Ataxia. Why does pathology form and develop?
"Ataxia" Literally translated from Greek it means “disorder.” However, our current understanding of the term is poorly coordinated movements associated primarily with damage to the cerebellum and/or cerebellar connections. In addition to cerebellar ataxia (which accounts for most cases of ataxia in clinical practice), there are also cases of so-called sensory and vestibular ataxia, caused respectively by damage to the spinal proprioceptive pathways and the vestibular system.
Clinical manifestations of various types of ataxias
Cerebellar ataxia
Clinically, cerebellar ataxia manifests itself as an unstable and unsteady gait with an extended base, as well as incoordination and clumsiness of movements, dysarthria (chanted, jerky speech), dysmetria of saccades and oscillations. Patients usually stand with their feet wide apart; when they try to put their feet closer together, they begin to sway or even fall; due to unstable balance, support or support is required from surrounding objects. Even minor manifestations of walking ataxia can be detected during so-called tandem walking in a straight line. Ataxia can be generalized or primarily affect walking, movements of the arms, legs, speech, and eye movements; may be one-sided or involve both parties. Ataxia is often accompanied by muscle hypotonia, slowness of movement, intention tremor (action tremor that increases in amplitude when approaching a target), impaired control of complex multi-joint movements (asynergy), increased postural reflexes, nystagmus (usually horizontal in cerebellar ataxia), and some cognitive and affective symptoms. changes (the so-called “cerebellar cognitive-affective syndrome”, usually caused by acute, fairly large ischemic damage to the posterior lobe of the cerebellum). It should be emphasized that motor disorders in ataxia are usually not associated with muscle weakness, hyperkinesis, spasticity, etc., however, all of them, as well as other additional symptoms, can complicate the clinical picture of the disease. In turn, severe ataxia can be the main cause of disability and social maladjustment.
Relatively isolated trunk ataxia with impairment of standing and walking is observed with limited lesions of the cerebellar vermis (patients deviate or fall forward with rotal lesions of the vermis and backward with caudal lesions). Ataxia in the limbs is usually attributed to damage to the cerebellar hemispheres, saccadic dysmetria to dysfunction of the dorsal parts of the vermis. Unilateral damage to the cerebellum is manifested by disturbances on the side of the same name: such patients stand with a lowered ipsilateral shoulder, stagger and deviate when walking in the direction of damage, coordination tests also reveal ataxia in the involved arm and leg. Although in humans there is no strict correspondence between specific body parts and cerebellar hemisphere regions, lesions of the anterosuperior hemispheres are thought to result predominantly in ataxia in the legs (a similar pattern seen in alcoholic cerebellar degeneration), while the posterolateral hemispheres are associated with movements in the arms , face and speech. Ataxia may also be associated with damage to the cerebellar pathways; sometimes it manifests with quite characteristic clinical symptoms, such as rough, high-amplitude “rubral” tremor when stretching the arms in front of oneself (typical of damage to the dentato-rubral loop, for example, in multiple sclerosis or Wilson-Konovalov disease).
Sensitive ataxia
Compared with cerebellar sensory ataxia, it is quite rare. It is usually a consequence of damage to the posterior columns and, accordingly, a violation of proprioceptive afferentation (for example, with Friedreich's disease, deficiency of vitamins E and B12, neurosyphilis). Sensitive ataxia can be diagnosed by a distinct proprioceptive deficit and a significant increase in symptoms with eye closure. Sometimes in such cases you can notice the phenomenon of “pseudoathetosis” in the affected limb.
Vestibular ataxia
Vestibular dysfunction can cause a syndrome called vestibular (or labyrinthine) ataxia. In fact, this syndrome can be considered a specific subtype of sensitive ataxia. Patients with vestibular ataxia demonstrate gross impairment of walking and standing (vestibular balance disorder), but without involvement of the limbs or speech. With unilateral lesions of the labyrinth, the “flanking gait” in the direction of damage is significantly impaired. This type of ataxia is often accompanied by dizziness, vomiting, and hearing loss.
Pathophysiology
Pathophysiologically, cerebellar ataxia is a failure of the normal anti-inertial mechanisms that are responsible for the smoothness, uniformity and precision of movements.
Under physiological conditions, any voluntary movement is the result of precisely coordinated and organized activity of many antagonistic and synergistic muscles. Coordinated in space and time, the interaction between various muscles is realized through bilateral connections of the cerebellum with various levels of the central nervous system involved in the performance of motor functions (motor areas of the cortex, basal ganglia, brainstem nuclei, reticular formation, spinal cord motor neurons, proprioceptive neurons and pathways ). Being the main coordinating center of movements, the cerebellum proactively receives information about any changes in muscle tone and the positions of body parts, as well as about any planned actions. Using this anticipatory information, the cerebellum corrects muscle activity, exercises fine motor control, and ensures precise execution of movements. Therefore, diseases affecting the cerebellum lead to desynchronization of muscle contractions, which is clinically manifested by confused irregular “jokes” - scanned speech, intention tremor, dysmetria, trunk titubation and other cerebellar phenomena.
Atactic disorders in cerebellar lesions
Lesions of the cerebellum and cerebellar tracts can be caused by acute or chronic pathology (see table).
Acute ataxia
Repeated paroxysms of acute ataxia are observed in periodic (episodic) ataxias. These hereditary diseases are caused by genetic defects in ion channels (calcium, potassium), which in turn lead to impaired excitability of neurons. Some patients with ataxic paroxysms may respond well to acetazolamide (acetazolamide-sensitive forms of periodic ataxias). Periodic ataxias belong to the group of so-called channelopathies.
Chronic ataxia
Chronic ataxia can be caused by a number of different diseases (see table) of both genetic and non-genetic nature. Chronic or subacute cerebellar ataxia, especially at a young age, is a typical manifestation of multiple sclerosis, the diagnosis of which is confirmed by a remitting course and multiple foci of demyelination in the brain and spinal cord on MRI. It should always be remembered that chronic or subacute cerebellar ataxia can be caused by a tumor (among the tumors characteristic of the cerebellum are cerebellopontine schwannoma, medulloblastoma and hemangioblastoma), normal pressure hydrocephalus (Hakimi-Adams syndrome) and paraneoplastic cerebellar degeneration (lung cancer and other systemic neoplasms); All these diseases require appropriate and timely surgical treatment. Cerebellar degeneration can also be caused by chronic alcoholism, hypothyroidism, celiac disease, vitamin B12 deficiency, heat stroke, and abuse of certain drugs with anxiolytic, hypnotic, and anticonvulsant effects.
Chronic progressive ataxia is a key feature of degenerative atactic syndromes, both hereditary and sporadic.
Hereditary ataxias are a clinically and genetically heterogeneous group of diseases, most often transmitted in an autosomal dominant or autosomal recessive manner.
For autosomal dominant ataxias (ADAs), to date, 28 loci have been mapped on different chromosomes, and 14 genes and their protein products have been identified. In most autosomal dominant SCA, mutations are represented by pathological intragenic expansions of trinucleotide repeats ("dynamic" mutations). The most common expansion is the expansion of CAG repeats, which are translated at the protein level into a proportional lengthening of the polyglutamine region of the protein (hence the name “polyglutamine” diseases and a specific mechanism of neurodegeneration). There is an inverse correlation between the number of trinucleotide repeats in the mutant gene and the age of onset of the disease; Moreover, the greater the extent of expansion, the more severe the clinical symptoms. In addition to dynamic mutations, SCA can also be caused by point mutations in genes encoding, for example, protein kinase gamma, fibroblast growth factor and a number of other proteins. The frequency of occurrence of certain forms of autosomal dominant SCA varies in different populations. For example, in Russia, more than 40% of families with dominant SCA are associated with mutations in the ATXN1 gene on chromosome 6p (SCA1), while in most Western European countries mutations in the ATXN3 gene (SCA3 or Machado-Joseph disease) predominate.
Among the autosomal recessive and X-linked recessive ataxias, the most common is Friedreich's ataxia, caused by the expansion of GAA repeats in the non-coding region of the FRDA gene on chromosome 9q. The protein product of this gene, frataxin, is thought to be involved in mitochondrial iron homeostasis. Thus, Friedreich's disease is a mendelian form of mitochondrial cytopathies. Typically, the disease manifests itself quite early (up to 20 years of age) and is manifested by mixed sensory-cerebellar ataxia, dysarthria, muscle weakness, cardiomyopathy, skeletal deformities, diabetes and a steadily progressive course. There is a fairly strict correlation between the length of the expansion and the clinical manifestations of Friedreich's disease, so a relatively late onset and a “benign” course are characteristic of a short expansion of GAA repeats.
Sporadic (idiopathic) degenerative ataxia is a heterogeneous group, which in turn includes parenchymal cortical cerebellar atrophy and olivopontocerebellar atrophy. The latter is now considered a form of multiple system atrophy, a severe neurodegenerative disease characterized by the involvement of a number of cerebral and spinal systems (cerebellum, basal ganglia, brain stem, autonomic nuclei of the spinal cord and motor neurons) and the presence of specific alpha-synuclein-positive glial cytoplasmic inclusions.
Diagnosis
In patients with ataxic disorders, the diagnosis is based primarily on neuroimaging (CT, MRI) and neurophysiological (evoked potentials, electroneuromyography, etc.) studies, which provide data on the structural and functional characteristics of the central and peripheral nervous system. In most cases of hereditary ataxia, verification of the diagnosis using DNA analysis is now available both for the patients themselves and for their clinically healthy relatives from the “risk” group. To prevent new cases of the disease in these families, medical genetic counseling and prenatal DNA diagnostics can be carried out.
In patients with sporadic ataxia, it is necessary to search for all possible somatic disorders that can cause cerebellar symptoms (neoplasms, endocrine diseases, etc.). Ataxia can be a manifestation of a number of metabolic diseases (see table), so appropriate biochemical screening should be carried out.
Treatment
Treatment and prognosis of ataxic syndromes are based on their cause. If radial treatment is available (such as surgery for cerebellar tumors or correction of vitamin deficiencies), complete or partial recovery or at least cessation of further progression can be expected.
There is no treatment for ataxia itself. Limited benefit has been reported in degenerative ataxias with amantadine, buspirone, L-5-hydroxytryptophan, thyrotropin-releasing factor and pregabalin, however, these data have not been confirmed by randomized trials. There are reports of successful treatment of cerebellar tremor with isoniazid and certain anticonvulsants (clonazepam, carbamazepine, and topiramate); in some cases, stereotactic surgery on the thalamic nuclei is possible.
Physiotherapy is an important component in the treatment of patients with ataxia. It is aimed at preventing various complications (such as contractures and muscle atrophy), maintaining physical fitness, improving coordination and walking. Special complexes of “cerebellar” and “sensory” exercises are recommended, as well as procedures with biofeedback and stabilography.
The first approaches to gene and cell therapy for hereditary ataxias are at the development stage; It is possible that these technologies will make a significant breakthrough in treatment in the future.
Table. Causes of acute and chronic ataxia
Acute ataxia | Chronic ataxia |
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Multiple sclerosis Traumatic brain injury Infection: Acute drug intoxication and poisoning:
MELAS, Leigh's disease and other acute-onset mitochondrial encephalomyopathies Tumors and malformations with acute and subacute manifestations Thiamine deficiency (Wernicke encephalopathy) Periodic ataxias Paraneoplastic cerebellar degeneration Hyperthermia (heatstroke) Hypoglycemia (insulinoma) Hereditary metabolic diseases:
| Multiple sclerosis Cerebellar tumors Chronic cerebral ischemia Normal pressure hydrocephalus (Hakim-Adams syndrome) Paraneoplastic cerebellar degeneration Cerebellar dysplasia or hypoplasia (congenital ataxia, usually not progressive) Prion diseases (atactic form) Chronic alcoholism Hypothyroidism Vitamin B12 deficiency Hyperthermia (heatstroke) Abuse of drugs with anxiolytic, hypnotic and anticonvulsant effects Gluten ataxia Hereditary ataxia with autosomal dominant, autosomal recessive and X-linked inheritance Sporadic idiopathic degenerative ataxias:
Genetic metabolic diseases:
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Impaired coordination of movements and the ability to maintain a posture associated with damage to the vestibular apparatus at any level. Vestibular ataxia manifests itself as unsteadiness in standing and sitting positions, as well as when walking. It is accompanied by systemic dizziness and nystagmus; Nausea and vomiting, autonomic disorders and symptoms characteristic of the pathological process that caused the development of vestibular ataxia may be observed. Diagnosis of the latter is the main goal of examining patients with vestibular ataxia. Treatment of vestibular ataxia is symptomatic. The main therapy should be aimed at the causative disease.
General information
The orientation of the body in space in the human body is provided by the vestibular analyzer. It is responsible for determining the position and nature of movement of the body and its individual parts, and provides the perception of gravity. Any change in body position in space is perceived by vestibular receptors - the so-called hair cells located in the labyrinth of the inner ear. From the receptors, nerve impulses travel along the vestibular nerve, which, together with the auditory nerve, is part of the VIII pair of cranial nerves. Next, the impulses enter the vestibular nuclei of the medulla oblongata, where information is synthesized and motor reactions are controlled. From the vestibular nuclei, regulatory nerve impulses disperse to various parts of the central nervous system: the cerebellum, spinal cord, reticular formation, autonomic nerve ganglia, oculomotor nuclei and cerebral cortex. They provide redistribution of muscle tone and reflex reactions to maintain balance.
Causes
Vestibular ataxia is associated with damage to any structure of the vestibular analyzer. Most often it is caused by damage to hair cells as a result of an inflammatory process in the inner ear - labyrinthitis. In turn, labyrinthitis can occur as a result of ear injury or when infection passes from the middle ear cavity in acute otitis media, chronic purulent otitis media, complicated aerootitis. The death of hair cells leading to the development of vestibular ataxia can occur as a result of invasive growth of an ear tumor or toxic effects of secretions from cholesteatoma of the ear. Paroxysmal vestibular ataxia accompanies Meniere's disease.
Less commonly, vestibular ataxia is caused by damage to the vestibular nerve, which can be infectious, tumor (with acoustic neuroma) or toxic (with ototoxic drugs) in nature. Often, vestibular neuronitis is associated with a viral infection: ARVI, herpes virus, influenza, etc.
Vestibular ataxia can occur when the vestibular nuclei located in the medulla oblongata are damaged. Thus, vestibular ataxia occurs as a result of compression of the medulla oblongata in individuals with craniovertebral anomalies (Chiari malformation, atlas assimilation, platybasia), brain stem tumors, encephalitis and arachnoiditis of the posterior cranial fossa, demyelinating diseases (multiple sclerosis, acute encephalomyelitis). Vestibular ataxia is a clinical manifestation of chronic ischemia of the brainstem caused by impaired vertebrobasilar circulation due to vertebral artery syndrome, atherosclerosis, hypertension, and cerebral aneurysm. In acute circulatory disorders of this area (TIA, ischemic or hemorrhagic stroke), vestibular ataxia is also observed.
Vestibular ataxia is often observed after a traumatic brain injury. Moreover, it can be caused either by the direct impact of a traumatic factor on the nuclei and roots of the vestibular nerve, or by circulatory disorders accompanying the injury (post-traumatic vascular spasm).
Symptoms of vestibular ataxia
Vestibular ataxia manifests itself both in movement (dynamic ataxia) and in a standing position (static ataxia). Vestibular ataxia differs from other types of ataxia in the dependence of its severity on rotation of the head and body. Increased ataxia when turning the head, eyes and body forces patients to avoid such movements or perform them smoothly and slowly. Visual control of movements partially compensates for dysfunction of the vestibular analyzer, so with closed eyes the patient feels more insecure and the manifestations of vestibular ataxia increase.
Lesions of the vestibular analyzer are most often unilateral. In such cases, vestibular ataxia manifests itself as unsteadiness when walking with the body always tilted in the same direction - in the direction where the lesion is localized. In a standing or sitting position, the patient also deviates to the affected side. This symptom is easily detected in the Romberg position and when the patient tries to walk several steps smoothly with his eyes closed.
A characteristic sign of vestibular ataxia is the presence of systemic vertigo, in which the patient experiences a feeling of rotation of his own body or movement of surrounding objects around him. Dizziness can occur even when lying down with your eyes closed. In such cases, it is usually accompanied by sleep disturbances with difficulty falling asleep. The activation of vestibulo-visceral nerve connections leads to the fact that dizziness with vestibular ataxia is often accompanied by nausea and vomiting. Vestibulo-autonomic interactions cause the appearance of autonomic reactions: pallor or redness of the face, feelings of fear, tachycardia, pulse lability, hyperhidrosis.
In most cases, vestibular ataxia is accompanied by horizontal nystagmus, the direction of which is opposite to the side of the lesion. Bilateral nystagmus is possible. When the vestibular nuclei are damaged, vertical nystagmus with a rotatory component may be observed. If there is a disturbance at the level of the peripheral part of the vestibular analyzer, nystagmus increases with head turns, but with repeated turns, nystagmus may decrease. In the presence of a craniovertebral anomaly, vestibular ataxia is accompanied by nystagmus, which intensifies when the head is tilted.
Diagnostics
Vestibular ataxia can be identified by the patient’s characteristic complaints and during his neurological examination. To differentiate vestibular ataxia from other types of ataxia (cerebellar, sensory, cortical), as well as to establish the level and nature of damage to the vestibular analyzer, the neurologist needs the results of instrumental examination methods: REG, Echo-EG, EEG, CT and MRI of the brain, x-ray studies . Since vestibular ataxia as a syndrome occurs in many diseases of the central nervous system, the most important point in clinical neurology is to identify the cause of its development.
REG allows you to obtain indirect data about the state of blood circulation in the brain. If necessary, it can be supplemented with angiography or MRI angiography of cerebral vessels. Using echo-EG, the state of the cerebrospinal fluid system of the brain is assessed. A displacement of the echo indicates the presence of a space-occupying formation (tumor, hematoma or
Ataxia(from the Greek ataxia - disorder) - disorder of coordination of movements; a very common motor disorder. Strength in the limbs is slightly reduced or completely preserved. Movements become inaccurate, awkward, their continuity and consistency are disrupted, balance in a standing position and when walking is disturbed. Static ataxia is a violation of balance in a standing position, dynamic ataxia is a violation of coordination when moving. Diagnosis of ataxia includes a neurological examination, EEG, EMG, MRI of the brain, and if the hereditary nature of the disease is suspected, DNA analysis. Therapy and prognosis for the development of ataxia depend on the cause of its occurrence.
General information
Ataxia(from the Greek ataxia - disorder) - disorder of coordination of movements; a very common motor disorder. Strength in the limbs is slightly reduced or completely preserved. Movements become inaccurate, awkward, their continuity and consistency are disrupted, balance in a standing position and when walking is disturbed. Static ataxia is a violation of balance in a standing position, dynamic ataxia is a violation of coordination when moving.
Normal coordination of movements is possible only with highly automated and cooperative activity of a number of parts of the central nervous system - conductors of deep muscle sensitivity, the vestibular apparatus, the cortex of the temporal and frontal regions and the cerebellum - the central organ of coordination of movements.
Classification of ataxias
Symptoms of ataxia
Emergence sensitive ataxia caused by damage to the posterior columns (gaulle and Burdach bundles), less often the posterior nerves, peripheral nodes, parietal cortex, thalamus opticum (funicular myelosis, tabes dorsalis, vascular disorders). It may manifest itself in all limbs, or in one leg or arm. The most indicative phenomena are sensory ataxia, which occurs as a result of a disorder of the joint-muscular sense in the lower extremities. The patient is unsteady, when walking he bends his legs excessively at the hip and knee joints, and steps too hard on the floor (stamping gait). Often there is a feeling of walking on cotton wool or carpet. Patients try to compensate for the disorder of motor functions with the help of vision - when walking, they constantly look at their feet. This can significantly reduce the manifestations of ataxia, and closing the eyes, on the contrary, aggravates them. Severe lesions of the posterior columns practically make it impossible to stand and walk.
Cerebellar ataxia- a consequence of damage to the cerebellar vermis, its hemispheres and peduncles. In the Romberg position and when walking, the patient falls (even to the point of falling) towards the affected cerebellar hemisphere. If the cerebellar vermis is damaged, it is possible to fall to any side or backward. The patient staggers when walking and places his legs wide. The flanking gait is severely impaired. Movements are sweeping, slow and awkward (more so on the part of the affected cerebellar hemisphere). Coordination disorder is almost invariable during visual control (open and closed eyes). There is a disturbance in speech - it slows down, becomes stretched, jerky, and often chanted. Handwriting becomes splayed, uneven, and macrography is observed. There may be a decrease in muscle tone (more on the affected side), as well as a violation of tendon reflexes. Cerebellar ataxia can be a symptom of encephalitis of various etiologies, multiple sclerosis, malignant neoplasm, vascular lesion in the brainstem or cerebellum.
Development cortical ataxia(frontal) is caused by damage to the frontal lobe of the brain caused by dysfunction of the fronto-pontocerebellar system. In frontal ataxia, the leg contralateral to the affected cerebellar hemisphere is most affected. When walking, there is instability (more so when turning), tilting or leaning to the side ipsilateral to the affected hemisphere. With severe lesions of the frontal lobe, patients cannot walk or stand at all. Vision control has no effect on the severity of walking disorders. Cortical ataxia is also characterized by other symptoms characteristic of damage to the frontal lobe - grasping reflex, mental changes, impaired sense of smell. The symptom complex of frontal ataxia is very similar to cerebellar ataxia. The main difference between cerebellar lesions is evidence of hypotonia in the ataxic limb. The causes of frontal ataxia are abscesses, tumors, and cerebrovascular accidents.
Hereditary Cerebellar Pierre-Marie ataxia- a hereditary disease of a chronic progressive nature. It is transmitted in an autosomal dominant manner. Its main manifestation is cerebellar ataxia. The pathogen has high penetrance, skipping generations is very rare. A characteristic pathological sign of Pierre-Marie ataxia is cerebellar hypoplasia, less often - atrophy of the inferior olives, the pons (pons). Often these signs are combined with combined degeneration of the spinal systems (the clinical picture resembles Friedreich's spinocerebellar ataxia).
The average age of onset is 35 years when gait disturbance appears. Subsequently, it is accompanied by disturbances in facial expressions, speech and ataxia in the hands. Static ataxia, adiadochokinesis, and dysmetria are observed. Tendon reflexes are increased (to pathological reflexes). Involuntary muscle twitches are possible. Strength in the muscles of the limbs is reduced. Progressive oculomotor disorders are observed - paresis of the abducens nerve, ptosis, convergence insufficiency, less often - Argyll Robertson's symptom, optic nerve atrophy, decreased visual acuity, narrowing of visual fields. Mental disorders manifest themselves in the form of depression and decreased intelligence.
Familial Friedreich's ataxia- a hereditary disease of a chronic progressive nature. It is transmitted in an autosomal dominant manner. Its main manifestation is mixed sensory-cerebellar ataxia, resulting from combined damage to the spinal systems. Consanguineous marriages are very common among patients' parents. A characteristic pathological sign of Friedreich's ataxia is increasing degeneration of the lateral and posterior columns of the spinal cord (up to the medulla oblongata). Gaulle's bundles are most affected. In addition, the cells of Clark's columns are affected, and along with them the posterior spinocerebellar tract.
The main symptom of Friedreich's ataxia is ataxia, expressed in an uncertain, clumsy gait. The patient walks in a sweeping manner, deviating from the center to the sides and placing his feet wide. Charcot designated this gait as a tabetic-cerebellar gait. As the disease progresses, incoordination spreads to the arms, chest muscles and face. Facial expressions change, speech becomes slow and jerky. Tendon and periosteal reflexes are significantly reduced or absent (primarily on the legs, later on the upper extremities). In most cases, hearing is reduced.
With the development of Friedreich's ataxia, extraneural disorders appear - cardiac lesions and skeletal changes. The ECG shows deformation of the atrial wave, rhythm disturbance. There is paroxysmal pain in the heart, tachycardia, shortness of breath (as a result of physical stress). Skeletal changes are expressed in a characteristic change in the shape of the foot - a tendency to frequent dislocations of the joints, an increase in the arch and extension of the fingers, as well as kyphoscoliosis. Among the endocrine disorders accompanying Friedreich's ataxia are diabetes, hypogonadism, and infantilism.
Ataxia-telangiectasia(Louis-Bar syndrome) is a hereditary disease (phakomatoses group), transmitted in an autosomal recessive manner. Very often accompanied by dysgammaglobulinemia and hypoplasia of the thymus gland. The development of the disease begins in early childhood, when the first ataxic disorders appear. In the future, ataxia progresses and by the age of 10, walking is almost impossible. Louis-Bar syndrome is often accompanied by extrapyramidal symptoms (hyperkinesis of the myoclonic and athetoid type, hypokinesia), mental retardation, and damage to the cranial nerves. There is a tendency to recurrent infections (rhinitis, sinusitis, bronchitis, pneumonia), which is primarily due to insufficient immunological reactions of the body. Due to the deficiency of T-dependent lymphocytes and class A immunoglobulins, there is a high risk of malignant neoplasms.
Complications of ataxia
Diagnosis of ataxia
Diagnosis of ataxia is based on identification of diseases in the patient's family and the presence of ataxia. EEG of the brain in Pierre Marie's ataxia and Friedreich's ataxia reveals the following disorders: diffuse delta and theta activity, reduction of the alpha rhythm. In laboratory studies, a disturbance in amino acid metabolism is observed (the concentration of leucine and alanine is reduced, and their excretion in the urine is also reduced). MRI of the brain reveals atrophy of the spinal cord and brain stems, as well as the upper parts of the vermis. Using electromyography, axonal demyelinating damage to the sensory fibers of peripheral nerves is detected.
When differentiating ataxia, it is necessary to take into account the variability of the clinical picture of ataxia. In clinical practice, rudimentary varieties of ataxia and its transitional forms are observed, when the clinical manifestations are similar to the symptoms of familial paraplegia (spastic), neural amyotrophy and multiple sclerosis.
To diagnose hereditary ataxias, direct or indirect DNA diagnostics is necessary. Using molecular genetic methods, ataxia is diagnosed in a patient, after which indirect DNA diagnostics are performed. With its help, the possibility of inheriting the ataxia pathogen by other children in the family is established. It is possible to carry out complex DNA diagnostics; it will require biomaterial from all family members (the child’s biological parents and all other children of this parental couple). In rare cases, prenatal DNA diagnosis is indicated.
Treatment and prognosis of ataxia
Ataxia is treated by a neurologist. It is predominantly symptomatic and should include: restorative therapy (B vitamins, ATP, anticholinesterase drugs); a special set of gymnastic exercises aimed at strengthening muscles and reducing incoordination. With Friedreich's ataxia, taking into account the pathogenesis of the disease, drugs that support mitochondrial functions (succinic acid, riboflavin, coenzyme Q10, vitamin E) can play a large role in treatment.
To treat ataxia-telangiectasia, in addition to the above algorithms, correction of immunodeficiency is necessary. For this purpose, a course of treatment with immunoglobulin is prescribed. Radiation therapy is contraindicated in such cases; in addition, excessive X-ray radiation and prolonged exposure to the sun should be avoided.
The prognosis of genomic hereditary diseases is unfavorable. There is a slow progression of neuropsychiatric disorders. Working capacity in most cases is reduced. However, thanks to symptomatic treatment and prevention of recurrent infectious diseases, injuries and intoxications, patients have the opportunity to live to an old age. For preventive purposes, the birth of children in families where there are patients with hereditary ataxia should be avoided. In addition, it is recommended to exclude the possibility of any related marriages.
Vestibular ataxia (labyrinthine) is a violation of coordination of movements and gait, which is associated with disruption of the vestibular apparatus. Accompanied by the presence of nystagmus, systemic dizziness, nausea and vomiting. Autonomic abnormalities may occur (tachycardia, pallor or redness of the face, increased sweating).
Since ataxia is not an independent disease, but a symptom of other diseases (develops against the background of traumatic brain injury, etc.), vestibular ataxia is also characterized by signs of an underlying, primary disease.
General information
Ataxia is a Greek word that translates as “confusion,” “disorder.” It has been used as a medical term since the time of Hippocrates.
Systemic dizziness is a frequently encountered symptom in medical practice, almost always accompanying vestibular ataxia. It is systemic dizziness that is often the reason for visiting neurologists (10% of all cases) and otolaryngologists (about 4% of all cases).
Labyrinthine ataxia is one of the main causes of falls and subsequent injuries in old age.
Forms
Depending on the nature of the manifested violations, the following are distinguished:
- static vestibular ataxia, which manifests itself in a standing position;
- dynamic vestibular ataxia, in which symptoms manifest themselves in movement.
It is usually unilateral, but a bilateral form is also found.
Reasons for development
Vestibular ataxia occurs when the structures of the vestibular apparatus are damaged at any of its levels (labyrinth, vestibular nerve (VIII pair), nuclei located in the brain stem, vestibular analyzer of the cortical center in the temporal lobe).
Pathology can occur when:
- Damage to the hair cells that are located inside the membranous labyrinth (inner ear).
- Ear injuries that are accompanied by damage to the labyrinth. More often there are injuries in which neighboring organs are also damaged (combined injuries).
- Inflammatory processes of the middle ear, which are accompanied by the spread of infection to the labyrinth (acute and chronic purulent otitis media).
- Ear neoplasms, which are characterized by penetration of tumor cells through tissue (invasive type of growth).
- Meniere's disease. This disease of the inner ear is characterized by the presence in the ear cavity of an increased amount of endolymph, which puts pressure on the cells responsible for balance. Labyrinthine ataxia in this case is paroxysmal in nature.
- Rarely occurring tumor, infectious (herpes, ARVI) or toxic damage to the vestibular nerve.
- Traumatic brain injuries leading to damage to the vestibular nuclei, which are located in the rhomboid fossa (the bottom of the fourth ventricle, formed by the bridge and the posterior surface of the medulla oblongata).
- Pathologies of the craniovertebral region (atlas assimilation, platybasia), causing compression of the medulla oblongata. Compression also causes the formation of a tumor on the brain stem.
- Blood flow disturbances due to atherosclerosis, high blood pressure, cerebral aneurysms, which lead to brain stem ischemia.
Encephalitis, multiple sclerosis, acute encephalomyelitis, and arachnoiditis of the posterior fossa also contribute to the development of vestibular ataxia.
Pathogenesis
The orientation of the human body in space is provided by the vestibular analyzer. It is thanks to the vestibular analyzer that the perception of gravity, the position and nature of the movement of body parts and the movement of the body in space are determined.
Every change in body position is perceived by hair cells - vestibular receptors, which are located on the thin basilar membrane in the receptor part of the auditory analyzer (inside the anterior part of the membranous labyrinth).
Hair cells transmit impulses along the vestibular nerve (belongs to the VIII pair of cranial nerves) to the vestibular nuclei, which are responsible for the synthesis of information.
Control of motor reactions is carried out through the transmission of regulatory nerve impulses from the vestibular nuclei to various parts of the central nervous system, which ensure the maintenance of balance and redistribution of muscle tone due to reflex reactions.
Damage to any part of the vestibular analyzer causes imbalance and coordination of movements.
Symptoms
Vestibular ataxia differs from other forms of this disorder:
- dependence of the severity of symptoms on movements and turns of the head and body;
- severe disturbances in walking and standing without involving the limbs and speech disorders.
Vestibular ataxia is characterized by the presence of:
- Systemic severe dizziness, which may be present even in a supine position. Often accompanied by nausea and vomiting.
- Horizontal nystagmus (involuntary oscillatory movements of the eyes along a horizontal line, which are characterized by high frequency), which, with a unilateral lesion, is directed to the side opposite the affected area. Damage to the vestibular nuclei is accompanied by vertical (usually asymmetric) nystagmus with a rotation component. When vestibular connections are disrupted, bilateral nystagmus may occur.
- Staggering when walking (tendency to fall), in which there is a deviation towards the existing lesion. Deviation to the affected side is also observed in a sitting or standing position.
Possible hearing loss. Coordination of hand movements is preserved.
Symptoms that intensify when turning the head, body or eyes force the patient to perform these movements very slowly and try in every possible way to avoid them. Visual control largely compensates for impaired coordination, so with closed eyes a person does not feel confident, and symptoms progress.
There are no violations of muscle-articular sensation.
If you experience dizziness while lying down with your eyes closed, sleep disturbances (difficulty falling asleep) are often present.
Vegetative reactions may also occur:
- pale or red face;
- feeling of fear;
- tachycardia;
- pulse lability;
Diagnostics
The diagnosis of vestibular ataxia is based on:
- Anamnesis data. The doctor clarifies when the first symptoms of the disease appeared, what the patient suffered from during his life, what hereditary diseases were in the family.
- General examination data. The examination includes assessment of reflexes and muscle tone, hearing and vision, and coordination tests. A “star test” is performed, in which the patient with his eyes closed tries to take several steps in a straight line, but at the same time the trajectory of his movement with ataxia is similar to a star, Romberg’s pose is assessed (feet in a standing position are moved together, eyes are closed, arms are extended straight in front of him ) etc.
- Data from laboratory and instrumental studies.
To determine the type of ataxia and identify the nature and level of damage to the vestibular analyzer, the following is carried out:
- X-ray studies that reveal craniovertebral anomaly. The skull and spine in the cervical region are examined.
- REG. This study is carried out to obtain indirect data on blood circulation in the brain. If there is a need to examine in detail the blood circulation of the cerebral vessels, angiography or MRI angiography is performed.
- Echo-EG, which allows you to assess the state of the liquor system. If the echo is displaced, we can conclude that there is a tumor, abscess or hematoma in the brain, which can provoke vestibular ataxia.
- EEG, which helps evaluate the bioelectrical activity of the brain.
- CT and MRI, allowing to identify space-occupying formations and the presence of demyelinating processes.
The vestibular analyzer is examined by a vestibulologist (in his absence, a neurologist or otolaryngologist) using:
- Vestibulometry, allowing to assess its functions. Includes caloric, rotational, index, finger-nose and pressor tests, Vojacek's otolith reaction (the study begins with the finger-nose and index test).
- Stabilography, which allows you to evaluate the vibrations of the human body while maintaining an upright posture.
- Videooculography, which records eye movements and allows you to analyze nystagmus (disturbances of the vestibular analyzer at the peripheral level are accompanied by increased nystagmus when turning the head with a decrease in nystagmus with repeated turns, increased nystagmus when tilting the head with craniovertebral anomaly, etc.)
- Electronystagmography, which allows you to record eye movements with closed eyelids.
To study hearing, threshold audiometry, tuning fork testing, electrocochleography, etc. are used.
Treatment
Treatment of vestibular ataxia is aimed at curing the primary disease. Includes:
- Antibiotic therapy for ear infections. Middle ear lavage, labyrinthectomy for labyrinthitis and other measures are also carried out to eliminate the purulent focus.
- The use of drugs that improve blood supply to the brain in case of vascular disorders (angioprotectors, nootropics), as well as drugs to normalize blood pressure.
- Taking hormonal drugs and plasmapheresis for demyelinating diseases.
- The use of diuretics and sedatives for Meniere's disease, as well as a low-salt diet and avoidance of alcohol and caffeine. Ototoxic antibiotics (gentamicin, etc.) are used for chemical ablation (cauterization, removal) of labyrinthine tissue.
- Surgical correction for severe craniovertebral anomalies.
- Surgical methods in the presence of tumor or hemorrhage.
Symptomatic treatment is also carried out, including:
- taking medications that improve the functioning and metabolism of nerve cells (ginkgo biloba, cerebrolysin, B vitamins, etc.);
- a physical therapy complex that strengthens muscles and trains coordination of movements.
Prevention
Prevention of vestibular ataxia consists of:
- timely and adequate treatment of infectious diseases;
- promptly consult a doctor if dizziness occurs;
- blood pressure control;
- maintaining a healthy lifestyle.
Impairments in coordination of movements or the ability to take a particular position associated with damage to the vestibular apparatus in any area are called vestibular. This pathology is manifested by instability in a sitting or standing position and during walking. The disease is accompanied by nystagmus, dizziness, nausea, vomiting, autonomic abnormalities and symptoms that are characteristic of the disease that caused the formation of ataxia.
Why does pathology form and develop?
The disease can be caused by damage to any area in the vestibular system. This is mainly damage to hair cells due to the formation of inflammation of the inner ear. This disease can manifest itself due to an ear injury or the spread of an infectious process from the middle ear in the acute form of otitis media, the chronic form of purulent otitis media. The death of hair cells, causing the development of vestibular ataxia, can begin due to the growth of an ear tumor or toxic poisoning from cholesteatoma secretions in the ear.
In rare cases, the disease can be triggered by damage to the vestibular nerve, which is tumorous, infectious or toxic. Often the causes are viral diseases, such as the herpes virus, ARVI, influenza, etc.
Vestibular ataxia can develop when the vestibular nuclei located in the medulla oblongata are damaged.
The disease also manifests itself due to pressure on the medulla oblongata in people with existing pathologies of the craniovertebral system, when a tumor forms on the brain stem. It is a clinical sign of ischemia in the brain stem caused by impaired blood flow due to atherosclerosis, increased blood pressure, and vascular aneurysms in the brain. With acute disturbances of blood flow in the brain, the formation of vestibular ataxia also begins.
It is important! The disease manifests itself after a traumatic brain injury. In this case, it can be provoked by the direct influence of injury on the roots and nucleus of the vestibular nerve or by injuries that cause disruption of blood flow.
Symptoms accompanying the development of pathology
Vestibular ataxia can manifest itself both in movement and in a standing position. The vestibular type differs from other forms of the disease in the dependence of its manifestations on turns and movements of the torso and head. Intensification of symptoms when turning the head, torso, or eyes forces a person to refuse to implement the listed body movements or perform them too slowly. Visual control noticeably compensates for coordination disorders, and therefore, when closing the eyes, a person feels insecure, and the symptoms progress.
Damage to the vestibular apparatus is mainly one-sided, so the disease is characterized by unsteadiness of gait, deviation of the body in the same direction as the location of the lesion. In a sitting or standing position, the patient also deviates to the injured side. This sign also becomes noticeable when a person tries to cover a short distance with his eyes closed.
A characteristic manifestation of ataxia is systemic dizziness, when the patient feels as if his own body is rotating. Sometimes dizziness can be felt when sitting with your eyes closed. In such a situation, it is accompanied by nausea and vomiting. The interaction of the vestibular apparatus and the autonomic nervous system leads to the appearance of paleness or redness of the face, disturbances in heartbeat and pulse, the formation of a feeling of fear and rashes on the skin.
Typically, vestibular ataxia is accompanied by nystagmus in a horizontal position, its direction opposite to the affected side. Vertical nystagmus may also develop.
With disorders in the periphery of the vestibular apparatus, nystagmus increases when moving the head or tilting the head.
Conduct and effectiveness of the treatment process
The treatment process for vestibular ataxia mainly involves treatment of the causative pathology. In case of an infectious disease in the ear, antibacterial therapy, washing of the middle ear area, sanitizing surgery and other measures are organized that involve eliminating foci of suppuration. 
If the pathology is caused by the manifestation of disturbances in the functioning of the vascular system, then the treatment of vestibular ataxia is aimed at taking medications that normalize the flow of blood to the brain. In advanced cases with the development of craniovertebral deviations, they are corrected using surgical intervention. Appropriate treatment is required to establish the presence of encephalitis, large neoplasms or arachnoiditis in the human body.
It is important! The vestibular form of ataxia itself is amenable to symptomatic therapy, which mainly consists of taking medications that improve metabolism and the functioning of nerve cells. In addition, patients require the organization of a special set of physical therapy exercises, which involves training to strengthen muscles and coordinate movements.
It is important to remember that ataxia requires utmost attention. Poor coordination of movements and difficulties maintaining balance can cause serious injuries. If a person has noted signs of developing pathology, it is better to visit a specialist as soon as possible, who will help take appropriate precautions.
