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Título

Ocular tilt reaction and vertical gaze palsy due thalamic stroke – a case report

RESUMO

Case report: A 70-year-old-man with uncontrolled hypertension presents at emergency department with sudden diplopia and dysarthria, initiated at home 10 hours late. Neurologic exam showed an upbeat nystagmus, vertical diplopia, vertical supranuclear gaze palsy with normal vestibule-ocular reflex, normal horizontal gaze, mild dysarthria, left head tilt (Bielschowsky sign), right eye with hypertropia, excyclotorsion of the left eye wich was in hypotropia and a comitant skew deviation. There was no more neurological deficits. Fundoscopic exam confirmed the contraversive ocular tilt reaction. A brain MRI study showed acute right paramedian-thalamic infartation. The etiology was atheroembolism and patient received aspirin and statin.

Discussion: Vertical gaze palsy with normal vestibule-ocular reflex suggests supranuclear lesion and probably located at the mesencephalic vertical gaze center. However, this topographic association cannot preserve cranial nerves and at the same time explain a comitant skew deviation, head tilt and the excyclotorsion of the eye in hypotropia, causing a contraversive ocular tilt reaction. There are graviceptives pathways responsible for vestibular tonus (vestibular thalamus) connected with the interstitial nucleus of Cajal, posterior commissure, interstitial nucleus of medial longitudinal fasciculus and Darkschewitsch nucleus (these structures are the vertical gaze center located at mesencephalon). These graviceptives pathways are located at thalamic nuclei of ventral posterolateral nucleus and probably were lesioned by the right paramedian stroke reported in this case.

Final considerations: There are so many different clinical presentations of neurovascular syndromes of thalamus. The clinical and anatomical correlation is difficult and neurologic exam is crucial to topographic diagnosis. This case report aims to get familiar to neurologists a rare presentation of a common disease, for which rapid diagnostic and treatment are important to better patient outcome.

Palavras Chave

thalamus, stroke, ocular tilt reaction