What Is Normal Pressure Hydrocephalus?
Normal pressure
hydrocephalus (NPH) is an abnormal increase of cerebrospinal fluid (CSF) in the brain's ventricles, or cavities. It occurs if the normal flow of CSF throughout the brain and spinal cord is blocked in some way. This causes the ventricles to enlarge, putting pressure on the brain.
Understanding the Ventricular System and CSF
The ventricular system is made up of four ventricles connected by narrow pathways. Normally, CSF flows through the ventricles, exits into cisterns (closed spaces that serve as reservoirs) at the base of the brain, bathes the surfaces of the brain and spinal cord, and then is absorbed into the bloodstream.
CSF has three important life-sustaining functions. It:
- Keeps the brain tissue buoyant
- Acts as a cushion or "shock absorber"
- Acts as the vehicle for delivering nutrients to the brain and removing waste
- Flows between the cranium and spine to compensate for changes in intracranial blood volume (the amount of blood within the brain).
The balance between production and absorption of CSF is critically important. Ideally, the fluid is almost completely absorbed into the bloodstream as it circulates; however, there are circumstances that, when present, will prevent or disturb the production or absorption of CSF, or that will inhibit its normal flow. When this balance is disturbed, normal pressure hydrocephalus is the result.
Who Does Normal Pressure Hydrocephalus Affect?
Normal pressure
hydrocephalus can occur in people of any age, but it is most common in the elderly population.
Causes of Normal Pressure Hydrocephalus
Normal pressure hydrocephalus may result from:
- A subarachnoid hemorrhage
- Head trauma
- Infection
- Tumor
- Complications of surgery.
However, many people develop this condition even when none of these factors are present. In these cases, the cause of normal pressure hydrocephalus is unknown.
Normal Pressure Hydrocephalus Symptoms
Symptoms of normal pressure hydrocephalus include:
- Progressive mental impairment
- Dementia
- Problems with walking
- Impaired bladder control leading to urinary frequency and incontinence
- Slower movements or complaining that the feet feel "stuck."
These symptoms are typical with this condition. However, it is important to remember that symptoms vary significantly from individual to individual. Also, these possible symptoms are not sure signs of hydrocephalus. Other problems can also cause these symptoms. Anyone with possible symptoms of normal pressure hydrocephalus should see a doctor so that the problem can be diagnosed and treated as quickly as possible.
Comparing Normal Pressure Hydrocephalus to Other Conditions
Because symptoms of normal pressure hydrocephalus are similar to those of other disorders, such as
Alzheimer's disease,
Parkinson's disease, and Creutzfeldt-Jakob disease, the condition is often misdiagnosed. Many cases go unrecognized and are never properly treated.
Diagnosing Normal Pressure Hydrocephalus
Doctors may use a variety of tests, including brain scans (CT and MRI), a spinal tap or lumbar catheter, intracranial pressure monitoring, and neuropsychological tests, to help them diagnose normal pressure
hydrocephalus and rule out other conditions.
Treatment Options for Normal Pressure Hydrocephalus
Treatment for normal pressure hydrocephalus involves surgical placement of a shunt in the brain to drain excess CSF into the abdomen (stomach), where it can be absorbed. This shunt allows the brain ventricles to return to their normal size. Regular follow-up care by a physician is important in order to identify subtle changes that might indicate problems with the shunt.
Prognosis for Normal Pressure Hydrocephalus
The symptoms of normal pressure hydrocephalus usually get worse over time if the condition is not treated, although some people may experience temporary improvements. While the success of treatment with a shunt varies from person to person, some people recover almost completely after treatment and have a good quality of life. Early diagnosis and treatment of this condition improves the chance of a good recovery.
