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NEW YORK (Reuters Health) - The cause of a parkinsonian syndrome is not always clear when the symptoms first appear, and the diagnosis often changes over time, according to a paper in the Journal of Neurology, Neurosurgery, and Psychiatry. Use of rigid criteria does not necessarily help make the diagnosis.
Parkinsonian syndrome refers to conditions that have the symptoms of Parkinson's disease, such as tremors, stooped posture, slowness, and shuffling gait. The term is simply used to describe a patient's symptoms; Parkinson's disease may or may not be the actual cause. For instance multiple small strokes can cause a parkinsonian syndrome.
"Accurate diagnosis of Parkinson's disease is important both in clinical practice, where it will influence management, and in research, where the validity of findings may be compromised if studies include (different) conditions," Dr. Carl Counsell, of the University of Aberdeen, UK, and colleagues write.
The report describes 66 patients who were followed for at least one year after an initial diagnosis of "possible or definite parkinsonian syndrome."
After follow-up of around 29 months, the clinical diagnosis had changed in 22 patients (33 percent). Most of the changes (82 percent) occurred in the first year. Reason for the modified diagnoses included development of additional clinical features, early thinking impairment, x-ray results, poor response to drug therapy, and lack of disease progression.
More than a third of those who were misdiagnosed with Parkinson's disease were eventually determined to have a related problem called dementia with Lewy bodies.
As part of their study, the researchers applied research criteria using records from patients' initial evaluation and latest yearly follow-up. In 8 patients (12 percent), the latest clinical diagnosis differed from the research-based diagnosis.
"The major implication is that doctors making the diagnosis of a parkinsonian syndrome need to be aware of the potential inaccuracy of the initial diagnosis and be prepared to review patients regularly (probably at least yearly) and change it as appropriate," Counsell said in an interview with Reuters Health. "A change in diagnosis may also require a change in treatment, either stopping unnecessary treatment or starting new treatment."
SOURCE: Journal of Neurology, Neurosurgery, and Psychiatry, November 2008.