Normal Pressure Hydrocephalus

Overview

Normal pressure hydrocephalus (NPH) is a condition in which excess cerebrospinal fluid (CSF) builds up in the brain, leading to problems with walking, balance, bladder control and thinking. It primarily affects older adults, most commonly people in their 70s and 80s.

CSF is a clear fluid that surrounds the brain and spinal cord. It cushions the brain, delivers nutrients, removes waste and is continuously produced and reabsorbed by the body. In people with NPH, the normal circulation and absorption of CSF becomes impaired, causing the fluid to gradually accumulate and enlarge the brain's fluid-filled spaces (ventricles). Although the pressure of the CSF remains within the normal range, the enlarged ventricles can stretch and compress nearby brain tissue, leading to the characteristic symptoms of NPH.

When recognized early, NPH is one of the few reversible causes of gait impairment and cognitive decline. However, because its symptoms can resemble those of normal aging, Parkinson's disease or dementia, NPH is often underdiagnosed or misdiagnosed. Early evaluation and treatment can significantly improve symptoms and quality of life.

Our approach to NPH

UCSF's Normal Pressure Hydrocephalus (NPH) Clinic brings together experts in neurology and neurosurgery to provide comprehensive evaluation and coordinated care for patients with suspected NPH.

Patients are referred by their neurologist and evaluated by our advanced practice providers (nurse practitioners and physician assistants), who perform a detailed clinical assessment and coordinate specialized diagnostic testing. Based on the results, patients are either referred to one of our specialized neurosurgeons to discuss shunt surgery or back to their neurologist for continued medical management or diagnostic work-up. This team-based approach ensures accurate diagnosis, individualized treatment recommendations and seamless care throughout the evaluation process.

Causes

In most cases of NPH, the cause is unknown and it's therefore called idiopathic NPH. Researchers believe that idiopathic NPH may be related to age-related changes in the production, circulation or absorption of cerebrospinal fluid (CSF), although the exact cause of those changes remains unclear. Less commonly, NPH develops because of another condition, such as a brain injury, stroke, brain tumor, infection or bleeding around the brain.

Signs & Symptoms

The symptoms of NPH typically develop gradually and may worsen over time. The most common symptoms include:

• Gait changes such as a slow, shuffling walk, difficulty lifting the feet, trouble initiating steps or problems with balance and climbing stairs. These are often the earliest and most noticeable symptoms.
• Urinary urgency, frequent urination, or loss of bladder control (incontinence)
• Changes in thinking or cognition, such as forgetfulness, difficulty concentrating, slowed thinking, reduced executive function or problems managing everyday tasks
• Noticeable mood or personality changes

Diagnosis

Because the symptoms of NPH can resemble those of normal aging or other neurological conditions, a thorough evaluation is needed to make the diagnosis. The evaluation may include:

• An in-person consultation to discuss your history and symptoms
• A MRI scan of the brain to look for enlargement of the brain's fluid-filled spaces (ventricles) and other findings suggestive of NPH
• A detailed gait (walking) and balance assessment
• A high-volume lumbar puncture (spinal tap), during which a sample of cerebrospinal fluid (CSF) is removed from around the spinal cord. Before and after the procedure, your care team will do a gait assessment to determine whether removing the extra fluid temporarily improves your walking, balance or other symptoms. If you do show improvement, that suggests that your symptoms are likely due to NPH and that you may benefit from shunt surgery.

Treatment

The most effective treatment for NPH is surgery to place a shunt. A shunt is a small, flexible tube that diverts excess CSF from the brain to another part of the body — usually the abdomen — where it is safely absorbed back into the body. The shunt contains an adjustable valve that regulates how much fluid drains, helping maintain an appropriate balance of CSF.

Many patients experience meaningful improvement in walking, balance, bladder control and thinking after shunt surgery, particularly when treatment is performed before symptoms become advanced. While not every symptom improves in every patient, early treatment generally offers the greatest chance for benefit.