Normal Pressure Hydrocephalus
Normal pressure hydrocephalus (NPH) is a brain condition characterized by fluid buildup within or around the brain. NPH affects brain-related activities, including the ability to think, concentrate, and memorize. The symptoms often overlap with dementia, but NPH is reversible in some cases. The condition is mainly seen in people over 65.
NPH results from the buildup of cerebrospinal fluid (CSF) in the brain. CSF is responsible for supplying nutrients to the brain and removing waste products from the brain. It also cushions and protects both the brain and spinal cord. When someone has NPH, the fluid buildup occurs gradually, leading to elevated CSF pressure. However, intracranial pressure remains within the normal range, which is why the condition is called normal-pressure hydrocephalus. Disruption of CSF flow can impact both the brain and spinal cord, leading to neurological symptoms.
A careful differential diagnosis is essential because NPH can be misdiagnosed as Alzheimer’s disease or Parkinson’s disease due to overlapping symptoms. Distinguishing between these conditions is important, as Alzheimer’s disease symptoms can be mistaken for or coexist with NPH. NPH is one of the few treatable forms of dementia, and early and properly diagnosed cases have a much better chance of improved outcomes.
The prevalence of NPH is estimated to be around 0.2% to 5.5% per 100,000 person-years, with higher rates in older adults. The classic triad of symptoms includes gait disturbance, cognitive impairment, and urinary incontinence, although not all symptoms may appear at once. Risk factors for NPH include increasing age, previous brain injury, brain infections, hemorrhages, or other neurological events.
What Causes Normal Pressure Hydrocephalus
NPH has two forms:
Primary (Idiopathic) NPH
In most cases, idiopathic NPH is related to age-related issues. In other words, the body’s ability to make, circulate, and absorb CSF is affected. Almost half of all cases are idiopathic NPH. Some research shows that NPH could be related to Alzheimer’s disease, dementia, and similar conditions. Risk factors for idiopathic NPH include age-related changes that impair fluid absorption, and the condition can be reversible if diagnosed early.
Secondary NPH
This type of NPH is related to another medical condition that affects the body’s ability to make, circulate, and reabsorb CSF. Brain aneurysm, intracranial hemorrhage, brain tumors, encephalitis, meningitis, stroke, head injury, and brain surgery are such medical conditions that can cause secondary NPH. NPH occurs when the normal flow of CSF throughout the brain and spinal cord is blocked, which can result from risk factors such as past injury, bleeding, infection, or brain tumors.
Symptoms
NPH symptoms start gradually and develop and worsen with time, usually between three and six months. Three symptoms of NPH are called Hakim’s triad, and these are:
Gait Issues
These symptoms affect walking-related movements, often described as 'difficulty walking.' Gait disturbance is generally the first and most common symptom to appear in normal pressure hydrocephalus, and it is also typically the first to resolve after treatment. Almost 80% or more patients have this problem, and the symptoms are similar to those of Parkinson’s disease. However, NPH symptoms usually only affect the feet and legs. Gait disturbances in NPH can include trouble walking, poor balance, and a feeling that the feet are stuck to the ground.
Cognitive Difficulties
The third set of symptoms includes mental or physical slowness, memory issues, difficulty managing thoughts, actions, and emotions, and overall emotional changes. Cognitive impairments associated with NPH can manifest as forgetfulness, confusion, and difficulty responding to questions.
Urinary Incontinence
NPH can also cause loss of control over the bladder. Patients often feel the urgent need to urinate or cannot control their urine.
A helpful way to remember the key symptoms of NPH is the ‘Wacky, Wobbly, and Wet’ triad: cognitive impairment (‘wacky’), gait disturbances such as difficulty walking, poor balance, and a feeling that the feet are stuck to the ground (‘wobbly’), and urinary incontinence (‘wet’).
Diagnosis and Medical Assessment
Diagnosing NPH requires a combination of clinical evaluation and diagnostic tests, as many symptoms overlap with other age-related conditions, such as dementia. Your healthcare provider may consider various options.
Further evaluation may include preoperative assessment and neuropsychological testing to document cognitive strengths and weaknesses and guide treatment decisions. These steps help determine the best approach for managing NPH.
Normal pressure hydrocephalus is diagnosed through a combination of these tests and procedures, ensuring accurate identification and optimal treatment planning.
Your Diagnostic Options
Your doctor will decide which tests you may need based on your symptoms.
Physical and Neurological Exam
Checks for visible signs of NPH, including gait disturbances, cognitive impairment, and urinary incontinence. Health providers also check senses, muscle reflexes, and strength in arms and legs. A detailed review of the medical history is also essential. A patient may have NPH with other conditions like Alzheimer’s. Differential diagnosis is important to distinguish NPH from other neurological disorders.
Diagnostic Imaging
MRI is the preferred imaging technique for diagnosing NPH, as it provides detailed images of brain structures. MRI can reveal ventricular enlargement and cerebral atrophy, which help differentiate NPH from other neurodegenerative conditions. In some cases, an additional cisternogram scan is recommended. Computed tomography (CT) scans aren’t as effective, but they can help rule out other conditions. CSF flow studies, such as aqueductal flow measurements, are also used to assess CSF dynamics and support the diagnosis of NPH.
Lab Tests
Your healthcare provider may suggest a lumbar puncture (lumbar tap) or spinal tap to collect CSF for testing. These diagnostic tests can help analyze CSF and assess brain pressure. CSF drainage procedures, such as temporary drains or continuous subarachnoid drainage, may be performed to see if prolonged CSF removal improves symptoms, aiding in the diagnosis and predicting the benefit of shunt surgery.
Treating NPH
NPH is usually treatable, but healthcare providers must first classify whether a patient has idiopathic or secondary NPH. The most common treatment for normal pressure hydrocephalus is surgery to implant a shunt—a flexible tube that diverts cerebrospinal fluid (CSF) from the brain to another part of the body, usually the abdomen, where it can be absorbed. Unlike many brain-related conditions, NPH doesn’t require extensive use of medications.
Idiopathic Normal Pressure Hydrocephalus
For primary NPH, surgery is often recommended. A special device called a shunt is implanted, with two catheters: one for fluid to enter and another for fluid to flow out. There is a valve between them. If the ventricle has excess fluid, the pressure forces it into the inflow catheter. This opens the valve, and the excess fluid exits through the other catheter, which is the outflow catheter. There are modern shunt valves that can be programmed. NPH shunting is highly effective, especially when the condition is diagnosed and treated sooner. Ask your doctor about side effects.
Secondary Normal Pressure Hydrocephalus
Secondary NPH is curable, provided the condition that caused it is also curable. The treatment depends on the underlying cause. Your doctor or neurologist will check all details, determine how to treat the causing condition, and improve your NPH symptoms.
As NPH has dementia-like symptoms, patients often don’t realize they have the condition. Most often, it is a family member or loved one who identifies the issues. NPH doesn’t go away on its own and needs treatment, and the condition is progressive, with symptoms getting worse in three to six months.
Living with NPH
Living with normal pressure hydrocephalus presents unique challenges, but with proper management and support, many people can maintain a good quality of life. Adapting to changes in mobility may involve using assistive devices, such as canes or walkers, to reduce the risk of falls and improve independence. Addressing bladder control issues, including urinary frequency or incontinence, may require lifestyle adjustments, pelvic floor exercises, or medications as recommended by your healthcare provider.
Cognitive symptoms, such as trouble thinking or mild dementia, can be managed with memory aids, structured routines, and support from family or caregivers. Regular follow-up appointments are essential to monitor for shunt responsiveness, shunt malfunction, or other complications. Connecting with organizations like the Hydrocephalus Association can provide valuable resources, education, and community support for both patients and caregivers.
Emotional well-being is also important, as living with a chronic condition can be stressful. Seeking counseling or joining support groups can help individuals and families cope with the changes brought on by NPH. With a multidisciplinary care team and proactive management, many people with NPH can continue to enjoy meaningful activities and maintain their independence.
Prognosis and Outcomes
The prognosis for individuals with normal pressure hydrocephalus depends on several factors, including how quickly the condition is diagnosed and treated. Early diagnosis and timely surgical treatment, such as shunt insertion or endoscopic third ventriculostomy, can lead to significant improvement in symptoms, especially gait disturbance and bladder control. Many patients experience a noticeable recovery in mobility and cognitive function, particularly if the symptoms have not been present for an extended period.
However, the degree of improvement varies from person to person. Some may continue to have mild dementia or cognitive symptoms, while others may regain much of their previous function. The use of supplemental prognostic tests, such as external lumbar drainage or neuropsychological testing, can help predict which patients are most likely to benefit from shunt surgery. Factors such as advanced age, severe dementia, or the presence of other neurological conditions like Alzheimer’s disease may limit the extent of recovery. Ongoing monitoring is important to detect shunt malfunction or recurrence of symptoms, as prompt intervention can help maintain quality of life.
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If you or a loved one is suffering from sudden changes, memory loss, concentration problems, or walking issues in Westchester or NYC, contact Chester Neurology now. We understand the concerns patients and their respective families face with NPH, and our team is committed to helping. We have all the advanced testing and treatment facilities.
Call us today at (914) 816-1941 or email info@chesterneurology.com to schedule an appointment.
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