Duane's syndrome
 

In the examination, this condition may be easily misdiagnosed as sixth nerve palsy. In Duane's syndrome, the main  feature being narrowing of the palpebral fissure on adduction and globe retraction. In classical Duane's syndrome (type I). The affected eye has limited abduction but normal adduction. There is narrowing  of the palpebral fissure on adduction. The affected globe retracts on adduction (you need to examine from the side to see  this well). Other features commonly seen include up-shooting or down-shooting when the eye is adducted. Both A and V  pattern may be seen on vertical eye movement. Other features: Remember that 20% of cases are bilateral Type II Duane's syndrome: reduced adduction but normal abduction Type III Duane's syndrome: reduced abduction and adduction Associated features: Goldenharg's syndrome Deafness Klipper-Fleil's syndrome (in which there is failure of the scapula to descend)

Questions:

1. What is the proposed pathogenesis of Duane's retraction syndrome?

answer
It is a congenital condition in which there is failure of the sixth nerve to innervate the lateral rectus. Instead, the lateral rectus is innervated by the oculomotor nerve through aberrant innervation. The retraction of the eye is due to cocontraction of the medial and lateral rectus muscles, and this cocontraction can also cause a peculiar upshoot or down shoot of the affected eye on attempted adduction. Aplasia of the abducens nerve has been found in post-mortem specimen.

2. The mother of a child with Type I Duane's syndrome wants you to correct the ocular appearance of her child
    because 'he looks odd on looking to the side'. How would you manage the request?

answer
The management of Duane's syndrome is conservative. The mother should have the condition explained and told that surgery is unlikely to alter the appearance. The patient should have regular orthoptic assessment to make sure he has normal binocular vision.
Surgery is only indicated is there is deviation in the primary position but this is uncommon. The other indication for surgery is if there is significant overshooting or downshooting on adduction.
 

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