Normal Pressure Hydrocephalus | Mechanism, Pathophysiology and Differentials

Beatrice is 78. A year of shorter steps, two falls, and a rush to the bathroom. Her CT report says "enlarged ventricles, consistent with age-related atrophy." Is it just age? How normal pressure hydrocephalus happens: fluid that can't be absorbed over the brain, the DESH footprint it leaves, and why the walk, a frontal kind of slowness and an urgent bladder follow (and what we still don't know about the mechanism). Then the look-alikes: Alzheimer's, Parkinson's and Lewy body disease, white-matter changes, healthy ageing and secondary causes. The tap test closes the case. CHAPTERS 0:00 The hook 0:20 The question 0:44 Where the fluid goes 1:13 The footprint on the scan 1:38 Why she walks this way 2:11 Mind and bladder 2:34 Look-alike one: Alzheimer's 3:05 Look-alike two: Parkinson's 3:34 Look-alike three: the rest 3:58 The test, and how it ended 4:28 Three to take home 5:01 Comment and close YOUR TURN A 75-year-old with small steps walks much better when he steps over lines taped on the floor, and he has a resting tremor. Which diagnosis moves up your list, and why? ABOUT THIS VIDEO Independent educational content for medical students and trainees. The patient is fictional. This is not medical advice and does not replace clinical judgment, supervision, or current local guidelines. REFERENCES 1. Nakajima M, Yamada S, Miyajima M, et al. Guidelines for Management of Idiopathic Normal Pressure Hydrocephalus (Third Edition): Endorsed by the Japanese Society of Normal Pressure Hydrocephalus. Neurol Med Chir (Tokyo) 2021;61(2):63-97. https://doi.org/10.2176/nmc.st.2020-0292 CREDITS Case, script and drawings are original. Music: "Slow Stride" by isaiah658 (CC0, opengameart.org). Sound effects: Kenney Interface Sounds (kenney.nl), CC0. Handwriting font: Architects Daughter (SIL Open Font License). Rounds Out Loud · Clinical reasoning, one case at a time.