Wernicke's encephalopathy unmasking progressive supranuclear palsy and Alzheimer's pathology: a diagnostic challenge in an older adult.

This case highlights the rare coexistence of Wernicke's encephalopathy, probable progressive supranuclear palsy and probable Alzheimer's disease. The patient presented with acute confusion, repeated falls, postural instability, bradyphrenia, apathy and vertical gaze palsy. Clinical examination raised suspicion of overlapping neurological syndromes. Complementary investigations included brain MRI which revealed periventricular hyperintense regions on T2 and on fluid-attenuated inversion recovery (FLAIR) sequences, suggestive of Wernicke's encephalopathy. A subsequent ioflupane (123I) single-photon emission computed tomography (SPECT) scan showed left-sided dysfunction of presynaptic dopamine transporters, supporting a parkinsonian syndrome. Cerebrospinal fluid biomarkers finally demonstrated elevated total and phosphorylated-tau levels and a decreased Aβ42/Aβ40 ratio, consistent with Alzheimer's pathology. Timely intravenous thiamine was initiated. Once the presumed diagnoses were clinically confirmed, multidisciplinary management was implemented, including physiotherapy and caregiver support.This case illustrates how acute syndromes can unmask or exacerbate chronic neurodegenerative conditions, underscoring, in addition to the need for early intervention, the necessity of a thorough clinical approach. This is especially the case in older adults presenting with complex cognitive and motor symptoms.