CNS: Huntington's Disease (HD)

Huntington Disease aka Huntington Chorea

• Huntington's Disease (HD), also known as Huntington Chorea, is a CNS condition that affects the TX 400 FT 500 PT areas.
• The condition is inherited and neurodegenerative
• Some symptoms include choreiform movements, which are brief, purposeless, random movements, progressive dementia.
• HD is progressive, with death typically occurring 15-20 years after the onset of neurological or psychological impairment.
• In adults, HD often manifests as involuntary movements, though rigidity can also be present.
• Males and females are diagnosed with HD in equal numbers.
• Symptoms typically appear between 35-55 years of age, but can emerge: in youth (20 years and under, known as Juvenile HD accounting for 10% of cases).
• Symptoms can present later in life (60+ years, known as Late Onset HD accounting for 10% of cases).
• The prevalence of HD in North America ranges from 4-8 cases per 100,000 people.
• The disease is inherited as an autosomal dominant disorder.
• Pathologic findings include consistent tissue changes in the brain.
• There is a mutation in the gene for the huntingtin protein, which is located on chromosome 4.
• The defect causes the cytosine, adenine, and guanine (CAG) sequence to replicate excessively.
• Each child of a parent with HD has a 50/50 chance of inheriting the gene.
• A child who doesn't inherit the gene won't develop the disease or pass it on to future generations.
• With HD, ventricles enlarge due to atrophy of the adjacent basal ganglia, specifically the caudate nucleus and putamen, caused by extensive loss of small and medium-sized neurons.
• The volume of the brain can decrease by 20%.
• Loss of neurons and neurotransmitters occurs.
• The normal balance of excitation and inhibition responses in the basal ganglia and thalamus is disrupted.

Signs and Symptoms

• Physical symptoms include weight loss, involuntary movements (chorea), diminished coordination, difficulty walking, talking, and swallowing.
• Impairment in voluntary movements vs involuntary movements has a greater impact on ability to work, perform ADLs, communicate, and maintain independence.
• Cognitive symptoms include difficulty with focus, planning, recalling information, making decisions, and impaired insight.
• Emotional symptoms include depression, apathy, irritability, anxiety, and obsessive behavior.
• Depression can result from injury to the brain and subsequent changes in brain function, rather than as a reaction to the diagnosis.

Early Stage Symptoms

• Individuals are still able to function well at work and home.
• Difficulties organizing routine and coping effectively with new situations can occur.
• Decreased ability to recall information, an inability to make decisions, and maintain attention to detail can also occur.
• Other Symptoms can include mood changes, irritability, minor involuntary movements("nervous" activity, fidgeting, twitching, excessive restlessness), and changes in handwriting.

Intermediate Stage Symptoms

• There are increased difficulties with working and managing a household, but can still deal with ADLs.
• More obvious involuntary movements occur (chorea).
• Increased difficulties walking, with coordination and balance.
• Difficulty may be encountered when speaking and swallowing.
• Problem solving becomes more difficult, with thinking processes impaired.
• Weight loss can occur due to energy expenditure from choreoathetoid movements.

Advanced Stages Symptoms

• Sufferers cannot manage ADLs and require proffessional care.
• Symptoms include decrease in involuntary movements and increase in rigidity
• Increased difficulties swallowing
• The ability to communicate diminishes, but understanding what is being said remains possible
• Significant weight loss, dementia, bradykinesia, and dystonia can occur (involuntary muscle contractions).

Juvenile and Late Onset Huntington's Disease

• Juvenile HD follows a more rapid course, with chorea being less prominent or absent altogether.
• Initial symptoms of Juvenile HD can include slow stiff movements (rigidity), sometimes tremors, seizures, falls, clumsiness, contracted & rigid muscles that affect gait, difficulties learning in school, and attention deficits, as well as an increase in responsive behaviors.
• Late Onset HD occurs when diagnosis happens past 60 years old.
• Late Onset HD is sometimes is misdiagnosed due to doctors believing patients may be "too old" to develops HD (typical onset is 35-55).

Diagnosis

• There is no diagnostic testing available.
• Diagnosis is based on clinical symptoms, family history, and genetic testing.
• Other tests to assess contributing factors include Neurological examination that tests motor, sensory, and psychiatric symptoms.
• Other tests to asses contributing factors include neuropsychological testing to check memory, reasoning, mental agility, language skills, and spatial reasoning.
• Psychiatric evaluation by a psychiatrist may be done to look at emotional state, patterns of behaviours, quality of judgement, coping skills, signs of disorder thinking, and evidence of substance abuse.
• Other contributing factors can be tested for using MRI, CT scan, genetic counseling & testing, and predictive genetic tests.

Treatment

• There is no cure for HD , but symptom management is possible.
• Medications can help control chorea.
• Psychiatric disorders related to HD can be treated using antidepressants, antipsychotics, and mood-stabilizing drugs.
• Psychotherapy – done by a psychiatrist, psychologist, or clinical social worker.
• Other treatment options include speech therapy, physical therapy, and occupational therapy.

Massage and Clinical Manifestations

• Individuals will present classic choreiform movements, with piano-playing motions in the fingers and facial grimaces.
• There will be trunk involvement, with a dancing gait.
• Can appear off balance but the ability to balance is well preserved
• Patients who develop HD by age 35 often become bedridden within 15-20 years
• Sufferes may appear argumentative, impulsive or erratic
• Sleep disorders and urinary incontinence are common
• Muscle strength and tendon reflexes are usually normal