Normal Pressure Hydrocephalus

When cerebrospinal fluid (CSF) accumulates abnormally in the ventricles of the brain, a condition known as normal pressure hydrocephalus (NPH) occurs. When cerebrospinal fluid (CSF) cannot move freely throughout the brain and spinal cord, this condition develops. As a result, the ventricles swell and exert pressure on the brain. Even though there is extra fluid in the brain, the pressure of the cerebrospinal fluid (CSF) measured by a spinal tap is usually within normal range in patients with normal pressure hydrocephalus. An increase in CSF volume within the ventricles of the brain can cause pressure on the surrounding brain tissue, which can cause issues with walking, cognition, and bowel and bladder control.

There are cases where normal pressure hydrocephalus can be managed by surgically implanting a shunt, a long, thin tube that drains CSF from the brain to the belly. Problems with walking are more likely to be resolved after surgery, but mental deterioration and incontinence are less likely to improve after treatment.

Diagnosing normal pressure hydrocephalus requires imaging of the brain’s structure, most often using magnetic resonance imaging (MRI) or computed tomography (CT), to detect swelling of the ventricles. The ventricles may appear enlarged due to total brain tissue atrophy in some brain illnesses, such as Alzheimer’s disease. Even when the ventricles are enlarged, brain tissue may not seem smaller in people with normal pressure hydrocephalus.

Experts recommend that a person suspected of having normal pressure hydrocephalus be evaluated by a neurologist with extensive experience evaluating brain disorders that affect movement, thinking skills, and physical functions because the clinical picture for normal pressure hydrocephalus can vary and symptoms can overlap with those of Alzheimer’s and other dementias.