Brown's syndrome
 

Left Brown's syndrome.

The main feature is the failure of elevation in the adducted eye.  Additional features:   in the primary position, the affected eye may be hypotropic there may be an abnormal head posture with the head tilt to the affected side, a face  turn to the normal side and chin elevation. there may be slight downshoot of the affected on adduction because of the mechanical effect of  a tight superior oblique tendon that cannot relax on adduction.  widening of the palpebral fissure on adduction and a V pattern Others: the condition is bilateral in 10% of cases the elevation may improve on repeated testing.

Questions:

1. How do you confirm the diagnosis of Brown's syndrome and what is its differential diagnosis?

answer
The forced duction test is useful in confirming the diagnosis. In Brown's syndrome, the forced duction test shows restriction of elevation in adducted position.
The differential diagnosis is of conditions that can affect the vertically acting muscles:
blow out fracture
thyroid eye disease
inferior oblique palsy
double elevator palsy
myasthenia gravis

2. What are the causes of Brown's syndrome?

answer
Congenital
tight superior oblique anterior tendon sheath
short superior oblique muscle and tendon
nodule on superior tendon
anomalous innervation
Acquired
inflammation such as rheumatoid arthritis
trauma
surgery such as superior oblique plication

3. How would you advise a mother with regard to her child with an unilateral congenital Brown's syndrome?

answer
In congenital Brown's syndrome without significant abnormal head posture or abnormal binocular vision. Observation is all that is needed, the condition becomes less obvious as the child grows due to the reduced need to look up (unless the child grows into a short adult). In patients with abnormal head posture or abnormal binocular vision due to ocular deviation, the treatment option includes tenectomy or tenoctomy of the superior oblique muscle but the mother should be warned ofthe unpredictable success rate.

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