What Is Subcortical Dementia?

Huntington's disease dementia was named after Huntington's first report in 1872. Is a single gene autosomal dominant genetic disease. The brain has a wide range of degeneration sites, especially the atrophy of the caudate nucleus, which is a rare idiopathic neurodegenerative disease. The main clinical manifestations are dementia and dance-like movements.

Huntington's disease dementia

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Huntington's disease dementia was named after Huntington's first report in 1872. Is a single gene autosomal dominant genetic disease. The brain has a wide range of degeneration sites, especially the atrophy of the caudate nucleus, which is a rare idiopathic neurodegenerative disease. The main clinical manifestations are dementia and dance-like movements.

Huntington's disease dementia usually occurs between the ages of 30 and 50, with an average age of 40 years. It rarely occurs in childhood, but it varies widely, from as small as childhood to as old as rare, and young people often have more severe symptoms. Clinical manifestations are dyskinesias and obvious and diverse mental changes. There are currently no drugs that can delay the progression of Huntington's disease dementia, mainly symptomatic treatment. The course of disease is generally longer than that of other primary dementias, and it is slowly progressive. It survives for about 13 to 16 years after the onset, and there are also people who are up to several decades. Generally, those with a late onset of disease have a longer survival period. The disease causes a decline in the quality of life due to dementia, so it is susceptible to various chronic physical diseases and secondary infections or failures in various systems.

Huntington's disease dementia

dementia in Huntington disease

Huntington's disease dementia; Huntington's disease dementia

Psychiatry> Cerebral organic mental disorders> Mental disorders associated with brain degenerative disorders

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Although numerous sources describe Huntington's disease dementia as an autosomal single-gene dominant inherited disease, sporadic cases have been reported. Dominant inheritance suggests that the disease is a congenital metabolic defect. The pathological changes mainly involve the frontal lobe and caudate nucleus. The loss of nerve cells is most obvious in the frontal lobe, with the formation of glial cells, and the basal ganglia atrophy.

Huntington's disease dementia is relatively rare. The prevalence varies widely, with estimates ranging from 4 / 100,000 to 7 / 100,000 (Folsrein et al., 1990). Shanghai mental hospital from 1956 to 1982, the disease accounted for 0.06 per thousand inpatients during the same period. There is no difference between men and women. The genetic emergence rate is 100%, and about half of the patients' offspring are sick. The incidence is usually between 20 and 50 years old, and there is no significant difference between men and women. Symptoms are generally more severe in younger patients, with muscle rigidity as the mainstay, dance symptoms in middle-aged patients, and intentional tremor in patients older than 60 years. Juvenile patients are rare.

The molecular genetics of Huntington's disease dementia is one of the remarkable achievements of molecular biology in neuroscience in recent years, and it is also a milestone in the application of molecular biology in clinical medicine. Huntington's disease dementia is a single-gene autosomal dominant inheritance and is completely penetrative. In 1983, Gusella et al. Found a DNA marker G8 that is closely linked to Huntington's disease dementia from a human DNA fragment cloned with a phage vector. This marker G8 is located on the fourth pair of chromosomes. Further research also identified Huntington Defective dementia is located in the short arm 4P16 region of the fourth pair of chromosomes.

A total of 151 patients in 15 families were reported in China from 1958 to 1985, of which only 1 had no family history.

The pathological changes of Huntington's disease dementia are symmetrical atrophy of the brain, and the atrophy of the frontal lobe and caudate nucleus is more obvious. The ventricular system was significantly enlarged, and the caudate nucleus was severely atrophied, which caused depressions in the arcuate protruding parts of the lateral ventricle surface. Microscopic examination often shows extensive loss of frontal cortical nerve cells, accompanied by glial hyperplasia. Caudal nucleus, bean-shaped nucleus, and white matter also have nerve fiber loss.

GABA levels in the basal ganglia and substantia nigra of patients with Huntington's disease dementia are reduced. GABA synthetase-glutamic acid decarboxylase (GAD) in the lenticular and pale nuclei is also significantly reduced. Elevated levels of qualitative DA and NE, excessive DA activity in the striatum may be related to involuntary exercise, and increased DA in the limbic system of the midbrain may be related to mental symptoms of Huntington's disease dementia.

Huntington's disease dementia is usually a single-gene autosomal dominant inheritance, with a few sporadic cases reported. The genetic genes were identified on the short arm of chromosome 4. A single gene dominant heredity suggests that the disease is a congenital metabolic defect. The pathogenesis is explained by the changes of different neurotransmitters, which are related to the decrease of basal nucleus and substantia nigra GABA levels, and the increase of striatum and substantia nigra DA and NE levels. The pathological changes were mainly atrophy of the frontal lobe and caudate nucleus. Microscopic examination of the frontal lobe neurons showed significant loss, with glial cell formation.

Huntington's disease dementia usually develops between the ages of 30 and 50, with an average age of 40. It rarely develops during childhood, but it can vary widely, from as little as childhood to as old as rare, and young people often have more severe symptoms. Clinical manifestations are dyskinesias and obvious and diverse mental changes.

Huntington's disease dementia is susceptible to a variety of chronic physical diseases and secondary systemic infections or failures due to degraded quality of life due to dementia.

Psychological laboratory tests are an important method to diagnose the presence and severity of dementia. In recent years, China has introduced and revised many simple and fast screening tools that are commonly used internationally. The diagnostic validity, sensitivity, and specificity are high. A brief overview is as follows:

Mini-MentalState Examination (MMSE)

The simple intelligence test was compiled by Folstein in 1975. The scoring criteria are as follows: if the answer or operation is correct, "1" is recorded, "5" is incorrectly recorded, and "9" or "7" is not recorded if you refuse to answer or say. The main total of "1" statistics (total MMSE score) is in the range of 0 to 300. The international standard is divided into 24 cutoffs, 18 to 24 are mild dementia, 16 to 17 are moderate dementia, and 15 are severe dementia. Our country found that the threshold is different due to different levels of education; illiteracy is 17 points, primary school (education period 6 years) is 20 points, middle school and above is 24 points.

Hasegawa Dementia Scale (HDS)

The Hasegawa Dementia Scale was developed by Kazuo Hasegawa in 1974. A total of 11 items, including orientation (2 items), memory (4 items), common sense (2 items), calculation (1 item), and remembering named memories (2 items).

The scale uses a positive scoring method with a perfect score of 32.5 points. The author's cut-off value was set as follows: dementia 10.5 points, suspicious dementia 10.5 to 21.5 points, marginal status 22.0 to 30.5 points, normal 31.0 points, and normal values can also be divided according to education level: illiteracy 16 points, primary school <20 points , <24 points above middle school.

Daily Living Ability Scale (Activity of Daily LivingScale, ADL)

The daily living ability scale was developed by Lawton and Brody in 1969, and is mainly used to assess the subjects' daily living ability.

ADL is divided into 14 items with a grade of 4: I can do it myself; Some difficulties; Need help; I can't do it at all. A score of 64 is a perfect score, and a total score of 16 is completely normal. If the score is greater than 16, the function decreases. A single item is divided into 1 normal, 2 to 4 points have decreased function, and 2 or more items 3 or a total score 22 are critical values, indicating a significant decrease in function. China's conventional total score is 18.5 ± 5.5.

Skull CT and MRI can show atrophy of the caudate nucleus. Positron emission tomography (PET) showed a significant decrease in tail nuclear metabolism.

1. Have a clear genetic history or clear evidence of brain disease.

2. Progressive dementia.

3. Depression, indifference, euphoria, hallucinations and delusions are the main symptoms of psychosis.

4. Dance-like movements occur before dementia.

1. It is often misdiagnosed as schizophrenia, affective psychosis, anxiety disorder, and personality disorder in the early stage. The identification points are clear family genetic history, evidence of brain degeneration, and later dance-like symptoms.

2. Differentiation from other brain degenerative diseases should be based on medical history, clinical manifestations, neurological examination and laboratory examination.

There are currently no drugs that can delay the progress of the disease, mainly symptomatic treatment.

For the treatment of Huntington's disease, dyskinesia itself does not require medication if it is not severe. Conversely, if a large range of exercise causes a fall, dopamine depleting agents such as lisepine can be added, but blood pressure and depression caused by lisepine should be monitored. Due to anxiety and stress, when involuntary exercise is aggravated, an anxiolytic benzodiazepine can be used. If the patient's muscles are strong, DA agonists can be used to improve muscle strength. Haloperidol, trifluoperazine, and fluphenazine are effective for dance-like symptoms and psychotic symptoms, but note that the above drugs can cause depression or exacerbate the original depression symptoms.

For psychotic symptoms, antipsychotics with mild side effects to the extrapyramidal system can be used. The dosage should be small. DA blocking may be effective in controlling dance-like movements. Depression can use a new generation of antidepressants such as paroxetine, sertraline, fluoxetine are effective for anxiety and depression, and the anticholinergic side effects of tricyclic antidepressants may aggravate chorea. In case of paranoid psychotic symptoms, antipsychotic drugs can be used, but the dosage should be small. Metidazine and clozapine may be more suitable due to the extrapyramidal response.

In addition, in view of mental and physical barriers, it is necessary to explain and explain to the patient, and to do nursing work in the later development stage.

Huntington's disease dementia usually lasts longer than other primary dementias and is slowly progressive. It survives for about 13 to 16 years after onset, and there are also people up to several decades. Generally, people with later onset age have longer survival. About half of the patients' deaths are not related to the disease, and suicide accounts for a certain proportion of the deaths.

Because Huntington's disease dementia is a single-gene autosomal dominant genetic disease. Patients and their families rarely know that their children are at risk for the same disease, so early genetic counselling is important. Hereditary diseases are hereditary and life-long incurable. They not only bring misfortune to the family, cause life-long pain to patients, but also pass the disease on from generation to generation. In order to control and reduce the incidence of hereditary diseases, it is necessary to focus on prevention. The implementation of the eugenics protection law should prevent births for those who are certain or likely to cause congenital diseases in future generations. China is currently enacting a eugenics protection law to prohibit close relatives from getting married. "Mother-in-law" will increase the incidence of some genetic diseases, and our marriage law has explicitly forbidden close relatives to marry. Try to avoid advanced births. Prenatal diagnosis should be made for older births (females over 35 years old and males over 45 years old). Those who have a history of genetic disease, a history of childbirth or multiple abortions should be genetically counseled. Through genetic counseling, some pregnant women who have indications should make the necessary prenatal diagnosis. If severe illness is found, pregnancy can be terminated in time To prevent the birth of fetuses with serious illness and defects.

Glutamate, Dopamine, Haloperidol, Triflurazine, Fluphenazine, Perphenazine, Paroxetine, Sertraline, Fluoxetine, Clozapine