What is Dementia in Huntington’s Disease?
Dementia is a chronic or progressive brain disorder in which higher cortical functions are impaired, including memory, thinking, orientation, understanding, counting, learning ability, language and judgment. Consciousness is not darkened. Symptoms are present for at least 6 months, although a more progressive onset of dementia is possible. Long-term medication, vitamin B12 and B6 deficiencies, metabolic imbalances due to kidney and liver diseases, as well as endocrine pathology, vascular pathology, depression, infections, head injuries, alcoholism, and tumors contribute to dementia. In the diagnosis of dementia, additional symptoms, such as delirium, hallucinations, and depression, are also noted.
Causes of Dementia in Huntington’s Disease
Hereditary degenerative disease caused by an autosomal defect in the synthesis of gamma-aminobutyric acid. Probably, the level of dopamine in the basal ganglia increases compensatory. Genetic transfer of the dominant type. Sporadic cases of pathology are described. A genetic marker for a disease can be polymorphic DNA. The families of patients with chorea described a high risk of criminal behavior, early malignant alcoholism. Degeneration is noted in the subcortical structures of the system of the caudate nucleus, more often in the pederatalamic nuclei. The development of atrophy from the cortex to the cortex leads to the fact that dementia is not accompanied by impaired memory. The disease is considered an “organic” model of schizophrenia, and such patients, being unrecognized, are often found among cases of schizophrenia with a pronounced defect.
Exposure in the population is up to a maximum of 1 patient per 10,000 per year. The ratio of men and women is 1: 1.
Symptoms of Dementia in Huntington’s Disease
There is no single clinical stereotype of the disease. It begins at the age of 20-40 years, the duration of the disease is from 2 to 30 years. The rate of increase of dementia can be predicted only with information about similar cases in families.
In the premorbid there are early alcoholism, a tendency to asocial and criminal behavior, schizoid and dissociative personality traits, an early increase in sexual attraction with homosexuality.
Although the clinical stereotype of the disease is absent, the central symptom is hyperkinesis, including facial, gestural postures, which are noticeable in gait. In the first stages, they can be compensated and look like habitual actions, for example, dropping hair, darting, lifting the shoulder. Handwriting may be distorted and ataxia, extrapyramidal rigidity, may occur. Sometimes before hyperkinesis, sometimes simultaneously with them or after them hyperkinesis of thinking occurs – that is, episodes of torn speech, instability of affect, formal disorders of thinking with its impoverishment. In other cases, delusions of relationship, persecution, exposure, Kandinsky’s syndrome – Clerambo, depressive states with delusions of guilt, states of undifferentiated anxiety and fear develop. The effects of neuroleptics at this stage quickly cause dyskinesias, and then it is difficult to distinguish motor complications from an overdose of neuroleptics from choreic motor disorders. In addition, it is likely that neuroleptics reveal a hidden atrophic defect, since they accumulate in thalamic structures. In other cases, antipsychotics cause epileptic seizures in susceptible patients. With an unfavorable course in several years, an apathetic-abulic defect forms, with a favorable course, relative safety in everyday life with psychopathisation is accompanied by hyperkinesis for several decades.
Diagnosis of Dementia in Huntington’s Disease
The diagnosis is made on the basis of identifying cognitive deficits not in the field of memory, but in the field of thinking, the presence of hereditary burdens with chorea and CT and NMR data, which can reveal atrophy, directly or indirectly (in terms of the lateral ventricles). Signs of atrophy on CT may be similar to those of schizophrenia, which were continuously treated with neuroleptics, for a long period of time.
The disease should be differentiated from other chorea, in particular, rheumatic, neurodegenerative diseases of subcortical structures, Gilles de la Tourette’s disease, schizophrenia.
Rheumatic chorea begins more often in childhood and adolescence, accompanied by other signs of rheumatic lesions, diencephalic somatovegetative paroxysms. More often marked ticose, but not hyperkinetic disorders.
Other neurodegenerative disorders are characterized by the fact that hyperkinesis is combined with a specific neurological focal symptoms, which dementiates the process later on. In particular, in case of Hallervorden-Spatz disease, associated with the accumulation of pigment in the region of the basal ganglia, the substantia nigra and the pale ball and developing in both children and adolescents, hyperkinesis precedes dementia. In this disease, along with hyperkinesis, disorders of muscle tone and predominantly torsional movements are also observed, and an increase in the density of the pale ball is noticeable in NMR.
In Gilles de la Tourette’s disease, voice and multiple motor tics occur in childhood and early adolescence, and are accompanied by secondary deprivation and reduced success, however, there is no productive disorders and dementia in this pathology. On CT in these cases, changes are not detected.
The most difficult differential diagnosis with schizophrenia with secondary neuroleptic dyskinesias. Meanwhile, schizophrenia still traces the developmental pattern and systematicity in the dynamics of individual forms, and hyperkinesis is fixed later, in most cases, the tolerance of large doses of neuroleptics is very high.
Dementia Treatment for Huntington’s Disease
Symptomatic, tranquilizers and antidepressants should be preferred, as well as carbamazepine, depakin, minimal doses of antipsychotic drugs for productive symptomatology. Psycho-surgical therapy consists of cryological effects on talamic structures, a pale ball.