NPH and Comorbidities

It’s important to realize that normal pressure hydrocephalus (NPH) can frequently co-exist with other age-related neurologic and medical conditions that may produce similar symptoms. If a shunt is working properly but gait, cognitive and urologic symptoms persist or worsen, here are some alternative comorbid diagnoses that should be considered.

Dementia

Dementia is not a specific disease. It’s a descriptive term that denotes a group of symptoms associated with a decline in memory, cognitive skills, perception, personality changes, or impaired intellectual functioning that severely interferes with normal activities and relationships. Dementia causes disturbances of multiple higher brain functions, including memory, thinking, orientation, calculation, comprehension, learning capacity, language challenges (writing, speaking, and reading), impaired visuospatial abilities, impaired reasoning, and poor judgment.

Dementia has multiple potential causes, of which some are reversible or partially reversible and some are not.

Dementia-like conditions that can potentially be reversed or partially reversed include, but are not limited to, infections and immune disorders, metabolic problems and endocrine abnormalities, nutritional deficiencies, depression, reactions to medications, and NPH.

Those that are not reversible include, but are not limited to, neurodegenerative diseases (e.g. Alzheimer’s disease (AD), Parkinson’s disease (PD), Dementia with Lewy Bodies, Frontotemporal dementia, cortico-basal degeneration, progressive supranuclear palsy), vascular dementia (e.g. stroke, leukoaraiosis, Binswanger disease), and dementia due to prior head trauma (e.g. chronic traumatic encephalopathy, subdural hematomas).

Gait and Balance

Other symptoms you may develop as part of the aging process include gait and balance disturbances. Gait refers to the process of walking.  Balance refers to the ability to maintain postural stability. Gait and balance disorders are common in older adults. 35% of adults older than 70 have abnormal gait and gait and balance disorders are major causes of falls in the older population.

Symptoms of impaired gait and balance that are commonly seen in NPH include difficulty initiating gait (feet stuck to the floor), freezing, hesitancy, altered posture, slow shuffling steps, trouble maintaining a normal rhythm of walking, episodes of involuntary acceleration, unsteadiness, and difficulty with turns or uneven surfaces. None of these symptoms, however, are specific for NPH and can occur in a variety of other neurologic and non-neurologic conditions. Balance symptoms that are not associated with NPH can include vertigo, lightheadedness, dizziness, and motion sickness.

There are both neurologic and non-neurologic causes of gait impairment. Neurologic causes include leg weakness or incoordination due to stroke, muscle or spinal cord disorders, Parkinson’s disease and related neurodegenerative problems, peripheral neuropathy, and vestibular disorders affecting the inner ear or associated brain circuitry. Non-neurologic causes include arthritis, cardiac disease, chronic lung disease, peripheral vascular disease, and impaired vision.

Urinary Incontinence

Urinary incontinence can happen to anyone, but it is more common in the aging process and women are more susceptible. Urinary incontinence means the loss of bladder control. Ultimately, symptoms can range from mild leaking to uncontrollable wetting.  Incontinence in NPH is due to an overactive bladder. This can frequently occur in women without neurologic disease.  It can also occur in men with an enlarged prostate. Other neurologic explanations can include stroke or spinal cord disorders. Alzheimer’s disease and other neurodegenerative dementias are also commonly associated with incontinence, particularly in the middle and more advanced stages.

The types of urinary incontinence include stress incontinence, urge incontinence (or overactive bladder), and other causes that exist, such as prostate problems and nerve damage.

If the shunt is working it may be necessary to consider changing or re-programming the shunt valve to achieve a higher degree of cerebrospinal fluid diversion. If this is not helpful or indicated, alternative neurologic explanations such as those described above should be considered as other specific treatments may be available.

For more detailed information, visit Complications of a Shunt System.

Epilepsy

Epilepsy is common in people with hydrocephalus. Epilepsy is a brain disorder that causes unprovoked, recurring seizures. A person experiences a seizure when there is excessive and abnormal brain cell activity. This often produces uncontrolled movements, decreased responsiveness, and/or unconsciousness.

Information you can trust! This article was produced by the Hydrocephalus Association, copyright 2021. We would like to thank James B. Golomb, MD for his valuable contribution and expert input.