Abulia without Motor Weakness – A Rare Presentation of a Lacunar Unilateral Internal Capsular Infarct

Abstract

Introduction: Typical lacunar strokes arising from lesions of the internal capsule result in pure motor dense hemiplegia, ataxic hemiparesis, clumsy hand-dysarthria syndrome, and capsular warning syndrome. Abulia usually occurs secondary to lesions of the frontal lobe, basal ganglia, or anterior cingulate cortex (Brodmann area 24). Internal capsular infarcts have been only rarely been reported in a few case reports to result in abulia in the absence of any motor deficit. Methods: We report the case of a 40-year-old male presenting with an abrupt onset abulic state without any motor deficit resulting from a right internal capsular infarct. Results: A 40-year-old male patient presented with an abrupt onset abulic state on awakening from an overnight sleep. No motor deficit or corticospinal tract signs were observed. Magnetic resonance imaging brain revealed an acute right internal capsular infarct which was responsible for the acute-onset abulia. The patient had a significant improvement with resolution of the abulia within 2 weeks. Conclusion: Neurologists, psychiatrists, and internists should be aware of this clinical presentation of an abulic or akinetic mute state without any motor deficit which could be easily passed off as a metabolic or toxic encephalopathy or as a psychiatric illness, and a high index of clinical suspicion and appropriate imaging are required to define the appropriate etiology.