It tends to strike older Americans, causing memory loss, difficulty walking, and other symptoms that lead many doctors to misdiagnose it as dementia or Alzheimer's disease.
But experts say up to 5 percent of Americans diagnosed with those incurable brain disorders actually have a treatable condition called "normal pressure hydrocephalus."
Many of the estimated 375,000 Americans who have NPH don’t even know it, because its symptoms are strikingly similar to dementia, mental-health specialists say. As a result, thousands of NPH patients never benefit from surgical procedures that can miraculously correct and reverse the condition.
Gary Small, M.D., a University of California-Los Angeles professor of psychiatry and aging, tells Newsmax Health that NPH can be detected by MRI or CT scans of the brain that help patients get the help they need. But doctors never order such tests for untold numbers of Americans with NPH.
"What can happen, and I'm not sure how frequent this misdiagnosis occurs, is people go in to their doctor with what look like dementia, or Alzheimer's symptoms or even Parkinson's — memory problems, and this unsteady gait, and incontinence," says Dr. Small, director of the Longevity Center and author of The Alzheimer’s Prevention Program.
"The doctor may think it looks like so many of my other [dementia] cases that I’m not going to bother to have a scan."
The condition, which is caused by a buildup of fluid in the brain, is rare and was only discovered in the 1960s, which may explain why it is frequently missed or misdiagnosed.
"In my 30 years of practice, I’ve seen at most three to four cases, so it’s not that common," notes Dr. Small, author of The Mind Health Report
newsletter. "But we always look for it and [doctors should] always check for it."
NPH has received an increased dose of media attention recently, but still remains under the radar for many doctors and patients.
According to the Hydrocephalus Foundation, NPH occurs when the brain's natural system for draining and absorbing cerebrospinal fluid malfunctions. The cavities in the brain — known as ventricles — enlarge and fill with extra fluid and put pressure on areas of the brain that control the movement, bladder functions, and mental processes such as memory, reasoning, problem solving, and speaking .
What causes NPH is unknown, but experts say it typically occurs after a head injury, stroke, meningitis, brain cancer, or surgery. Most people with NPH are diagnosed after age 60. In addition to memory loss and a decline in mental processes (similar to Alzheimer's), NPH typically can causes difficulty walking (like Parkinson's) and urinary incontinence. It can also cause speech problems, changes in mood and behavior, headache, nausea, and vision problems.
The Hydrocephalus Association estimates about 5 percent of Americans diagnosed with dementia actually have NPH, with a total of 375,000 cases in the U.S. But that figure is expected to grow as the population ages.
The good news is that NPH — unlike Alzheimer's and Parkinson's — can be treated and its symptoms reversed, but only if it is diagnosed correctly, Dr. Small notes. Brain scans can identify the hallmark signs of NPH — dilated ventricles in the brain that fill with cerebrospinal fluid.
"If you see what look like dilated ventricles, it suggests concern [for NPH]," he explains. "Those ventricles surround that fluid in the brain. Hydrocephalus means 'water on the brain.' "
NPH can be treated through surgery, during which a shunt — a thin tube — is implanted in the brain by a neurosurgeon to drain excess fluid. The tube is threaded under the skin from the head to another part of the body, usually the belly. A valve can be opened to release the fluid when the pressure builds up. The fluid drains harmlessly and is absorbed by the bloodstream. Although a shunt operation won't cure the underlying cause of NPH, it can relieve the symptoms.
Shunt operations don't work for everyone, but the Hydrocephalus Association reports many patients report miraculously regaining their ability to remember, walk, talk, and control their physical and mental abilities. The earlier the NPH is diagnosed, the better the odds a patient will benefit from surgery.
"If it's recognized early you have the opportunity to intervene and have the benefit of that intervention, and release the pressure surgically," Dr. Small says. "Neurosurgeons have a way of testing to see if surgery will help."
A widely publicized study of NPH suggests that almost one-third of American physicians have never even heard of NPH. Harold Conn, M.D., a retired Yale University professor, was diagnosed with NPH 10 years ago after mistakenly being told by his doctors that he had Parkinson's. After recovering he surveyed 166 doctors and found 30 percent were completely unaware of NPH. Most graduated from medical school before NPH was first described in medical literature in 1965.
Dr. Small says the upshot is that family members of individuals with symptoms of dementia should be aware that they may actually be suffering from NPH or other conditions that are treatable.
"What’s important is people need to know if they're having memory problems or a cognitive decline — even though Alzheimer's is the leading cause of these things — there are a lot of other things that can cause these symptoms," he notes.
"It could be NPH, depression, a thyroid imbalance, anemia. Even a drug toxicity, a sleeping medicine, or medicine that interacts badly with other medicines [can] cause this. And sometimes some of these causes are reversible."
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