Approach to the evaluation of a patient with possible normal pressure hydrocephalus (NPH)

MRI: magnetic resonance imaging; DESH: disproportionately enlarged subarachnoid space hydrocephalus; OP: opening pressure; ICP: intracranial pressure; CSF: cerebrospinal fluid.
* Signs and symptoms of increased ICP, such as headaches, nausea/vomiting, papilledema, and visual loss, are not consistent with NPH and suggest an alternative diagnosis and need for additional evaluation beyond the scope of this algorithm.
¶ Examples include cervical or lumbar spondylosis, vestibular dysfunction, osteoarthritis, deconditioning, visual impairment, peripheral neuropathy, and medication side effects.
Δ Typical neuroimaging findings for NPH include:

• Absent or modest cortical and hippocampal atrophy
• Disproportionately enlarged subarachnoid space hydrocephalus (DESH)

Refer to UpToDate topic review on NPH for further additional details and imaging examples.
◊ Focally entrapped fluid in sulci, which is seen in DESH, should not be confused with cortical atrophy and ex vacuo hydrocephalus.
§ High-volume lumbar puncture is generally sufficient, although some clinicians and centers prefer lumbar drain trial. CSF should be analyzed for cell count, differential, total protein, and glucose. Refer to UpToDate topic reviews for additional details.
¥ Unfavorable prognostic factors for response to shunting include early appearance of cognitive impairment in relation to other symptoms, moderate to severe dementia, dementia present for >2 years, gait disorder absent or appearing after onset of dementia, alcoholism, marked white matter disease, and diffuse sulcal enlargement (cortical atrophy) and/or hippocampal atrophy.