Spinal muscular atrophy symptoms in newborns. Spinal muscular atrophy in children

Spinal muscular atrophy (orspinal amyotrophy) is a group of hereditary diseases characterized by progression muscle weakness and atrophy of muscle fibers due to damage to motor neurons (motor nerve cells) in the spinal cord or brain. The incidence of this pathology is about 1 case per 6-10 thousand newborns. At the same time, every second child with spinal muscular atrophy does not live up to 2 years.

Causes

The cause of spinal muscular atrophy is a mutation of the gene responsible for the synthesis of the SMN protein, localized on chromosome 5q. This defect subsequently leads to the gradual death of the motor neurons of the anterior horns of the spinal cord and the brain stem, as a result of which the respiratory, swallowing muscles, as well as the muscles of the face and body are affected (reduced muscle tone) and eventually atrophy. Most forms of spinal amyotrophy (childhood forms) are inherited in an autosomal recessive manner, that is, the disease is possible if both parents are carriers of the defective gene. However, the adult form (type IV) is linked to the X chromosome, and therefore only males are affected.

Symptoms of spinal muscular atrophy

Clinical manifestations of spinal amyotrophy depend on the form of the disease. Common features of all forms of spinal muscular atrophy are the manifestation of general and muscle weakness, the preservation of sensitivity and intelligence, and the decrease or absence of tendon reflexes.

The mildest course of childhood forms is characteristic of type III spinal muscular atrophy (Kugelberg-Welander syndrome). The first manifestations, as a rule, are found in children after 1.5 years and are characterized by difficulties with complex motor skills (running, climbing stairs, etc.). Symptoms progress slowly, swallowing and chewing disorders develop much later.

Type II spinal amyotrophy is characterized by an earlier manifestation (6-18 months) and a chronically progressive course. In such children, there is a lag in motor development, tremor of the fingers, progression of the weakness of the cough reflex, shallow diaphragmatic breathing and intercostal muscles. Initially, children with this form of the disease can crawl, sit unsupported, and some even stand with support, but these abilities are lost as they grow and gain weight. Skeletal and muscular deformities (including scoliosis, chest deformities and pseudohypertrophy of the gastrocnemius muscle), contractures, and respiratory disorders (up to the development of respiratory failure) are formed.

The most severe form is type I spinal muscular atrophy (Werdnig-Hoffmann syndrome), manifesting in early childhood (in the first 6 months). The “flaccid child” syndrome is characteristic (weak cry, reduced motor activity, sluggish sucking, weight loss, reduced swallowing, sucking and cough reflexes). Such children are unable to hold the head, roll over and sit, lag behind in motor development (gross delay). Deformities of the joints and limbs, contractures, respiratory and bulbar disorders may develop. The average life expectancy of such children is 2 years. The cause of death is usually severe respiratory failure or the development of pneumonia.

The adult form (type IV) has a mild course, in which the muscles of the shoulder girdle are most often affected first.

Diagnostics

Diagnosis of spinal muscular atrophy includes a neurological examination, a biochemical blood test (creatine kinase may be slightly increased), an electroneuromyography (a decrease in nerve impulses with normal sensory nerve conduction is determined), an x-ray of bones (the presence of deformities), a muscle biopsy (atrophy of muscle tissue), as well as genetic testing.

Classification

There are the following forms of spinal muscular atrophy:

Type I - infantile (Verdnig-Hoffman disease);

Type II - intermediate (Dubovitz's disease);

Type III - juvenile (Kyugelberg-Welander disease);

IV type - adult.

Patient's actions

If there is a suspicion of muscle weakness, it is recommended to consult a specialist (geneticist and neurologist).

Treatment of spinal muscular atrophy

Specific therapy that can cure this pathology has not yet been developed. However, a slight slowdown in the rate of progression of symptoms was noted with the use of B vitamins and drugs that improve the trophism of the nervous tissue. Otherwise, palliative support is indicated to improve the quality of life of patients with spinal muscular atrophy. It consists in providing assistance in self-care and movement, breathing exercises, massages, occupational therapy, physiotherapy, feeding through a gastrostomy with the development of problems with swallowing, respiratory support (including mechanical ventilation) - with the development of respiratory failure.

Complications

Most often, spinal amyotrophies are complicated by pneumonia, secondary infections, and severe respiratory failure.

Prevention of spinal muscular atrophy

Prevention of this pathology does not exist. Perhaps genetic counseling at the stage

Spinal muscular atrophy is reported to occur in approximately 1 in 6,000 births. In most cases, this happens for genetic reasons. A carrier of the mutant gene may not show any symptoms of the disease. Typically, one in 35 people has this gene. And only at the meeting of two mutant genes - father and mother, this disease can develop. Heredity is the main cause of severe illness.

Symptoms

The disease affects the large spinal muscles of the child, which, due to atrophy of nerve cells, do not receive motor signals from the spinal cord. The immobilization is progressing. Muscles rapidly atrophy, as they are in an inactive state. As a result, the respiratory function of the child also suffers. Breathing becomes harder and harder.

Pronounced symptoms of muscle atrophy in children are:

decreased muscle tone;
absolute absence of reflexes;
impaired mechanism of sucking and swallowing;
the child cannot chew food on his own;
scoliosis occurs;
joint problems;
paresis of the diaphragm;
general developmental defects;
dementia;
the chest is deformed.

With such severe symptoms, children rarely live beyond the age of 9.

Diagnosis of spinal muscular atrophy in children

Diagnosis is carried out by a doctor on the basis of an examination and a detailed study of family history. This is necessary in order to differentiate spinal muscular atrophy from other diseases with similar symptoms.

Methods for diagnosing spinal muscular atrophy in children are as follows:

enzyme blood tests;
genetic testing;
according to the indications, a muscle biopsy is prescribed;
measurement of nerve conduction velocity;
electrical activity of muscles.

Based on the examinations, the doctor will establish an accurate diagnosis and appropriate treatment will be prescribed, taking into account the individual characteristics of the child. A complete cure for this disease is almost impossible. All the efforts of doctors are aimed at maximally supporting the vital activity of the baby's body.

Depending on the degree of damage to the spinal cord, individual measures are selected to adapt the child to life functions. For example, it has been noticed that even before the age of 3, kids learn to skillfully manage a wheelchair and move independently on it.

Complications

Unfortunately, spinal muscular atrophy is an incurable disease. Treatment involves symptomatic supportive therapy. Complications and consequences of the disease are very serious:

paralysis develops as a result of an increase in muscle mass;
development of severe respiratory complications;
extinction of chewing and swallowing functions;
development of severe forms of scoliosis;
chest deformities of varying degrees;
muscle wasting;
fatal outcome.

Treatment

What can you do

If you begin to notice any symptoms of spinal muscular atrophy in your baby, then the best thing to do is to seek qualified medical help in a timely manner. Based on the results of the examinations, the doctor will establish a diagnosis and treatment will be prescribed, as well as measures to improve the child's adaptation to everyday life.

According to the indications, a special wheelchair is selected, in which the child learns to move independently. Depending on the degree of muscle wasting, other devices may be recommended, such as a walker to help the child move around. Parents of a sick child should be closely monitored, especially in the initial period, so that the baby learns to use the devices.

Special physiotherapy procedures are also prescribed, which must be taken regularly. Do not ignore the appointments of doctors whose efforts are aimed at helping you and your baby in a difficult situation.

What does a doctor do

The actions of doctors involved in the treatment of a child diagnosed with spinal muscular atrophy are directed in several directions:

for the treatment of dysfunction of the respiratory muscles;
for the treatment of dysfunction of the swallowing muscles;
for the treatment of lethargy of the spinal muscles and curvature of the spine;
for the treatment of an abnormal reaction to muscle relaxant drugs.

The task facing physicians is not an easy one. It is also necessary to take into account the stressful state of parents who are informed about a formidable disease in their baby. However, with the joint efforts of doctors and parents, it is possible and necessary to fight the disease. Currently, medicine is making fairly successful steps in the study of the disease and the development of new methods of its treatment.

Prevention

Measures to prevent the disease are aimed at its timely recognition, which in some cases can be done even in the womb. Early diagnosis expands the possibilities of medical care for children diagnosed with spinal muscular atrophy, as well as for their parents.

If the family has already faced the problem of having a child with this disease, then prevention is aimed at preventing the re-birth of offspring with a similar diagnosis. Special genetic tests will determine the presence of a mutant gene in parents.

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Arm yourself with knowledge and read a useful informative article about spinal muscular atrophy in children. After all, being parents means studying everything that will help maintain the degree of health in the family at the level of “36.6”.

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In the article, you will read everything about the methods of treating a disease such as spinal muscular atrophy in children. Specify what effective first aid should be. How to treat: choose drugs or folk methods?

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And caring parents will find on the pages of the service full information about the symptoms of spinal muscular atrophy in children. How do the signs of the disease in children at 1.2 and 3 years old differ from the manifestations of the disease in children at 4, 5, 6 and 7 years old? What is the best treatment for spinal muscular atrophy in children?

Take care of the health of your loved ones and be in good shape!

spinal muscular atrophy(SMA), or amyotrophy, is a disease of a hereditary nature, which is accompanied by acute disturbances in the activity of neurons in the brain and spinal cord. Processes affect motor neurons. For the first time, the disease was described in accordance with the medical picture in the 19th century. It belongs to the group of genetic disorders caused by mutations.

The specificity of muscle atrophy lies in the fact that only one type of spinal pathology - the first - develops in a newborn within 1-2 months of life. Other forms of the disease make themselves felt only in adulthood. A complex form of spinal atrophy and methods of its treatment are studied in such disciplines as genetics, neurology and pediatrics.

There are varying reports on how common spinal muscular atrophy occurs in newborns. The density of cases is directly related to the population of a particular place on the planet. Due to the fact that pathology is often detected only in adulthood, the number of cases after 20 years is greater than in infancy. Approximately 1 person in 20,000 suffers from some form of the disorder.

Fact! Among infants, severe forms of spinal disease occur on average 5-7 times per 100,000 people.

The hereditary factor does not manifest itself in everyone. So, parents may be carriers of the mutated gene. But it will manifest itself only in a child with a probability of 50-70%. It is believed that the prevalence of SMA among carriers is 1 in 80 families, or 160 people of different sexes.

SMA is one of the most common forms of hereditary degenerative processes in children. It ranks second after cystic fibrosis and is considered the #1 cause of hereditary diseases leading to the death of a child before they reach 15-18 years of age.

Death occurs due to respiratory failure. The earlier spinal pathology manifests itself, the worse the prognosis will be. On average, children with musculospinal atrophy live up to 10-11 years. At the same time, the state of intelligence does not affect the progress of spinal amyotrophy.

The disorder is more common in boys than girls and is much more difficult for them. For every 1 female patient, there are 2 male patients. But from the age of 8, the increase among girls increases.

Genetic factors of the disease

Spinal muscular atrophy appears when the recessive genome of chromosome 5 is inherited. If both people who gave birth to a baby are carriers of SMA, then there is at least a 25% chance that they will pass the gene on to the baby. As a result, the synthesis of protein structures is disturbed, the destruction of motor neurons of the spinal cord occurs several times faster than recovery.

During the period of embryonic development, the child's nervous system produces only half of the required volume of motor neurons. Over time, with SMA, this process slows down significantly. After birth, due to lack of structures, spinal atrophy develops.

Features of the functioning of neurons

An active brain constantly sends impulses to the spinal cord, and nerve cells serve as conductors. They deliver signals to the muscles, as a result of which their movement is triggered. If this process is disturbed, then movement becomes impossible.

With spinal muscular atrophy, the motor neurons of the legs that are part of the spinal cord do not work correctly. They are responsible for the signals by which the brain supports functions such as crawling, supporting the neck, squeezing and moving the arms and legs, as well as the breathing and swallowing reflex.

Important! Upon receipt of defective copies of the SMN1 gene from parents, the child's nervous system stops producing a protein that controls the process of synthesis and exchange of neurons.

As a result, muscles that do not receive constant signals begin to atrophy.

Classification of types of atrophy

There are 4 common groups of spinal muscular atrophy in children and adults:

Infant form. The most complex type of musculospinal atrophy, also called Werdnig-Hoffmann pathology. The course of pathology in this form is complicated by the rapid development of severe symptoms: there are difficulties with swallowing, sucking and breathing. Babies with SMA1 cannot hold their heads or sit normally.
intermediate form. SMA2, or Dubowitz's disease, differs somewhat in severity. With this form of pathology, the child can maintain a sitting position and even eat, since swallowing functions are not partially impaired. But he can't walk. The prognosis is directly related to the degree of damage to the respiratory muscles responsible for lung activity.
youth form. SMA3, or Kugelberg-Welander disease, is more easily tolerated by adolescents than the first types of spinal muscular atrophy. The child can stand, but will suffer from great weakness. The risk of disability is high - the need for a wheelchair remains with the majority.
adult type. SMA4 occurs mainly after 35 years of age. Life expectancy with the disease does not change, but the patient has a pronounced weakness of the muscles, a decrease in tendon reflexes. As it progresses, a wheelchair is required.

It is very difficult to suspect spinal muscular pathology immediately after birth. But early detection can ease the suffering of patients, so you need to be aware of the common symptoms of spinal muscular atrophy.

Symptoms of different forms of the disease

There is a general set of features of SMA that can be suspected if no other problems are found or the diagnosis is in doubt. A group of symptoms is reduced to the manifestation of flaccid peripheral paralysis:

severe muscle weakness or atrophy of different muscle groups;
first, the limbs are involved in the process - symmetrically, the legs, and then the arms, the torso is gradually drawn in;
there are no sensory disorders and pelvic disorders;
the most pronounced problems affect the proximal or distal muscle groups.

Patients develop twitches and fibrillations - atrial fibrillation.

Signs of SMA1

There are 3 types of Werdnig-Hoffmann disease:

congenital form. Begins within 1-6 months of life, has severe symptoms. You can detect signs in fetal development - the embryo will move little. Hypotension is observed immediately after the birth of a child. Such babies do not hold their heads, they cannot sit. They are constantly in the pose of a frog with spread limbs. The symptoms appear first in the legs, then in the arms, after which the respiratory muscles suffer. Mental development in such children is slow, they rarely live up to 2 years.
Early spinal muscular atrophy. The first signs begin to disturb the patient up to 1.5 years, most often after any infection. Even if the child could stand and sit before, now he loses these functions. Paresis develops, and then the respiratory muscles are affected. The child dies, usually as a result of prolonged pneumonia or respiratory failure at the age of 3-5 years.
late form. Pathology occurs after 1.5 years, motor abilities are preserved in a child up to 10 years. The slow progress of symptoms leads to respiratory failure and death before the age of 18 years.

SMA1 is the most severe form of pathology, you always have to prepare for the worst outcome.

Symptoms of Kugelberg-Welander disease

Occurs between the ages of 2 and 15 years. First, the lower limbs are involved in the process, then the pelvic girdle, in the last stages the shoulder girdle and the respiratory system suffer. Approximately 25% of patients develop a syndrome of muscle pseudohypertrophy, which is why the pathology is confused with Becker's muscular disease.

Spinal muscular atrophy of Kugelberg-Welander is not accompanied by bone deformities, and patients are able to serve themselves for many years.

Amyotrophy Kennedy

This pathology is included in the adult group, males are ill after 30 years. Women do not suffer from pathology. The course is moderate, first the leg muscles are affected, for the next 10-20 years the patient maintains the usual rhythm of life. Only then do the muscles of the arms and head begin to suffer. In many patients, endocrine changes occur over time: testicular atrophy, lack of libido, diabetes mellitus.

Distal SMA

This form of spinal muscular atrophy also develops in adult patients after 20 years of age. Its second name is SMA Duchenne-Arana. The risk of developing pathology persists up to 50 years. Atrophy begins in the arms, causes the "clawed paw" syndrome, then moves to large muscles. Over time, paresis of the muscles of the lower extremities appears, and the trunk rarely suffers. The prognosis for this form is favorable, if torsion dystonia or Parkinson's disease does not join.

SMA Vulpiana

Scapulo-peroneal form of spinal muscular atrophy, accompanied by a symptom of "winged" shoulder blades. Appears at an average age of 20-40 years, later it is less common. The shoulder girdle is affected, and after a while, the arms and lower limbs. With this form of spinal disease, the patient's motor functions remain for 30-40 years.

Methods for diagnosing pathology

It is possible to recognize spinal muscular atrophy with a 100% guarantee only with the help of DNA analysis for molecular genetic factors. With it, you can find a defective gene on chromosome 5.

Biochemical analysis is also used to determine the state of the protein. An electrophysiological study of the brain is necessary to determine the activity of impulses and nerve trunks. MRI and CT are rarely prescribed, as these methods are not very effective.

Treatment Methods

There is no effective treatment for spinal muscular atrophy. However, mild stages can be corrected. With the help of physiotherapy, massage and medicines, you can maintain a comfortable state of the child. In adulthood, therapy is more effective, since these forms of atrophy are not so difficult to tolerate.

Medicines

To correct the work of muscle fibers and nerve impulses, drugs are used that improve blood circulation and slow down the destruction of neurons:

Anticholinesterase. Means inhibit the activity of the enzyme that breaks down acetylcholine: "Prozerin", "Oksazil", "Sangviritrin".
Vitamins and dietary supplements. They use antioxidants, carnitine, B vitamins to maintain metabolism and tone.
Nootropics. Improve the functioning of the nervous system: "Nootropil", "Kaviton", "Semax".
Means for activating metabolism. This group includes various products: nicotinic acid, Actovegin, Potassium Orotate.

It is also important to maintain proper nutrition of the child, to prevent the abuse of fats and refined foods.

Physiotherapy

Physiotherapy procedures for spinal muscular atrophy improve tone, blood circulation, metabolism, and help reduce pain. Assign: UHF, electrophoresis, manual techniques, breathing apparatus for stimulating the lungs.

Attentive breath control

Since spinal muscular atrophy is often associated with disorders such as breathing, it is necessary to strictly monitor the functioning of this system in a child:

prescribed chest physiotherapy;
clear the airways of the resulting mucus;
prescribe painkillers;
take drugs that reduce secretion production;
use non-invasive ventilation techniques that increase patient comfort and prevent hypoventilation at night;
apply invasive methods - artificial ventilation with the help of an inserted tube.

The latter method is used in severe cases when the respiratory reflex becomes impossible.

Child nutrition

If spinal muscular atrophy has developed to such an extent that the patient can no longer swallow on his own, he needs outside help. Muscle weakness needs to be corrected.

A doctor who leads muscular atrophy tells in detail about how to feed a small patient with impaired swallowing functions. Sometimes professional medical assistance is required to achieve these goals.

Important! The treatment of patients with SMA does not require adherence to a strict diet or the introduction / restriction of any products containing certain substances, vitamins and minerals.
In children with SMA, the digestive process can be disturbed, which causes children to suffer from constipation. Sometimes reflux disease develops.

Forecast and possible consequences

If spinal muscular atrophy is detected in a patient in adulthood, then the prognosis is more favorable. The pathology of SMA1 rarely leaves hope - most of the children do not live up to 2 years, the rest die before the age of 5 years.

Death occurs due to respiratory failure, less often due to acute, not passing, pneumonia. Currently, there are no ways to prevent the disease.

Adults with a diagnosis of SMA should give up bad habits, extreme sports, and an irregular rest/work schedule. This will significantly slow down the progress of spinal muscular disease.

Genetic Werdnig-Hoffmann disease belongs to the group of spinal amyotrophies, inherited in an autosomal recessive manner.

Spinal muscular atrophy (SMA) is characterized by congenital or acquired degenerative changes in striated muscles, symmetrical muscle weakness of the trunk, limbs, absence or decrease in tendon reflexes while maintaining sensitivity.

Morphological studies detect pathology of motor neurons of the spinal cord, "bundle atrophy" in skeletal muscles with a characteristic alternation of affected fibers and healthy ones.

There is a violation of the conductive function of nerve fibers, a decrease in muscle contractility.
Statistics

1 out of 40-50 people is a carrier of the mutant SMN gene. Pathology appears with a frequency of 1: 6,000 - 10,000 newborns.

Causes of the disease

The main cause of Verdnig Hoffman's spinal amyotrophy is a mutation of the SMN (survival motor neuron) gene. The motoneuron survival gene is located on chromosome 5, represented by two copies:

SMNt - telomeric copy, functionally active;
SMNc - centromeric copy of the gene, partially active.

The product of this gene is the SMN protein involved in the formation and regeneration of RNA.

Protein deficiency causes motor neuron pathology.

In 95% of cases of Werdnig-Hoffmann disease, there is a deletion (loss) of SMNt, which causes a deficiency of the SMN protein. The copy of SMNc only partially compensates for the absence of a telomeric copy.

The number of SMNc copies ranges from 1 to 5. The greater the number of centromeric copies, the more complete the protein is reproduced and the less pronounced the pathology of the neuron.

In addition to the number of SMNc copies, the severity of the disease is determined by the length of the deletion site and gene conversions of 3 more genes: NAIP, H4F5, GTF2H2. The involvement of additional modifying factors explains the clinical diversity of symptoms.

Forms of spinal amyotrophy by Werdnig Hoffmann

I single out such kinds:

early childhood or SMA 1 - signs of the disease appear before 6 months of age;
late form or SMA 2 - symptoms appear after 6 months to 1 year.

Symptoms of the disease

SMA 1 and SMA 2 have different symptoms and signs.

Form of spinal amyotrophy Werdnig CMA 1

The first symptoms are detected even during pregnancy by weak fetal movement.

Photo: spinal amyotrophy of Werdnig Hoffmann

From birth, children have respiratory failure, congenital spinal amyotrophy of Werdnig Hoffmann are noted:

low muscle tone, the child does not hold his head, cannot roll over;
lack of reflexes;
violations of sucking, swallowing, twitching of the tongue, fingers, weak crying.

The baby takes the characteristic “frog” position with arms and legs bent at the joints, lying on his stomach. With SMA 1, partial paralysis of the diaphragm- Cofferat's syndrome.

The phenomenon is characterized by difficulty breathing, shortness of breath, cyanosis.

On the side of paralysis, there is a bulging of the chest, and the risk of pneumonia increases.

In infants, deformations of the skeletal system are observed, expressed in the limitation of joint mobility, the appearance of scoliosis, and a change in the shape of the chest.

CMA form 2

The first months of life, children develop normally: they begin to hold their heads, sit, and stand in time.

After 6 months appear first symptoms, usually after an acute respiratory or foodborne infection.

Limbs are affected first., especially the legs, tendon reflexes are reduced.

Then the muscles of the trunk and arms, intercostal muscles, diaphragm are gradually involved in the process, which causes deformation of the chest. The gait changes, acquiring resemblance to a "clockwork doll".

Children become awkward, often fall. Twitching of the tongue, trembling of the fingers are observed.

Course of the disease

SMA 1 characterized by a malignant course. Severe disorders of respiratory function, cardiovascular insufficiency often lead to death in the first months of life. Up to 5 years, 12% of patients survive.

SMA 2 also has a severe prognosis, although it proceeds somewhat milder. Lethal outcome is noted at 14-15 years.

Diagnostics

With Verdnik's spinal amyotrophy, the diagnosis consists in conducting a genetic analysis, revealing mutations or deletion of the SMN gene.

If a deletion of the telomeric copy of SMNt is detected, the diagnosis is considered confirmed.

In the absence of a deletion, additional research:

study of nerve conduction;
creatine kinase test;
biopsy of muscle and nerve tissue.

With normal levels of the creatine kinase enzyme, SMNc copies are counted. In the case of a single copy, the point mutation is identified, making the final decision.

Differential Diagnosis

Similar symptoms are observed with congenital myopathy - a violation of muscle tone.

Completely exclude muscle hypotension allow the results of the biopsy.

A certain similarity with the Werdnig-Hoffmann disease has acute poliomyelitis. It begins violently, with a sharp rise in temperature, asymmetrical multiple paralysis.

The acute period lasts for several days, then the process passes into the recovery stage.

Glycogenoses and congenital myopathies are also characterized by reduced muscle tone. Changes are caused, in contrast to spinal muscular amyotrophy, by metabolic disorders, carcinoma, and hormonal imbalance. Gaucher's disease, Down's syndrome, botulism should also be excluded.

Therapeutic techniques

Treatment of spinal amyotrophy is symptomatic and aimed at stabilizing the patient's condition.

Assign medicinal funds:

sick prescribe orthopedic procedures in combination with warm baths, therapeutic exercises, soft massage, oxygen therapy, sulfide baths are shown.

Types of spinal amyotrophies

Conventionally, proximal and distal forms of SCA are distinguished. 80% of all types of spinal amyotrophies belong to the proximal form.

These include, in addition to the disease Werdnig-Hoffmann:

SMA 3 or disease Kuldberg-Welander- get sick at the age of 2 to 20, the pelvic muscles are the first to suffer. There is a tremor of the hands, lordosis.
Lethal X-linked form- described in 1994 by Baumbach, inherited by a recessive trait, predominantly lesions of the muscles of the pelvis and shoulder girdle are observed.
Infantile degeneration- reflexes of sucking, swallowing, breathing are disturbed. Death may follow up to 5 months of age.
Spa Ryukyu- the linkage gene was not detected, there is a lack of reflexes, muscle weakness of the limbs after birth.

This group also includes Norman's disease, SMA with congenital arthrogryposis, SMA with congenital fractures.

Distal spinal amyotrophies include progressive Fazio-Londe infantile paralysis, Brown-Vialette-van Laere disease, SMA with diaphragmatic paralysis, epilepsy, and oculomotor disorders.

Genetic diseases manifested by muscle atrophy and caused by degenerative changes in spinal motor neurons and motor nuclei of the brain stem. A common symptom complex is symmetrical flaccid paralysis with muscle atrophy and fasciculations against the background of an intact sensory sphere. Spinal amyotrophies are diagnosed according to family history, neurological status, EPS of the neuromuscular apparatus, MRI of the spine, DNA analysis, and morphological examination of muscle biopsy. Treatment is ineffective. The prognosis depends on the form of spinal muscular atrophy and the age of its onset.

General information

Spinal amyotrophies (spinal muscular atrophy, SMA) are hereditary diseases, which are based on the degeneration of motor neurons of the spinal cord and brain stem. Described at the end of the 19th century. Thanks to modern genetics, it has been established that the emerging degenerative processes of motor neurons are caused by mutations in the SMN, NAIP, H4F5, BTF2p44 genes located on the 5th chromosome at the 5q13 locus. Despite the fact that spinal amyotrophies are determined by aberrations of one chromosomal locus, they represent a group of heterogeneous nosologies, some of which appear in infancy, while others manifest in adults.

About 85% of spinal muscular atrophies are proximal forms with more pronounced weakness and atrophy of the proximal muscle groups of the limbs. The distal forms account for only 10% of SMA. In most cases, amyotrophies are inherited in an autosomal recessive manner. Their frequency is 1 case per 6-10 thousand newborns. Today, spinal amyotrophies are of practical interest for a number of disciplines: pediatric and adult neurology, pediatrics, and genetics.

Classification of spinal amyotrophies

It is generally accepted to divide spinal muscular atrophies into children's and adults. Children's spinal amyotrophies are represented by Werdnig-Hoffmann amyotrophy, juvenile form of Kugelberg-Welander, chronic infantile SMA, Vialetto-van Lare syndrome (bulbospinal form with deafness), Fazio-Londe syndrome. Adult SMA include: Kennedy's bulbospinal amyotrophy, scapuloperoneal, facial-shoulder and oculopharyngeal forms, distal SMA and monomelic SMA. Children's spinal amyotrophies are classified into early (debuting in the first months of life), later and juvenile. Adult forms of SMA manifest between the ages of 16 and 60 and are characterized by a more benign clinical course.

There are also isolated and combined spinal amyotrophies. Isolated SMA are characterized by a predominance of spinal motor neuron involvement, which in many cases is the only manifestation of the disease. Combined spinal amyotrophies are rare clinical forms in which the symptom complex of amyotrophy is combined with another neurological or somatic pathology. Combinations of SMA with congenital heart defects, deafness, oligophrenia, pontocerebellar hypoplasia, and congenital fractures have been described.

Symptoms of spinal amyotrophies

Common to spinal muscular atrophies is a symptom complex of symmetric flaccid peripheral paralysis: weakness, atrophy and hypotension of the muscle groups of the same limbs (often both legs first, and then the arms) and trunk. Pyramidal disorders are not typical, but may develop in advanced stages. There are no sensory disturbances, the function of the pelvic organs is preserved. More pronounced damage to the proximal (with proximal SMA) or distal (with distal SMA) muscle groups draws attention. The presence of fascicular twitches and fibrillations is typical.

Werdnig-Hoffmann disease occurs in 3 clinical variants. The congenital variant debuts in the first 6 months. life and is the most malignant. Its symptoms can manifest themselves even in the prenatal period with a slight movement of the fetus. Children from birth have muscular hypotonia, they are not able to roll over and hold their heads, with a later debut they cannot sit. The frog posture is pathognomonic - the child lies with the limbs spread apart and bent at the knees and elbows. Amyotrophies are ascending in nature - first they occur in the legs, then the arms are involved, later - the respiratory muscles, muscles of the pharynx and larynx. Accompanied by mental retardation. By 1.5 years, death occurs. Early spinal amyotrophy manifests up to 1.5 years, often after an infectious disease. The child loses motor abilities, cannot stand or even sit. Peripheral paresis is combined with contractures. Once the respiratory muscles are involved, respiratory failure and congestive pneumonia develop. Death usually occurs before the age of 5 years. The late variant debuts after 1.5 years and is distinguished by the preservation of motor ability up to 10 years of age. Lethal outcome occurs by 15-18 years.

Juvenile spinal Kugelberg-Welander amyotrophy characterized by debut in the period from 2 to 15 years. It starts with damage to the proximal muscles of the legs and the pelvic girdle, then captures the shoulder girdle. About a quarter of patients have pseudohypertrophy, which makes the clinic similar to the manifestations of Becker muscular dystrophy. In terms of differential diagnosis, the presence of muscle fasciculations and EMG data are of great importance. The course of Kugelberg-Welander amyotrophy is benign without bone deformities; for a number of years, patients remain capable of self-care.

Kennedy bulbospinal amyotrophy inherited recessively linked to the X chromosome, manifests only in men after 30 years of age. Typically slow, relatively benign course. Debuts with amyotrophy of proximal leg muscles. Bulbar disorders appear after 10-20 years and, due to slow progression, do not cause violations of vital functions. There may be a tremor of the head and hands. The pathognomonic symptom is fascicular twitching in the perioral muscles. Endocrine pathology is often noted: testicular atrophy, decreased libido, gynecomastia, diabetes mellitus.

Distal SMA Duchenne-Arana can have both recessive and dominant type of inheritance. The debut occurs more often at the age of 20, but can occur at any time up to 50 years. Amyotrophies begin in the hands and lead to the formation of a "clawed hand", then cover the forearm and shoulder, in connection with which the hand takes on the form of a "skeleton hand". Paresis of the muscles of the legs, thighs and torso join much later. Cases of manifestation of the disease by monoparesis (lesion of one hand) are described. The prognosis is favorable, except in cases where this type of SMA is combined with torsion dystonia and parkinsonism.

Scapulo-peroneal SMA of Vulpiana manifests in the period from 20 to 40 years with amyotrophies of the shoulder girdle. "Pterygoid vanes" are typical. Then the lesion of the peroneal muscle group (extensors of the foot and lower leg) joins. In some cases, the peroneal muscles are first affected, and then the shoulder girdle. Vulpian's spinal amyotrophy is characterized by a slow course with the preservation of the ability to move 30-40 years after its debut.

Diagnosis of spinal amyotrophies

In the neurological status of patients, flaccid para- or tetraparesis and muscle atrophy are determined with a predominant lesion of the proximal or distal muscles, a decrease or complete loss of tendon reflexes, the sensory sphere is not disturbed. Bulbar disorders, damage to the respiratory muscles can be detected. To determine the nature of a neuromuscular disease, an EFI of the neuromuscular apparatus is performed. EMG fixes the "palisade rhythm" typical for damage to the anterior horns of the spinal cord, ENG shows a decrease in the number of motor units and a decrease in the M-response.

Spinal amyotrophies are not always accompanied by changes on MRI of the spine, although in some cases atrophic changes in the anterior horns are visible on tomograms. A biochemical blood test with the determination of CPK, ALT and LDH does not reveal a significant increase in the level of these enzymes, which makes it possible to differentiate SMA from progressive muscular dystrophies. In order to clarify the diagnosis of "spinal amyotrophy", a muscle biopsy is performed. The study of biopsy specimens diagnoses "bundle atrophy" of myofibrils - the alternation of hypertrophied fibers with clusters of small atrophied fibers. The final verification of the diagnosis is possible with the help of genetics and DNA diagnostics. Spinal amyotrophy is an indication for hospitalization during the initial diagnosis, deterioration of the patient's condition with the onset of respiratory disorders, the need for a second course of treatment (2 times a year). So far, there is no effective treatment for SMA. The therapy is aimed at stimulating the conduction of nerve impulses, enhancing peripheral circulation and maintaining energy metabolism in muscle tissue. Apply anticholinesterase pharmaceuticals (sanguinarine, ambenonium chloride, neostigmine); means that improve energy metabolism (coenzyme Q10, L-carnitine); vitamins gr. AT; drugs that simulate the work of the central nervous system (piracetam, gamma-aminobutyric acid).

In the US and Europe, neurologists use the drug riluzole for the treatment of ALS, but it has many side effects and low efficiency. Along with courses of drug treatment, massage and physiotherapy procedures are recommended for patients. The development of joint contractures and skeletal deformities is an indication for consulting an orthopedist with a decision on the use of special adaptive orthopedic structures.

The prognosis depends entirely on the clinical variant of SMA and the age of its manifestation. Children's spinal amyotrophies have the most unfavorable prognosis; when they begin in infancy, they often lead to death during the first 2 years of a child's life. Spinal amyotrophies of adult age are distinguished by the ability of patients to independently serve themselves for many years, and with slow progression they have a favorable prognosis not only for life, but also for the working capacity of patients (when creating optimal working conditions for them).