Abstract Details

Title Levodopa-responsive Parkinsonism with Normal DAT Scan and Peripheral Synucleinopathy: Benign MSA Versus PD with False Negative DAT?

Topic Movement Disorders

Presentation(s) P9 - Poster Session 9 (11:45 AM-12:45 PM)

Poster/Presentation
Number 5-027

Objective To describe the clinical features and skin biopsy of patients with levodopa-responsive parkinsonism with normal dopamine transporter imaging (DaT) scans.

Background

Multiple System Atrophy (MSA) parkinsonism type (MSA-P) can be mistaken as Parkinson's disease (PD) especially when it presents with asymmetric tremor and bradykinesia. MSA is often suspected if their DaT scans are normal and autonomic symptoms are prominent. Rarely, MSA-P may progress very slowly, and have sustained levodopa-responsiveness and even levodopa-induced dyskinesias. This variant of MSA-P is referred to as Benign MSA.

Design/Methods Retrospective chart review of all patients seen in one center from 2012-2024 with levodopa-responsive parkinsonism with normal DaT scans and P-SYN(+) skin biopsies. Patients with dementia and prominent hallucinations were excluded.

Results 13 patients were identified with average age at time of biopsy=70.2yrs (range-54-83). Mean age at onset of motor symptoms=62.8yrs (range 49-78). Though all 13 had normal initial DaT scans, repeat DaT scans were done in 7/13 patients 1-8yrs later (mean=3.86yrs), of which 3/7(43%) became abnormal. Baseline mean motor UPDRS=28.2(range=12-41). All 13 were treated with levodopa, with all having subjective benefit. Objective mean optimal improvement of motor UPDRS with levodopa was 40% (range-20-62%). 5/13(38%) developed motor fluctuations, whereas 2/13(15%) developed levodopa-induced dyskinesias. Mean total daily levodopa dose at last follow-up was 534.6mg (range 200-1500mg). To date, length of levodopa-responsiveness has ranged from 1-7yrs (mean=3yrs). SCOPA-Autonomic was available for 9/13 with mean=20.6(range=9-30). Cardiac MIBG was done in 8/13: all were either normal or only mildly abnormal.

Conclusions Longitudinal follow-up of DAT(-), P-SYN(+) non-demented parkinsonism patients with sustained levodopa-responsiveness reveals that around 1/3 may have abnormal follow-up DAT scans, thus most likely representing PD with initial false(-) DAT scans. The majority though have normal follow-up DAT scans which may represent Benign MSA. The presence of prominent dysautonomia and normal or mildly abnormal cardiac MIBG favor Benign MSA over PD.

Authors/Disclosures
Virgilio Gerald H. Evidente, MD, FAAN (Movement Disorders Center of Arizona) PRESENTER	Dr. Evidente has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Revance. Dr. Evidente has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Abbvie. Dr. Evidente has received personal compensation in the range of $10,000-$49,999 for serving on a Speakers Bureau for Teva. Dr. Evidente has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Medtronic. Dr. Evidente has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Neurocrine. Dr. Evidente has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Amneal. Dr. Evidente has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Abbvie. The institution of Dr. Evidente has received research support from CND. The institution of Dr. Evidente has received research support from Aeon. The institution of Dr. Evidente has received research support from Bukwang Pharmaceuticals. The institution of Dr. Evidente has received research support from Jazz Pharmaceuticals. The institution of Dr. Evidente has received research support from Scion Neurostim. The institution of Dr. Evidente has received research support from Theravance Biopharma. Dr. Evidente has received research support from Cerevance. Dr. Evidente has received research support from Ipsen.
Todd D. Levine, MD (Honor Health)	Dr. Levine has received personal compensation for serving as an employee of CND life sciences . Dr. Levine has received personal compensation in the range of $100,000-$499,999 for serving as a Consultant for Nufactor. Dr. Levine has received personal compensation in the range of $50,000-$99,999 for serving as an Expert Witness for PNA. Dr. Levine has or had stock in CND Life Sciences.Dr. Levine has or had stock in Corinthian reference lab.
Roy L. Freeman, MD (Beth Israel Deaconess Hosp)	Dr. Freeman has received personal compensation in the range of $50,000-$99,999 for serving as a Consultant for Cutaneous Diagnostic Life Sciences. Dr. Freeman has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Vertex. Dr. Freeman has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Theravance. Dr. Freeman has received personal compensation in the range of $10,000-$49,999 for serving as an officer or member of the Board of Directors for Inhibikase. Dr. Freeman has received personal compensation in the range of $10,000-$49,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for Elsevier. The institution of Dr. Freeman has received research support from NIH. The institution of Dr. Freeman has received research support from Theravance. The institution of Dr. Freeman has received research support from Biohaven. The institution of Dr. Freeman has received research support from Lundbeck. Dr. Freeman has received research support from Regeneron.
Danica Evidente	Danica Evidente has nothing to disclose.
Christopher H. Gibbons, MD, FAAN (Beth Israel Deaconess Medical Center)	Dr. Gibbons has received personal compensation for serving as an employee of CND Life Sciences. Dr. Gibbons has or had stock in CND Life Sciences.Dr. Gibbons has received publishing royalties from a publication relating to health care.

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