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Strabismus & Ocular Motility > Double Elevator Palsy, Marcus Gunn, Aberrant Regeneration > Flashcards

Double Elevator Palsy, Marcus Gunn, Aberrant Regeneration Flashcards

1
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A
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3
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What are the features of a double elevator palsy?

A
  • Can affect one or both eyes
  • Limitation elevation
    ABDuction & ADDuction

-No manifest deviation in PP or Hypotropia
Pseudo ptosis

  • Ptosis
    True/pseudo ptosis
  • Intact Bell’s phenomenon (in most cases)
  • Chin elevation AHP
  • +VE FDT (restrictive)
  • Associated Marcus Gunn jaw winking and DVD
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4
Q

Do we have a manifest deviation in pp or hypotropia in double elevator palsies?

A

No

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5
Q

What is the AHP in double elevator palsy?

A

Chin elevation

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6
Q

What is Bell’s phenomenon like in double elevator palsy?

A

Intact in most cases

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7
Q

What are the potential aetiologies of double elevator palsies?

A
  • Congenital
  • Supranuclear Defect
  • Contracture of IR
  • SR Paresis
    Approx 50% of cases; reduced SR volume shown on MRI
  • Absent Bells
    Sup div CNIII palsy with spread of concomitance
  • Acquired Upgaze Palsy
    Suspect dorsal midbrain lesion (less common in children, more common in adults)
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8
Q

How might we notice congenital double elevator palsies?

A

Parents may notice their child doesn’t look up at them like when sitting on their lap. Most common cause

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9
Q

What’s the most common cause of double elevator palsy?

A

Congenital

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10
Q

What is a supranuclear defect aetiology leading to double elevator palsy?

A

(Negative FDT so muscle can move but due to a higher up brain issue in the dorsal root they’re not getting the signal)

+ve Bells

full passive movement

-ve FDT & full elevation under GA

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11
Q

How might familial cases be linked to double elevator palsy?

A

TUBB3 Gene (Thomas et al., 2019)

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12
Q

What do we need to look for during OMs for signs of double elevator palsy?

A
  • True vs pseudo ptosis
  • Jaw wink (fluttering of eyelids
    when jaw moves like when talking, chewing or swallowing)
  • Bells phenomenon
  • Lower lid crease
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13
Q

Why is the lower lid crease important in double elevator palsy?

A

The lower lid crease is examined in double elevator palsy, also known as monocular elevation deficiency,to identify inferior rectus contracture:

Appearance
In children with double elevator palsy, the lower eyelid fold becomes more prominent when attempting to look up.This is a sign of inferior rectus contracture

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14
Q

What saccades will be reduced in double elevator palsy and why?

A

Upward saccadic velocity can be reduced which indicated SR weakness

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15
Q

What are the differential diagnoses for Double Elevator Palsy?

A
  • Congenital fibrosis
    Contracted / fibrotic IR
  • Blow out Fracture (if issue with trauma or orbital floor)
  • Graves Orbitopathy (potential limitation of upgaze)
  • Brown’s syndrome (just in adduction is the elevator issue)
  • Superior division 3rd N palsy / SR palsy
    with spread of concomitance
  • Absent SR
    Congenital
  • Orbital mass / cellulitis
  • Vertical Duane’s
  • Myasthenia Gravis
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16
Q

What management do we use in Double Elevator Palsy?

A
  • Conservative where possible
  • Refraction
  • Treat amblyopia
    strabismic
    stimulus deprivation
    meridional
    anisometropic
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17
Q

What do we need to consider before surgery in double elevator palsy?

A
  • Marked AHP
  • Hypotropia & Pseudo Ptosis
  • Ptosis
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18
Q

Do we do ptosis or strabismus surgery first in DEP?

A
  • Strabismus before ptosis surgery
  • Choice of strabismus surgery dependent on FDT
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19
Q

What surgery do we do in DEP when you have a -ve FDT?

A

Knapp procedure (potentially with augmented Foster sutures)

  • Transpose LR & MR up to the borders of SR
  • May have an increased effect over time
  • Can be graded
  • When they have a minimal restriction of elevation
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20
Q

What surgery do we do in DEP when you have a +ve FDT?

A

Indicates contracture of IR

  • IR weakening
  • +/- Knapp procedure
  • Usually perform both
  • When they have a marked restriction of elevation
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21
Q

What is a Double Depressor Palsy?

A
  • Very rare and congenital
  • Differentiate: IR palsy / absent IR
    spread of concomitance
    limited depression
  • FDT - if +ve determines contracture of SR
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22
Q

What is the FDT like in Double Depressor Palsy?

A

FDT - if +ve determines contracture of SR

23
Q

What surgery do we do in Double Depressor Palsy?

A
  • Inverse Knapp
  • SR recession - if FDT +ve for SR contracture
24
Q

What is Marcus Gunn also known as?

A
  • Marcus Gunn phenomenon
  • Jaw winking ptosis
  • Trigemino-oculomotor synkinesis
25
Q

What are some features of Marcus Gunn?

A
  • Congenital & unilateral (can be bilateral)
  • Misdirection of nerve supply
    Branch of mandibular division of CNV (supplies pterygoid muscles)
    Misdirected into superior division CNIII (supplying the levator)
  • Partial ptosis
  • Upper lid position changes with jaw movement

Supported by MRI evidence (Conte et al, 2012)
Structural abnormality in brainstem (midbrain tegmentum)
Neural misdirection happens in brainstem

? supranuclear synkinesis
Can be familial

26
Q

What causes Marcus Gunn?

A

Misdirection chewing muscles nerve supply being sent to CNIII to fire to the lid elevators

27
Q

What spectrum is Marcus Gunn a part of?

A

Part of the CCDD (cranial congenital dysinnervation disorder) spectrum:

  • 4 patients with CFEOM1 and Marcus Gunn Reported
  • All Male and Left sided
  • KIF21A

(Yamada et al, 2005)

28
Q

What does partial ptosis look like in Marcus Gunn?

A
  • Variable in different patients
  • 2-13% congenital ptosis
29
Q

How does the upper lid position change with jaw movement?

A
  • Increase ptosis (lid lowers)
    Move jaw to the affected side =
    Close mouth
  • Decrease ptosis (lid lifts)
    Move jaw to the unaffected side =
    Open mouth
    Project mandible forwards
30
Q

When does ptosis increase in Marcus Gunn?

A

Increase ptosis (lid lowers)
Move jaw to the affected side =
Close mouth

31
Q

When might the lid change position in Marcus Gunn?

A
  • Chewing
  • Sucking
  • Jaw protrusion
  • Smiling
32
Q

What are associated features of Marcus Gunn?

A
  • Strabismus
  • Amblyopia
  • Anisometropia (pressure on front of eyes may lead to astigmatism? 34 minutes in)
  • OM defect
    DEP
    SR palsy
    Hypotropia
    Hypertropia
  • AHP
    To maintain BSV
    To avoid ptosis
  • Other developmental abnormalities
  • Rarely - other synkineses

OBSERVE! Treat refraction and amblyopia

33
Q

What is synkineses?

A

Synkineses - unwanted contractions of the muscles of the face during attempted movement.

34
Q

What might we see on ocular movements in Marcus Gunn?

A
  • Lid position
    Important because if covering pupil then this can cause amblyopia
    lid crease & brow position (Lid crease with normal elevator muscle – if don’t have it have a lax tendon in that elevator)
    ? pupil covered - at worst & at best
    ? normal situation
  • Lid movement
    anomalous movement
    observe during OM
    lid closure
  • Ptosis
    true VERSUS pseudo
    measurement
    levator function
  • Variability (check start and end of assessment)
35
Q

How do we differentiate between a ptosis and pseudoptosis?

A

Differentiate between ptosis and pseudoptosis (like swelling). A hypertropia can cause the lids to look different in the way that they sit so this is a pseudoptosis. Cover the fixing eye, get to cover with HT eye and see if the eye goes up, lid should then go up with it and can measure the palpebral fissure and then compare to the other eye.

36
Q

What are the differential diagnoses in Marcus Gunn?

A
  • Aberrant regeneration –
    Can ask in history if previously having had CNIII palsy
  • SR palsy
    Superior division 3rd NP
  • Double elevator palsy
  • HoT & pseudoptosis
  • Congenital ptosis
  • Myasthenia Gravis – l
    Less likely to have fluttering like in Marcus Gunn
37
Q

How do we manage Marcus Gunn?

A
  • Refraction
  • Occlusion
  • AHP
  • May learn to disguise/minimise jaw wink
  • Surgery
    Strabismus before ptosis. Leave ptosis alone where possible due to risk of eyelid retraction from surgery and may improve as they get older.
38
Q

When would we do surgery in Marcus Gunn?

A
  • Surgery only if cosmesis extremely poor
  • Patient and parents must be aware of limited prognosis for improvement
39
Q

What type of surgery do we do in Marcus Gunn?

A
  • Unilateral levator excision & frontalis suspension
    can perform this Sx bilaterally to try & gain a more symmetrical result
  • Levator resection
  • Fasenella-Servat procedure
  • Levator myectomy
  • Removal of levator aponeurosis & muscle
40
Q

What post-op complications may there be in Marcus Gunn?

A
  • Lagophthalmos on downgaze
  • Eyelash malposition
  • Loss of eyelid crease
  • Eyelid contour abnormality
  • Entropion
  • Residual ptosis
  • Recurrence of ptosis (10%)
  • Residual jaw winking that’s cosmetically unacceptable (psychosocial symptoms)
41
Q

How might aberrant regeneration occur in CNIII?

A
  • Lid elevates on adduction or downgaze
  • Adduction on attempted gaze
  • Globe retraction on upgaze &/or downgaze
  • Pupil constriction on adduction

See pictures on Slide 35 & 37

42
Q

When/why might we see aberrant regeneration?

A
  • Not all signs present in every case
    Lid elevation most common
  • Abnormal movements due to co-contraction of muscles supplied by CNIII
  • 8-12 weeks after onset of CNIII palsy
    6 weeks
    Cosmetically upsetting
43
Q

What is the aetiology of aberrant regeneration?

A
  • Trauma
    usually significant head injury
    ? loss of consciousness
    ? other neurological deficits
  • Compressive lesion – aneurysm
  • Damage to the structure of the nerve

Almost never occurs in diabetic or microvascular CNIII palsy. If seen in a presumed microvascular CNIII palsy then imaging and further investigation is needed

44
Q

What are the theories of aberrant regeneration?

A
  • Misdirection theory
  • Central synaptic reorganisation
  • Ephaptic transmission
    A type of cell-to-cell communication that occurs when a neuron’s electrical field alters the excitability of nearby neurons
45
Q

What is ephaptic tranmission?

A

A type of cell-to-cell communication that occurs when a neuron’s electrical field alters the excitability of nearby neurons; especially if myelin sheaths have been damaged by slow compression. Neuronal transmission occurs between nerve axons instead of at the synapse.

It’s a slow growing lesion

Can be the aetiology for aberrant regeneration in CNIII palsy

46
Q

What is misdirection theory in CNIII palsy?

A

A theory of how aberrant regeneration occurs

Traumatic damage to 3rd CN:

  • Fibres regrow but innervate different muscles
  • ‘Misrouting of axons’

Confirmed by some EMG evidence but doesn’t explain mechanism in every case

Experimental evidence in rats showed fibres regenerate along the length of the nerve and not just at the site of the lesion

47
Q

What is Central Synaptic Reorganisation in CNIII palsy?

A

A theory for how aberrant regeneration occurs

  • Disruption of synapses of 3rd CN nuclei
  • Central mechanism
  • Axonal injury > changes then affect & disrupt:
    Organisation of cell bodies
    Synapses
  • Supported by cases of primary regeneration without 3rd N palsy
48
Q

How might we manage aberrant regeneration in CNIII palsy?

A
  • Observe and allow for recovery (6 months)
  • Conservative
    Prisms

Occlusion (total or sector)

AHP & head movements

  • Management dependent on symptoms & BSV
49
Q

What are the symptoms of aberrant regeneration?

A
  • Diplopia
  • Aberrant features (lid, abnormal eye movements, pupil)
50
Q

What management do we do when there’s a query potential for BSV in aberrant regeneration in CNIII palsy?

A
  • Prisms in free space
  • Synoptophore
51
Q

What management do we do when there’s potential for BSV in aberrant regeneration in CNIII palsy?

A
  • Surgery to achieve this (after the 6 month mark of stability)
52
Q

What management do we do when there’s NO potential for BSV in aberrant regeneration in CNIII palsy?

A
  • Query traumatic loss of fusion
  • Improve eye alignment
  • Occlusion if necessary if having small area of BSV.
53
Q

If someone has BSV what test is important to do in CNIII palsy?

A

Field of BSV important
- Expand Field of BSV - Can we move it to a more useful position i.e. pp and downgaze.

54
Q

What surgery might we do in CNIII palsy with aberrant regeneration?

A
  • Contralateral Eye
    May worsen aberrant signs if operate on affected eye
  • Weaken o/a muscles
  • Faden procedure
  • Adjustable sutures
  • Strabismus surgery before ptosis surgery (ptosis surgery more unpredictable)
  • Can involve >1 surgery procedure
  • Occlusion

Strabismus & Ocular Motility (23 decks)

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