Movement Disorders: Diagnosis and Pathophysiology

• Movement disorders involve alterations in normal movement, categorized as excessive movements (hyperkinesis) or decreased movement (hypokinesis).

Definitions of Movement Disorder Terms

• Akathisia: Restlessness relieved by movement.
• Asterixis: Brief flapping of outstretched limb due to muscle inhibition.
• Ataxia: Unsteady, irregular movements.
• Athetosis: Slow, writhing, involuntary movement.
• Chorea: Involuntary, irregular movements flowing between body parts.
• Dyskinesia: General term for abnormal involuntary movement, including paroxysmal, hypnogenic, and tardive types. Tardive dyskinesia is induced by dopaminergic agents.
• Dystonia: Sustained involuntary muscle contraction causing twisting postures.
• Myoclonus: Sudden, irregular muscle jerking.
• Myokymia: Fine muscle quivering, often benign in facial muscles.
• Stereotypy: Repetitive, coordinated movement or compulsion.
• Tics: Sudden, repetitive motor or vocal contractions.
• Tremor: Rhythmic oscillation of body parts, classified as resting, postural, or action/intention tremor.

Common Movement Disorders

• Common hyperkinetic disorders: essential tremor, restless legs syndrome, dystonia, Tourette syndrome.
• Less common hyperkinetic disorders: hemifacial spasms, blepharospasm, ataxias and Huntington disease.
• Common hypokinetic disorder: Parkinson disease.
• Less common hypokinetic disorders: progressive supranuclear palsy and multisystem atrophy.

Pathophysiology of Movement Disorders

• Voluntary movement relies on interactions between pyramidal tracts, cerebellum, and basal ganglia.
• Abnormal movements often stem from pathologic changes in these structures or elsewhere in the CNS or PNS.
• The underlying causes of many movement disorders are unclear, genetic and environmental factors are suspected.

Clinical Presentation and Examination

• A careful history is crucial, focusing on functional limitations, age of onset, body regions affected, symptom progression, movement quality, and factors that worsen or improve symptoms.
• Family history, medication, alcohol, and drug use should be thoroughly investigated.
• Physical examination should be systematic, including a complete neurologic assessment (cognition, cranial nerves, motor/sensory function, reflexes, gait). Evaluate the characteristics of the movement.
• Observe rhythm, duration, continuity, type of oscillations, and amplitude of movements. Note if movements occur at rest or during action, and assess speed, force, complexity, and associated sensory symptoms.

Diagnostics

• Essential initial diagnostics: CBC, comprehensive metabolic panel and thyroid studies.
• Additional diagnostics: Infection workup, toxicology screens, neurologic imaging.

Initial and Focused Diagnostic Workup

• Initial diagnostic tests should include a CBC, comprehensive metabolic profile, and thyroid function studies.
• Focused workup: Infection workup (CBC, urinalysis, chest X-ray), drugs/alcohol assessment (toxicology screen, ammonia level, liver function tests).
• Imaging: CT scan.

Differential Diagnosis

• Requires defining the types of movements occurring.

Interprofessional Collaborative Management

• Treatment goals: treat underlying conditions, define the movement disorder, and manage symptoms.
• Management includes medication, physical therapy, and occupational therapy.
• Medications: β-blockers, anticonvulsants, or benzodiazepines (with caution).
• Surgical treatments: deep brain stimulation and botulinum toxin injections.

Physician Consultation

• Neurology referral is indicated for uncertain diagnosis, lack of response to standard treatment, or deteriorating condition.

Complications

• Vary depending on severity, including medication side effects, functional impairments (independence, ADLs), balance and safety issues.
• Psychosocial issues include depression, communication difficulties, self-consciousness, and employment problems.

Life Span Considerations

• Different movement disorders are more prevalent at certain ages, consider older adults may be more sensitive to medication.
• Movement disorders may lead to social and employment issues in younger people.

Patient and Family Education

• Provide information about diagnostic evaluation, prognosis, treatment options, and complications.
• Offer Web-based or written resources and referrals to support groups.
• Emphasize how medications can relieve symptoms and potential side effects.
• The International Parkinson and Movement Disorder Society website is a good resource for patients.

Essential Tremors: Definition and Epidemiology

• Essential tremor is a benign, chronic neurologic condition with symmetrical, rhythmic trembling of upper extremities, head, or voice.
• Tremor is present during voluntary movement, worsens with emotional stress, and improves with alcohol/rest.
• It is the most common movement disorder, often familial/hereditary, affecting men and women equally, onset around age 45.

Pathophysiology of Essential Tremor

• Cause is largely unknown, no structural defects identified on autopsy, diagnostic studies typically normal.
• Believed to be caused by focal oscillatory activity within the CNS from genetic predisposition and/or environmental toxins.

Diagnostics for Essential Tremor

• Diagnosis is based on history and examination findings.
• Laboratory/diagnostic testing is considered when other neurologic findings are present such as CBC, comprehensive metabolic panel, thyroid function studies, drugs/alcohol toxicology screen.

Differential Diagnosis of Essential Tremor

• Tremors may originate in the CNS, from metabolic abnormalities, or induced by medication/alcohol.
• CNS tremors: Parkinson disease, Huntington chorea, Sydenham chorea, cerebellar.
• Metabolic tremors: thyroid abnormality, pheochromocytoma, liver disease.

Interprofessional Collaborative Management of Essential Tremor

• Pharmacologic management: Propranolol or primidone are initial medical therapy.
  • β-Blockers (Propranolol): Start at low dose, titrate to effect, reevaluate after 1-2 weeks
  • Anticonvulsants (Primidone): Reduces tremor amplitude, gabapentin and topiramate may help, but less evidence.
  • Combined therapy: Propranolol and primidone together may be more effective.
  • Benzodiazepines: Alprazolam and clonazepam may be effective, but use caution due to side effects, dependency, and misuse.
  • Alcohol: Not recommended as a long-term strategy.
• Nonpharmacologic management:
  • Surgical treatments: Deep brain stimulation, focused ultrasound ablation and stereotactic radio surgery are safe and effective at reducing tremor by as much as 80%.
  • Botulinum injections: into wrist tendons for essential tremor and choice for voice tremor when a skilled clinician is preforming the injections.
  • Rehabilitation: Physical and occupational therapy can provide resistance training, dexterity training, transcutaneous nerve stimulation, and massage.

Physician Consultation For Tremors

• Specialist referral is indicated for uncertain diagnosis, lack of response to standard treatment, or deteriorating condition.

Complications and Life Span Considerations for Tremors

• Complications: medication side effects, functional impairments, balance/safety issues, psychosocial issues.
• Severe tremors can significantly interfere with activities of daily living; treatment and rehabilitation aim to control severity.

Patient and Family Education and Health Promotion

• Advise patients to avoid stimulants such as caffeine, soda, and over-the-counter allergy/cold preparations.
• Educate about the disease's chronicity, progression, and prognosis.
• Emphasize potential psychosocial implications, requiring frequent reevaluation and support.
• Encourage appropriate diet and exercise, address alcohol abuse concerns.

Test your knowledge of movement disorders with this quiz. Questions cover diagnosis, differentiation of conditions like chorea and athetosis, and associated factors like medication use. Explore the pathophysiology and impact of lesions on movement.