- Last edited on December 4, 2023
Approach to Normal Pressure Hydrocephalus (NPH)
Primer
Normal-pressure hydrocephalus (NPH) is a neurological condition in which excess cerebrospinal fluid (CSF) occurs in the ventricles, and with normal or slightly elevated cerebrospinal fluid pressure. As the fluid builds up, it causes the ventricles to enlarge and the pressure inside the head to increase, compressing surrounding brain tissue and leading to neurologic and psychiatric symptoms. The etiology of NPH remains poorly understand and diagnosis and management remains controversial to this day.[1]
Comorbidity
Prognosis
- It is thought that even in shunt-responsive patients, improvements are primarily with gait, but cognition may not consequently improve.[4]
Diagnosis
See also:
Diagnostic Criteria for NPH
Adapted from: Fasano, A., Espay, A. J., Tang‐Wai, D. F., Wikkelsö, C., and Krauss, J. K. (2020). Gaps, controversies, and proposed roadmap for research in normal pressure hydrocephalus. Movement Disorders, 35(11), 1945-1954.| International Guidelines (2005) | Japanese Guidelines (2012) | |
|---|---|---|
| Clinical features (Probable) | Gait/balance disturbance and at least 1 of the following:a. Cognitive impairment b. Urinary incontinence/urgency | At least 2 of the clinical triad:a. Gait disturbance b. Cognitive impairment c. Urinary incontinence |
| Clinical features (Possible) | Symptoms of either: a. Incontinence and/or cognitive impairment in the absence of gait/balance disturbance b. Gait disturbance alone | Same as probable |
| Brain imaging (Probable) | Ventriculomegaly (EI > 0.3) and at least 1 of the following:a. Narrow callosal angle b. Enlargement of the temporal horns c. Periventricular signal changes not attributable to ischemic changes or demyelination | Ventriculomegaly (EI > 0.3) and narrowing of the sulci over the high convexity, or presence of disproportionately enlarged subarachnoid space hydrocephalus (DESH) |
| Brain imaging (Possible) | Ventriculomegaly (EI > 0.3) | Ventriculomegaly (EI > 0.3) |
| Duration of symptoms | >3 months | N/A |
| Age | >40 years | >60 years |
| Comorbidities | No other condition | Other neurological condition possible (but “mild”) |
| Opening pressure | 70–245 mm H2O | ≦200 mm H2O |
Classic Triad
- The classic NPH triad consists of gait deviation, dementia, and urinary incontinence (commonly referred to as “wet, wacky, and wobbly” or “weird walking water”). However, this true pathognomonic triad is only present in less than 25% of cases.[5] Gait deviations are present in nearly all patients and usually the first symptom.
- Notably, the urinary symptoms often begins as polyuria or urgency rather than true incontinence.[6]
Psychiatric Symptoms
- Individuals with NPH can have non-specific symptoms including psychiatric syndromes.
- Case reports have identified frontal lobe deficit symptoms, such as apathy, somnolence, personality changes, anxiety, depression, psychosis, obsessive compulsive symptoms, Othello syndrome (delusional jealousy), shoplifting, and mania.[7][8][9]
Approach
Physical Exam
"Magnetic Gait"
Magnetic Gait
YouTube: Classic NPH Gait Pre-Shunt Surgery- A classic “magnetic gait” can be seen in NPH, and this gait is often described as if one's feet were “stuck to the ground.”[11]
Differential Diagnosis
- Combinations of ventriculomegaly, dementia, and factors affecting gait (e.g. - cervical spondylosis, large joint arthritis, peripheral neuropathy, impaired vision, vestibular dysfunction, and antipsychotics)
- Vascular dementia, including subcortical ischemic encephalopathy or Binswanger’s disease
- Parkinsonian syndromes (dementia with Lewy bodies, corticobasal degeneration, progressive supranuclear palsy, and multiple system atrophy)
- Frontotemporal dementia with caudate atrophy
Investigations
Neuroimaging
See also:
- Neuroimaging findings suggestive of NPH include vertex crowding and callosal angle narrowing.
- Disproportionately Enlarged Subarachnoid-space Hydrocephalus (DESH) is a feature of NPH that is often not well known or recognized.[12]
- DESH is characterized by a pattern of “tight high-convexity and medial subarachnoid spaces, and enlarged Sylvian fissures with ventriculomegaly (on coronal imaging view), this is also described as sulcal effacement.[13]
- In contrast, a normal appearance involves the presences of grooves (sulci) on coronal view.
- Radiological reports may report “ventriculomegaly” if there are dilated ventricles, but this should only be called if DESH is present, otherwise, it should be called generalized volume loss
- DESH can also be misinterpreted as cortical atrophy and misdiagnosed as neurodegenerative disease.[14]
- Combined with the clinical signs of NPH, DESH appears to be a robust imaging finding for NPH that can in predict whether the NPH will be shunt-responsive.[15]
- Remember also that ventricles do increase in size with age.[16]
Treatment
- A trial of a large volume lumbar puncture and observing for improvement in gait and cognition is one way of treating NPH temporarily
- A ventriculoperitoneal (VP) shunt is the preferred long-term treatment solution for patients that can tolerate surgery
- VP shunts are a thin plastic tube that helps drain extra cerebrospinal fluid (CSF) from the brain
Resources
Research
References
1)
Fasano, A., Espay, A. J., Tang‐Wai, D. F., Wikkelsö, C., & Krauss, J. K. (2020). Gaps, controversies, and proposed roadmap for research in normal pressure hydrocephalus. Movement Disorders, 35(11), 1945-1954.
2)
Román, G. C., Verma, A. K., Zhang, Y. J., & Fung, S. H. (2018). Idiopathic normal-pressure hydrocephalus and obstructive sleep apnea are frequently associated: A prospective cohort study. Journal of the neurological sciences, 395, 164-168.
3)
Román, G. C., Jackson, R. E., Fung, S. H., Zhang, Y. J., & Verma, A. K. (2019). Sleep-disordered breathing and idiopathic normal-pressure hydrocephalus: recent pathophysiological advances. Current neurology and neuroscience reports, 19(7), 1-9.
4)
Koivisto, A. M., Alafuzoff, I., Savolainen, S., Sutela, A., Rummukainen, J., Kurki, M., ... & Kuopio NPH Registry (www. uef. fi/nph). (2013). Poor cognitive outcome in shunt-responsive idiopathic normal pressure hydrocephalus. Neurosurgery, 72(1), 1-8.
5)
Boon, A. J., Tans, J. T. J., Delwel, E. J., Egeler-Peerdeman, S. M., Hanlo, P. W., Wurzer, H. A., & Hermans, J. (2000). The Dutch Normal-Pressure Hydrocephalus Study: How to select patients for shunting? An analysis of four diagnostic criteria. Surgical neurology, 53(3), 201-207.
6)
Conn, H. O. (2007). Normal pressure hydrocephalus: a case report by a physician who is the patient. Clinical medicine, 7(3), 296.
7)
Oliveira, M. F., Oliveira, J. R., Rotta, J. M., & Pinto, F. C. (2014). Psychiatric symptoms are present in most of the patients with idiopathic normal pressure hydrocephalus. Arquivos de neuro-psiquiatria, 72, 435-438.
8)
Price, T. R., & Tucker, G. J. (1977). Psychiatric and behavioral manifestations of normal pressure hydrocephalus: A case report and brief review. Journal of Nervous and Mental Disease.
9)
Lindqvist, G., Andersson, H., Bilting, M., Blomstrand, C., Malmgren, H., & Wikkelso, C. (1993). Normal pressure hydrocephalus: psychiatric findings before and after shunt operation classified in a new diagnostic system for organic psychiatry. Acta Psychiatrica Scandinavica, 88(S373), 18-32.
10)
Noble, D. J., Scoffings, D., Ajithkumar, T., Williams, M. V., & Jefferies, S. J. (2016). Fast imaging employing steady-state acquisition (FIESTA) MRI to investigate cerebrospinal fluid (CSF) within dural reflections of posterior fossa cranial nerves. The British Journal of Radiology, 89(1067), 20160392.
11)
Mori, E. (2008). Gait disturbance in idiopathic normal pressure hydrocephalus. Brain and nerve= Shinkei kenkyu no shinpo, 60(3), 219-224.
12)
McCarty, A. M., Jones, D. T., Dickson, D. W., & Graff-Radford, N. R. (2019). Disproportionately enlarged subarachnoid-space hydrocephalus (DESH) in normal pressure hydrocephalus misinterpreted as atrophy: autopsy and radiological evidence. Neurocase, 25(3-4), 151-155.
13)
Mangalore, S., Vankayalapati, S., & Gupta, A. K. (2021). Hydrocephalic Dementia: Revisited with Multimodality Imaging and toward a Unified Imaging Approach. Journal of Neurosciences in Rural Practice, 12(02), 412-418.
14)
McCarty, A. M., Jones, D. T., Dickson, D. W., & Graff-Radford, N. R. (2019). Disproportionately enlarged subarachnoid-space hydrocephalus (DESH) in normal pressure hydrocephalus misinterpreted as atrophy: autopsy and radiological evidence. Neurocase, 25(3-4), 151-155.
15)
McCarty, A. M., Jones, D. T., Dickson, D. W., & Graff-Radford, N. R. (2019). Disproportionately enlarged subarachnoid-space hydrocephalus (DESH) in normal pressure hydrocephalus misinterpreted as atrophy: autopsy and radiological evidence. Neurocase, 25(3-4), 151-155.
16)
Kwon, Y. H., Jang, S. H., & Yeo, S. S. (2014). Age-related changes of lateral ventricular width and periventricular white matter in the human brain: a diffusion tensor imaging study. Neural regeneration research, 9(9), 986.