Neurology · Year 3 · from Neurology

Case 3: Huntington's Disease

Patient Demographics

  • Age: 42 years
  • Sex: Male
  • Occupation: Former sales manager (currently disabled)

Chief Complaint

"I can't stop moving and my memory is getting worse."

History of Present Illness

The patient's wife reports that over the past 3 years, he has developed involuntary, jerky movements of his limbs, face, and trunk that worsen with stress. He appears restless and fidgety. His speech has become slurred. Cognitively, he has had progressive difficulty with concentration, planning, and decision-making. He was fired from his job 18 months ago due to poor performance. He has become irritable, depressed, and occasionally paranoid. His father died at age 50 in a psychiatric facility with dementia and involuntary movements. Two paternal uncles had similar presentations.

Neurological Examination Findings

Mental Status:

  • Alert but distractible
  • Impaired attention (serial 7s difficult)
  • Executive dysfunction: Poor clock drawing, difficulty with alternating sequences
  • Slowed processing speed
  • Mild depression on questioning
  • Irritable affect

Cranial Nerves:

  • Oculomotor abnormalities: Difficulty initiating saccades, slowed saccades, cannot suppress reflexive glances
  • Facial chorea - grimacing, tongue protrusion involuntary
  • Dysarthria - speech slurred, irregular

Motor Examination:

  • Chorea:
  • Continuous, random, flowing movements of all extremities
  • "Piano-playing" movements of fingers
  • Facial grimacing, tongue movements (serpentine)
  • Movements incorporated into voluntary acts ("parakinesia")
  • Motor impersistence: Cannot maintain sustained tongue protrusion or hand grip
  • Tone: Hypotonic (may become rigid in later stages)
  • Strength: 5/5 throughout (weakness masked by chorea)

Reflexes:

  • 2+ symmetric
  • Plantar responses flexor

Coordination:

  • Difficult to assess due to chorea
  • No clear ataxia

Gait:

  • Wide-based, irregular
  • "Dancing" quality with chorea incorporated
  • Sudden lurching movements

Neuro Workup

  • MRI Brain: Bilateral caudate atrophy with ex vacuo enlargement of frontal horns of lateral ventricles ("box-car" ventricles)
  • Genetic Testing: HTT gene CAG repeat expansion - 45 repeats (normal <36; 40+ = full penetrance)
  • PET scan (research): Decreased caudate glucose metabolism

Diagnosis

Huntington's Disease - genetically confirmed

  • Autosomal dominant inheritance
  • CAG trinucleotide repeat expansion in huntingtin gene (chromosome 4)
  • Anticipation: Earlier onset in successive generations

Management

Symptomatic Treatment of Chorea:

  1. First-line: Tetrabenazine 12.5 mg daily, titrate to 25 mg TID
  • VMAT2 inhibitor - depletes presynaptic dopamine
  • Side effects: Depression, parkinsonism, sedation
  • Screen for depression before initiating
  1. Alternative: Deutetrabenazine (Austedo) - longer half-life, fewer daily doses
  2. Second-line: Antipsychotics (risperidone, olanzapine) - also help behavioral symptoms
  3. Avoid: Dopamine agonists, levodopa (worsen chorea)

Psychiatric Management:

  1. Depression: SSRIs (sertraline, citalopram)
  2. Irritability/aggression: Antipsychotics, mood stabilizers
  3. Psychosis: Atypical antipsychotics
  4. Apathy: No proven treatment; stimulants sometimes tried

Cognitive Management:

  1. No disease-modifying treatment available
  2. Cognitive rehabilitation
  3. Structured routines, memory aids
  4. Speech therapy for dysarthria and dysphagia

Multidisciplinary Care:

  1. Neurology, psychiatry, social work, PT, OT, speech therapy
  2. Genetic counseling for family members
  • At-risk individuals may pursue predictive testing (complex ethical considerations)
  • Reproductive counseling (IVF with PGD available)
  1. Advance care planning early in disease course
  2. Home safety evaluation
  3. Huntington's Disease Society of America support

Prognosis:

  • Average survival 15-20 years from symptom onset
  • Death typically from aspiration pneumonia, falls, suicide

Clinical Image

Image Description: Axial T2-weighted MRI showing bilateral caudate nucleus atrophy with characteristic widening of the frontal horns of the lateral ventricles in Huntington's disease.

Attribution: Image from Radiopaedia.org, Case courtesy of Dr. Matt Skalski. Licensed under CC BY-NC-SA 3.0. Source: https://radiopaedia.org/cases/huntington-disease-8

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