Spinocerebellar ataxia: causes, symptoms, diagnosis, treatment

Every day, a person performs a large number of targeted movements in the implementation of which involve different muscle groups( muscle-antagonists, muscle synergists, muscle-agonists, fixative muscles), vestibular apparatus, brain, spinal cord, visual analyzer.

One of the most complex motor processes in our body is walking and maintaining balance. Muscles of the trunk and extremities are successively contracted and relaxed - a step appears, the central nervous system regulates the pace of the step, initiates and stops walking, adapts movement to changing environmental conditions( ascent, descent, etc.), the visual analyzer transmits information about the surrounding world, the vestibular apparatusparticipates in maintaining equilibrium in space.

At a time when one of the systems ceases to accurately monitor the process of walking or any other motor act, disorganized, poorly coordinated movements appear. To denote this condition, the term "ataxia" is used.

Ataxia can be static, when a person can not keep his balance in a standing position, or dynamic - the coordination of movements is disrupted.

Depending on the formation in which the lesion is located, several types of ataxia are distinguished:

• vestibular;
• cortical;
• cerebellar;
• sensitivity et al.

Spinocerebellar degeneration

The gait of a person with cerebellar pathology is uncertain, unsteady, reminiscent of a drunkard's gait.

The term spinocerebellar degeneration is used to refer to a group of diseases of the nervous system that are manifested in a violation of coordination of movements as a result of combined damage to the cerebellum, brainstem and spinal cord. This group includes idiopathic and hereditary spinocerebellar ataxia.

For all ataxia of this group, a progressive disorder of movements and combined lesion of CNS structures are common.

The defeat of the cerebellum in clinical practice is manifested by a shaky gait( drunk walk), torso deviation to the side, a miss( it can not reach the nose with a finger, insert a key into the lock, etc.), incorrect estimation of the distance to the object. A person can not quickly perform opposite, alternating actions( turning his hands palms up and down), starts to get confused, to lose his rhythm. There is a tremor in the hands or feet during movement( intentional tremor).The speech becomes jerky, slow, "chopped phrases," with incorrect emphasis. Speech disorders denote the term cerebellar dysarthria, and motor disorders - cerebellar ataxia.

Hereditary spinocerebellar ataxia

Among all hereditary CNS diseases, ataxia is the second most frequent after neuromuscular diseases. To date, a single classification of this group has not been developed, since hereditary ataxia in clinical manifestations are very diverse and sometimes not clear, it is the same version or another.

Let us dwell on the most common forms of hereditary spinocerebellar degenerations.

Friedreich disease

Every 120 people in the world are carriers of a mutant gene that is responsible for the development of the disease. The disease is transmitted autosomal recessive type equally often to boys and girls.

Reasons for

The mechanism of ataxia development is associated with a violation of the synthesis on the mitochondria of the frataxin protein, which regulates the transport of iron ions through cell membranes. As a result of the mutation, the mitochondria and cells of the central nervous system, pancreas, myocardium and other organs die. In the central nervous system, spinal cord pathways, posterior roots of the spinal cord, posterior and lateral columns of the spinal cord are damaged. In the late stages of the disease, the nucleus of the cranial nerves, the legs of the cerebellum, the jagged nucleus, and the peripheral nerves are involved in the pathological process. All these structures are responsible for coordination of movements.

Symptoms of

The first clinical signs appear in children over the age of 10 years. The child begins to experience difficulties when moving in the dark, there is an uncertain gait, stumbling and staggering. Gradually, the sound production( dysarthria) is violated, the coordination of movements in hands, which is manifested by difficulty in writing and changing the handwriting. As the disease progresses, weakness and atrophy( death) of the muscles of the legs and hands appear, which lead to a complete loss of independent movement and rivet the person to bed. Pelvic disorders in the form of incontinence of urine and feces are revealed in the majority of patients. In some patients, atrophy of the optic nerves occurs, manifested by complete or partial loss of vision. Dementia may not be all. In the late stages of the disease a person loses the ability to self-service.

When examined, the neurologist reveals an important symptom of Friedreich's ataxia - the disappearance of tendon reflexes( knee, Achilles, etc.) up to complete areflexia.

The pathological process involves the heart, the musculoskeletal system, the endocrine system. A person complains of pains in the region of the heart, shortness of breath, palpitations. Cardiomyopathy is developing. Symptoms from the cardiovascular system may appear much earlier than neurological manifestations.

Skeletal deformations are represented by the curvature of the spine, the "Friedreich foot"( the high arch of the foot is combined by re-opening the fingers in the initial phalanges and flexing them in the terminal phalanges).The fingers of the hands are also deformable.

Endocrine disorders are diagnosed with diabetes mellitus, dysfunction of the ovaries, impaired puberty, obesity and other diseases.

Life expectancy at Friedraich ataxia is rarely more than 20 years. The main cause of death is the development of cardiac or pulmonary insufficiency, infectious complications.

Allocate an atypical form of ataxia, which is characterized by a later debut( 30-50 years), favorable course, slow progression. With this form, do not reveal cardiomyopathy, endocrine disorders, extinction of reflexes.

Diagnostics of

• DNA testing is considered a decisive method in the diagnosis of Friedreich's ataxia.
• ENMG( electroneuromyography) is one of the important methods of investigation, in which the lesion of sensitive spinal tracts is detected with preservation of motor nerves.
• MRI.Diagnose the atrophy( death) of the substance of the spinal cord.
• ECHO-KG, ECG and other studies show changes in the heart muscle.
• Blood test for sugar, hormonal profile diagnoses endocrine changes.
• Radiography of the spine, stop helps to identify abnormalities.

Diagnosis is based on data from all research methods.

Treatment of

Special therapy not developed. All therapeutic measures are symptomatic.

1. Drugs( nicotinic acid, riboflavin, ascorbic acid) improve the work of mitochondria.
2. Physiotherapy( electrostimulation).
3. Massage and exercise therapy.
4. Orthopedic measures: insoles and shoes, surgeries on the spine.

Hereditary ataxia due to lack of vitamin E

This disease is based on a mutation of a certain gene, leading to a deficiency in the body of vitamin E.

The disease occurs less frequently at Friedreich's ataxia, is transmitted by an autosomal recessive type. Another name for the disease is "Friedreich's ataxia with vitamin E deficiency," or "AVED syndrome."

Causes of

At the heart of the disease is a gene mutation that is responsible for integrating vitamin E into the structure of low-density lipoproteins( involved in antioxidant cell defense).

Symptoms of

In clinical manifestations, ataxia with a deficiency of vitamin E is almost impossible to distinguish from Friedreich's ataxia. The first symptoms in the form of impaired coordination of movements appear in children aged 4 to 18 years. Violation of speech, fading of reflexes also occur in this form. It should be noted that the defeat of the cardiovascular, bone and endocrine systems is several times less common. Toward the age of 30, most patients lose their ability to move independently and self-service, are riveted to bed.

Diagnosis of

All patients with ataxia should be tested for serum vitamin E. The reduction or absence of serum vitamin E is a reliable marker of the disease.

Treatment of

The appointment of lifelong therapy with vitamin E at a daily dosage of 5-10 mg / kg leads to the disappearance of symptoms and the clinical recovery of a person, especially with the early onset of treatment.

Autosomal dominant spinocerebellar ataxia

This ataxia group includes a number of independent diseases that are very difficult to distinguish from each other in clinical manifestations.

The development of genetic engineering allowed them to be classified into separate units using DNA diagnostics. Today, more than 13 genes have been studied, the mutations of which lead to the development of dominant ataxia. Diseases were named according to the ordinal number of the gene on which the anomalies were found: the dominant spinocerebellar ataxia of type 1, type 2, type 3,. .., type 13, etc.

Causes of

A gene mutation leads to the synthesis of insoluble intracellular molecules that cause cell death. At each type of dominant ataxia certain nerve cells are affected.

Symptoms of

Regardless of the type of ataxia, the clinical picture focuses on the defeat of the cerebellum and its connections with other departments of the central nervous system. Identify cerebellar ataxia, cerebellar dysarthria and other symptoms.

Dominant forms of ataxia differ from each other in the debut of symptoms and the course of the process.

• Spinocerebellar ataxia of type 1 occurs at the age of 30-40 years. A person develops unstable, awkward movements with fast walking and running. In a few years, the symptoms are associated with a violation of handwriting, dysarthria. The gait becomes atactic, the hand trembles when moving. Violated coordination of movements. At the same time, muscle tone increases in the arms and legs, which leads to a decrease in the total volume of movements in the joints and forced bending of the limbs. As the disease progresses, dementia( dementia) develops, pelvic disorders( fecal incontinence, urine), tremor of the head, impaired swallowing. Man completely loses his ability to move. The lethal outcome occurs after 10 or more years from infectious complications.
• Spinocerebellar ataxia of type 2 is similar in clinical manifestations to type 1 ataxia. For this type, the coordinated movements of the eyeballs( saccades) are characteristic, the suppression of tendon reflexes occurs more often and faster.
• Spinocerebellar ataxia of type 3( Machado-Joseph disease).Cerebellar ataxia in this type is combined with other neurological symptoms: slowing gait and speech, slowing movements in mimic muscles, fanciful and violent movements in the body and limbs( dystonia), lowering of the upper eyelid, weakness in the arms and legs( paresis), "bulging eyes", Twitching of the muscles of the mouth and other symptoms.
• Spinocerebellar ataxia of type 4 is manifested by coordination disorders in combination with sensory neuropathy, which is manifested by pain sensations and a sensitivity disorder in the area of ​​the affected nerve.
• Spinocerebellar ataxia of type 5 and type 6.These two types of ataxia appear at the age of 50-60 years, slowly progressing, do not lead to deep disability of a person, retain the patient's ability to move independently and serve himself. The main symptom is a shaky walk, there may be a speech disorder. Spinocerebellar ataxia type 7.A characteristic feature of this type of ataxia is a combination of motor disorders with retinal damage, which can lead to blindness of the person.
• Spinocerebellar ataxia of 8 and subsequent types are poorly studied, as single cases of these diseases have been reported today.

Diagnosis of

• CT or MRI( reveals specific changes in the brain, excludes other diseases).
• DNA testing( the main method of diagnosis).

Treatment of

To date, there is no specific, effective therapy.

As an auxiliary treatment is applied LFK, vestibular gymnastics.

Other forms of hereditary spinocerebellar ataxia

This group includes dentatorbro-pallidoluis atrophy( DRPLA), episodic( periodic, paroxysmal) ataxia, Marinescu-Sjogren's syndrome.

Diseases are extremely rare, the treatment is only symptomatic.

A lecture by a specialist on Friedreich's ataxia: