Vertical Strabismus and Positive Bielschowsky Head-Tilt Test: Atypical Presentation of a Maxillary Mucocele

Abstract Test of skew has become a cornerstone in the approach of a patient with vestibular symptoms but a detected vertical misalignment may be caused by an oculomotor disturbance and not a skew deviation. We report the case of an elderly patient with a 1-month history of dizziness and visual disturbance that revealed on bedside examination a spontaneous left head-tilt and a pathologic alternate cover test, with right eye hypertropia and excyclotorsion, worse with right head-tilt. Dizziness was assumed to have a visual origin with unrecognized binocular diplopia, caused by an acquired right eye superior oblique muscle palsy. However, imaging revealed a right maxillary mucocele that eroded the orbit floor into the orbit. The change of the intraorbital component of the maxillary fluid-filled mass with head-tilt through a dehiscent orbital floor may explain the findings of vertical strabismus and positive Bielschowsky head-tilt test in this case. Endoscopic treatment improved symptoms and findings.