Unilateral internuclear ophthalmoplegia, strabismus and transient torsional nystagmus in focal pontine infarction.

Vertebrobasilar stroke carries a high mortality rate and can have symptom patterns that are complex and difficult to diagnose. Isolated infarcts of the pons are uncommon and the neuro-ophthalmic presentation of pontine stroke can be quite variable. There is a paucity of cases in the literature documenting neuro-ophthalmic pathology as the sole or primary manifestation of pontine stroke. Here is presented the case of a unilateral internuclear ophthalmoplegia (INO) with concomitant skew deviation, contralesional exotropia and ipsiversive torsional nystagmus as the initial and only presenting feature of an isolated pontine stroke. This case illustrates the need to consider a cerebrovascular event early in the differential of a complex ocular motility disturbance not in keeping with specific cranial nerve palsy. It similarly highlights non-paralytic pontine exotropia and skew deviation as important causes of acute onset acquired strabismus, and transient torsional nystagmus as a rare but relevant localising feature in pontine strokes causing INO. Acute onset of this constellation of signs is highly suggestive of pontine infarction.