Page 775 - TNFlipTest

Toronto Notes 2019 Movement Disorders Neurology N33
• multiplesystematrophy:synucleinopathypresentingaseithercerebellarpredominant(MSA-C, previously olivopontocerebellar atrophy) or parkinsonism predominant (MSA-P, previously nigrostriatal degeneration); both are associated with early autonomic dysfunction (previously Shy- Drager syndrome)
• vascularparkinsonism:multi-infarctpresentationwithgaitinstabilityandlowerbodyparkinsonism; less likely associated with tremor
Huntington’s Disease
Etiology and Pathogenesis
• genetics:autosomaldominantCAGrepeats(withanticipation)inHuntington’sgeneonchromosome4, which leads to accumulation of defective protein in neurons
• pathology:globalcerebralatrophy,especiallyaffectingthestriatum,leadingtoincreasedactivityofthe direct pathway, and decreased activity of the indirect pathway
Epidemiology
• NorthAmericanprevalence4-8/100,000
• meanageofonset35-44yr,butvarieswithdegreeofanticipationfrom5-70yr
Clinical Features
• typicalprogression:insidiousonsetwithclumsiness,fidgetiness,andirritability,progressingover15yr to major NCD, psychosis, and chorea
■ major NCD: progressive memory impairment and loss of intellectual capacity
■ chorea: begins as movement of eyebrows and forehead, shrugging of shoulders, and parakinesia
(pseudo-purposeful movement to mask involuntary limb jerking)
■ progresses to dance-like or ballism, and in late stage is replaced by dystonia and rigidity ■ mood changes: irritability, depression, anhedonia, impulsivity, bouts of violence
• Juvenile-onsetHD(Westphalvariant)characterizedbyParkinsonismanddystonia
Investigations
• MRI
■ enlarged ventricles, atrophy of cerebral cortex and caudate nucleus
• genetictesting
■ expansion of the cytosine-adenine-guanine (CAG) trinucleotide repeats in the HTT gene ■ CAG repeats (>28) on chromosome 4p16.3 that encodes the protein huntingtin
Treatment
• nodiseasealteringtreatment
• psychiatricsymptoms:antidepressantsandantipsychotics • chorea:neurolepticsandbenzodiazepines
• dystonia:botulinumtoxin
Dystonia
Epidemiology
• thirdmostcommonmovementdisorderafterParkinson’sdiseaseandessentialtremor
Clinical Features
• sustainedtwitchingmovementscausedbyco-contractionofagonistandantagonistmuscles
• symptomsexacerbatedbyfatigue,stress,andemotions;relievedbysleeporspecifictactile/
proprioceptive stimuli (‘geste antagoniste’, e.g. place hand on face for cervical dystonia)
• morelikelytobeprogressiveandgeneralizeifyoungeronsetorlegdystonia
Treatment
• localmedical:botulinumtoxin
• systemicmedical:anticholinergics(benztropine),musclerelaxants(baclofen),orbenzodiazepines,
dopamine depletors (tetrabenazine); dopamine for dopa-responsive dystonia
• surgical:surgicaldenervationofaffectedmuscle,stereotacticthalamotomy(unilateraldystonia),
posteroventral pallidotomy, or DBS
Tic Disorders
Definition
• aticisasudden,rapid,recurrent,nonrhythmic,stereotypedmotormovementorvocalization • commoncriteria
■ tics may wax and wane in frequency but have persisted for an extended period of time
■ onset is <18 yr
■ disturbanceisnotattributabletothephysiologicaleffectsofasubstanceoranothermedicalcondition
Clinical Classification
• Tourette’sSyndrome:multiplemotorand≥1vocalticsthathavepersistedfor>1yrsinceonset
• persistent(chronic)motororvocalticdisorder:singleormultiplemotororvocaltics(butnotboth
motor and vocal) that have persisted for >1 yr since onset