View source for Normal pressure hydrocephalus

==Background==
*Possible reversible cause of dementia
*CSF buildup in the ventricles leading to increased intracranial pressure with edema of the periventricular white matter and corona radiata
**Sacral motor nerve fibers that produce gait instability; incontinence ensues when compressed

==Clinical Features==
*Gait disturbance is most common and earliest finding
**"Glue-footed" gait: move slowly, take small steps, often wide base, with difficulty turning
*Memory loss and [[dementia]] symptoms may be mild, subtle
*[[urinary incontinence|Incontinence]] is usually later stage, though sensation of urinary urgency is usually present before incontinence
*Usually do ''not'' have symptoms of increased intracranial pressure, such as headache, nausea, vomiting, visual loss

==Differential Diagnosis==
*[[Alzheimer's]]
*[[Stroke]]
*[[Parkinson's disease]]
*[[Electrolyte abnormality]]
*[[brain tumor|Malignancy]]
*[[uremia|Uremic encephalopathy]]
*Hydrocephalus ex vacuo (diffuse cerebral atrophy on CT)

==Evaluation==
*Initial ED workup
**CBC
**Chem 7
**[[CT brain]] non-con: Ventriculomegaly without signs of obstruction at the level of the third or fourth ventricles
*Additional workup (in coordination with neurology/neurosurgery), consider:
**MRI (done as part of the general work-up, and should be done before LP)
**[[LP]] (definitive diagnosis), with normal opening pressure and CSF studies 
***Symptom improvement supports diagnosis<ref name="medscape">Schneck MJ. Normal pressure hydrocephalus. [http://emedicine.medscape.com/article/1150924-overview Medscape. Retrieved 8/4/2016]</ref>

===Normal pressure hydrocephalus vs brain atrophy<ref> Ishii M, Kawamata T, Akiguchi I, Yagi H, Watanabe Y, Watanabe T, Mashimo H (March 2010). "Parkinsonian Symptomatology May Correlate with CT Findings before and after Shunting in Idiopathic Normal Pressure Hydrocephalus". Parkinson's Disease. 2010: 1–7. doi:10.4061/2010/201089. PMC 2951141. PMID 20948890.</ref>===
{|class="wikitable"
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! Normal pressure hydrocephalus !! Brain atrophy
|-
|  |
|align="center"|[[File:Normal pressure hydrocephalus versus atrophy, NPH.jpg|335px]]
|align="center"|[[File:Normal pressure hydrocephalus versus atrophy, CA.jpg|333px]]
|-
| Preferable projection ||colspan=2| Coronal plane at the level of the posterior commissure of the brain.
|-
| Modality in this example || CT || MRI
|-
| CSF spaces over the convexity near the vertex (red ellipse) || Narrowed convexity ("tight convexity") as well as medial cisterns || Widened vertex (red arrow) and medial cisterns (green arrow)
|-
| Callosal angle (blue V) || Acute angle || Obtuse angle
|-
| Most likely cause of leucoaraiosis (periventricular signal alterations, blue arrows)
| Transependymal [[cerebrospinal fluid]] diapedesis
| Vascular encephalopathy, in this case suggested by unilateral occurrence
|}
[[File:CT of Evan's index.jpg|thumb|Evan's index is the ratio of maximum width of the frontal horns to the maximum width of the inner table of the cranium. An Evan's index more than 0.31 indicates hydrocephalus.<ref>hii M, Kawamata T, Akiguchi I, Yagi H, Watanabe Y, Watanabe T, Mashimo H (March 2010). "Parkinsonian Symptomatology May Correlate with CT Findings before and after Shunting in Idiopathic Normal Pressure Hydrocephalus". Parkinson's Disease. 2010: 1–7. doi:10.4061/2010/201089. PMC 2951141. PMID 20948890.</ref>]]

==Management==
*Fall precautions
*Consult neurology and/or neurosurgery to decide if patient is candidate for inpatient vs outpatient MRI and LP.
*LP is rarely done in the ED as it requires MRI before LP, and workup is typically non-emergent and can often be done as outpatient.

==Disposition==
*Workup typically is extensive, but can often be done as outpatient, depending on your institution.
*Decide plan for workup with neurology and/or neurosurgery
*Consider admission if patient lives alone (fall risk), has no follow-up, or is significantly altered.

==Also See==
*[[Stroke (Main)]]
*[[Ataxia]]
*[[Parkinson's Disease]]

==References==
<references/>
[[Category:Neurology]]