Multiple variant type thalamic infarcts: pure and combined types.

Abstract

Variant topographic patterns of thalamic infarction with distinct manifestations have been classified into three territories: anteromedian, central, and posterolateral. The purpose of this study was to determine clinical, etiological, and radiological features of multiple variant thalamic infarcts. We reviewed 8400 patients with a first clinical stroke included in the Ege Stroke Registry between 2000 and 2013. Among 80 patients with an acute multiple thalamic infarcts confirmed by MRI, we selected all patients with lesions outside the classical territories and studied their clinical, etiological, and radiological features. Among 8400 patients with first-ever stroke in our registry, 21 patients (26% of all multiple thalamic infarcts) showed infarction outside the classical territories, allowing us to delineate three variant distributions; (i) unilateral multiple variant infarcts [seven patients (9%) in the anteromedian, central, and posterolateral territories] presented with predominantly decreased vigilance (66% with right lesions, 75% with left lesions), cognitive impairment including amnesia (71%), aphasia (57%) in left-sided or bilateral lesions, and executive dysfunction (43%). The most frequent stroke mechanism was cardioembolism (43%). (ii) Bilateral multiple variant infarcts [five patients (6%)], with lesions on the variant territories of the thalamus, resulting in a variety of neurological and neuropsychological signs, consciousness disturbances (80%), sensory-motor deficits (80%). Cardioembolism (60%) was the most frequent etiology. (iii) Combined multiple variant and classical infarcts [nine patients (11%)], characterized by hemihypesthesia (89%) as the most frequent manifestation, followed by hemiataxia (78%), and cognitive deficits. Cardioembolism (56%) and large-artery disease of the vertebrobasilar system (33%) were the main stroke mechanisms. We described multiple variant topographic patterns of thalamic infarction with distinct manifestations and etiologies. We thought that multiple variant infarcts are the result of variation in thalamic arterial supply or reflect a source of embolism.