Intermittent Vertical Diplopia as a Rare Manifestation of a Rare Cerebral Infarct: Artery of Percheron Ischemic Infarct and Sidelights on the Phenotypic Variability of Thalamic Ocular Disorders

Abstract

The thalamus is a complex structure with over 40 named nuclei. Ischemic lesions of the thalamus exhibit a panorama of phenomena ranging from facial numbness to ocular and visual field disturbances to hemiplegia, behavioral disorders, and stupor. It is a dense neuronal hub with a bewildering variety of connections and functions. We present an intriguing case of intermittent vertical diplopia due to an artery of Percheron ischemic infarct of the bilateral paramedian thalami. We seize upon this opportunity to simplify the thalamic nuclei sub-divisions and their vascular supply. In this process, we outline the phenotypic variability of thalamic diplopia and ophthalmoplegia and their various underlying mechanisms.

Keywords: stroke; vision disturbance.

Figure 1. DWI MRI: bilateral mesial thalamic ischemic infarcts implying an artery of Percheron infarct (black arrows)

Color, saturation and hue adjusted to highlight infarcts. DWI - diffusion-weighted images

Figure 2. Thalamic vascular territory: branches from the posterior cerebral artery and posterior communicating artery

P1, P2 - posterior; ANT - anterior; LAT - lateral; MED - medial; Post - posterior The image is reprinted under the Creative Commons Attribution License. Source: [12]

Figure 3. Magnetic resonance angiography: variants of the paramedian artery

Ipsilateral origin on each side (yellow arrow), common origin from one isolated trunk supplying bilateral paramedian nuclei (red arrow), arcade pattern (purple arrow). The image is reprinted under the Creative Commons Attribution License. Source: [14]