Duane's Retraction Syndrome Flashcards
What is Duane’s Retraction Syndrome and when is it thought to happen?
- Mechanical congenital disorder but v often not detected until child is slightly older
- Comparing this to a congenital 6th palsy
- Thought to happen in 1st 12 weeks in utero – when CNs are developing
What is the pathophysiology of Duane’s Retraction Syndrome?
- Multiple factors, difficult to ascribe to a singular cause
- Hypoplasia of 6th nerve &/or nucleus – restricted abduction
- Aberrant innervation of LR by 3rd nerve leading to co-contraction of medial & lateral recti when either muscle is activated – retraction, restricted mobility
- Fibrosis of LR muscle leading to loss of elasticity – restricted motility, sudden up/downshoots
- Brainstem abnormalities – embryological development
- Other EOMs can also be abnormally innervated – e.g. elevators
What is the epidemiology of Duane’s Retraction Syndrome?
- More common in females – 3:2
- Genetic element – dominant inheritance documented in families
- Can be associated w/ other abnormalities:
o Goldenhar’s Syndrome – limbal dermoids, pre-auricular skin tags, ear/nose/palate defects
o Klippel-Feil defect – cervical vertebrae fusion w/ restricted neck movement
o Pupillary anomalies
o Coloboma
o Cleft palate
o among others
What is the aetiology of Duane’s Retraction Syndrome?
- Innervation of lateral rectus by extra branches of 3rd nerve in place of absent or deficient 6th nerve fibres
- Genetic component
- Considered mechanical not neurogenic
o If something is mechanical then no matter what you do to the other eye, the affected eye CANNOT move
Called Duane’s retraction because eye will be retracted in direction of issue
Describe Type I Duane’s Retraction Syndrome?
o Marked limitation of abduction & widening of palpebral fissure due to lack of innervation to LR
o Normal or slight limitation of adduction w/ narrowing of palpebral fissure & retraction of globe due to maximum innervation of LR when eye is adducted (due to co-contraction of MR & LR)
o THINK TYPE 1 ONLY HAS ONE ‘d’ – eye will be more eso
Describe Type II Duane’s Retraction Syndrome?
o Limitation of adduction by co-contraction of horizontal recti on attempted adduction with normal or slightly reduced abduction
o THINK TYPE 2 HAS 2 ‘ds’ – eye will be more exo
Describe Type III Duane’s Retraction Syndrome?
o Limitation of both adduction & abduction
o EYE WILL HAVE BOTH ESO & EXO – most common type
What are the signs/clinical features of Duane’s Retraction syndrome?
- Mechanical limitation of abduction or adduction
- Widening of palpebral aperture on attempted abduction
- Narrowing of the palpebral aperture on adduction
- Globe retraction on adduction
Palpebral fissure changes
Retraction
Sudden up/downshoots
Sudden Y patterns
Can also have atypical motility or a different type in each eye
When will the deviaion in Duane’s Retraction Syndrome be bigger?
Who is more likely to have Duane’s Retraction Syndrome?
Mechanical – tend NOT to have a v big deviation in PP – will be bigger when move in direction of problem
- Watch for strabismus, face turn
- Usually sporadic, also think Goldenhars syndromes
- Left more common than right
- Females > Males
- Watch also for vertical pull, leashing phenomenon
- Occasional absent CN6 nucleus
Describe syergistic divergence (paradoxical abduction)?
- Abduction occurs when attempting to adduct the eye
- Cosmetically poor but rare – also difficult to treat
- Caused by innervation of LR 3rd nerve & concurrent poor innervation of MR by same nerve
- Causes LR to act more than MR when attempting to adduct
What are the key pictures of Duane’s Retraction Syndrome?
- Palpebral aperture widens as px attempts to abduct
- Globe retraction of adduction (key point) – palpebral aperture decreases
o They become endopthalmic instead of proptotic - Can be unilateral or bilateral
What will the patient also have if they have Duane’s Retraction Syndrome?
What do you know if the ductions = version in Duane’s Retraction Syndrome?
Duane’s – parents looked at eye and they are not sure with what is wrong but they think eyes are not straight
If have Duane’s retraction syndrome – you can have other syndromes too look for low set ear or webbing of the neck
If ductions = versions –> proves it is mechanical
- 6th nerve palsy will not have binocular single vision in PP
- No changes in lid features in a 6th nerve palsy – but will in Duane’s
Palpebral aperture narrows –> ~6mm
What are the aims of investigations into Duane’s Retraction Syndrome?
o Diagnose type of Duane’s Syndrome
o Document all motility defects & any other sign
o Establish level of binocular vision
o Gather clinical information to determine management plan
What are the clinical test into Duane’s Retraction Syndrome?
- Case History:
o Birth history – prematurity, birth weight, development
o Family history – developmental anomalies, Duane’s
o General health – developmental anomalies
o Signs/symptoms – diplopia, strabismus, AHP, abnormal OM - Refraction, fundus & media check:
o Worth correcting small amounts of hypertropia if esodeviation present
o Fundus check to ensure no colobomata
o Media check for congenital cataracts, hyaloid artery remnant, pupillary abnormalities etc - Observe your px carefully for facial anomalies
- VA – although amblyopia rare due to nature of condition
- CT – strabismus surprisingly uncommon
o Type I: Esotropia/phoria or orthotropic
o Type II: Exotropia/phoria or orthotropic
o Type III: Pretty much anything but most likely orthotropic
o Do CT w/ & w/o AHP
May or may not be able to take up fixation to midline - OM – look for all signs, not all may be present
o Motility findings determine the type of Duane’s present - Lees:
o Squashed field & overaction of contralateral synergist muscles (i.e. mechanical restriction)
o Up & downdrifts on adduction
o May need to tape lid up when doing adducted positions due to retraction - Convergence:
o May be reduced due to restriction - Binocular functions – (w/ & w/o AHP if they can control deviation successfully)
o Horizontal fusional amplitudes: base in & base out
o Stereoacuity - Measure angle of deviation (w/ & w/o AHP):
o PCT if they can take up fixation to midline
o If they cannot, use Krimsky’s test (pen torch fixation target & equalise corneal reflections through prism), synoptophore (equalise or corneal reflections by moving synoptophore arm) or Hess chart
o Big secondary deviation when fixating w/ unaffected eye aim to neutralise movement in eye under prism - AHP
What is the management of Duane’s Retraction Syndrome?
- Aims:
o Refer or not?
o Restore or strengthen BV
o Treat amblyopia if present
o Reduce AHP if uncomfortable or musculoskeletal changes occurring - Referral:
o If 1st time being diagnosed, refer to hospital for screening for developmental anomalies
o If poor cosmesis, binocular function compromised or uncomfortable AHP & conservative management options fail, refer to discuss surgical options
o Otherwise can manage within practice - Amblyopia:
o Amblyopia infrequent due to adoption of AHP to preserve BV
o If amblyopia present, treat with short doses of occlusion spaced throughout the day to reduce chance that deviation will decompensate - Alignment:
o Usually best to leabe well alone – often well controlled with head movements & slight AHP that does not cause any discomfort
o Practical advice e.g. positioning of objects away from affected side can help w/ everyday life
o If decompensating despite use of AHP or AHP is uncomfortable:
Try Fresnel prism to reduce deviation in PP – blurs VA dependent on strength – if helpful then surgery will make a difference & better long-term option
Use yoke prism to reduce head posture - If all these fails, refer to discuss surgical options
- Surgery:
o Muscle function cannot be restored – have to compensate instead
Up/downshoots: Y-split LR muscle & recess it
Retraction: recess MR as well as LR, or disinsert LR & fix to orbital wall
PP deviation: recess LR is exotropic, MR if esotropic
If recessions don’t improve motility, transposition of vertical recti can replace LR function (more common in bilateral Duane’s)
