Normal Pressure Hydrocephalus: How Neurosurgery Saved One Man's Life

In late 2020, Lewis Popper’s memory and cognition began to fade. A retired attorney who volunteered for various organizations near his home in Northampton, Mass., he could no longer think straight. A simple task, like setting an alarm clock, confounded him.

“I didn’t have answers to whatever questions were in front of me. But worse, I couldn’t even figure out how to start thinking about the questions,” Popper recalls.

The troubles were also physical. An active hiker who could clamber up and down steep hills with a group he’d started for seniors, Popper now became breathless after easy walks. In time, his once confident stride turned into a weak shuffle.

He was in his early 70s and in otherwise good health. Was this normal aging? He and his wife consulted various specialists, and no one could figure it out. In early February 2021, they went to see a geriatrician. After watching him walk, the physician was certain he had a rare condition called normal pressure hydrocephalus (NPH). 

In this disorder, which primarily affects men and women over 60, the brain overproduces cerebrospinal fluid (CSF). The extra fluid in the brain puts pressure on brain cells and damages them, which can lead to a variety of mental and physical symptoms.

While there is a surgical treatment for NPH, both his geriatrician and the staff of a well-regarded hospital thought it was too late for Popper as his symptoms had become significant. So, Popper’s grown children researched the condition and obtained the name of someone they were told could help their father: Charles Matouk, MD, a neurosurgeon at Yale Medicine. 

Dr. Matouk first met Popper during a telehealth appointment in early March 2021. As director of the Yale Medicine Normal Pressure Hydrocephalus Program, Dr. Matouk was no stranger to the problems Popper was experiencing. CSF, he explains, plays an important role in our bodies.

“CSF serves as a cushion, so our brain doesn’t bump into the hard box of the skull,” he says. “It also provides a mechanism for nutrients to get to the brain. We all make CSF at a constant rate, and we all get rid of it at a constant rate, too.”

However, when someone has normal pressure hydrocephalus, the CSF builds up. “We tend to think of it not so much as a problem with too much being made, but as a problem with not enough being able to get out—as if the pipes are blocked,” Dr. Matouk says.

More than 700,000 Americans have NPH, but less than 20% are properly diagnosed.

Its cause is unknown, and it can be difficult to diagnose. Adults with NPH typically have three symptoms: difficulty walking; cognitive impairment, including trouble making decisions or slowed thinking; and urinary incontinence.

For the walking troubles, Dr. Matouk describes it as someone being unstable on their feet. “They can’t catch their balance as easily, and their gait could be described as magnetic,” he says. “The stride length shortens, and it feels like you can’t pick your feet up off the floor. The brain is not communicating with the legs to provide stability and gait quality.”

All three main NPH symptoms are common in the elderly population, which makes NPH difficult to diagnose, Dr. Matouk adds.

“Plus, there are many reasons why someone might not be able to walk well. They might have a bad knee, a bad hip, or arthritis in their back. If you only take a symptom in isolation, about 20 or 30% of the population over the age of 75 or 80 has some form of gait instability,” Dr. Matouk says. “And the same is true for mild cognitive issues and urinary frequency, which are very common in men and women as they age.”

Unfortunately, Dr. Matouk says, it can take a long time—sometimes years—to properly diagnose NPH. “And during that time, patients continue to decline,” he says. “If we get to patients too late, they're not going to experience as much improvement from the treatment as they might have if their symptoms were caught earlier.”

After Popper and Dr. Matouk’s first virtual meeting, they decided Popper should come to New Haven for a full evaluation.

Brain scans of an adult with NPH usually show large CSF ventricles, but the ultimate test to diagnose NPH is a spinal tap, and there are two ways to do this. One is what’s called a large volume lumbar puncture, also known as a spinal tap.

“The fluid in your brain, the CSF, is connected to the fluid in your spine. So we can place a needle in your back, and when we withdraw fluid from the spine, we’re actually withdrawing it from your brain,” Dr. Matouk explains. “We remove a large amount of water and see if a patient’s symptoms improve over the next few hours.”

The other testing method for NPH is a lumbar drain trial, which entails placing a drain in the spine and leaving it in for three days to remove fluid continuously. “This mimics the effects of the traditional surgical treatment we would do for NPH, which is to place a shunt in the brain to remove the fluid,” he says. “And because this is done for longer than a few hours, we can better see if there’s an improvement in symptoms.”

This type of testing, combined with a dedicated NPH program, is found in only a few hospitals in the U.S. “I consider lumbar drain trials to be the gold standard for determining whether or not someone would benefit from a shunt or some other treatment for NPH,” he says. “This kind of testing requires a large number of people to administer it. Patients are admitted to an intensive care unit to ensure the right amount—not too much—of fluid is drained. Daily assessments by physical therapists and occupational therapists track objective and subjective metrics. And we also do a videotape analysis to see whether there's improvement in the quality of someone's gait and how they respond to different questions.”

At the end of three days of testing, the team and the family meet to discuss whether or not there was an improvement—and if the improvement justifies the risks of surgery, which would be the next step in treatment.

“We don't want to subject someone who is older with other medical conditions that put them at higher risk to a surgical procedure unless there is a good chance it will improve their symptoms," says Dr. Matouk. “With the lumbar drain trial, we can be relatively certain if we’re going to see improvement in their symptoms with surgery—and also the degree to which their symptoms will improve. So, it gives people confidence in deciding whether or not to move forward with surgery.”

At the end of Popper’s trial in late March, enough improvement was noticed that he was given the option of shunt surgery. He and his wife decided he should do it.

The surgery was planned for the next day. Typically, patients come for their trial on a Monday so that surgery can be done at the end of the week, and discharge takes place over the weekend.

“In terms of neurosurgery, it’s a relatively simple procedure,” Dr. Matouk says. “Several small incisions are made on the head and abdomen. Next, the surgeon drills a hole in the skull, and a catheter, or plastic tube, is placed inside the brain and connected to a shunt. The shunt creates a bypass—or another channel by which fluid can exit from the fluid-filled center of the brain down this long plastic tube, which flows into your peritoneum. This is the inner lining of the abdomen, which has a natural ability to absorb fluid.”

The surgery takes about 40 minutes. Patients are up and walking pretty quickly after the procedure and can be discharged within 24 to 48 hours, says Lauren Danis, APRN, who works in the Yale NPH Program.

(Since Popper’s surgery, Yale has become involved in a clinical trial for a minimally invasive NPH surgical treatment.)

“The shunt is the first step in the recovery of this disease. I think the more difficult part comes after surgery, when our patients have to work hard in physical therapy,” Danis says. “Before the shunt, they weren’t making progress because NPH can cause muscle weakness, which contributes to difficulties with walking. After surgery, however, physical therapy can help retrain their vestibular system and also build strength.”

Physical therapy can be done in an office or at home. Some patients are deconditioned to the point that they need to go to short-term rehab. In Popper’s case, he had a nurse, physical therapist, and occupational therapist visit his home.

“Very soon after the surgery, I could ask and answer questions much more clearly, but about 10 days later, my wife had the feeling that I was becoming less alert, which worried her,” Popper says.

Dr. Matouk said he should come in for a visit. There, the surgeon performed what appeared to Popper to be a magic trick. Dr. Matouk held a magnet over Popper’s skull to adjust the shunt so that it drained more CSF from his brain.

“Our shunts are all adjustable. One size doesn't fit all. Some patients need a little bit more drainage than others. It takes about 10 seconds to do,” Danis explains. “It almost acts as a floodgate. When we first do the surgery, we put the shunt in and have the floodgate cracked, so it's not draining much fluid. Mr. Popper had a good response to that—just having the floodgate cracked. But we made the adjustment when we realized he needed more fluid drained.”

Popper quickly experienced improvements.

“My thinking pretty soon went back to what most people say is the way I used to be. I might still take a little longer to get a joke, and complicated things like legal analyses are a little harder to follow,” Popper says. “But it’s also hard for us to know if that’s just age or the remainder of the NPH. Physically, I am rebuilding my strength and can now walk 2 to 3 miles in a forest, but I’m no longer doing 5 miles and climbing up boulders like I used to. I’m still grateful for all that I can do.”