Normal pressure hydrocephalus (NPH) develops slowly over time and is primarily restricted to older adults. It is an accumulation of cerebrospinal fluid (CSF) within cavities called ventricles inside the brain. Every day, the average adult produces about one pint of CSF, which cushions the brain from injury and carries nutrients to and waste products away from the brain. In NPH, the CSF is produced in normal amounts but it is prevented from being normally re-absorbed.
The ventricles of the brain enlarge to accommodate the increased volume of CSF. Consequently, when measured by lumbar puncture (spinal tap), remains normal. However, brain tissue is damaged or destroyed when compressed by the fluid-filled ventricles. If this process has an identifiable cause that can be corrected, the symptoms may reverse or at least stop getting worse. If there is no identifiable cause, the disorder is often progressive.
The symptoms caused by this disorder include urinary incontinence, progressive gait ataxia, and cognitive deficits. The latter can include disorientation, confusion, apathy, decreased attention span, mental slowing, anxiety, and frequently memory loss. These symptoms resemble those of primary dementias. Although published rates vary widely, NPH may account for about 5% of all dementias.
Because these same symptoms can characterize the aging process, NPH is often under diagnosed or misdiagnosed as other conditions common among the elderly such as Parkinson's or Alzheimer's disease. Even when NPH is diagnosed, neurologists and neurosurgeons may hesitate to institute treatment because traditional approaches to management with fixed flow shunts have been associated with high rates of serious complications. As a result, individuals with NPH can lose many years of what otherwise might have been an active, vigorous retirement. In the United States alone, this menacing disease afflicts 300,000 to 400,000 people over the age of 65 years.
Gait disturbances. These range from mild imbalance to the inability to stand or walk. Gait may be widespread, short, slow and shuffling, or individuals may have trouble picking up their feet. Gait disturbance is often the most pronounced symptom and the first to become apparent.
Mild dementia. Loss of interest in daily activities, forgetfulness, difficulty dealing with routine tasks, and short-term memory loss are characteristic.
Impairment in bladder control. Severity ranges from urinary frequency and urgency in mild cases to complete loss of bladder control (urinary incontinence) in more severe cases.
The normal process of aging can lead to softening of the brain. This can cause the ventricles in your brain–hollow areas where CSF accumulates–to expand as a result of fluctuations in the amount and pressure of CSF. This expansion and the resulting pressure it puts on other areas of your brain can cause the classic symptoms of NPH. In some cases, NPH can develop as the result of head injury, cranial surgery, subarachnoid hemorrhage, meningitis, tumors, cysts, subdural hematomas, bleeding during surgery, and infections.
Although there is no known way to prevent NPH, establishing a healthy lifestyle, including maintaining an appropriate weight, not smoking, and regular exercise, may help avoid conditions such as high blood pressure, heart disease, diabetes, and stroke that might contribute to NPH.
For more information about NPH, please call 1-800-BARROW1 (227-7691) or 602-406-6281.