DaTscan helps UMMC physicians properly diagnose Parkinson's disease
By Patrice Guilfoyle
Madison resident Gan Nelson presented Dr. Alexander Auchus with somewhat of a quandary. Nelson had been diagnosed with Parkinson's disease in 2006, but her symptoms, more than five years later, only exhibited on her left side. The tremor and rigidity often associated with Parkinson's had not shifted across her body.
"I was doubtful it was Parkinson's disease because after a year, it's usually bilateral," said Auchus, professor and McCarty chair of neurology.
Enter Dr. Vani Vijayakumar, professor of radiology and chief of the Division of Nuclear Medicine. She recently began offering a procedure using DaTscan, an imaging radiopharmaceutical drug that helps a physician determine if certain symptoms are related to an essential tremor or Parkinsonian syndrome, such as Parkinson's disease, progressive supranuclear palsy or multiple-system atrophy.
The Medical Center is one of two places in the state to offer DaTscan, a new drug recently approved by the FDA. Vijayakumar said DaTscan is a significant breakthrough for patients suffering from Parkinsonian symptoms because it helps physicians to make a correct diagnosis and to prescribe an appropriate course of treatment.
"A lot of patients have tremor but not all of them have Parkinson's disease. DaTscan can help physicians know what to do," she said.
In Nelson's case, the procedure answered Auchus' question of proper diagnosis. A brain image confirmed that the levels of dopamine, a chemical that controls movement, were abnormal. Nelson had Parkinson's disease, just an atypical presentation of the illness.
"It was very helpful in convincing me where to go when I doubted the diagnosis," Auchus said. "That empowered me and the patient to change therapies."
Nelson said the new drug therapy has helped manage her disease.
"I've gotten rid of the stiffness. The main thing for me is it got me on the right medications. I'm really not having problems with it," she said.
Vijayakumar said before DaTscan, diagnosing Parkinson's disease wasn't so clear cut. The process involved physicians using their experience and best judgment based on symptoms.
DaTscan is injected into the bloodstream to help the doctor assess the level of a dopamine. Parkinsonian syndromes occur when the brain is not getting enough of the dopamine it needs to perform certain functions. This affects the ability of the brain to control movement and other muscle functions.
Brain SPECT imaging is performed three to six hours after intravenous injection of DaTscan, which takes about 30 minutes.
"It was very simple," Nelson said. "It helped us rule out everything except the Parkinson's disease."
Sensitivity reactions (such as rash or itching) have been reported after DaTscan administration. In clinical trials, the most common side effects were headache, nausea, dry mouth or dizziness.