Atypical Presentation of an Internal Capsule Infarct With Isolated Acute Confusion: A Case Report

Stroke of the internal capsule characteristically presents with pure motor or sensory deficits from the disruption of the corticospinal and thalamocortical fibers. However, specific involvement of several subcortical pathways can result in cognitive rather than motor or sensory presentations. We report the case of a 70-year-old woman presenting with acute confusion and word-finding difficulty. Computed tomography (CT) of the brain was reported as negative for acute ischemia or hemorrhage, but magnetic resonance imaging (MRI) demonstrated an acute infarct involving the posterior limb of the left internal capsule with extension into the medial temporal lobe and caudate nucleus. The patient's cognition improved rapidly, and she was discharged on anticoagulation and secondary prevention for concurrently diagnosed atrial fibrillation. This case stresses that subcortical infarcts can produce isolated cognitive symptoms. Recognition of atypical presentations is essential, with early MRI facilitating timely diagnosis, leading to the correct management with anticoagulation, rate control, and secondary prevention.