The symptoms are insidious and progressive:

• Gait disturbance and/or impaired balance or falls—the gait often described as shuffling with short steps.
• Cognitive decline or mild dementia.
• Bladder urgency that may progress to loss of bladder control.

NPH may be caused by prior injury to the brain, bleeding, infection, tumor, or prior surgery termed secondary NPH. However, the cause is often unknown and termed primary or idiopathic NPH.CSF cushions the brain and brings nutrients to and waste away from the brain. In NPH, the CSF accumulates. To accommodate the increase in CSF volume, the ventricles expand, which compresses the surrounding brain and results in the triad of symptoms.

The Hydrocephalus Association estimates that more than 800,000 Americans have NPH but fewer than 20% receive the diagnosis, as it often goes unrecognized. 1% to 5% of patients with dementia are estimated to have NPH. NPH is one of the few causes of dementia that can be treated.

The diagnosis of NPH may be challenging because the triad of symptoms are common, and each may have multiple causes. In addition, the symptoms may overlap with other common conditions such as Parkinsonism and Alzheimer’s disease. The evaluation by a multidisciplinary team includes:

• Discussion of patient symptoms and physical examination including evaluation of gait. 
• Brain imaging (CT or MRI) and laboratories.
• Lumbar puncture to simulate treatment for NPH and determine shunt responsiveness.