Torsipulsion, a useful diagnostic sign in lateral medullary infarction

Abstract

A number of ocular motility disturbances such as skew deviation, saccadic/smooth pursuit abnormalities, Horner's syndrome, and nystagmus have been reported in lateral medullary infarction. We report 3 patients who had torsipulsion as the main ocular movement abnormality directly attributable to lateral medullary infarction. Patients 1 and 2 had a clockwise torsional movement that was diagnosed on slit lamp. The movement was elicited on asking the patients to make a horizontal saccade. Both patients were noted to have dorsolateral medullary infarction on MRI of the brain. Neither patient had symptoms directly attributable to torsipulsion. Patient No. 3 was referred for non-resolving left 6th nerve palsy. He had infarcts in the left pons, cerebellum and dorsolateral medulla. Torsipulsion was the only ocular motility disorder caused by medullary infarction. Different pathways in the dorsolateral medulla have been implicated in the various ocular motility and neurological abnormalities seen in lateral medullary syndrome. It is possible that sparing of some and involvement of others could result in varied clinical presentations reported in literature. It is important for the ophthalmologist to be aware of torsipulsion as a diagnostic sign of lateral medullary infarction.