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.
Symptoms
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 underdiagnosed 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.
