Movement Disorders: Introduction

Overview of Movement Disorders

• Classified as hyperkinetic (excessive movement) or hypokinetic (reduced movement).
• Hyperkinetic disorders: include tremors, chorea, dystonia, myoclonus, tics, and stereotypical movements.
• Patients can show mixed symptoms from both categories, exemplified by Parkinson's disease presenting with shuffling gait (hypokinetic) and resting tremors (hyperkinetic).
• Classification is essential for accurate diagnosis and management.

Tremors

• Classified based on behavior patterns and observation during specific actions.
• Types:
  • Resting tremors: prevalent in conditions like Parkinson's disease.
  • Action tremors: associated with cerebellar lesions, found in essential tremors.
• Differential diagnosis relies heavily on identifying the tremor type for effective management.

Hyperkinetic Movement Disorders

Chorea

• Characterized by involuntary, abrupt, and irregular body movements.
• Pathophysiology involves basal ganglia damage, disrupting motor control.
• Associated Conditions:
  • Huntington's Disease: caused by CAG repeat expansion affecting basal ganglia.
  • Wilson's Disease: copper metabolism disorder, leads to chorea with Kayser-Fleischer ring around the iris.
  • Drug-induced chorea: often consequence of neuroleptics or dopaminergic medications.
  • Toxic exposures: ethanol and carbon monoxide can result in chorea-like movements.
  • Thyrotoxicosis: hyperthyroidism can also induce similar movements.
  • Immunological disorders: SLE and post-streptococcal conditions related to chorea development.

Dystonia

• Defined by sustained muscle contractions resulting in repetitive twisting or abnormal postures.
• Pathophysiology involves basal ganglia dysfunction disrupting motor commands.
• Types:
  • Focal Dystonia: affects a specific area (e.g., blepharospasms, spasmodic dysphonia).
  • Segmental Dystonia: impacts adjacent regions.
  • Generalized Dystonia: affects multiple areas throughout the body.
• Causes:
  • Idiopathic Dystonia: no identifiable cause, includes torsion dystonia linked to genetics.
  • Secondary Dystonia: stems from cerebral issues, neurodegeneration, hypoxic injury, and drug-related causes.

Myoclonus

• Sudden, lightning-like muscle contractions, typically brief and abrupt.
• Quick like dystonia but characterized by distinct muscle contractions.
• Causes range from physiological factors and epilepsy to metabolic disorders and brain trauma.
• Management often includes benzodiazepines (e.g., clonazepam) and antiepileptics (e.g., valproate) to reduce the frequency and intensity of movements.

Tics

• Abrupt, coordinated, repetitive movements or sounds.
• Suppression of tics can lead to anxiety, commonly observed in Tourette’s syndrome.
• Coprolalia refers to involuntary swearing or inappropriate remarks in some patients with Tourette's.
• Management strategies focus on behavioral therapies and medications, depending on severity.

Clinical Considerations

• A 75-year-old with a shuffling gait may also exhibit resting tremors, indicating a possible diagnosis of Parkinson's disease.
• Huntington disease is identified by abrupt onset chorea, characterized by irregular movements flowing unpredictably through the body.
• Wilson disease may present as sustained muscle contractions and abnormal posturing, typically classified as hyperkinetic secondary dystonia.

This quiz introduces the classification of movement disorders, focusing on hyperkinetic and hypokinetic types. It covers examples like tremors, dystonia, and Parkinson's disease, helping students understand the distinctions between these disorder categories.