Unilateral Duane syndrome

Clinical History

4-year-old female child came with chief complaints of restriction of eye movement on the left side. She was unable to abduct the left eye. Her neurodevelopment was normal.

Imaging Findings

MR imaging with axial 3D gradient nerve sequence revealed absent left abducens (VI) nerve.
Right abducens nerve was normal in course and calibre.
Cerebral parenchyma and orbital sections showed no significant abnormality.

Discussion

Duane syndrome is an eye movement disorder characterised by either restriction or reduced movement in adduction, abduction or both movements of the ipsilateral eye.
According to inability of a particular movement, it has been classified as:
Duane type I which affects abduction movement, Duane type 2 which affects adduction movement, and Duane type 3 which affects both movements [1].
Causes of Duane syndrome are complex with most of the cases being sporadic. Few cases show a familial pattern. Duane syndrome contributes to 1-5 % of the total eye movement disorders with female preponderance [1].
The main pathology seen in absent abducens (VI) nerve, which supplies the lateral rectus muscle. Instead of the abducens nerve, a branch of the oculomotor (III) nerve supplies the ipsilateral lateral rectus muscle [1].
Imaging with MR helps to look for absence of the abducens nerve in this eye movement disorder.
MR imaging is important predominantly with 3D gradient nerve sequence which reveals absent cisternal portion of abducens nerve at pontomedullary sulcus [2].
Treatment of Duane syndrome is symptomatic, either managed conservatively or surgically.
Surgical treatment is recession and transposition of muscle, however, the main pathology of absent abducens nerve cannot be treated. The outcome also depends on associated syndromes like Mobius syndrome, Goldenhar syndrome, Holt-Oram and Okihiro's syndrome [1].
Patients presenting with eye movement disorders should be imaged carefully with thin nerve sequence to differentiate absence of nerve, palsy or orbital pathology.

Differential Diagnosis List

Final Diagnosis

Unilateral Duane syndrome on the left side.

URL:	https://eurorad.org/case/14974
DOI:	10.1594/EURORAD/CASE.14974
ISSN:	1563-4086