NEW YORK – One reason to (PD) is that a small but substantial proportion of patients with PD-like symptoms have a different diagnosis, according to an expert overview at the International Conference on Parkinson’s Disease and Movement Disorders.
Ted Bosworth/MDedge News
Dr. A.V. Srinivasan
“Fifteen to 20% of patients treated for Parkinson’s disease, even in the most established centers of excellence, do not have Parkinson’s disease on necropsy,” said A.V. Srinivasan, MD, PhD, DSc, of The Tamil Nadu Dr. M.G.R. Medical University, Chennai, India.
This does not preclude benefit from antiparkinson drugs in those patients with PD-like symptoms but a different etiology. Many can benefit from increased dopamine availability, even in the absence of PD, but it emphasizes the complexity of clinical diseases associated with diminished dopamine function, according to Dr. Srinivasan. He characterized this complexity as a reason to avoid a regimented approach to PD management.
“You can just imagine how much this influences our data analysis,” said Dr. Srinivasan, referring to clinical trials designed to generate evidence-based treatment. “We should remember that we should not be too statistically oriented,” he added, citing the adage that “statistics can cause paralysis in your analysis.”
PD is associated with a vast array of neurologic and physical symptoms attributable to PD that overlap with other neurologic disorders, which is the reason that a definitive diagnosis is challenging, according to Dr. Srinivasan. Listing symptoms that should prompt consideration of an alternative diagnosis, Dr. Srinivasan said hallucinations suggest diffuse Lewy body disease, myoclonus suggests corticobasal degeneration, and amyotrophy suggests multiple system atrophy.
“These are only clues, however,” said Dr. Srinivasan, suggesting their presence should prompt consideration of alternative diagnoses, but their absence does not confirm PD.
In some cases, further work-up with one or more of the array of increasingly sophisticated imaging strategies, such as the combination of SPECT and PET, might help clinicians reach a more definitive diagnosis of the underlying pathology, a step that might guide use of dopaminergic therapies. However, effective treatment of PD symptoms does not depend on a definitive diagnosis.
Rather, Dr. Srinivasan advocated an open mind to the management of symptoms, which he indicated are best addressed empirically. As PD or other progressive movement disorders advance, the goal is to keep patients functional and comfortable.
This includes managing patients beyond prescription drugs to address such complications as dysphagia or impaired balance. He advocated practical solutions for causes of impaired quality of life such as soft foods to facilitate swallowing or walkers to keep patients ambulatory. No option that leads to symptom relief should be discounted, including alternative therapies.
“Some clinicians are strongly opposed to nontraditional therapies, such as naturopathy and homeopathy, but these have all been used in Parkinson’s,” Dr. Srinivasan said. Although he did not present data to show efficacy, he indicated that relief of symptoms and improvement of quality of life is the point of any treatment, which should be individualized by response in every patient.
And individualized therapy – in relationship to patient age – is particularly important, according to Dr. Srinivasan. While younger patients typically tolerate relatively aggressive therapies aimed at both PD and its specific symptoms, older patients may accept less ambitious functional improvements to achieve an adequate quality of life.
“After 70 years of age, every additional year is a bonus. After 80 years, every week is a bonus. After 90 years, every minute is a bonus,” said Dr. Srinivasan, in emphasizing an appropriate clinical perspective.