Feed

Creutzfeldt-Jakob disease (CJD) is a rare, rapidly progressive, fatal prion disorder that may initially mimic delirium, metabolic encephalopathy, psychiatric illness, or more common neurodegenerative conditions. Diagnostic recognition is particularly difficult when an acute medical illness provides an apparently plausible explanation for confusion. We report the case of a 74-year-old woman with insulin-dependent diabetes mellitus who was admitted after being found collapsed at home with vomiting and was diagnosed with diabetic ketoacidosis (DKA). Although the metabolic disturbance resolved, collateral history revealed several months of progressive dizziness, gait instability, recurrent falls, and visual hallucinations. During admission, she developed worsening cognitive decline, ataxia, myoclonus, reduced speech output, functional dependence, and eventual incontinence. Initial brain imaging was not diagnostic; however, neuroradiology review identified subtle basal ganglia and thalamic signal abnormalities on diffusion-weighted imaging (DWI) and fluid-attenuated inversion recovery (FLAIR) sequences. Cerebrospinal fluid (CSF) real-time quaking-induced conversion (RT-QuIC) testing returned positive, supporting the diagnosis of sporadic CJD. This case highlights the importance of reconsidering apparent delirium when neurological decline progresses despite correction of metabolic disturbance or exclusion of infection. Progressive cognitive impairment with hallucinations, ataxia, and myoclonus should prompt evaluation for rapidly progressive dementia, including sporadic CJD.