370.3 🏥 內科專科考前版

370.3.1 Mechanistic Deep Dive

370.3.1.1 Basal Ganglia Circuitry

  • Direct pathway: facilitates movement
  • Indirect pathway: inhibits unwanted movement
  • Hyperkinetic: ↓ indirect (chorea, ballism)
  • Hypokinetic: ↑ indirect / ↓ direct (Parkinson)

370.3.1.2 VMAT-2 Mechanism

  • Inhibits vesicular monoamine transporter
  • ↓ Dopamine packaging into vesicles
  • ↓ Dopaminergic transmission
  • For hyperkinetic disorders

370.3.1.3 Dopa-Responsive Dystonia Pathophysiology

  • ↓ BH4 (tetrahydrobiopterin) cofactor
  • ↓ Tyrosine hydroxylase activity
  • ↓ Dopamine synthesis
  • Replaceable with levodopa

370.3.2 Recent Trials & Updates

370.3.2.1 Valbenazine + Deutetrabenazine for TD

  • KINECT-3 + ARM-TD trials
  • FDA 2017
  • Effective

370.3.2.2 Focused Ultrasound (FUS) Thalamotomy

  • Non-invasive
  • FDA 2016 ET
  • 2020 PD tremor
  • 2021 dyskinesia
  • Increasing utilization

370.3.2.3 DBS Advances

  • Directional leads
  • Adaptive DBS
  • Closed-loop systems

370.3.2.4 Anti-IgLON5 Syndrome

  • Autoimmune
  • REM + non-REM sleep disorder + chorea + parkinsonism + bulbar
  • IgLON5 antibodies
  • Immunotherapy partial response

370.3.2.5 Hereditary Spastic Paraplegias (HSP)

  • 80 genetic subtypes

  • Spastic paraparesis
  • Most autosomal dominant

370.3.2.6 NBIA (Neurodegeneration with Brain Iron Accumulation)

  • PKAN, INAD, others
  • “Eye of the tiger” on MRI
  • Dystonia + parkinsonism + cognitive
  • Mostly children/young adults

370.3.3 High-Yield Specialist Points

370.3.3.1 Wilson Disease + Movement

  • Tremor + dystonia + parkinsonism + dysarthria + psychiatric
  • KF rings
  • Low ceruloplasmin, high urine copper
  • Treat with chelators or zinc

370.3.3.2 Functional (Psychogenic) Movement Disorders

  • Inconsistent
  • Variable
  • Distractible
  • Suggestibility
  • Often female, young
  • CBT + physical therapy

370.3.3.3 Stereotypies

  • Repetitive, purposeless
  • Autism, intellectual disability
  • Often comforting

370.3.3.4 Hemifacial Spasm

  • Unilateral facial twitching
  • Vascular compression CN VII often
  • BTX
  • Microvascular decompression

370.3.3.5 Myoclonus-Dystonia (DYT11)

  • ε-Sarcoglycan
  • Alcohol-responsive

370.3.3.6 Paroxysmal Dyskinesias

  • PKD (kinesigenic): triggered by movement; brief; carbamazepine
  • PNKD (non-kinesigenic): unprovoked; longer; alcohol, caffeine triggers
  • PED (exercise-induced)

370.3.3.7 Cervical Dystonia BTX Protocol

  • Multiple muscles target
  • Sternocleidomastoid, splenius, trapezius, etc.
  • Repeat q3-4 months
  • Onset 1-2 weeks, peak 4-6 weeks

370.3.3.8 Spasticity vs Dystonia

  • Spasticity: velocity-dependent ↑ tone, UMN syndrome
  • Dystonia: sustained contraction, abnormal posture, often action-induced

370.3.3.9 Apraxia

  • Loss of ability to perform learned motor act
  • Despite intact motor/sensory/coordination
  • Different from movement disorder
  • Cortical (parietal, frontal)

370.3.4 Pearls

  • Tremor: rest (PD), postural (ET), kinetic (cerebellar)
  • ET: propranolol/primidone, DBS, FUS
  • Dystonia focal: BTX first-line
  • DRD: levodopa trial always
  • HD: AD, CAG, chorea + cognitive + psychiatric; tetrabenazine
  • Sydenham: post-strep
  • Tourette: motor + vocal tics; CBIT
  • RLS: iron + α2ÎŽ ligands first-line now
  • Tardive dyskinesia: valbenazine, deutetrabenazine
  • Wilson: always consider in young with movement
  • Myoclonus: cortical (epilepsy), post-anoxic, asterixis (metabolic)