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Strabismus & Ocular Motility > Duane's Retraction Syndrome > Flashcards

Duane's Retraction Syndrome Flashcards

1
Q

What type of disorder is Duane’s Retraction Syndrome?

A

A congenital cranial dysinnervation disorder

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2
Q

What are the features of Duane’s?

A
  • Congenital (acquired rare)
  • Limited abduction
  • Limited adduction common though may not be present
  • Retraction of the globe and narrowing of palpebral fissure on adduction
  • Protrusion of the globe and widening of the palpebral fissure on abduction
  • Unilateral or bilateral
  • Updrift or downdrift on adduction
  • AHP usually face turn to achieve BSV
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3
Q

Where do people with Duane’s have BSV?

A

BSV in primary position

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4
Q

What do we see on the palpebral fissures in Duane’s?

A
  • Limited abduction, widening of palpebral fissure
  • BSV in pp
  • Narrowing of palpebral fissure
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5
Q

What do we see in terms of protrusion in Duane’s?

A

Retraction in adduction & protrusion in abduction

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6
Q

Do we see an alphabet pattern in Duane’s?

A

Yes! A or V pattern

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7
Q

What are some possible features of Duane’s Retraction Syndrome?

A
  • Defective convergence
  • Positive FDT (dependent on aetiology and duration) so blockage is mechanical
  • Unilateral is more common in females
  • Bilateral is more common in males (often asymmetrical so look for subtle limitations in other eye)
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8
Q

How often does Duane’s occur in strabismus?

A

1-5%
1 in 1,000 to 1 in 10,000 of the population

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9
Q

How often is Duane’s sporadic?

A

80%

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10
Q

Which eye is more commonly affected in Duane’s and does it affect males or females more?

A

Left eye (74%) and females (60%%) more commonly affected (Mohan et al., 2008)

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11
Q

Why was Duane’s initially thought of as solely mechanical?

A
  • Originally thought lack of movement of LR or MR leading to fibrosed muscle which is why it is considered a mechanical issue. Doesn’t explain retraction/protrusion or the apertures changing (next slide)
  • Congenital anomalous of the LR, tight due to nuclear aplasia or birth trauma
  • Dual insertion – MR was rotated and inserted posteriorly, used to explain globe retraction

But not these theories are thought to be unlikely!

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12
Q

What did Breinin (1956) find about Duane’s Retraction Syndrome?

A

Breinin (1956) measured electrical potentials generated by the muscles at various potentials

No LR activity in attempted abduction but maximum LR generated in adduction, possible reason for co-contraction and globe retraction. This led to co-contraction of MR and LR in adduction. = Paradoxical innervations to the muscles

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13
Q

What did Strachan & brown find about Duane’s?

A

Paradoxical innervations observed using electromyography which revealed variable LR activity but MR consistent

  • Occasionally synergistic innervation between MR and vertical recti/obliques
  • Reduced saccadic velocities showed reduced LR innervation and slowing of adducting saccades concluding paradoxical innervation
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14
Q

How did Brown (1950) classify Duane’s?

A
  • Type A
    Marked limitation of abduction and much less limitation of adduction
  • Type B
    Limited abduction but normal adduction (B = ABduction only)
  • Type C
    Limited adduction that exceeds the limitation of abduction
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15
Q

What is Brown’s (1950) classification based on?

A

Based on ocular motility assessment

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16
Q

How did Huber (1974) classify Duane’s?

A
  • Type 1 (70 - 80%)
  • Type 2 (7%)
  • Type 3 (15%)

Does not tell us about the aetiology of the conditions so Huber looked at this

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17
Q

What did Huber (1974) say about Type 1 Duane’s?

A
  • Marked limitation of abduction, minimal or normal adduction, globe retraction, and Palpebral Fissures (PF) narrowing adduction and widening abduction
  • Paradoxical innervation of LR with max. impulses on adduction and deficient impulses in abduction. MR normal
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18
Q

What did Huber (1974) say about Type 2 Duane’s?

A
  • Limitation of adduction, abduction normal or limited, globe retraction and PF narrowing in adduction.
  • Exotropia also present
    LR peak impulses on abduction but secondary paradoxical impulse on adduction. MR normal
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19
Q

What did Huber (1974) say about Type 3 Duane’s?

A
  • Limitation of abduction & adduction, globe retraction and PF narrowing in adduction
  • Simultaneous LR and MR innervation in primary position, adduction and abduction.
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20
Q

What is Schliesser et al’s. (2016) classification of Type 4 Duane’s?

A
  • 19/179 (5%) Synergistic Divergence
  • Exotropia in Primary position, AHP, Palpebral fissure changes
  • Full to nearly full abduction with absent adduction, and simultaneous abduction when viewing unaffected side
  • Cause? Requires further investigation
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21
Q

What did Xia et al. (2014) find out about MRI in the 3 types of Duane’s?

A
  • Type 1
    Absence of VIth nerve, hypoplasia of SO muscle and aberrant innervation of LR by extra branch of IIIrd nerve
  • Type 2
    Dual innervation of LR from both the VIth and an aberrant IIIrd nerve branch and hypoplasia of SO muscle
  • Type 3
    Hypoplasia of IIIrd nerve, the MR, IR & IO muscles (one patient)
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22
Q

What is a ‘splitting’ of the Lateral Rectus?

A
  • Splitting caused by incomplete fusion of the superior and inferior mesodermal complexes
  • Speculation that upper part innervated normally by 6th nerve and lower part receives branch of inferior division 3rd nerve
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23
Q

How id LR ‘splitting’ related to Duane’s?

A

Okanobu et al. (2009) - 2/5 participants with Duane’s showed LR split

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24
Q

What is Duane’s most common in as a co-morbid condition?

A

Congenital Cranial Dysinnervation discorders (CCDD) of which Duane’s is the most common (large cohorts of CCDD in some parts of the world)

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25
Q

What is the genetic basis for Duane’s?

A
  • DURS1 Gene located on Chr 8q13 (Vincent et al., 1994)
  • DURS2 - CHN1 Gene located on Chr 2q31.1 (Miyake et al., 2008) that is an autosomal dominant gene
  • DURS3 - MAFB Gene located on CHr 20q12 (Park et al., 2016)
26
Q

What is the DURS2 - CHN1 Gene?

A

MRI studies show absent/hypoplasia of 6th, small ON and small 3rd Nerve and hypoplasia SO muscle

3rd Nerve dysinnervation of the LR is secondary due to failue of innervation by the 6th nerve

Duanes Type 1 and 3 observed

27
Q

What is the DURS3 - MAFB Gene?

A
  • Autosomal Dominant
  • Occurs with or without hearing loss
  • Mouse and embyro models reveal MAFB is expressed where the abducen nerve develops and in the absent of the nerve aberrant innervation of the LR by fibres from the Ocular Nerve
  • Duanes Type 1 and 3 observed
28
Q

What is Duane-Radial Ray Syndrome (DRRS/Okihiro syndrome) – SALL4 Gene Chr:20q13.2 (Al-Baradie et al, 2002)?

A
  • Autosomal Domiant
  • DURS with hand and upper extremities
  • Variable expression of cardiac, renal, hearing and vertebral abnormalities in addition to DURS
29
Q

What is the HOXA1 Chr: 7p15.2 (Tischfield et al, 2005) gene related to?

A
  • Bosley-Salih-Alorainy Syndrome
  • Athabaskan brainstem dysgenesis syndrome
30
Q

What are the possible reasons for retraction of the globe on adduction in Duane’s?

A
  • Inelasticity of LR
  • Co-contraction MR and LR
  • Anomalous insertion MR
  • SR and IR try to help to adduct
31
Q

What are the possible reasons for narrowing of palpebral fissures in Duane’s?

A
  • Mechanical ptosis due to retraction of globe
  • Decrease in electrical activity of levator
32
Q

What are the possible reasons for protrusion and widening of the palpebral fissures in Duane’s?

A
  • Inhibition MR
  • Co-relaxation
  • SO and IO trying to aid abduction
  • Mechanical effect of lid
33
Q

What are the possible reasons for updrift and downdrift on adduction in Duane’s?

A
  • Retracted eye more in line with the obliques
  • Co-contraction of SR and/or IR with the LR
  • Slippage of the LR up or down (‘Bridle’ effect)
34
Q

What are the possible reasons for A or V or X patterns in Duane’s?

A
  • Changes in innervation to LR on elevation or depression
35
Q

When are we likely to get acquired Duane’s?

A

Acquired is rare
- Tumour in wall of 4th ventricle
- Report of skull base meningioma

36
Q

See investigations on slides 26 & 27

A
37
Q

What is the management plan for Duane’s Retraction Syndrome?

A
  • Correct refractive error
  • Treat amblyopia
  • Observation (most common)
  • Prisms
  • BT
  • Surgery (where marked AHP, decompensating, cosmesis or troublesome diplopia)
38
Q

How do we use BT diagnostically in Duane’s?

A

To ascertain if likely to reduce AHP and or increase field of BSV to reduce symptoms

39
Q

How do we use BT therapeutically in Duane’s?

A
  • As results of surgery can be unpredictable some patients choose to continue with maintenance BT (14%)
  • Some patients (53%) demonstrate a long term reduction in the deviation (Dawson et al 2010)
40
Q

What is surgery based on in Duane’s?

A
  • Deviation (ET vs. XT)
  • Size of AHP
  • Severity of globe retraction and overshoots
  • Degree of limitations
  • FDT
  • Extent of Field of BSV
41
Q

What surgery do we do when there’s a primary ET in Duane’s?

A
  • MR recession of affected eye
  • Large contralateral recession of unaffected eye (-2 or better) caution with large co-contraction
  • Large deviation or bilateral duane’s, bilateral MR recession
  • With large globe retraction – LR recess
  • Transposition of vertical recti muscles to LR, with or without augmentation sutures and adjustable (Britt et al 2004, Snir et al 2005)
42
Q

What surgery do we do when there’s a primary XT in Duane’s?

A

Exotropia in primary position

  • Unilateral LR recession (XT common in type 3/2)
  • Bilateral LR recession in large deviation
  • Vertical recti transposition can also be performed
  • Synergistic divergence – no definite surgical procedure
43
Q

What surgery do we do with a globe retraction in Duane’s?

A

Mild globe reaction, can be MR recess and resection of LR, if severe recess both MR and LR

44
Q

What surgery do we do when there’s an overshoot in Duane’s?

A
  • Y splitting of the LR with or without recessions (Rao et al, 2003)
  • Each half balances the other
  • IO myectomy with or without horizontal recti recess
45
Q

See slide 36 flowchart on surgeries

A
46
Q

Read

A

Kekunnaya R, Negalur M. Duane retraction syndrome: causes, effects and management strategies.

47
Q

What causes Duane’s/was thought to cause Duane’s?

A

Duane’s retraction syndrome is due to innervation of LR by extra branches of CNIII in place of absent or deficient CNVI nerve fibres. The inferior division of CNIII bifurcated giving off several small branches entering the LR.

48
Q

What did Huber suggest about the LR having 3 parts?

A
  • Normally innervated portion
  • Portion innervated by CNIII
  • Denervated and therefore fibrotic portion
49
Q

What does the Chimerin 1 (CHN1) gene have to do with Duane’s?

A

At present chimerin 1 (CHN1) is the only gene in which at least 7 mutations are known to cause familial isolated Duane syndrome. They overregulate aproteins that disrupt the normal growth of neurons in certain parts of the brain and so VI and III and EOMs don’t develop normally.

50
Q

What horizontal deviation do most patients have with Duane’s?

A

Most patients are ET with an increased deviation for distance and so common head posture is a head turn to the affected side that’s more marked for distance fixation.

51
Q

What does head posture look like in Duane’s?

A

Head posture can be different in A or V patterns (i.e. V pattern to head depression to minimise the ET).

52
Q

What do patients with Duane’s do to maintain BSV?

A

Patients who maintain BSV can be seen to use head tracking rather than eye tracking.

53
Q

What is globe retraction, limitation of adduction and narrowing of the palpebral fissures in Duane’s a result of?

A

Both globe retraction, limitation of adduction and narrowing of the palpebral fissure are the result of co-contraction of the horizontal rectus muscles. Greater the co-contraction, the greater the retraction and limitation of movement.

54
Q

Why is widening of the palpebral fissures on attempted abduction in Duane’s not as significant as narrowing in adduction?

A

Widening of palpebral fissure on attempted abduction is observed but this also happens in acquired sixth nerve palsy

55
Q

When is updrift or downdrift in abduction seen in Duane’s?

A

An updrift or downdrift is seen in the abducting eye when there’s inferior or superior oblique muscle overaction in the contralateral eye and this eye maintains fixation

56
Q

What is the relation between convergence and Duane’s?

A

Convergence deficiency is sometimes present when there’s significant limitation of adduction.

57
Q

What are some useful diagnostic clues in Duane’s?

A

1) Significant head turn

2) obvious head tracking (because field of BSV is so restricted the child turns head to follow)

3) Small size of ET despite marked abduction limitation

4) Limitation of adduction with reduced near point of convergence or XT on contralateral gaze

58
Q

What investigations should we do in Duane’s?

A
  • CT
  • OMs – note difference in amount of horizontal movement elicited when tested above and below the midline and observing any up or downshoot on adduction or abduction. A or V pattern should be noted.
  • Near point of convergence
  • Change in width of palpebral fissure
  • Look at retraction
  • Deviation should be measured fixing with each eye for near and distance with the head straight.
  • Confirm BSV with AHP
  • Hess – stabilise the patient’s head
  • Field of BSV – presence or absence of diplopia should be investigated
59
Q

What other conditions would you have in your differential diagnosis of this Duane’s syndrome?

A
  • Congenital ET
  • CNVI palsy
  • Graves
  • Orbital inflammation
60
Q

When would you consider intervention in a patient with Duane’s?

A
  • Decompensating phoria with diplopia
  • Marked head posture
  • Unacceptable appearance of deviation or retraction

Strabismus & Ocular Motility (23 decks)

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