The Mask of Delirium: Uncovering a Presumed Cardioembolic Stroke Through Comprehensive Clinical Evaluation.

Delirium and aphasia exhibit overlapping clinical features, complicating the diagnosis of acute neurological disturbances in older adults. Both conditions impair communication and orientation, leading to incoherence; however, they arise from distinct pathophysiological mechanisms and require different management strategies. This case concerns an 83-year-old woman with a 48-hour history of acute-onset confusion and abnormal speech. Magnetic resonance imaging (MRI) revealed an acute infarct in the inferior division of the left middle cerebral artery (MCA) territory, with cardioembolism considered the likely cause. Initial assessment attributed her fluent but semantically meaningless speech, inattention, and fluctuating responsiveness to hyperactive or mixed delirium superimposed on probable pre-existing cognitive impairment. New-onset atrial fibrillation (AF) with a controlled ventricular rate was identified, along with elevated high-sensitivity cardiac troponin I concentrations (1026.3 and 1060.5 ng/L) and N-terminal pro-B-type natriuretic peptide (7451 pg/mL) in the context of severe ventricular dysfunction. Treatment for possible acute coronary syndrome was initiated but discontinued after cardiology review. Persistent and stereotyped language abnormalities prompted systematic neurological re-evaluation, which identified a Wernicke-type aphasia profile. Computed tomography (CT) of the head demonstrated a left parietotemporal infarct. Given the 48-hour clinical presentation, MRI was performed to further characterise the lesion and revealed left temporal diffusion-weighted imaging (DWI) hyperintensity with corresponding apparent diffusion coefficient (ADC) hypointensity, confirming acute restricted diffusion in the left temporal lobe. The MRI abnormality corresponded anatomically with the left temporal component of the CT finding, although movement artefact prevented precise lesion co-registration. Echocardiography demonstrated severe biventricular dysfunction with a left ventricular ejection fraction of 15% to 20%. This case underscores the clinical risks of misattributing a structured language disorder to delirium and highlights the importance of focused neurological assessment, including systematic language evaluation, in all older adults presenting with acute confusion.