What’s Wrong With Billy Joel

By Eva Briggs, M.D.

Like many Billy Joel fans, I was sad that he had to cancel his scheduled Syracuse concert because he was diagnosed with normal pressure hydrocephalus (NPH). This condition is uncommon but not rare and probably underdiagnosed.

A review of brain anatomy and physiology will help to understand NPH.

Your brain has specialized ependymal cells that produce cerebrospinal fluid (CSF). This clear colorless fluid surrounds the brain and spinal cord and also flows into four cavities in your brain called ventricles. CSF helps cushion the brain, regulate blood flow and transports waste products away. Other specialized brain areas resorb CSF. Normally the amount of CSF produced each day equals the amount resorbed, assuring a constant amount in the central nervous system.

When CSF production exceeds resorption, the CSF volume increases. Too much CSF is called hydrocephalus. In NPH, excess CSF expands the ventricles which compress the surrounding brain tissue. In NPH the process is slow and insidious. Although the central nervous system accumulates too much fluid, the pressure of the fluid doesn’t rise, thus the “normal pressure” part of the name. About half of cases are idiopathic, which means the cause is unknown. NPH can also be secondary to trauma, infection or bleeding. There are other forms of hydrocephalus caused by excess CSF production or obstruction to the normal circulation of CSF.

Three symptoms are considered classic for NPH, although not all patients have all three and they don’t necessarily develop simultaneously. The first is gait disturbance or trouble walking. The gait becomes slow, wide-based and unsteady. It can worsen to require the use of a cane or walker and in severe cases lead to inability to walk. This abnormal gait can resemble the gait of a person with Parkinson’s disease. The second symptom is progressive cognitive impairment or dementia. The third symptom is urinary frequency and/or incontinence. This often occurs late in the disease.

The diagnosis is made by history, exam and tests such as lumbar puncture (spinal tap) and imaging such as MRI.

The first-line treatment is surgical placement of a shunt to drain the excess CSF. The most common procedure is the ventriculoperitoneal (VP) shunt. This consists of a catheter with a one-way valve that drains CSF from the brain ventricles to the abdominal cavity (peritoneum.) The fluid is then resorbed in the abdomen. This procedure has risks: infection, shunt obstruction, excess or insufficient drainage and bleeding. The earlier in the course of disease that a shunt is placed, the better the outcome.

There are no medications known to provide long term relief of NPH. A medicine called acetazolamide can provide brief temporary relief. Transient improvement after a dose of acetazolamide is often a good predictor of how well a patient might respond to placement of a shunt.

Although the cause of idiopathic NPH remains unknown, its prevalence increases with age. As many as 3% of people older than 65 develop NPH. Because the symptoms overlap with other conditions such as Parkinson’s and Alzheimer’s, many cases of NPH are probably misdiagnosed.

The prognosis depends on the underlying cause and how long the disease has been present. Patients with a successful VP shunt often do very well and resume normal activities.