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Dystonia 101 (& 102). John Fang, M.D. September 19, 2011. Key Topics. Types of Dystonia: Primary vs. Secondary Dopa-Responsive Kinesigenic Genetic Dystonias Basic Management Strategies. Dystonia Vocabulary. Blepharospasm Craniocervical ( Meige ) Oromandibular Focal Segmental
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Dystonia 101 (& 102) John Fang, M.D. September 19, 2011
Key Topics • Types of Dystonia: • Primary vs. Secondary • Dopa-Responsive • Kinesigenic • Genetic Dystonias • Basic Management Strategies
Dystonia Vocabulary • Blepharospasm • Craniocervical (Meige) • Oromandibular • Focal • Segmental • Hemi- • Generalized • Geste Antagonist (Sensory Trick) • Tardive • ε-Sarcoglycan • TorsinA • Westphal variant • Wilson’s disease
Secondary Dystonia • Drug-induced (D2 blockers, flecainide) • Structural • Psychogenic • Toxic (Mn, CO, CS2, Hymenoptera) • Metabolic • DRD - TH deficiency, sepiapterin, GCH-deficiency • Lesch-Nyhan • PKAN • NBIA
Wilson’s Disease • Excessive copper accumulation due to mutation of the ATP7B gene • Low ceruloplasmin • High urine copper, sometimes requiring penicillamine challenge • Kayser-Fleischer Rings • May affect liver, bone, behavior
Wilson’s Disease Treatment • Acute treatments: • Penicillamine • Trientene • TTMB • Long-term treatments: • Zn • low Cu diet • Liver transplant
Pseudo-Dystonia • Atlanto-axial subluxation • CN IV palsy • Camptocormia (Bent spine) • Pleurotonus (Pisa syndrome)
Degenerative Dystonias • CBD • Alien-limb • Lubag • aka DYT3 • x-linked • Philippines
Tyrosine Hydroxylase Deficiency • TH converts Tyr to DOPA • Tetrahydrobiopterin is cofactor • GTP cyclohydrolase (GCH) • 6-pyruvoyltetrahydropterin synthase (PTPS) • Sepiapterin reductase (SR) • Tetrahydrobiopterin also affects metabolism of nitric oxide, serotonin, and phenylalanine • Sapropterin is FDA approved for PKU
Treatment Options • Anticholinergics • Dopamine agonists or levodopa • GABA agonists (A and B, also intrathecal) • Other anticonvulsants • VMAT inhibitor • Botulinum toxins • Surgical (Myectomy, SDR, DBS, thalamotomy)
Tetrabenazine • Inhibits Vesicular Monoamine Transporter 2 • Typical starting dose = 6.25mg bid • Typical effective dose = 25mg bid • Metabolism affected by CYP2D6 • FDA approved for Huntington’s Chorea • Also effective for tardive dyskinesia and some dystonias • Sleepiness and depression are major SE’s
Botulinum Toxin • Inhibits presynaptic Ach release by destroying SNARE proteins • Dosing can be tricky • FDA approved for cervical dystonia, blepharospasm, and a few other disorders • Typical duration of action = 90-120 days • Weakness is the major SE • Four current formulations: 3 A and 1 B
Botulinum Toxin Formulations • abobotulinumtoxinA (Dysport) • incobotulinumtoxinA (Xeomin) • onabotulinumtoxinA (Botox) • rimabotulinumtoxinB (Myobloc)
Final Points • There are many types and causes for dystonia • Do not miss: • DRD • Wilson’s disease • Pseudo-