Patient with Sudden Onset Atraumatic Diplopia

A 74-year-old man with a past medical history significant for hypertension and active tobacco use disorder had sudden onset vertical and horizontal double vision 7 months ago. He denied preceding head trauma or substance use. He had had a 2-month history of 16-pound unintentional weight loss. Patient presented with isolated partial Parinaud with supra-nuclear superior gaze palsy and convergence‐retraction nystagmus as a presenting manifestation of PNS with neuronal antibodies directed toward synaptic proteins has not been described in the literature.