Key Takeaways
Robbed of a Normal Life
Phillip G. St. Louis, a neurosurgeon in Orlando, Florida -- and an expert in NPH -- puts it bluntly. “Most clinicians are not aware of this disorder. So when one of their patients develops a shuffling gait or forgetfulness, they are likely to ascribe those problems to old age or, alternatively, Parkinson’s or Alzheimer’s. “These patients are being robbed of their normal life, and it’s not necessary.” One of his patients, 69-year-old Alicia Harper, vividly shows the seriousness of diagnosing a condition as dementia when, in fact, it’s something else. She found herself unable to walk properly, relying at first on a walker, then later on a wheelchair. She developed incontinence. She became forgetful and confused. Everyday activities of normal living, like dressing and bathing, became impossible for her. Four years passed before she was sent to Dr. St. Louis. He diagnosed NPH. After surgery, her condition rapidly improved, and she is nearly back to her old self. Her husband described her recovery as "a miracle."Another example is Norman Dombey, a UK professor of theoretical physics.
After various cognitive tests and even an MRI scan, he was diagnosed with Alzheimer's disease. Mr. Dombey wisely sought a second opinion. His new doctor changed the diagnosis to NPH.
Before surgery, he couldn't draw a clock face – one of the simple tests used to diagnose dementia. Just months later, he was writing a book review for a physics journal.
"Jaw-Dropping Improvement"
NPH is usually seen in people past the age of 60. It occurs when the normal cerebrospinal fluid (CSF) flow gets blocked and builds up in the brain, stretching nerve pathways. This gives rise to the gradual onset of three key symptoms:- Broad-based gait: Starts with mild imbalance but develops into walking with legs more widely apart while taking short shuffling steps. May lose the ability to walk altogether.
- Cognitive problems: Slowed thought processes and concentration. Short-term memory loss. Impaired decision-making and planning. Personality and behavioral changes.
- Loss of bladder control: An increasing need to rush to the bathroom. It may develop into incontinence.
Because these problems are seen in other aging conditions, a doctor faces a diagnostic challenge to determine if NPH causes the symptoms. Tests include measurement of intracranial pressure, CSF outflow resistance, and brain scans.
Once the excess fluid is known to be present, the patient undergoes temporary external CSF lumbar drainage.
If draining off the excess fluid produces some symptomatic relief, the next step is for the patient to consult a neurosurgeon about a procedure whereby a thin tube (shunt) is inserted into the brain. This continually diverts excess CSF to the abdominal cavity, which gets absorbed into the bloodstream. The shunt includes a programmable valve that controls the flow of fluid.
While this operation involves some risk, Richard Edwards, a consultant neurosurgeon from Bristol, England, describes the kind of change that can come after surgery:
"Patients who present with moderate to severe dementia can occasionally experience almost complete reversal of cognitive impairment after the operation. Some will have a jaw-dropping improvement in terms of mobility and cognition."
Few Are Diagnosed Early if at All
In most cases, early diagnosis and treatment is needed for best results. Because this rarely happens, most patients will see more modest improvements than they could otherwise have experienced. "Patients aren’t as aware of it, and doctors aren’t as aware of it. I would estimate that probably less than five per cent of the people who have [NPH] are actually getting treatment," says Dr. Mark Hamilton, a neurosurgeon at the University of Calgary, Canada. Surgery is also restricted for another reason, explains Michael Williams, Professor of Neurological Surgery at the University of Washington School of Medicine and a leading expert on NPH: "There’s a widely held perception that the risks of treating patients are so high that it doesn’t make sense to evaluate patients for hydrocephalus. "But the literature in the past 15 years shows that if you conduct the right tests and select the right patients, the likelihood of benefit is quite high, and the risk of harm is quite low."Our Takeaway
NPH isn't the only disorder that's being mistakenly identified as Alzheimer's. Mayo Clinic researchers just discovered a new memory disorder, Limbic-Predominant Amnestic Neurodegenerative Syndrome (LANS), which results in memory loss and is often misdiagnosed as Alzheimer's.
Recently, we've reported on several other health issues that can mimic early dementia. For example, the treatable liver condition hepatic encephalopathy can cause memory problems that resemble dementia. So can hidden medical conditions including anemia, vitamin B deficiencies, and prescription drug side effects.
Summary
Normal Pressure Hydrocephalus (NPH) is often mistaken for Alzheimer’s, affecting up to 600,000 Americans. It causes cognitive decline, walking issues, and incontinence but can be treated with surgery to drain excess cerebrospinal fluid. Timely diagnosis and treatment can lead to dramatic improvements, though the condition remains underdiagnosed and misunderstood by many physicians.
