Highlights & Basics
- Normal pressure hydrocephalus is characterized by the clinical features of hydrocephalus (i.e., levodopa-unresponsive gait apraxia with or without cognitive impairment or urinary symptoms), but without significantly raised cerebrospinal fluid pressure.
- Cannot be reliably diagnosed using neuroimaging alone.
- Differential diagnosis includes other causes of parkinsonism and common dementia disorders.
- Responds to ventriculoperitoneal shunting if treated early enough.
- Selection of patients for surgery is challenging as many are considered a high surgical risk.
Quick Reference
History & Exam
Key Factors
Other Factors
Diagnostics Tests
Treatment Options
Definition
Epidemiology
Etiology
Pathophysiology
Images
Approximately 0.5 mL of cerebrospinal fluid is produced by the choroid plexus and is reabsorbed at the arachnoid granulations every minute. However, more important is the bidirectional flow of CSF at the foramen magnum, which in a healthy individual peaks at 4 mL every second and facilitates efficient perfusion of blood in the brain
Normal CT scan in patient with levodopa-unresponsive gait apraxia, emphasizing that the condition is not necessarily a radiologic diagnosis
MRI fluid attenuation inversion recovery (FLAIR) sequence showing periventricular high signal (leukoaraiosis) and central and peripheral brain atrophy
Citations
INPH Guidelines Study Group. Guidelines for the diagnosis and management of idiopathic normal pressure hydrocephalus. Neurosurgery. 2005;57(Suppl 3):S2-1-S2-52.[Full Text]
Halperin JJ, Kurlan R, Schwalb JM, et al. Practice guideline: Idiopathic normal pressure hydrocephalus: Response to shunting and predictors of response: Report of the Guideline Development, Dissemination, and Implementation Subcommittee of the American Academy of Neurology. Neurology. 2015 Dec 8;85(23):2063-71.[Abstract][Full Text]
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24. National Institute for Health and Care Excellence. Lumbar infusion test for the investigation of normal pressure hydrocephalus. June 2008. [internet publication].[Full Text]
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30. Andrén K, Wikkelsø C, Hellström P, et al. Early shunt surgery improves survival in idiopathic normal pressure hydrocephalus. Eur J Neurol. 2021 Apr;28(4):1153-59.[Abstract][Full Text]
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