Normal Pressure Hydrocephalus (NPH) is one of the trickier causes of dementia.
- It causes the brain to fail by causing a buildup of putting pressure from the insite.
- They symptoms creep in slowly over time as excessive Cerebrospinal Fluid (“brain water”) builds up inside the compartments of the brain.
- This buildup is called hydrocephalus
- The pressure of this fluid builds up in waves at times that cause worsening of symptoms.
- Over the years, this constant battering takes its toll on the blood vessels of the brain, causing poor blood flow and oxygen delivery.
- As patients age, the pressure elevations come more frequently and severely. The brain tissues take a beating and eventually starts to fail.
When does NPH start?
- It is usually diagnosed in people who are older than 70 years of age.
- The truth is that the symptoms often start years earlier, in a very subtle fashion.
- Eventually, the symptoms get bad enough that they become obvious. In some people, it starts as early as the 40s and 50s, and slowly progresses, causing gradual social decline (see SHYMA)
Making the Diagnosis – There are three classic findings associated with NPH:
1. Difficulty walking.
2. Memory loss.
3. Urinary incontinence.
Not all of these are present in everyone with NPH, and there is overlap with other conditions that can cause the same problems. Also, there are subtle nuances that are helpful to know:
1. Difficulty walking (“Gait apraxia.”)
– In a nutshell, the patient forgets how to walk. He or she appears to have a difficult time convincing the legs and feet to cooperate.
– Patients may start out with a wobbly, clumsy gait, simply an unsteadiness.
– As the years pass, and the pressure takes its toll on the brain, walking and balance deteriorate. Posture becomes stooped and hunched over.
– Eventually patients will appear to be walking on stilts. They will need a lot of assistance just to get up out of bed.
– Patients will often fall for no apparent reason. Sometimes they will stay on the floor, unable to convince their legs to move. If the patient lives alone, she may suffer the effects of prolonged dehydration, muscle breakdown, and even death before being discovered.
2. Memory loss.
– Most patients with NPH are aware that they are developing memory loss (as opposed to Alzheimer’s Dementia) and are quite frustrated by it.
– Cognitive abilities wax and wane. That is to say that, when the pressure rises in the brain, the patient will deteriorate and seem to lose memories, reasoning abilities and skills.
– When the pressure subsides, often the patient can appear quite normal.
– Early on, this can get quite confusing to caregivers, because one day the patient may look the picture of health, the next day she may appear completely incompetent. If different people are taking care of the patient, they may get into disagreements about the patient’s abilities.
– In middle stages, patients can be quite impulsive. They lose judgment and may try to jump up too quickly from a bed or chair. This is a problem when the legs are not cooperating, and this is the riskiest stage for bodily injury due to careening around the room and falling.
– Eventually, left untreated, the memory loss causes patients to require continuous care around the clock, to prevent unnecessary injury to themselves. Most patients become institutionalied (Nursing home residents) within a year after diagnosis, if not treated.
– The loss of function causes patients to fail to thrive, They may lose weight and get malnourished. This sets them up for infections and they become more prone to osteoporosis and bone fractures.
– Infections will often cause delirium, which is also called encephalopathy. These patients will act sleepy, lethargic and confused, and these symptoms can come on fairly rapidly, over hours to days.
3. Urinary incontinence.
– This one is tricky. Most people don’t like to admit that they are incontinent and shy away from this, denying any problems.
– But by asking probing questions, you may find that the patient has the urgency to urinate, so that they have to get to the bathroom quickly. And many will admit that they have indeed had an accident or two along the way, especially if their poor walking ability is slowing them down.
– Even when patients deny incontinence, they may smell of urine or have stains on their clothing.
– The incontinence often leads patients to avoid drinking water. Then they may develop dehydraion, urinary tract infections, and electrolyte imbalances. These can contribute to the encephalopathy that is the rapid worsening of memory loss described above.
NPH often is seen in people who have had:
1. Traumatic brain injury. This can cause proteins in the brain tissue to shear off and float through the spinal fluid, clogging up the drainage mechanism.
2. Bleeding into the brain. Again, the proteins in blood can block the drainage of spinal fluid, eventually leading to hydrocephalus – sometimes many years later.
3. Advanced age. The very process of getting older causes our brains to shrink. This leads to a sagging of brain tissue, changing the conformation of the drainage system. This kinking of the drain blocks it off, leading to buildup of brain pressure.
4. Genetic predisposition. NPH seems to run in some families.
- This can be very challenging, because NPH looks and acts so much like other neurological disorders.
- It can mimic stroke, seizures, syncope, migraine, patients often don’t get to the point of diagnosis until other bad things start happening to their brains.
- NPH shares features with Alzheimer’s Disease and Parkinson’s Disease. It is possible that around 250,000 patients diagnosed with Alzheimer’s Dementia may instead have NPH. Some patients have both.
There are three ways to make the diagnosis:
1. On clinical grounds. Just hearing the story in a younger patient (someone in their 60s is young, in our clinic) can be enough to make the diagnosis, especially if the classic brain imaging findings are present.
2. Spinal fluid removal. Decompressing the brain chambers by removing the excess fluid can cause dramatic improvement in symptoms in many patients. Sometimes, walking immediately gets better after spinal fluid removal. Also, the more subtle aspects of memory loss can disappear, causing the patient to instantly appear younger and more like themselves. Spinal fluid that is removed can be sent for testing for other causes of dementia, which makes this procedure doubly useful.
3. Neuroimaging studies. On an MRI or CT scan of the brain, there is a fairly characteristic appearance in somebody with NPH. But usually imaging findings are not enough to clinch the diagnosis in most patients, because there are some look-alikes that mimick it.
The good news here is that this is one of the treatable causes of dementia. Many patients with NPH can enjoy a return of walking abilities, memory function and urinary control, sometimes immediately. Not all patients are that lucky, though, especially older ones who have gone undiagnosed for many years.
- The diagnosis really should be as precise as possible. This is because long-term treatment usually involves procedures to remove excess spinal fluid, and these have the potential for complications that can be quite significant.
- Most patients will do very well and suffer few or no side effects from therapy, so the fear of complications should not prevent the patient from getting help.
- Gentle encouragement from other family members may help, since the patient’s judgement and decision-making abilities may be compromised.
- Treatment has to be individualized. No two people are the same, and many different factors will influence what kind of treatment to choose.
- Even when NPH has been diagnosed, it is important to make sure that other factors that may be contributing to the symptoms have been addressed.
1. Conservative: Medication.
– Usually this means a short trial of acetazolamide (Diamox®) or topiramate (Topamax®) which temporarily may decrease the pressure of the cerebrospinal fluid compartment. These medications are not reliable long-term solutions. They may cause a drop in potassium levels, and reduce the appetite leading to weight loss.
– Amantadine may help to improve alertness and reduce Parkinsonian symptoms, such as muscle stiffness and tremor.
– Steroids and NSAIDs theoretically might help reduce any inflammatory component that could be contributing to symptoms.
2. Less conservative: periodic spinal taps (“Lumbar puncture”)
– A good compromise for very elderly or high-risk patients.
– Pro: Does not require surgery. Effect can be very long lasting in some patients.
– Con: Hassle to come in and get done. Effect wears off early in some patients.
3. Definitive treatment: brain shunt (“bypass”)
– This is the best long-term treatment, and it is performed by a Neurosurgeon.
– Involves placing a drain through the skull into the deep chambers of the brain.
– Reroutes CSF through a tube that is tunneled underneath the skin down the neck, chest and dumping into the abdominal cavity, where the fluid is absorbed by the outer lining of the intestines (See figure below).
– A one-way valve prevents backflow of fluid, reducing the risk of infection.
– This valve is adjustable, to alter the amount of fluid that is removed. This is important, because if too much fluid is drained too quickly, the brain can decompress rapidly. This strains the veins on the surface of the brain, causing them to snap and bleed around the brain. So this valve allows a more slow, gradual removal of fluid.
4. The Basics and Supplements:
– Good hydration helps keep cerebrospinal fluid less viscous and flowing better.
– Vitamin B12 may help if deficiency is present.
– Vitamin D3 might help if 25-OH-vitamin D level is less than 50 ng/mL.
– Protandim might help. It’s a sophisticated turmeric/milk thistle combo that may reduce inflammation.
– Cut back on caffeine intake. Caffeine speeds up production of cerebrospinal fluid.