To describe a case of presumed end-stage AD that was ultimately diagnosed as NPH and reversed following ventriculoperitoneal (VP) shunt placement.

An 81-year-old woman with a remote traumatic head injury and a 2-year history of subtle cognitive and gait decline presented with acute delirium.  MRI showed ventriculomegaly out of proportion to cortical atrophy. A VP shunt was placed after multidisciplinary review. Given the acute delirium episode in 2025, despite a CSF profile showing elevated p-Tau/Abeta42 ratio (0.083) and low Abeta42 (294 pg/mL) suggestive of AD pathology, her family advocated for a large-volume lumbar puncture (30 mL). Dramatic but transient improvement in cognition and function followed.

Post-shunt, the patient experienced sustained recovery in memory, speech, mood, and independence. She resumed daily activities, including gardening, storytelling, and socializing. Neurology and neurosurgery teams noted her outcome exceeded expectations and influenced future evaluation pathways for elderly patients with mixed cognitive presentations.