[Webino syndrome caused by meningovascular syphilis. A rare entity with an unexpected cause].

CASE REPORT The patient is a 57-year-old obese and hypertensive male. His chief complaints were double vision and dizziness, with mild exodeviation in both eyes in primary gaze position in the ocular motility examination, but more predominant in the left eye. The exotropia was noticeably more evident on the attempted upgaze. On horizontal gaze, the abducting eye deviated fully, but the adducting eye did not cross the midline. Nystagmus in the abducting eye and convergence impairment were found. Pupil size and testing were normal. Ataxia and areflexia were also present. Bilateral internuclear ophthalmoplegia was suspected and imaging and laboratory tests were performed. The CAT scan showed a right occipital hypo-attenuated lesion. In the MRI scan, a mesencephalic subacute ischemic lesion was found, involving the medial rectus sub-nuclei. Blood and cerebrospinal fluid test for syphilis were positive. DISCUSSION Bilateral internuclear ophthalmoplegia is a very uncommon -and difficult to diagnose- condition. In the reported case the lesion involved the medial rectus sub-nuclei. This fact could explain the exotropia in the primary gaze position, and supports that is not possible to exclude the involvement of the medial rectus sub-nuclei in the webino syndrome. The rapid identification of the pathology contributed to the better prognosis of the patient.