HUNTINGTON DISEASE aka Huntington Chorea Flashcards
HUNTINGTON DISEASE aka Huntington Chorea
Is an inherited disease characterized for choreiform (brief, purposeless and random) movements and progressive dementia
It is a progressive neurologic disorder usually leading to
death in 15-20 yrs after onset of neurologic or psychological impairment
In adults, HD most often causes
involuntary movements, but rigidity can also be a feature
Males and females are diagnosed in equal numbers
Symptoms usually do not develop until a person is
aged 35 yrs or older; usually by the time of diagnosis, many people already have children and may have passed the gene on to them
10% of people may have juvenile form of the disease which the onset of symptoms may occur when the patient is younger than 20 yrs
Pathophysiology
Is inherited as an autosomal dominant disorder
An HD gene has been identified with an abnormal protein (huntingtin) that can be identified in the brain
The gene is present on chromosome 4
Pathologic findings show
a consistent pattern of tissue changes in the brain
The ventricles are enlarged as a result of atrophy of the adjacent basal ganglia, specifically caudate nucleus and putamen
This is due to extensive loss of small and medium-sized neurons
The volume of the brain can decrease by 20%
With the loss of neurons, neurotransmitters are affected
The normal
Clinical Manifestations
Between ½ and ¾ of patients present with primary complaints of involuntary movements or rigidity
In the remainder of cases, the primary presentation is one of early mental status changes that initially appear as increased irritability, moodiness, or antisocial behaviour
Classic choreiform movements begin as a
piano-playing motion of the fingers or as facial grimaces
Fast eye movements are often impaired (saccades)
As the disease advances and involves the trunk, a characteristic dancing gait evolves; although appearing to be off-balance, the ability to balance is actually well preserved
Sleep disorders
Urinary incontinence
Muscle strength usually normal
Tendon reflexes usually normal
Dementia develops as
the disease progresses
Childhood cases tend to present with rigidity rather than chorea
Younger patients may develop seizures
Rigidity and dystonia predominate in later stages of the disease in adults; as does bradykinesia
Symptoms become worse with anxiety or stress
Behavioural problems may be the first noticeable issues; depression occurs early
Patients may be argumentative, impulsive or erratic
Patients who develop HD by the time they are aged 35 yrs often become
bedridden within 15-20 yrs
Dramatic weight loss may occur due to energy expenditure from choreoathetoid movements
Diagnosis
Family history is of paramount importance in made the diagnosis
If a patient with a movement disorder or dementia is known to have a parent with HD, the diagnosis of HD is highly likely
The typical clinical picture of HD may appear in patients who have no family history of the disease
MRI
DNA evaluation
Complications
Dementia eventually progresses in every patient and may be disabling
Patients may develop difficulty swallowing and may suffer choking episodes
Chorea or rigidity nearly always is present
Personality changes may be prominent
Patients with depression may be at risk for suicide
Management
Treatment is symptomatic
Anticonvulsant and antipsychotic drugs are helpful for the chorea; although if the abnormal movements are slight, drug therapy should be held in reserve due to the high incidence of side effects
Education of the client and family about movement disorders, including gait and safety in mobility
With disease progression, postural stability becomes impaired and axial chorea may throw the client off balance
Apraxia, the ability to perform skilled or purposeful movements, may become severe
This may lead to significant disability in performing ADLs (dressing and grooming)
In those with predominant bradykinesia, there is a propensity to freeze which may lead to falls
Positioning to prevent soft tissue deformities and safety in transfers should be taught
