Spontaneous consecutive Brown syndrome following superior oblique palsy

A 28-year-old female presented with a left trochlear nerve palsy, after indirect head trauma, with no fracture or orbital lesion. She had diplopia, a hypertropia and excyclotropia on right downgaze. Three months later the trochlear palsy had been replaced by Brown's syndrome: a deficit of elevation in adduction, with diplopia, incyclotropia and hypertropia in up-gaze. The Brown syndrome remained the same over a period of 18 months. A 31-year-old male suffered from severe brain contusion with intracerebral haemorrhage and bilateral trochlear nerve palsy. Three years later, he had a bilateral trochlear palsy with bilateral severe Brown's syndrome, with a right hypertropia and 10° to 25° incyclotropia in upgaze and 5° to 10° excyclotropia in downgaze. The field of binocular vision was shifted to left gaze. Orbital CT scan was normal. At surgery, the forced duction test was positive for Brown's syndrome on both sides and the tendon of the superior oblique muscle of the right eye was thickened. The field of binocular vision was centralized after surgery but torsional diplopia in upgaze and downgaze was present as before. Secondary Brown's syndrome after (persisting or vanishing) trochlear nerve palsy without any direct trauma to the superior oblique muscles or the orbit could be caused by a fibrotic reaction of the superior oblique tendon or adjacent structures. This could be due to inactivity or to indirect trauma.