dunes retraction syndrome Flashcards
what are the features of duanes
congenital (case reports) but rare
limited abduction
limited adduction common though may not be present
retraction of globe and narrowing of peripheral fissure on adduction
can be unilateral or bilateral
what happens when you widen the palpebral fissure
limited adduction when the palpebral fissure is widened
bsv in primary position
what globe changes happen in duanes
retraction of the globe
protrusion of the globe
what are other features of duanes
possible features
ahp - usually face turn to achieve bsv
updrift or downdraft on adduction
defective convergence
positive force duction test (dependent on ateiology and duration)
unilateral more common in females
bilateral - more common in males -
what are the 3 types of browns
type a - marked limitation of abduction but less adduction
type b - limited abduction but normal adduction
type c - limited adduction which exceeds the limitation of abduction
what are the mri findings for each type of duanes
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)
(Xia et al 2014)
what are the associations between duanes and splitting of the lateral rectus
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
2/5 pts with DRS showed split LR
how are supra nuclear and infranuclear defects associated with drs
Findings at autopsy:1) Absence of cell bodies of 6th nerve
2) Absence of nerve itself
Supply to LR from inferior division 3rd nerve
Fibrosis present where LR has poor innervation
Association with other conditions:
Marcus Gunn, Crocodile tears and unilateral abducting nystagmus
Combination of absence of nerve and absence of innervation - Mechanical Fibotic syndromes to Congenital Cranial Dysinnervation discorders (CCDD) of which Duane’s is the most common, followed by CFEOM
is their a heditary aspect to duanes retraction syndrome
reports of families and evidence of a genetic basis
large cohorts of ccdd in some parts of the world e.g. Saudi Arabia
25/110 affected in one extended family
monozygotic twins concordant and discordant for duanes reported
is their a heditary aspect to duanes retraction syndrome
reports of families and evidence of a genetic basis
large cohorts of ccdd in some parts of the world e.g. Saudi Arabia
25/110 affected in one extended family
monozygotic twins concordant and discordant for duanes reported
is their a genetic basis for duanes
DURS1 – location Chr 8q13 (Vicent et al, 1994)
Multiple patients mapped to this gene.
Complexity of cytogenetic causes.
DURS2 – CHN1 gene – Chr 2q31.1 (Miyake et al, 2008)
Autosomal Dominant
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
what genes are involved in the development of duanes
DURS3 – MAFB gene – Chr 20q12 (Park et al, 2016)
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
Duane-Radial Ray Syndrome (DRRS/Okihiro syndrome) – SALL4 Gene Chr:20q13.2 (Al-Baradie et al, 2002)
Autosomal Domiant
DURS with hand and upper extremities
Variable expression of cardiac, renal, hearing and vertebral abnormalities in addition to DURS
HOXA1 Chr: 7p15.2 (Tischfield et al, 2005)
Bosley-Salih-Alorainy Syndrome
Athabaskan brainstem dysgenesis syndrome
what are some possible reasons for retraction of the globe on adduction and narrowing of palpebral fissures
Retraction of the globe on adduction
Inelasticity of LR
Co-contraction MR and LR
Anomalous insertion MR
SR and IR try to help to adduct
Narrowing of palpebral fissure
Mechanical ptosis due to retraction of globe
Decrease in electrical activity of levator
what are reasons for profusion and widening of palpebral fissure and updrift or downdraft on adduction
profusion and widening of palpebral fissure
Inhibition MR
Co-relaxation
SO and IO trying to aid abduction
Mechanical effect of lid
updrift or downdraft on adduction
what are the possible reasons for a or v or x patterns
changes in innervation to lateral rectus on elevation or depression
how likely is acquired duanes retraction syndrome
very rare
tumour in 4th wall ventricle (case report)
report of skull base meningioma
differential diagnosis
traumna
mechanical cause e..g thyroid eye disease , myositis , neoplasms
neurogenic palsies
congenital esotropia
how would you manage duanes retraction syndrome
correct refractive error
treat any amblyopia
observation
prisms
botulinum toxin
surgery if marked ahp
decompensating
unaaccpetbale appearance of deviation of retraction
diplopia which is troublesome
how is botulinum toxin used diagnostically
To ascertain if likely to reduce AHP and or increase field of BSV to reduce symptoms
how is botulinum toxin used therapeutically
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)
when is surgery indicated for duanes
Based on:
Deviation – ET vs XT
Size of AHP
Severity of Globe retraction and overshoots
Degree of limitations
FDT
Extent of Field of BSV
what surgery is indicated if they have esotropia In primary position
MR recession of affected eye
Large contralateral recession of unaffected eye (-2 or better) caution with large co-contraction
Large deviation or bilateral duanes, 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)
what surgery is indicated if they have a exotropia in primary position
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
how would you surgically correct globe retraction and overshoots with surgery
Globe retraction
Mild globe reaction, can be MR recess and resection of LR, if severe recess both MR and LR
Overshoots
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
if someone has duanes estortopia and there globe retraction is. more than 50 % then what surgery is perfumed
lateral rectus recession
if someone has duanes and they have a ahp and a primary positon angle is more than 20 degrees
medial rectus recession
vertical recti transposition and foster suture
if it less than or equal to 20 degrees than medial rectus recession and vertical recti transposition
if someone has a up or down shoot what surgical procedure will be done
mechanical
lateral rectus recession and y split
innervational - vertical rectus recession
