Lateral Medullary Infarction Presenting as Opalski Syndrome Associated with Headache Attributed to Orthostatic Hypotension.

Lateral medullary infarction is rarely associated with Opalski syndrome and autonomic dysfunction. Herein, we present the first case involving a 66-year-old patient with cancer who developed mild dysarthria, left-sided Horner's syndrome and lower limb-dominant ataxic hemiparesis, reduction in right-sided painful thermal sensation, and severe truncal ataxia, followed by orthostatic headache. The Schellong test revealed severe orthostatic hypotension. The patient was diagnosed with Opalski syndrome associated with headache attributed to orthostatic hypotension caused by the cerebral infarction in the caudal part of the lateral medulla oblongata. The patient's headache had poor response to analgesics. However, it resolved with orthostatic hypotension improvement.