Oculomotor Palsy in a Subject with Thalamic Infarction: A Case Report

Abstract

The thalamus is a highly complex nuclear structure comprising approximately 50–60 distinct nuclei, strategically positioned between the cerebral cortex and the midbrain. It plays a pivotal role in regulating sensory pathways, motor integration, consciousness, sleep, and cognitive functions. Through its vast interconnections, the thalamus serves as a key hub for neurocommunication, facilitating signal relay between cortical and subcortical areas.

This case report presents a rare instance of paramedian thalamic infarction selectively involving the dorsomedial nucleus of the thalamus, manifesting clinically as isolated oculomotor nerve palsy. Such presentations challenge conventional understanding of oculomotor dysfunction, which is typically attributed to midbrain lesions. The absence of brainstem involvement in this patient highlights the diagnostic importance of thalamic pathology in neuro-ophthalmologic syndromes. Our objective was to examine the visual and oculomotor manifestations associated with this atypical vascular event and assess clinical outcomes from an ophthalmologic standpoint. Key features analyzed include gaze abnormalities, ptosis, skew deviation, and pupillary asymmetry, all of which carry significant implications for quality of life and functional independence. The findings underscore the need for comprehensive neuro-ophthalmologic evaluation in cases of deep brain infarction, particularly those involving paramedian thalamic territory.

This report contributes to the growing recognition of thalamic strokes as important etiological factors in oculomotor dysfunction and provides insights into their clinical trajectory, prognostic markers, and rehabilitative strategies. Given their potential to mimic brainstem pathology, accurate early identification is essential for guiding neurorehabilitation and improving patient outcomes.