Idiopathic normal pressure hydrocephalus
A couple of weeks ago we mentioned iNPH, or idiopathic normal pressure hydrocephalus, as a form of dementia that often masquerades as Alzheimer’s disease or Parkinson’s disease — but isn’t. The reason it’s so important to be aware of this condition is because dementia caused by iNPH can be controlled or reversed with proper treatment. The Hydrocephalus Association estimates that more than 700,000 Americans (twice the number from 10 years ago) have iNPH. The average age of onset is about 70 years old; men and women are affected in equal numbers; and less than 20 per cent receive an appropriate diagnosis and treatment. But, you ask, if things are “normal,” what’s the problem?
That misnomer came from one of the earliest papers written about the condition. In 1964, Dr. Salomon Hakim described the neurologic symptoms of dementia accompanied by gait disturbances and lack of bladder control. Those three symptoms — which is what a good specialist will look for when diagnosing iNPH — were thought to be going on even though there was no perceived fluid buildup in the brain. But now we know that’s wrong. There is fluid — and hence, pressure — buildup in the brain.
With today’s scanning technologies using a CT or MRI, doctors can see exactly where a buildup of cerebral fluid is occurring. And we know how to alleviate the pressure, and hopefully reverse the symptoms. So now you can think of the name of the condition as a tag identifying where you want to be and what you want to achieve: normal pressure.
The fluid that builds up in the brain and causes the debilitating symptoms is called cerebrospinal fluid. It originates deep in the brain, flows out and around it, and into the spinal canal and subdural space around the spinal cord. Your body maintains about 150 ml (2/3 of a cup) while producing a total 500 ml a day of this fluid (you pee out the rest). The fluid acts as a cushion, an auto-regulating, cerebral-waste-product cleaner and a helper for cerebral blood flow. Usually it’s reabsorbed or flushed through the system, but for some reason, and we’re not entirely sure why, in iNPH the reabsorption process of that extra 350 ml a day is interfered with, and CSF buildup occurs.
After finding a neurologist who has diagnosed this condition before (go to www.hydroassoc.org to find a qualified M.D.), get an exam, and maybe a second opinion. Then, if it looks like you’re a candidate for treatment, you’ll have a CT scan or an MRI. What the doctors are looking for are enlarged ventricles in the brain (there are four) that become engorged due fluid backup.
If they find what looks like harmful CFS pressure buildup, the next step is an external lumbar drainage (spinal tap), which will identify the folks who will respond to shunt surgery. The shunt is a drain that’s placed either at the base of the brain or in the spine (wherever your specialist deems appropriate) to relieve the buildup of CSF.
The shunts are programmable and deliver the excess fluid to a part of the body (sometimes the bladder) that will help you excrete the fluid. Properly selected patients who receive the shunt have a 60 to 80 per cent chance of improvement.
So, if you or someone you know has the onset of a foot-dragging, shuffling gait to one side, is experiencing incontinence and/or exhibiting signs of depression and short-term memory loss, take action now. For more insight into the condition and treatment, have a look at Bob Fowler’s YouTube video from 2005. (Google “Normal Pressure Hydrocephalus Bob Fowler 2005”.) He’s no longer with us, but he pioneered NPH awareness after he was given his life back following shunt surgery over 14 years ago.
Medical science has come a long way since then. There’s no reason for anyone to go through a misdiagnosis of Alzheimer’s disease or Parkinson’s disease when the problem is actually iNPH.
Mehmet Oz, M.D. is host of “The Dr. Oz Show,” and Mike Roizen, M.D. is Chief Wellness Officer and Chair of Wellness Institute at Cleveland Clinic. To live your healthiest, tune in to “The Dr. Oz Show” or visit www. sharecare.com.