Vertical one-and-a-half syndrome in artery of Percheron infarct

A 68-year-old lady with a 5-year history of hypertension was traveling in a bus at night and she slept off.When relatives tried to wake her up at destination, she was found unresponsive.She was taken to a hospital, where she recovered her consciousness in 30 min.On regaining consciousness, she was complaining of binocular vertical diplopia.There was no history of headache, vomiting, dysarthria, oscillopsia, weakness, ataxia, or sensory symptoms.There was no history of any memory impairment.On examination, she was alert and oriented.Her blood pressure was 150/90 mm of Hg and pulse was 80/min and was regular.There was no ptosis.There was bilateral up gaze palsy and impaired infraduction in the right eye.There was upbeat nystagmus on up gaze.Horizontal eye movements were normal.Bells phenomenon and convergence were preserved.Pupils were equal and reacting to light and accommodation.Motor, sensory and cerebellar system examination was normal.Plantars were flexor.Her computerized tomography head was normal.Magnetic resonance imaging of the brain showed acute bilateral paramedian thalamic and right paramedian midbrain infarcts (Figs.123).Magnetic resonance angiography was normal.Biochemical evaluation showed hypercholesterolemia. Bilateral medial thalamic infarcts with the right rostral paramedian mesencephalic infarct suggested right artery of Percheron (AOP) infarct.In view of up gaze palsy, right infraduction impairment and upbeat nystagmus on up gaze suggested the involvement of the rostral interstitial nucleus of the medial longitudinal fasciculus (riMLF) and interstitial nucleus of Cajal (INC) with or without the involvement of posterior commissure.Grard Percheron first described the AOP in 1973.It is a single arterial trunk originating from either proximal posterior cerebral artery and nourishes the bilateral paramedian thalamus and rostral midbrain.This variation is found in between 4% and 12% of the population.AOP infarct usually presents with a triad of symptoms, including altered consciousness, memory deficits, and supranuclear vertical gaze palsies [1].Altered mental status can present anywhere on the spectrum from drowsiness or confusion to hypersomnolence