370.1 🎓 醫孞生版

370.1.0.1 📌 䞀頁重點

370.1.0.1.1 Tremor

370.1.1 Types

Rest Tremor: - Present at rest, decreases with action - Parkinson disease (pill-rolling, 4-6 Hz) - DRD, drug-induced

Postural Tremor: - With sustained posture (arms outstretched) - Essential tremor (4-12 Hz) - Physiological (enhanced by anxiety, caffeine, fatigue) - Drug-induced

Kinetic/Intention Tremor: - During movement - Cerebellar (intention worsening near target) - Holmes (rubral) tremor

Task-Specific: - Writing tremor - Primary orthostatic tremor (when standing)

370.1.2 Essential Tremor (ET)

  • Most common adult movement disorder
  • Bilateral upper limb postural/kinetic tremor
  • ± Voice, head, jaw
  • Onset variable (peaks bimodal 20s + 60s)
  • Family history 50%
  • Improves with alcohol
  • Treatment:
    • Propranolol 40-320 mg/d
    • Primidone 50-750 mg/d
    • Topiramate, gabapentin, clonazepam
    • Botulinum toxin (head)
    • DBS (Vim thalamic nucleus) for refractory
    • Focused ultrasound (FUS) — non-invasive thalamotomy (FDA approved 2016)

370.1.3 Parkinsonian Tremor

  • Rest, asymmetric onset, pill-rolling
  • See Ch379
370.1.3.0.1 Dystonia

370.1.4 Definition

  • Sustained muscle contraction
  • Twisting + repetitive movements
  • Abnormal posture
  • Often triggered/worsened by voluntary movement
  • May be task-specific

370.1.5 Classification

By Distribution: - Focal (single body part — blepharospasm, cervical dystonia, writer’s cramp) - Segmental (adjacent regions) - Multifocal - Hemidystonia - Generalized

By Etiology: - Primary (isolated) — no other neuro signs, often genetic - Secondary — structural, drug-induced - Heredodegenerative — Wilson, NBIA, Huntington

370.1.6 Common Forms

Cervical Dystonia (Torticollis): - Most common focal in adults - Head turn, tilt, anterior/posterior - Botulinum toxin (Tx of choice)

Blepharospasm: - Involuntary eye closure - Botulinum toxin - Can progress to Meige syndrome (with oromandibular)

Writer’s Cramp: - Task-specific - Botulinum, OT

Spasmodic Dysphonia: - Vocal cord dystonia - Adductor (more common) vs abductor - Botulinum

Dopa-Responsive Dystonia (DRD, Segawa): - Childhood onset - Diurnal worsening - Dramatic response to small dose levodopa - GCH1 mutation usually

DYT1 (TOR1A): - Generalized, early-onset - Ashkenazi Jewish - Limb-onset

370.1.7 Treatment Approach

  • Botulinum toxin (focal/segmental — first-line)
  • Anticholinergics (trihexyphenidyl)
  • Baclofen
  • Benzodiazepines
  • Levodopa trial (rule out DRD)
  • DBS (GPi) for generalized
  • Surgical (selective denervation, intrathecal baclofen)
370.1.7.0.1 Chorea

370.1.8 Definition

  • Irregular, brief, unpredictable, flowing movements
  • Variable distribution
  • Sometimes incorporated into purposeful action (“dance-like”)

370.1.9 Causes

Huntington Disease (HD): - AD, CAG repeat in HTT (≥ 40 abnormal) - Anticipation - Onset 30-50s typically - Triad: chorea + cognitive decline + psychiatric - Atrophy of caudate (“box-car” ventricles) - No disease-modifying therapy - Symptomatic for chorea: tetrabenazine, deutetrabenazine, valbenazine

Sydenham Chorea: - Post-streptococcal - Children - Major Jones criterion for rheumatic fever - Self-limited

Chorea Gravidarum: - Pregnancy - Often history of Sydenham

Drug-Induced: - Levodopa - Antipsychotics (tardive) - Stimulants - Phenytoin - OCPs

Other: - Lupus, antiphospholipid - Stroke (basal ganglia) - Neuroacanthocytosis - Wilson disease

370.1.10 Treatment

  • Tetrabenazine, deutetrabenazine, valbenazine (VMAT-2 inhibitors)
  • Antipsychotics
  • Treat underlying
370.1.10.0.1 Ballism
  • Severe high-amplitude flinging
  • Hemiballism: unilateral, subthalamic nucleus stroke
  • Self-limited often
  • Treatment: dopamine antagonists, tetrabenazine
370.1.10.0.2 Myoclonus

370.1.11 Definition

  • Sudden brief shock-like movements
  • Can be physiological (hypnic jerks)

370.1.12 Types

Cortical: - Action-induced - Often associated with epilepsy - Treatment: valproate, levetiracetam, clonazepam

Subcortical: - Reticular - Brainstem

Spinal: - Segmental - Propriospinal

Negative Myoclonus (Asterixis): - Brief loss of muscle tone - Hepatic encephalopathy, uremia

370.1.13 Causes

  • Post-anoxic (Lance-Adams)
  • Drug-induced (opioids, antidepressants)
  • Metabolic
  • Epilepsy syndromes (juvenile myoclonic epilepsy)
  • Creutzfeldt-Jakob disease
  • Subacute sclerosing panencephalitis (SSPE)
  • Mitochondrial (MERRF)

370.1.14 Treatment

  • Valproate
  • Levetiracetam
  • Clonazepam
  • Piracetam
370.1.14.0.1 Tics

370.1.15 Definition

  • Stereotyped, brief, repetitive movements
  • Suppressible (with effort, but builds urge)
  • Urge preceding (“premonitory”)
  • Can be simple (blinking, throat clearing) or complex (touching, coprolalia)

370.1.16 Tourette Syndrome

  • Childhood onset (5-7 yo typically)
  • Motor + vocal tics > 1 year
  • Comorbidities: OCD, ADHD
  • Treatment:
    • Behavioral: CBIT (comprehensive behavioral intervention)
    • α2 agonists: clonidine, guanfacine
    • Antipsychotics: aripiprazole, haloperidol, risperidone
    • VMAT-2 inhibitors
    • DBS (refractory severe)
370.1.16.0.1 Restless Legs Syndrome (RLS) / Willis-Ekbom

370.1.17 Diagnostic Criteria

  • Urge to move legs
  • Worse at rest
  • Relieved by movement
  • Worse in evening/night

370.1.18 Causes

  • Idiopathic (genetic)
  • Iron deficiency (most common secondary — check ferritin)
  • Pregnancy
  • ESRD
  • Neuropathy
  • Medications (antidepressants, antipsychotics)

370.1.19 Treatment

  • Iron if ferritin < 75
  • α2ÎŽ ligands (gabapentin, pregabalin, gabapentin enacarbil) — first-line now
  • Dopamine agonists (pramipexole, ropinirole, rotigotine patch) — augmentation concern with long-term
  • Opioids (severe refractory)
370.1.19.0.1 Akathisia

370.1.20 Definition

  • Inner restlessness
  • Need to move
  • Different from anxiety
  • Drug-induced (especially antipsychotics, antidepressants, antiemetics)

370.1.21 Treatment

  • Reduce/change offending medication
  • Propranolol
  • Benzodiazepines
  • Anticholinergics
  • Mirtazapine
370.1.21.0.1 Tardive Syndromes
  • After chronic antipsychotic exposure
  • Tardive dyskinesia (oro-facial-lingual, choreoathetoid)
  • Tardive dystonia
  • Tardive akathisia
  • Tardive tremor

370.1.22 Treatment

  • Reduce/discontinue antipsychotic if possible
  • VMAT-2 inhibitors:
    • Valbenazine (Ingrezza) — FDA 2017
    • Deutetrabenazine (Austedo) — FDA 2017
    • Tetrabenazine
  • Switch to clozapine/quetiapine (lower risk)

370.1.22.1 🩺 床邊速查

  • Tremor types: rest (PD), postural (ET), kinetic/intention (cerebellar), task-specific
  • Essential tremor: propranolol + primidone; DBS or FUS thalamotomy refractory
  • Dystonia focal: botulinum toxin first-line
  • Dopa-responsive dystonia: levodopa dramatic response — always trial
  • Huntington: AD, CAG, chorea + cognitive + psychiatric → tetrabenazine/deutetrabenazine
  • Tics + Tourette: CBIT, α2 agonists, antipsychotics, VMAT-2
  • RLS: iron if ferritin < 75; α2ÎŽ ligands first-line now
  • Tardive dyskinesia: VMAT-2 inhibitors (valbenazine, deutetrabenazine)