Huntington’s disease


Huntington’s disease is a genetic, autosomal dominant, neurodegenerative disorder characterized clinically by disorders of movement, progressive dementia, and psychiatric problems along with cognitive decline.
Huntington’s disease gets noticeable in mid adult life. Huntington’s disease is also one of the most common causes of abnormal involuntary writing movements called as chorea that is why the disease used to be called as Huntington’s chorea.

Age/sex prevalence of Huntington’s disease

Huntington’s disease affects individuals of mid adult life. Physical symptoms of Huntington’s disease can begin at any age from infancy to old age but usually begin between 35 and 44 years of age.

Races affected by Huntington’s disease

Huntington’s disease more commonly affects Europeans than Asians or Africans.

Causes of Huntington’s disease

Huntington’s disease is a genetic autosomal dominant disorder. Persons who have 36 or more CAG repeats in the HD gene have inherited the disease mutation and eventually develop symptoms if they live to an advanced age. Each of their children has a 50% risk of inheriting the abnormal gene.

Signa nd symptoms of Huntington’s disease

• Early motor symptoms often include dystonic posturing and rigidity, but these changes give way to prominent choreiform activity in most affected adults.
• Frequent, irregular, and sudden jerks and movements of any of the limbs or trunk occur.
• Grimacing, grunting, and poor articulation of speech may be prominent.
• Mental status exam
• The patient appears older than stated age.
•Patient is well oriented in all spheres.
•Patient appears alert.
•Affect is appropriate.
• Mood is euthymic.
• Presents self in a disheveled and sloppy fashion.
• Eye contact can be described as limited.
• Speech is illogical, incoherent, garbled, and not goal-directed.
• An increased risk for suicidal and homicidal thinking occurs due to the poor prognosis and erratic thinking, which can be accompanied by paranoia.
• Recent memory appears moderately to severely impaired. Remote memory is not impaired.
• Psychomotor activity can be characterized by choreic movements and hyperactivity.
• A negligible to severe degree of conceptual disorganization is evident.
• Thought content is characterized by delusions, hallucinations, and violent ideation at times.
• Regarding perceptual functioning, the patient has hallucinations and none are evident.
• Attitude can be described as cooperative but disinterested.
• The patient verbalizes no awareness of problems and does not see consequences. Judgment is poor.
• Attention/concentration is characterized by an inability to attend and maintain focus.
• The patient is not reflective and unable to resist urges.
• The gait is disjointed and poorly coordinated. Patients with HD, like healthy subjects, depend more on proprioceptive cues than on visual cues to maintain balance; however, patients with HD develop more sway compared with healthy subjects when proprioceptive cues and vision are altered.
• Given the presence of choreiform movement and subcortical neuropathology, performance on manual dexterity tasks is impaired.
• Cognitive symptoms include the following:
• Memory frequently is not impaired until late in the disease, but attention, judgment, and executive functions may be seriously deficient at an early stage.
• Early signs of dementia often include forgetfulness, disorganization, and affective disorders.
• Free recall may be severely impaired.

Memory deficits involve both recent and remote function. Studies show that patients with HD can accurately recognize recently presented verbal material only when cues are used in memory retrieval. Other studies show that the patients sometimes recall words the next day that they had not recalled during testing sessions, further supporting a delayed-retrieval hypothesis.

Patients have significant problems with frontal executive functions, such as problems with maintenance, cognitive flexibility, abstraction, judgment, reasoning, sequencing, organizing, planning, and adapting.

Skilled motor-procedural learning deficits are reported. Working memory may be affected in patients with HD because of frontal lobe dysfunction associated with the bidirectional connections with the caudate.

Insight, orientation, factual information, and overall intelligence quotient scores are preserved relatively well into the disease process.

• Verbal skills are discussed as follows:
• Verbal skills are the least impaired in patients with HD.
• Reduced fluency in the face of preserved confrontation naming occurs.
• Letter and category fluency are also impaired.
• Sensory motor deficits occur, such as poor olfactory perception, slow sequential or graphomotor movements, and impaired prism adaptation.

Investigations of Huntington’s disease

Investigations to be done are as follows
Laboratory studies to be done are as follows
• DNA repeat expansion
• Dopamine homovanillic acid in cerebrospinal fluid

Imaging studies to be done are as follows
• Computed tomography or magnetic resonance imaging
• Single photon emission computed tomography scanning

Other tests to be done are as follows
• Wechsler memory scale-revised
• Wisconsin card scorting test
Histological findings of the striatum

Treatment of Huntington’s disease

Medications to be given are as follows
• Antipsychotics
• Benzodiazepines
• Anticonvulsants
• Antidepressents
In surgical care there is only one solution that is neural transplant.

Prognosis of Huntington’s disease

Huntington’s disease has a great impact on patients’ physical and psychosocial well-being, the latter being more severely affected.

Differential diagnosis of Huntington’s disease

• Alzheimer disease
• Tourette syndrome
• Wilson disease
• Parkinson disease dementia

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