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Binocular Vision > Duane’s And Browns Syndrome - Miriam > Flashcards

Duane’s And Browns Syndrome - Miriam Flashcards

1
Q

What are characteristics of mechanical anomalies?

A
    • Limited movement on forced duction test
  • Globe retraction
  • Up-shoots and down-shoots
  • Equal limitation on duction and version
  • Limitation opposite positions (abd and add)
  • Does not have 3rd or 4th muscle sequeale
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2
Q

What is the forced duction test?

A

A surgically done test to see if the eye muscles are working well and there are not restrictions/ mechanical anomalies

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3
Q

Describe what a muscles sequelae is ?

A

u/a of a muscle (e.g right SR)
o/a of contralateral synergist (e.g left IO)
o/a of ipsilateral antagonist (e.g right IR)
u/a of contralateral antagonist (e.g left SO)

*if all this occurs then it is concomitant

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4
Q

What is Duane’s retraction syndrome?

A

A classed congenital cranial dysinnervation disorder (CCDD)
- non-progressive
-abnormalities are caused from defects cranial nerve
- involves abnormal horizontal eye movements
- abnormal branch of the 3rd nerve innervating the lateral rectus muscle as a result of hypoplasia or aplasia of the 6th nerve

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5
Q

What are epidemiology of Duane’s?

A
  • Congential
  • 1/1000 have it
  • F(60%)>M (40%)
  • Genetic link (2-5%)
  • Abormal H eye movement. Unilateral more common.
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6
Q

What is the aetiology of Duane’s? (There are two causes)

A

Neurogenic Theory - LR is innervated by 6th AND 3rd nerve or by the 3rd nerve ONLY (due to absent or underdeveloped 6th nerve)

OR

Myogenic fibrosis (thickening of muscle) or inelasticity of the LR & MR muscle inserts abnormally

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7
Q

What are clinical signs of Duane’s?(there is a lot )

A
  • Complete or less often partial absence of abduction
  • Partial loss of adduction. (this is becasue of co-contraction of the 3rd nerve and the 6th nerve)
  • Deviations in PP. Abduction problem = eso. Adduction problem = exo
  • CHP
  • Poor convergence
  • A or V pattern
  • Reduce BV (they may have suppression)
  • Up/down shoots
  • Globe retraction on adduction + narrowing of palpebral aperture (induced ptosis)
  • Widening of palpebral aperture on abduction attempted
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8
Q

If someone had their face turned towards affected side, at distance will they have and eso or exo deviation?

A

ESO ; to get away from abduction

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9
Q

If someone had their face turned to unaffected side, at near would they have an eso or exo deviation?

A

Exo ; to get away from aduction

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10
Q

What are the three classifications of Duane’s (Browns method using OM)?

A

Type A
Type B
Type C

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11
Q

What does Type A mean + what deviation would they have?

A

Loss of aBduction> aDduction
eso

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12
Q

What is Type B + what deviation would they have?

A

Loss of aBduction only
Eso

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13
Q

What is Type C + what deviation would they have ?

A

Loss of aDduction> aBduction
Exo

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14
Q

What are the three classifications of Duane’s (using Huber’s method of electrophysiology EMG)?

A

Type I
Type II
Type III

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15
Q

What is Type I + what deviation would they have + what browns classification does it correspond to?

A

Max innervation LR in aDduction, eso, Type B ABd only

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16
Q

What is Type II + what deviation would they have + what browns classification does it correspond to ?

A

Co-contraction of the MR and LR on aDduction, Exo, Type C ADd>ABd

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17
Q

What is type III + what deviation would they have + what browns classification does it correspond to?

A

Co-contraction of the MR and LR on aDduction and loss of innervation to LR on ABduction, ESO, type A ABd> ADd

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18
Q

What type of Duane’s is the most common and what CHP would they have?

A

Duane’s type A/ type III
Face towards affected side

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19
Q

What CHP would a type B/ type I have?

A

Face turned towards affected side

20
Q

What CHP would a Type C / type II have and what other issue may they have?

A

Face turned to unaffected side + could have poor convergence

21
Q

What are other associated developmental ocular abnormalities with Duane’s?

A

Coloboma
Heterochromia
Lens opacities
Microphthalmos
Persistent pupillary membrane
Crocodile tears

22
Q

What are some systematic associations with Duane’s?

A

Goldenhar’s syndrome
Klippel-Feil syndrome
Other syndromes
Abnormal ear formation
Deafness
Syndactyly
Thalidomide syndrome (those no arm kids by the pool)

23
Q

How would you investigate Duane’s?

A
  • FH
  • VA
  • CT
  • OM
  • BSV (PFR/Stereo)
  • Measurement (Hess, field of BSV, PCT)
  • Refraction
  • Fundus/ media
  • (you may want to do a forced duction test too)
24
Q

After diagnosis, what should happen?

A

General physical examination, evaluation of other family member

25
Q

How is Duane’s managed in under 8 year olds?

A

1.Non-urgent referral,
check ocular/ systemic association,
ensure BSV is maintened,
treat amb,
give specs,
treat if severe

26
Q

How are over 8 year olds with Duane’s managed?

A
  1. Can refer, check ocular/systemic associations
    treat if severe which will improve symptoms + cosmesis
27
Q

What treatment is included in management of Duane’s?

A
  1. Refraction if significant,
    2.use of CHP,
    3.occlusion for amb,
    4.prisms,
    5.surgery
    6.botulinum Toxin
28
Q

Which CN innervates the lateral rectus?

A

VI

29
Q

If the VIth nerve is underdeveloped, which nerve innervates the LR as a secondary dysinnervation?

A

IIIrd
Similarly, if VIth is absent then LR will be innervated by III nerve only

30
Q

What is the aetiology of Browns syndrome?

A

Congenital abnormality of SO muscle/ tendon
(Short tendon sheath, short tendon, inelastic muscle, orbital adhesions)
Or
Acquired due to Trochlear damage or SO tendon abnormalities

31
Q

What are some examples how Trochlear damage can occur?

A

Traumatic event such as a vehicle accident, iatrogenic, inflammatory, orbital masses

32
Q

What are some causes of SO tendon abnormalities?

A

Inflammatory, SO tendon cyst, iatrogenic

33
Q

What does iatrogenic mean?

A

Caused by medical examination or treatment

34
Q

Which palsy is browns similar to?

A

IO palsy as it is only mechanical

35
Q

Why cant some with Brown’s elevate their eyes?

A

When the eye is aDducted at 51 degrees it becomes a pure elevator, agonist IO contracts producing elevation but the antagonist SO is unable to relax so there is no elevation

36
Q

What symptoms are associated with Brown’s?

A
  • Sporadic
  • Pain/ discomfort
  • Diplopia
  • CHP with their chin/ head up
  • Unable to elevate
  • Uni lateral (in 90% of cases)
37
Q

What are clinical signs of browns syndrome?

A
  • Limitation of elevation in aDduction with elevation
  • Down drift of affected eye
  • O/a of contralateral synergist
  • A or v pattern
  • Forced duction- restricted in elevation in adduction
  • Chin elevation
  • Head tilt towards affected side
  • Face turn towards normal side
  • Straight in PP
38
Q

What are treatment options for early onset Brown’s?

A

No treatment, less problematic as grow older because dont need to look up as much

39
Q

What is the management for under 8s with Brown’s?

A

Non-urgent referral to confirm binocularly stable + monitor

40
Q

What are treatment options for over 8s with Brown’s?

A

No need to refer if binocularly stable, non-urgent referral if symptomatic

41
Q

What are treatment options for acquired Brown’s?

A

Refer and treat pathology, steroid injection, occasionally surgery

42
Q

What is the acutal problem with browns?

A

The superior oblique muscle cannot relax. (it is able to contract just not relax)

43
Q

Because the superior oblique muscle can contract can the eye look down?

A

Yes

44
Q

what is happening then with the muscles with elevation?

A

The inferior rectus is contracting but the superior oblique cannot relax, which is causing problems

45
Q

What would the hess chart look like?

A

Binocular Vision (30 decks)

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