What is Normal Pressure Hydrocephalus?
Normal Pressure Hydrocephalus (NPH) typically affects patients 60 and older and is one of over 100 dementias that is reversible if it’s caught early. The Hydrocephalus Association estimates that 5% of those diagnosed with dementia are in reality misdiagnosed cases of NPH, which is treatable. Those with normal pressure hydrocephalus have an excessive amount of cerebrospinal fluid (CSF) that accumulates in the brains ventricles and causes them to enlarge, which causes progressive dementia like symptoms as the fluid builds up.
Normally, cerebrospinal fluid surrounds the brain and spinal cord to cushion the brain and the spinal cord and provide it with nutrients. However, when there is an excess amount of cerebrospinal fluid it collects in the brains ventricles and normal pressure hydrocephalus occurs. As the brain ventricles enlarge, due to the excess fluid, they disrupt and damage brain tissue causing symptoms of NPH. If left untreated the increased pressure in the brain may result in increased symptoms over time or permanent brain damage. If NPH is diagnosed and treated early patients may recover almost completely after treatment.
It is estimated that up to 80% of patients with NPH remain untreated due to the difficulty of distinguishing NPH from other neurodegenerative disorders.
What Causes Normal Pressure Hydrocephalus?
Most cases of normal pressure hydrocephalus have no known cause and are referred to as primary NHP. In the other cases, patients may have a history that includes a head injury, brain tumor or cyst, brain hemorrhage, meningitis or other brain trauma.
What are the Signs and Symptoms of NPH?
The symptoms of normal pressure hydrocephalus, which can vary in severity, include difficulty with cognitive processing such as memory, problem solving, reasoning and speaking as well as the loss of control of legs and bladder function. These symptoms mimic the classic signs of dementia, which causes 5% of those with normal pressure hydrocephalus to be misdiagnosed with dementia, Alzheimer’s or Parkinson’s disease.
The hallmark symptoms of normal pressure hydrocephalus are:
- Gait and balance problems range in severity, from mild imbalance to the inability to stand or walk. Many patients may have trouble picking up their feet, walking up stairs or curbs and they may have frequently falls. They may also walk with their feet held wider apart than normal, shuffle their feet or have general unsteadiness.
- A noticeable decline in cognitive skills that includes an overall slowing of thought process, impaired reasoning or planning ability, a decrease in concentration and/or changes in personality and behavior.
- Urinary incontinence typically occurs later in the disease and includes frequent urination, increase in urgency, or incontinence.
How is NPH Diagnosed?
Normal Press Hydrocephalus can be diagnosed through a clinical neurological evaluation and by using one or more of the following tests: ultrasound, computerized tomography (CT), magnetic resonance imaging MRI, lumbar puncture (spinal tap), or pressure-monitoring techniques and neuropsychological testing after a lumbar punch.
Confirming the Diagnosis of NPH
To confirm the diagnosis of NPH a trial removal of cerebrospinal fluid may be done in a procedure called a lumbar puncture. This procedure helps determine if functional improvement occurs after lumbar drainage and helps to determine whether the patient is a good candidate for shunt placement.
Treating Normal Pressure Hydrocephalus
If a patient shows a positive response to the diagnostic testing or the lumbar puncture a shunt is typically proposed to drain excess cerebrospinal fluid the brain into another part of the body. The goal of the shunt is to drain the correct amount of fluid from the brain so the patient has relief from all symptoms of normal pressure hydrocephalus.
The surgical procedure of inserting a shut last lasts 2 to 3 hours and can lead to significant improvements in NPH symptoms for patients diagnosed with NPH in up to 60% of patients. Ongoing monitoring is required after the shunt is placed to ensure that the proper amount of cerebrospinal fluid is drained.