Differential Diagnosis in Neurology

14.6. Tic Disorders

• General considerations:
  • Definition: repetitive intermittent stereotypic movements that include the following features:
    • Sudden and rapid
    • Predominantly clonic
    • Temporarily suppressible for variable lengths of time
    • Preceded by a strong urge to make the specific movement
    • Spectrum of tics:
      • Simple blinks or jerks
      • Complex coordinated movements and vocalizations
      • Clonic
      • Choreic
      • Dystonic
• Clinical features:
  • Simple tics:
    • One group of muscles is involved
    • Often start around the eyes or mouth and then spread to the neck; shoulders or generalize.
    • Consist of:
      • Eye blinking
      • Nose twitch
      • Jerking extension of the head
      • Shoulder shrug
  • Complex tics:
    • A stereotypic series of movements that involve different groups of muscles; a coordinated sequence of movements.
    • Neck turning, snorting and hand movements
    • Linguistically meaningful utterances
  • Chronic tic
  • Tonic or dystonic tic:
    • Slower in onset
    • Prolonged
  • Vocal tics:
    • Motor tics that involve respiratory, laryngeal, pharyngeal, oral and nasal musculature
    • Complex vocalizations:
      • Coprolalia
      • Echolalia

Differential Diagnosis of Tic Disorders

• Drugs:
  • Levodopa
  • Neuroleptics
  • Carbamazepine
  • Phenytoin
  • Lamotrigine
  • Phenobarbital
• Basal ganglia diseases:
  • Neuroacanthocytosis
  • Encephalitis lethargica
  • Vascular disease
  • Carbon monoxide poisoning
  • Carbon disulfide poisoning
  • Trauma
  • Gilles de la Tourette syndrome
  • Obsessive compulsive disorders

Gilles de la Tourette Syndrome (GTS)

• General considerations:
  • Genetics:
    • AD
    • Bilinear or polygenic
  • Prevalence between 1–10 per ten thousand children
• Clinical features:
  • Childhood onset; prior to age 22
  • Simple or complex motor tics
  • Vocalizations:
    • Sniffing, throat clearing, spitting
  • Complicated motor activity:
    • Jumping, kicking, bizarre gait
  • Coprolalia (obscene language)
  • Copropraxia (obscene gesturing)
  • Severe Gilles de la Tourette (GTS):
    • Elaborate sequential multiple complex movements
    • Echolalia and coprolalia
  • Mild GTS:
    • Tics are primarily in the face
    • Minor vocalization
• Associated disorders:
  • Attention deficit hyperactivity disorder
  • Obsessive compulsive disorders
  • Behavior disorders
• Pathology:
  • Atrophy of caudate and putamen (versus congenital smallness)