NPH: The Great Pretender
It looks like Parkinson's, acts like Alzheimer's, seems like dementia. The difference? It's treatable.
You've seen the ads. A stooped old man slowly shuffles down a darkened hall, dazed, confused. In a voiceover, he tells us he has a rare neurological condition called Normal Pressure Hydrocephalus.
By the commercial's end, we see him standing upright, walking the hall in half the time.
Are we witnessing a medical miracle? Something like it, say doctors who treat patients with the condition.
"NPH is known among doctors as a 'fascinoma' because we are fascinated when we find a patient with this disorder" says Dr. Robert S. Tan, associate professor of family and community medicine at The University of Texas Medical School at Houston and medical director of the Garden Terrace Alzheimer's Center. "We really like to see it, because it can be so successfully treated."
Normal Pressure Hydrocephalus, or NPH, happens when too much fluid builds up in the brain. Normally the fluid, called cerebrospinal fluid, cushions the brain and spinal cord from injuries and provides nutrients to the central nervous system. In patients with NPH, too much cerebrospinal fluid in the brain's ventricles increases pressure in the head. The increased pressure may cause brain damage.
NPH is a rare neurological disease, affecting just one in 100,000 people, but causing an estimated 5 percent of dementias. It is more common in people age 60 and older. Unlike other diseases that damage the brain and the nervous system, the progression of NPH can be halted. In some cases, it can be reversed.
NPH causes walking problems, dementia and urinary incontinence - symptoms that mimic neurodegenerative diseases such as Alzheimer's and Parkinson's. The similarities between those diseases and NPH make it hard to diagnose. However, patients with NPH experience very specific problems when they try to walk.
"It is like they forget how to walk," says Dr. Mya Schiess, associate professor of neurology at the UT Medical School. "They usually have so much trouble getting started. Once they are out of their chair, simply lifting one foot up and placing it in front of them becomes an enormous task. They feel like their feet are stuck to the floor."
The inability to walk normally is usually the first symptom that shows up with NPH. Cognitive diminishment or intellectual changes follow or coincide with gait issues. Urinary incontinence usually shows up last. However, Schiess cautions against waiting until all three symptoms are present before seeking help. By then, the disease has progressed, and may not be as treatable. She recommends going to the doctor for a checkup if you have any problems walking, and not to dismiss it as a normal part of the aging process.
Tests confirm condition
If a doctor suspects NPH, the patient will be referred to a neurologist for further evaluation. The neurologist will also examine the patient, and may order imaging scans of the brain, such as computerized tomography (CT) or magnetic resonance imaging (MRI). The scans will show the area of the brain with an excess of fluid.
The neurologist may also do a spinal tap to check the pressure level in the brain. In this procedure, the neurologist uses a needle to remove cerebrospinal fluid from the spine. The patient is then observed for an hour or two to see whether his or her walking improves. Results of these exams and tests help the neurologist diagnose or rule out NPH as the cause of symptoms.
Surgery offers hope
Surgery is the only way to relieve the pressure of cerebrospinal fluid on the brain. The current treatment available uses a shunt to drain the excess fluid from the brain down into the abdominal cavity.
While surgical methods vary, typically, a flap is cut in the scalp and a small hole is drilled in the skull. The neurosurgeon then passes a small catheter into a ventricle of the brain. A pump is attached to the catheter to keep the fluid away from the brain. Another catheter is attached to the pump and tunneled under the skin, behind the ear, down the neck and chest and into the abdomen.
The neurosurgeon adjusts the pump to control the pressure of the flow of the fluid. Newer shunt systems can be programmed to control pressure. Doctors can use a programmer to remotely make adjustments to the shunt's pressure, eliminating the need to perform additional surgery to reprogram the shunt.
Surgical treatment improves symptoms in about half of cases, according to the National Institutes of Health. Patients who have the least symptoms when they undergo surgery have the best prognosis.
"You can see profound improvement when gait impairment is a prominent feature," Schiess says. "If you can intervene when patients have had dementia for a year, certainly no more than two years, then there can be a profound improvement in cognitive function as well."
Shunting may also help improve urinary incontinence, greatly improving a patient's quality of life. Schiess stresses that, as with all surgery, patients must weigh the risks and benefits.
Patients, who don't respond well to shunting, may benefit from drugs prescribed to help improve the symptoms of neurodegenerative diseases such as Alzheimer's and Parkinson's.
Timing is crucial
When diagnosed and treated early, patients with NPH can experience a miraculous recovery. But timing is of the essence. For best results, patients should receive treatment by one year after they first start noticing symptoms.
The problem is, many people may blame those symptoms on old age. Schiess hopes the latest blitz of media coverage on NPH may help raise awareness about the condition.
"People assume that as we age that our gait should change," Schiess says. "That is not the case. Even if gait problems are due to aging, it is usually due to people not maintaining exercise and weakening their muscles. So a change in gait, or a change in mental faculties should be evaluated immediately."