First clinical guidelines to help improve the diagnosis and treatment of people with normal pressure hydrocephalus

Sep 21 2005

An international team of medical experts led by a Virginia Commonwealth University researcher has established the first clinical guidelines to help improve the diagnosis and treatment of people with normal pressure hydrocephalus, a debilitating condition in the brain that often goes undiagnosed or is misdiagnosed as Alzheimer's or Parkinson's disease.

The international advisory panel led by Anthony Marmarou, Ph.D., professor of neurosurgery and director of research in the Virginia Commonwealth University School of Medicine's Department of Neurosurgery, developed the guidelines for normal pressure hydrocephaly, NPH, which appeared as a supplement to the September edition of Neurosurgery, the official, peer-reviewed journal of the Congress of Neurological Surgeons.

"NPH was first identified in the mid-1960s," said Marmarou. "Since that time, there have been several thousand articles published in the field. We've taken all this information and reached consensus on how to diagnose and treat these patients."

The new guidelines deal exclusively with idiopathic NPH, the form of NPH that develops from no known cause. Doctors are advised of which tests to use to make a diagnosis and how to determine if treatment with a shunt – a flexible tube and valve – will help reverse or improve the condition. NPH is treated with the surgical implantation of a shunt that drains excess fluid from the brain and relieves pressure in the skull.

"In the early days doctors were reluctant to treat NPH because they didn't think treatment would help," he said. "We now have evidence that shows a combination of diagnostic tests can predict 90 percent of the time if a patient will respond to a shunt."

According to the guidelines, physicians should carefully review the patient's clinical history and conduct a physical exam and other diagnostic procedures including brain imaging with the use of a magnetic resonance imaging (MRI) or a computerized tomography (CT) Scan.

If images reveal enlarged brain ventricles, a lumbar puncture or spinal tap should be performed to see if symptoms are relieved. If responsive, doctors and patients should then weigh the risks and benefits of the surgery before having a shunt implanted.

NPH is a progressive neurological disorder that affects about 375,000 people in the United States and typically occurs in adults 55 years and older. It results from a build-up of cerebrospinal fluid, which causes the ventricles of the brain to enlarge. This enlargement stretches the nerve tissue of the brain, causing a classic triad of symptoms that includes difficulty walking or a shuffling gait, dementia or mild confusion, and urinary urgency or incontinence. Many patients become extremely debilitated and require constant care. NPH, however, is one of the only forms of dementia that can be controlled or reversed with treatment.

The five-member medical advisory panel was assembled in September 2000. The consensus guidelines were presented and reviewed by panels of experts in the United States, Europe and Asia.