So many of us face the dilemma of a family member, an older family member, a parent, and aunt and uncle, who starts having some memory problems and there are the issues of dementia. Unfortunately, many dementias are difficult to treat, tend to be progressive, and over time that which is most valuable to us, our mind gets damaged progressively and we lose tremendous function and ultimately pass away from complications related to the brain not functioning well. There is however, a very common cause of reversible dementia, so somebody could be having memory loss and there actually could be a problem that’s completely reversible and that’s called Normal Pressure Hydrocephalus (NPH) and in Normal Pressure Hydrocephalus, there’s typically a triad. Usually the first thing that happens is the patient will have difficulty with walking. They might have what we call a wide based kind of shuffling gait. This will go on for some period of time and people usually just describe it to, oh, grandpa’s getting older, or grandma’s getting older and then it might progress to them having intermittent problems with controlling their bladder and having accidents. Again, this can get ascribed to old age, oh, he couldn’t move fast enough to get to the bathroom, or grandma had four kids through natural childbirth and it’s not uncommon for somebody to have some incontinence in their older age. Then they also start to develop some memory problems and some thinking problems and lack of clarity. And this is the fairly classic progression of Normal Pressure Hydrocephalus.
So what is Normal Pressure Hydrocephalus? Well, let’s take apart the word. Normal pressure, meaning the pressure inside the brain is normal. Hydrocephalus means fluid on the brain. Now, most of the time when people develop Hydrocephalus, whether it’s a baby or following some other event, it can happen with aneurysmal rupture or head trauma or many other reasons–brain infections–there’s fluid buildup on the brain and the brain has these fluid spaces called ventricles. So when you have Hydrocephalus, typically those fluid spaces will get bigger. As those fluid spaces get bigger, there’s more pressure on the brain and the brain function will deteriorate, and that is the classic Hydrocephalus. Doctors, neurosurgeons will often treat Hydrocephalus by drilling a hole in the skull and passing a tube into that fluid space. You then connect that tube to a little valve and then another tubr that can snake down the body and puncture into the abdominal cavity. Then the fluid of the brain, the cerebral spinal fluid, can go up the tube through the valve and into the belly and drain the fluid out of the brain and keep the pressure in the brain normal, and you can reverse the symptoms of Hydrocephalus.
Now, in Normal Pressure Hydrocephalus, which we typically see in older patients, for reasons we don’t understand the ventricles get big. But if you test the pressure, the pressure is normal, but we do know empirically that in some of these patients, if we shunt the fluid that they actually will get much better and you can actually reverse many of the symptoms and problems. So how do you know if you have Normal Pressure Hydrocephalus? Well, the big dilemma is many types of dementia cause the brain to shrink. You lose brain tissue. Well, as you lose brain tissue, your head doesn’t shrink, so that means that as the brain takes up less space and fluid has to take up more space and the fluid spaces will get bigger. Now, when you have a classic dementia like Alzheimer’s, when the brain gets smaller, when it shrinks, the fluid spaces get bigger, yes, but also the brain itself, since it’s getting smaller, the bumps and grooves in the brain get more dramatic, and we call it sort of a walnut, a walnut brain. If you’ve ever seen a picture of the brain, the bumps are pushed together, so even though there are little slots between the bumps, these, these valleys, because the brain is full, it’s like this. When the brain shrinks, those spaces get larger. You’ll also see these other changes in the rest of the brain and we tend to call that Hydrocephalus ex vacuo. In that the brain is getting smaller because there’s just nothing else, the fluid spaces are getting larger because the brain is just disappearing. It’s not always clear cut with pictures. You can’t just look at an MRI and know this patient has Hydrocephalus ex vacuo, and this patient has Normal Pressure Hydrocephalus. In fact, even with history and exam, you can’t always tell them apart. When it’s clear cut, sometimes I will take a patient and talk with the patient and the family and offer shunt right out of the gate. Say this is clear cut, the history is clear cut, the pictures are clear cut, and a shunt is something we should consider and I’ll talk to them about the risk benefits of shunting, the risks of infection, causing brain bleeding, other injuries and talk about the benefits potentially reversing the problems they’re having.
Many times though I can’t figure out exactly what’s going on just by talking to the patient, examining the patient, looking at the films, and I’ll offer a provocative test and in doing a provocative test, what I will often do is admit the patient to the hospital and put a drain in their back in their spinal fluid and then every hour I’ll have the nurses remove some cerebral spinal fluid. We’ll do this for a few days and I’ll want the family to be around to help us see what’s going on and we’ll also have therapists evaluate the patient and we’ll see how’s their walking, how’s their thinking, and how does it progress over the couple of days that were draining the CSF. If we drain the CSF and the patient does better and better and better, then that’s a pretty good sign that if I put a shunt in permanently, that that’ll be very helpful. If I put this tube in and we drained CSF and it makes the patient worse and they complain of headaches, nausea and vomiting, and no matter what we do with the tube and no matter how we drain the fluid, it makes them feel miserable, then there’s no way I’m going to put a permanent tube in. That would seem like, why would you do that to somebody? So that’s one way to potentially get a clue about which way to go. Amazingly though, if a patient has this Normal Pressure Hydrocephalus and you put a shunt in, I’ve had the family say, you gave me my father back, or you gave me my grandparent back, they’re just like they were before. It’s really quite dramatic and a wonderful thing to be able to do for people.
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