A condition where an excessive amount of cerebrospinal fluid accumulates within the skull, hydrocephalus was, in older times, referred to as “water on the brain.” A clear fluid that surrounds and protects both the brain and spinal cord from impacts and jarring, cerebrospinal fluid also acts as a transporter of nutrients down the spinal cord and well as a remover of waste and regulator of pressure on the brain—too much pressure, as in those suffering from hydrocephalus, can lead to permanent brain damage and death.

The normal pressure form of hydrocephalus occurs in adults and is very slow to develop. With this condition, cerebrospinal fluid is partially blocked from leaving the ventricles of the brain and slowly builds up over time, abnormally enlarging the ventricles. It’s therefore not detected immediately as it doesn’t cause a drastic and sudden change in pressure within the brain.

Normal pressure hydrocephalus is typically seen in individuals over the age of 60 (it’s thought to affect less than one percent of the population over the age of 65) and can result from an injury to the head; a brain tumor; a subarachnoid hemorrhage; infection; or from complications after surgery. Symptoms, which again appear very slowly, can include changes in cognitive function and memory loss; problems with balance and coordination; and incontinence.

A physician who suspects that a condition of normal pressure hydrocephalus exists will review a patient’s medical history and conduct physical and neurological tests that will look at brain function as it relates to thinking, mobility etc. A lumbar puncture to collect and test cerebrospinal fluid pressure may also be performed.

Once it begins, normal pressure hydrocephalus will most likely get worse with time and can lead to death if not treated. Surgeries are the most common treatments and will seek to relieve any pressure on the brain being caused by the accumulation of cerebrospinal fluid. This is accomplished by removing any obstruction causing a blockage or using a shunt to allow fluid to flow away from the brain and into a part of the body where it will be safely absorbed. Also, a surgeon may make a small hole in the bottom of a ventricle and create a new path for fluid to drain away.