixth and
the seventh nerve & hypoplasia of extraocular muscles and
intraorbital motor nerves

• Systemic features :
 Bilateral facial palsy which is usually asymmetrical
giving rise to a mask-like facial expression and
problems with lid closure
 Paresis of the 12th cranial nerves which results in
atrophy of the tongue
 Mild mental handicap
 Limb & Chest wall anomalies
• Ocular features :
 Horizontal gaze palsy is present in 50% of cases.
 Bilateral 6th nerve palsy
 Occasionally 3rd and 4th nerve palsy and ptosis
CLINICAL FEATURES of Mobius Syndrome

• Non surgical management-
Detection & treatment of amblyopia, corneal
exposure & refractive errors
• Surgical management-
No single surgery useful
Medial rectus muscle recession is tried
Transposition of vertical recti to insertion of Lateral
Rectus described
MANAGEMENT of Mobius Syndrome

STRABISMUS FIXUS
• It is a rare congenital anomaly in which both eyes are
fixed in either the convergent position caused by fibrous
tightening of the Medial Recti
(Convergent Strabismus Fixus)

OR
• fibrosis of both Lateral Recti
(Divergent Strabismus Fixus)

• No horizontal movement is possible
• Diplopia does not occur because of suppression of image
from one eye
• Amblyopia also does not develop because the patient
tends to use both eyes alternately.
TREATMENT OF STRABISMUS FIXUS-
• Involves recession of medial recti along with recession of
conjunctiva & tenon’s capsule
but abduction beyond midline can never be achieved

MARCUS GUNN JAW-WINKING
SYNDROME
• Characterized by a congenital ptosis that includes an
associated winking motion of the affected eyelid on the
movement of the jaw
• Usually unilateral & is a form of synkinetic ptosis.
• An aberrant connection appears to exist between the
motor branches of the trigeminal nerve (CN V3)
innervating the external pterygoid muscle and the fibers of
the superior division of the oculomotor nerve (CN III) that
innervate the levator superioris muscle of the upper eyelid

Signs and Symptoms of Marcus Gunn jaw-winking syndrome:
• Mild-to-moderate blepharoptosis, usually unilateral
• Synkinetic upper eyelid movement with jaw-winking after one
of the following:
 Mouth opening
 Jaw movement toward the contralateral side
 Chewing
 Sucking
 Jaw protrusion
 Clenching teeth together
 Swallowing
• Usually, parents first notice the phenomenon while the baby
is bottle-feeding or breastfeeding.
• Strabismus- Vertical deviations, usually a hypotropia on the
involved side

OCULAR MYOPATHIES

MYASTHENIA GRAVIS
• Is a Neuromuscular disorder characterized by weakness
& fatigability of skeletal muscles
• It is an autoimmune disease in which antibodies mediate
damage & destruction of acetyl choline receptors at
neuromuscular junction.
• Thus there is decrease in the number of available AchRs
at the neuromuscular junction although Ach is released
normally; leading to failure of generation of Action
potential in the muscle fibers.

• The amount of ACh released per impulse also declines on
repeated activity (called presynaptic rundown) resulting in
activation of fewer and fewer muscle fibers by successive
nerve impulse responsible for FATIGUE
• How the autoimmune response in Myasthenia is initiated
is not completely understood. However, the thymus
appears to play a role.
• Thymic tumors are seen in about 10% patients.

• Affects individuals in all age groups
• More common in women specially in their twenties &
thirties
• Affects men in their fifties & sixties
• The cardinal features are weakness and painless
fatigability of muscles. The weakness increases on
repeated use of the muscle (or exercise) and improves
following rest.
• Therefore symptoms are worse toward the end of the day
& less in the morning after sleep.
CLINICAL FEATURES OF MYASTHENIAGRAVIS

• The distribution of muscle weakness often has a
characteristic pattern, the lid & extraocular muscles being
involved early in the course followed by facial weakness &
muscles involved in mastication and speech.
• Most frequent presentation is with Ptosis & Diplopia
• In 85% of patients weakness becomes generalized,
affecting the limb muscles as well.

SIGNS:
a. Peripheral-
• Weakness, particularly of the arms and proximal
muscles of the legs.
• Permanent myopathic wasting may occur in long-
standing cases.
b. Facial-
• Lack of expression and Ptosis (myopathic facies)
c. Bulbar-
• Dysphagia
• Dysarthria and
• Difficulty in chewing
d. Respiratory- rarely respiratory crisis may occur

OCULAR FEATURES:
90% patients have both ptosis & weak extraocular movements
a. Ptosis-
• Bilateral and frequently asymmetrical
• Increases on prolonged upgaze (>30secs)
• Cogan Twitch Sign is a brief upshoot of eyelid when the
patient looks straight ahead after looking down for
several minutes
• Positive Ice Test: An Ice pack is placed on the eyelid for
2 minutes which results in an improvement in the severity
of ptosis
(Cold improves neuromuscular transmission)

b. Diplopia-
• Is frequently vertical, although any or all of the
extraocular muscles may be affected
• When myasthenia is limited to ocular muscles and no
generalized involvement is present, it is known as
Ocular Myasthenia

• Serum anti-AChR antibodies levels
The presence of anti-AChR antibodies is diagnostic
of Myasthenia, but a negative test does not exclude
the disease.
• Thoracic CT or MRI
to detect thymoma
• Single-fiber Electromyography (SFEMG) is the latest
diagnostic test & the most sensitive investigation.
• Edrophonium Test or the Tensilon Test
INVESTIGATIONS for Myasthenia Gravis

EDROPHONIUM TEST:
a. Objective baseline measurements are made of the
ptosis, or of the diplopia with a Hess test
b. Intravenous injection of atropine 0.3 mg is given to
minimize muscarinic side-effects
c. Intravenous test dose of 0.2 mL (2 mg) edrophonium
hydrochloride is given. If definite symptomatic
improvement is noted, the test is terminated forthwith
d. The remaining 0.8 mL (8 mg) is given after 60 seconds,
provided there is no hypersensitivity
e. Final measurements/repeat Hess testing are made and
the results compared
But Edrophonium being ultra short acting, its result lasts
only for 5 mins during which the measurements are made

• Anticholinesterase Medications:
Pyridostigmine most commonly used
Started at a dose of 30-60mg 3-4 times a day
Increased or decreased as per patient’s response
• Thymectomy:
To remove a thymoma if present
Also tried as a treatment in generalized MG
• Immunosuppression:
Steroids or Azathioprine
For refractory cases high dose Cyclophosphamide
• Plasmapheresis &
• Intravenous Immunoglobulin
TREATMENT of Myasthenia Gravis

MYOTONIC DYSTROPHY
• Myotonia means delayed muscular relaxation after
cessation of voluntary effort which is the characteristic
feature of the disease.
• Shows Autosomal Dominant Inheritance
• Presentation is in the 3rd–6th decades with weakness of
the hands and difficulty in walking.
• Successive generations exhibit progressively earlier onset
and greater severity of disease
(Anticipation)

Signs-
• Peripheral- Difficulty in releasing grip, muscle wasting and
weakness.
• Central- Mournful facial expression caused by bilateral
facial wasting with hollow cheeks, and slurred speech
from involvement of the tongue and pharyngeal muscles.
• Other- Frontal baldness in males, hypogonadism, mild
endocrine abnormalities, cardiomyopathy, pulmonary
disease, intellectual deterioration and bone changes

Ocular Features-
• Early Onset Cataract-
“Christmas Tree Cataract”
• Ptosis
• Others-
External Ophthalmoplegia,
pupillary light-near dissociation,
mild pigmentary retinopathy,
bilateral optic atrophy and low
intraocular pressure
(because of its
resemblance to the
coloured lights on a
Christmas tree)

Myotonic Facies

CHRONIC PROGRESSIVE EXTERNAL
OPHTHALMOPLEGIA
• Chronic progressive external ophthalmoplegia (CPEO) is
a disorder characterized by slowly progressive paralysis
of the extraocular muscles.
• Patients usually experience bilateral, symmetrical,
progressive ptosis, followed by weakness of the
extraocular muscles months to years later
• Ciliary and iris muscles are not involved

• CPEO is the most frequent manifestation of mitochondrial
myopathies
• It may occur in isolation
or
• In association with certain syndromes like:
Kearns–Sayre syndrome & Oculopharyngeal Dystrophy
• Mitochondrial DNA encodes for essential components of
the respiratory chain. Deletions of various lengths of
mtDNA results in defective mitochondrial function.
• Extraocular muscles are affected preferentially because
their fraction of mitochondrial volume is several times
greater than that of other skeletal muscle.

• Impaired protein synthesis in these mitochondria accounts
for the histological hallmark- Ragged Red Fibers
• Muscle fibers stained with Gomori trichrome stain show
an abnormal accumulation of enlarged mitochondria
beneath the sarcolemma giving the unusual appearance

• CPEO tends to begin in young adulthood
• Ptosis usually is the first clinical sign, which is bilateral &
symmetrical
• As the ptosis progresses, the patient may use the frontalis
muscle to elevate the eyelids and adopt a chin-up head
position
• External ophthalmoplegia is also typically symmetrical
• It is characterized by a progressive course without
remission or exacerbation.
• Initially upgaze is involved subsequently lateral gaze is
affected
• Because of symmetrical loss of eye movements there is
no diplopia [differentiating feature from Myasthenia Gravis]
CLINICAL FEATURES of CPEO

• Multiorgan System Disorder
• Triad of Clinical findings:
1. Onset before the age of 20yr
2. Chronic Progressive External Ophthalmoplegia
3. Pigmentary Retinopathy
• Plus features like- Complete Heart Block & Cerebellar
Ataxia
• Other features-
Deafness, diabetes, short stature, renal disease and
Dementia
Kearns–Sayre Syndrome

Fundus typically shows a ‘salt and pepper’ appearance

DIAGNOSTIC TESTS-
• Lumbar puncture shows elevation of CSF protein
concentration (>1 g/l).
• ECG demonstrates cardiac conduction defects

• Autosomal Dominant Inheritance
• Weakness of pharyngeal Muscles: causing Dysphagia
&
• Wasting of temporalis
• Ophthalmic features
Bilateral Ptosis and
Progressive External Ophthalmoplegia
Oculopharyngeal Dystrophy

Lambert-Eaton Myasthenic Syndrome
• An autoimmune disorder of the neuromuscular junction
often associated with underlying,
Small Cell Bronchial Carcinoma
• Systemic features include gradual difficulty in walking that
may precede clinical manifestation of the associated
carcinoma by up to two years.
• Ophthalmic features are ptosis and diplopia

CHRONIC
PROGRESSIVE
EXTERNAL
OPHTHALMOPLEGIA
MYASTHENIA
GRAVIS
LAMBERT-EATON
MYASTHENIC
SYNDROME
FATIGUABILITY No Yes No
DIPLOPIA No Yes Yes
Other eye signs
Pigmentary
Retinopathy
- -
RNS test -
Decremental
Response
Incremental
Response
Differentiation of Conditions Producing Ptosis &
Extraocular Muscles Weakness

REFERENCES
• Clinical Ophthalmology–A Systematic Approach 7th edition
(by Jack J Kanski)
• Ophthalmology 4th edition- Yanoff & Duker
• Pediatric Ophthalmology & Strabismus (Section 6),
American Academy of Ophthalmology(AAO)
• Manual Of Squint- Leela Ahuja
• Harrison's Principles of Internal Medicine Vol-II (17th Ed)

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