Muscular dystrophy: symptoms, causes, diagnosis, treatment, recovery period and consequences for the body.

Muscular dystrophy, or, as doctors also call it, myopathy, is a disease of a genetic nature. In rare cases, it develops for external reasons. Most often, this is a hereditary disease, which is characterized by muscle weakness, muscle degeneration, a decrease in the diameter of skeletal muscle fibers, and in especially severe cases, muscle fibers of internal organs.

What is muscular dystrophy?

During this disease, the muscles gradually lose their ability to contract. There is a gradual disintegration. Muscle tissue is slowly but inevitably replaced by adipose tissue and connective cells.

The progressive stage is characterized by the following:

• reduced pain threshold, and in some cases, practical complete immunity to pain;
• muscle tissue has lost its ability to contract and grow;
• with some varieties of the disease - pain in the muscles;
• skeletal muscle atrophy;
• incorrect gait due to underdevelopment of the muscles of the legs, degenerative changes in the feet due to the inability to withstand the load when walking;
• the patient often wants to sit down and lie down, because he simply does not have the strength to be on his feet - this symptom is typical for female patients;
• constant chronic fatigue;
• in children - the inability to study normally and assimilate new information;
• muscle change in size - a decrease to one degree or another;
• gradual loss of skills in children, degenerative processes in the psyche of adolescents.

The reasons for its appearance

Medicine still cannot name all the mechanisms for triggering muscular dystrophy. One thing can be stated with absolute certainty: all the reasons lie in a change in the set of dominant chromosomes that are responsible in our body for protein and amino acid metabolism. Without adequate protein absorption, there will be no normal growth and functioning of muscles and bone tissue.

The course of the disease and its form depend on the type of chromosomes that have undergone a mutation:

• An X chromosome mutation is a common cause of Duchenne muscular dystrophy. When a mother carries such damaged gene material, we can say that with a probability of 70% she will pass the disease on to her children. At the same time, she often does not suffer from pathologies of muscle and bone tissue.
• Myotonic muscular dystrophy is manifested due to a defective gene belonging to the nineteenth chromosome.
• Sex chromosomes do not affect the localization of muscular underdevelopment: lower back-limbs, as well as shoulder-blade-face.

Diagnosis of the disease

Diagnostic measures are varied. There are many ailments that resemble indirect myopathy in one way or another. Heredity is the most common cause of muscular dystrophy. Treatment is possible, but it will be long and difficult. Be sure to collect information about the patient's daily routine, about the lifestyle. How he eats, whether he eats meat and dairy products, whether he uses alcoholic beverages or drugs. This information is especially important in the diagnosis of muscular dystrophy in adolescents.

Such data are necessary to draw up a plan for carrying out diagnostic measures:

• electromyography;
• MRI, computed tomography;
• biopsy of muscle tissue;
• additional consultation of an orthopedist, surgeon, cardiologist;
• blood test (biochemistry, general) and urine;
• scraping of muscle tissue for analysis;
• genetic testing to determine the patient's heredity.

Varieties of the disease

Exploring the development of progressive muscular dystrophy over the centuries, doctors have identified the following types of illness:

• Becker's dystrophy.
• Shoulder-scapular-facial muscular dystrophy.
• Duchenne dystrophy.
• Congenital muscular dystrophy.
• Limb-belt.
• Autosomal dominant.

These are the most common forms of the disease. Some of them can be successfully overcome today thanks to the development of modern medicine. Some have hereditary causes, chromosome mutation and therapy are not amenable.

The consequences of the disease

The result of the emergence and progress of myopathies of various origins and etiologies is disability. Severe deformity of the skeletal muscles and spine leads to a partial or complete loss of the ability to move.

Progressive muscular dystrophy, as it progresses, often leads to the development of renal, cardiac and respiratory failure. In children - to mental and physical developmental delay. In adolescents - to impaired intellectual and mental abilities, stunting, dwarfism, memory impairment and loss of learning ability.

Duchenne dystrophy

This is one of the most difficult forms. Alas, modern medicine has not been able to help patients with progressive Duchenne muscular dystrophy to adapt to life. Most patients with this diagnosis are disabled since childhood and do not live beyond thirty years.

Clinically manifested at the age of two or three years. Children cannot play outdoor games with their peers, they get tired quickly. Often there is a lag in growth, in the development of speech and cognitive functions. By the age of five, muscle weakness and underdevelopment of the skeleton in a child become quite obvious. The gait looks strange - weak leg muscles do not allow the patient to walk smoothly, without staggering from side to side.

Parents need to start sounding the alarm as early as possible. Make as soon as possible a series of genetic tests that will help to accurately establish the diagnosis. Modern methods of treatment will help the patient lead an acceptable lifestyle, although they will not fully restore the growth and function of muscle tissue.

Becker's dystrophy

This form of muscular dystrophy was investigated by Becker and Keener as early as 1955. In the world of medicine, it is referred to as Becker muscular dystrophy, or Becker-Kener.

The primary symptoms are the same as those of the Duchenne form of the disease. The reasons for development also lie in the violation of the gene code. But unlike Duchenne dystrophy, Becker's form of the disease is benign. Patients with this type of disease can lead almost full-fledged life and live to an advanced age. The sooner the disease is diagnosed and treatment is started, the more likely it is for the patient to live a normal human life.

There is no slowdown in the development of human mental functions, which is characteristic of malignant muscular dystrophy in the form of Duchenne. With the disease under consideration, cardiomyopathy and other abnormalities in the work of the cardiovascular system are very rare.

Shoulder-scapulo-facial dystrophy

This form of the disease progresses rather slowly, has a benign type of course. Most often, the first manifestations of the disease are noticeable at the age of six or seven years. But sometimes (about 15% of cases) the disease does not manifest itself until thirty or forty years. In some cases (10%), the dystrophy gene does not awaken at all during the entire life of the patient.

As the name implies, the muscles of the face, shoulder girdle and upper limbs are affected. The lag of the scapula from the back and the uneven position of the shoulder level, the curved shoulder arch - all this indicates weakness or complete dysfunction of the anterior dentate, trapezius and Over time, the biceps muscles, the posterior deltoid are included in the process.

An experienced doctor, when looking at a patient, may get a misleading impression that he has exophthalmos. The function of the thyroid gland at the same time remains normal, the metabolism is most often not affected. The intellectual capabilities of the patient are also, as a rule, preserved. The patient has every opportunity to lead a full, healthy lifestyle. Modern medicines and physiotherapy will help to visually smooth out the manifestations of shoulder-blade-facial muscular dystrophy.

Myotonic dystrophy

It is inherited in 90% of cases in an autosomal dominant manner. Affects muscle and bone tissue. Myotonic dystrophy is a very rare occurrence, with an incidence of 1 in 10,000, but this statistic is an underestimate because this form of the disease often goes undiagnosed.

Children born to mothers with myotonic dystrophy often suffer from what is known as congenital myotonic dystrophy. It is manifested by weakness of the facial muscles. In parallel, neonatal respiratory failure, interruptions in the work of the cardiovascular system are often observed. Often you can notice a lag in mental development, a delay in psycho-speech development in young patients.

congenital muscular dystrophy

In classical cases, hypotension is noticeable from infancy. Characterized by a decrease in muscle and bone tissue in volume along with contractures of the joints of the arms and legs. In the analyzes, the activity of serum CK is increased. A biopsy of the affected muscles reveals a standard pattern for muscular dystrophy.

This form is not progressive in nature, the patient's intelligence almost always remains intact. But, alas, many patients with a congenital form of muscular dystrophy cannot move independently. Respiratory failure may develop later. Computed tomography sometimes reveals hypomyelination of the white matter layers of the brain. This has no known clinical manifestations and most often does not affect the adequacy and mental viability of the patient.

Anorexia and mental disorders as precursors of muscle disease

Refusal of many adolescents from eating brings with it an irreversible dysfunction of muscle tissue. If amino acids do not enter the body within forty days, the processes of synthesis of protein compounds do not occur - muscle tissue dies by 87%. Therefore, parents should monitor the nutrition of children so that they do not follow the newfangled anorexic diets. A teenager's diet should include meat, dairy products, and plant sources of protein daily.

In cases of advanced eating disorders, complete atrophy of some muscle areas can be observed, and kidney failure often appears as a complication, first in acute and then in chronic form.

Treatment and drugs

Dystrophy is a serious chronic hereditary disease. It is impossible to cure it completely, but modern medicine and pharmacology make it possible to correct the manifestations of the disease in order to make the life of patients as comfortable as possible.

List of drugs needed by patients for the treatment of muscular dystrophy:

• "Prednisone". Anabolic steroid that supports a high level of protein synthesis. With dystrophy, it allows you to save and even build up the muscle corset. It is a hormonal agent.
• "Difenin" is also a hormonal drug with a steroid profile. It has many side effects and is addictive.
• "Oxandrolone" - was developed by American pharmacists specifically for children and women. Like its predecessors, it is a hormonal agent with an anabolic effect. It has a minimum of side effects, is actively used for therapy in childhood and adolescence.
• Growth hormone injectable is one of the newest remedies for muscle atrophy and stunting. A very effective remedy that allows patients to stand out in no way outwardly. For the best effect, it must be taken in childhood.
• Creatine is a natural and practically safe drug. Suitable for children and adults. Promotes muscle growth and prevents their atrophy, strengthens bone tissue.

Muscular dystrophy is a disease of the muscles (most often skeletal), which is chronic. The disease is characterized by muscle degeneration, which manifests itself in a decrease in the thickness of muscle fibers and increasing muscle weakness. Patients begin to lose their ability to contract over time, then they begin to gradually disintegrate and connective and adipose tissue appears in their place.

The most common form of this disease is that the symptoms of this disease can be observed in boys, but sometimes they are also found in adults.

To date, medicine has not yet found such ways that the patient can completely get rid of this disease. But still, there are many treatments that help relieve the patient's symptoms of muscular dystrophy, as well as significantly slow down the development of the disease.

Some information about the disease

Muscular dystrophy in medicine is called a set of diseases that cause muscle atrophy. The main cause of this disease is the lack of a protein in the human body, which is called dystrophin. One of the most common types of this disease is Duchenne muscular dystrophy.

Currently, medical scientists are conducting various tests to create a way to fight muscular dystrophy at the gene level. In the meantime, it is impossible to completely recover from this disease.

Muscle dystrophy, progressing, causes a gradual weakening of the muscles of the skeleton. Usually the disease is diagnosed in males. According to statistics, 1 out of 5 thousand people has such a pathology.

The disease is transmitted at the genetic level, therefore, if one of the parents has such an ailment, then it is very likely that the symptoms of muscular dystrophy in children will also appear.

Types of muscular dystrophy

There are several varieties of this disease. These include:

Symptoms of the disease

The symptoms of muscular dystrophy in adults and children are basically the same. In patients, muscle tone is significantly reduced, skeletal muscle atrophy leads to impaired gait. Patients do not feel muscle pain, but the sensitivity in them is not impaired. Muscular dystrophy in a small patient leads to the fact that he loses the previously acquired skills when he was still healthy. A sick child stops walking and sitting, cannot hold his head, and much more.

The disease is constantly progressing, in place of the muscle fibers that die off, connective tissue appears, and as a result, the muscles increase in volume. The patient feels constantly tired, he completely lacks physical strength.

In childhood, if the cause of the disease is genetic failures, various neurological disorders in behavior can occur, for example, attention deficit disorder, hyperactivity, a mild form of autism.

Below are the symptoms of Duchenne muscular dystrophy, since this form is the most common. They are very similar to the similar Becker's disease, the only difference is that this form begins no earlier than 20-25 years, proceeds more gently and progresses more slowly.

Early and late symptoms

Early symptoms of muscular dystrophy include:

• feeling of stiffness in the muscles;
• the patient has a waddling gait;
• difficult to run and jump;
• there are frequent falls;
• Difficulty being in a sitting or standing position
• it is easier for the patient to walk on his toes;
• it is difficult for a child to teach anything, he cannot concentrate his attention on one thing, he begins to speak later than healthy children.

Late symptoms:

Cause of muscular dystrophy

Treatment works best when the causes of the illness are known. Medical research shows that muscular dystrophy is caused by mutations on the X chromosome, with each individual form of the disease having a different set of mutations. But, nevertheless, they all do not allow the body to produce dystrophin, and without this protein, muscle tissue cannot be restored.

Of the total amount of proteins that are present in striated muscle, only 0.002 percent is the protein dystrophin. But without it, the muscles cannot function normally. Dystrophin belongs to a very complex group of proteins that are responsible for the proper functioning of muscles. Protein holds the various components inside the muscle cells together, and also binds them to the outer membrane.

In the absence or deformation of dystrophin, this process is disrupted. This leads to weakening of the muscles and destruction of muscle cells.

When diagnosed with Duchenne muscular dystrophy, there is a very small amount of dystrophin in the body of a sick person. And the smaller it is, the more severe the symptoms and course of the disease. Also, a significant decrease in the amount of dystrophin is observed in other types of this muscle disease.

Diagnosis of the disease

Different methods are used to diagnose muscular dystrophy. The genetic mutations that cause this pathology are well known in medicine and are used to diagnose the disease.

The following diagnostic methods are used in medical institutions:

• Genetic testing. The presence of genetic mutations indicates that the patient has muscular dystrophy.
• Enzymatic analysis. When muscles are damaged, creatine kinase (CK) is produced. If the patient does not have any other muscle damage, and the CK level is elevated, then this may indicate a disease of muscular dystrophy.
• cardiac monitoring. Studies using an electrocardiograph and an echocardiograph will help detect changes in the muscles of the heart. Such diagnostic methods are good in determining myotonic muscular dystrophy.
• Biopsy. This is a diagnostic method in which a piece of muscle tissue is separated and examined under a microscope.
• Lung monitoring. The way the lungs perform their function can also indicate the presence of pathology in the muscles.
• Electromyography. A special needle is inserted into the muscle and electrical activity is measured. The results show whether there are signs of muscular dystrophy syndrome.

How to treat the disease

Until now, scientific medicine has not yet come up with drugs that could completely cure the patient of such muscle pathology. Various treatments can only support a person's motor functions and slow down the progression of the disease for as long as possible. In adults and children, muscular dystrophy, symptoms and treatment are determined by the doctor. As a rule, drug treatment and physiotherapy are used to combat such a disease.

For drug treatment of muscular dystrophy in a child, as well as in an adult, two groups of drugs are used:

• Corticosteroids. Medicines in this group help slow down the progression of the disease and increase muscle strength. But if you use them for a very long time, then this can lead to a weakening of the bones of the skeleton and significantly add weight to the patient.
• Heart drugs. They are used when the disease adversely affects the normal functioning of the heart. These are drugs such as angiotensin-converting enzyme inhibitors and beta-blockers.

Physiotherapy

This method of treatment includes the implementation of special physical exercises for stretching and muscle movement. Such physical therapy gives the patient the opportunity to move for a longer time. In many cases, simple walking and swimming also help slow the progression of the disease.

Since the progression of the disease leads to a weakening of the muscles that are needed for breathing, the patient may need respiratory assistance. For this, special devices are used to help improve oxygen delivery at night. In the later stages of the disease, a ventilator may be needed.

It is very difficult for a sick person to move around. In order to somehow help him in this, it is recommended to use canes, walkers, wheelchairs.

Orthoses are also used to slow the shortening of muscles and tendons and keep them stretched. In addition, such a device additionally supports the patient during movement.

Prevention of muscular dystrophy

The fact whether a child will have Duchenne muscular dystrophy can be determined in our time even before the baby is born. Prenatal diagnosis of the disease is carried out as follows - amnoic fluid, fetal blood or its cells are taken and a study is carried out for the presence of mutations in the genetic material.

If the family plans to have a child, but one of the relatives has muscular dystrophy, then the woman must undergo an examination before planning a pregnancy. After it, it will become known whether she has such a pathology.

In women, the defective gene may appear due to changes in the hormonal background. Their causes may be pregnancy, the onset of menstruation or menopause. If a mother has such a gene, then it is passed on to her son. At the age of 2-5 years, muscular dystrophy appears.

In modern neurology, there is a huge number of diseases, the nature of the occurrence of which cannot be rationally explained by specialists. Such diseases include a group of ailments such as muscular dystrophy. There are nine varieties of this disease, but first things first…

Muscular dystrophy is a chronic hereditary disease resulting in damage to the human muscular system. Affected muscles cease to function normally, become thinner in size, and a fatty layer gradually grows at their location in the body.

Varieties of muscular dystrophy

In modern neurology, this ailment is classified into nine different diseases. The classification of the disease is associated with:

• localization of muscle disorders;
• disease characteristics;
• aggressive development;
• age.

So, muscular dystrophy happens:

• Duchenne;
• myotonic (Steinert's disease);
• Becker;
• Erba Roth;
• juvenile form of Erba-Roth dystrophy;
• shoulder - scapular facial form (Landuzi-Dejerine);
• alcoholic myopathy;
• distal form;
• Emery-Dreyfus myodystrophy.

Duchenne dystrophy

The most well-known form of progressive Duchenne dystrophy (pseudohypertrophic dystrophy, merosin - negative congenital dystrophy). This type of disease manifests itself in childhood from two to five years. First of all, the muscles of the lower extremities suffer from this disease, which, despite a sedentary lifestyle in young patients, gradually increase in size. This feature is associated with an increase in adipose tissue instead of muscles.

Healthy child on the left, sick child on the right

Gradually, as the disease progresses, it moves to the upper part and affects the muscles of the upper limbs. As a rule, by the age of twelve, a small patient stops moving completely. The lethality of this disease is very high, approximately 85-90% of patients do not live up to 20 years of age.

Males are at risk, as this disease practically does not affect girls.

Steinert's disease

It is not in vain that Steiner's congenital dystrophy is called myotonic, since as a result of the progression of the disease, the muscles relax too slowly after their contraction (this phenomenon is called myotonia).

This disease, unlike the previous one, is common in adults aged 20 to 40 years. There are also cases of disease progression in children, usually in infancy, however, this is the exception rather than the rule.

Facial signs of myotonia (open mouth and eyelids)

The disease does not have a gender dependence and equally affects both men and women. It is noted that with an illness, weakness of the facial muscles of the face, as well as limbs, is manifested. Progression, unlike Duchenne disease, is slow.

A distinctive feature of the disease is the possibility of damage not only to the muscles of the limbs, but also to the internal muscles (heart muscle), which in turn poses a great danger to human life.

Becker's disease

This form of the disease also progresses for a long time, and the patient feels well for a long time. An exacerbation of the disease can occur against the background of injuries or various diseases of the nervous system, which, with their course, will accelerate the development of the disease.

At risk are people of short stature.

Erb-Roth disease and its youthful form

This autosomal recessive disease develops in patients after 20 years of age, and the youthful form in children and adolescents 11-13 years of age. The progression of the disease occurs in an ascending variant, that is, the muscles of the lower extremities are first affected, and the disease gradually ascends to the upper extremities.

A distinctive feature of the disease is the presence of protruding shoulder blades, which, as they progress, become more pronounced and obvious.

During walking, the patient's transshipment, protrusion of the abdomen and retraction of the chest are noted.

Landouzy-Dejerine disease

The shoulder-blade-facial form of this disease is the most indiscriminate form, as it affects people aged from five to 55 years. This disease is characterized by a very long development, the patient can remain able to work up to 25 years of life with this disease.

Distinctive symptoms are damage to the facial muscles, as a result of which the patient may have problems with the clarity of pronunciation, due to incomplete closing of the lips. In addition, incomplete closure of the eyelids is noted.

As the patient develops, the facial muscles, muscles of the shoulders, limbs and trunk atrophy.

This form does not depend on a genetic mutation.

Alcoholic myopathy

This type of disease is also not associated with gene mutations and there is only one reason for its occurrence - alcohol abuse. Patients may experience pain syndromes in the extremities associated specifically with muscle damage.

There are acute and chronic alcoholic myopathy.

Distal form

The distal form of muscular dystrophy is a benign variant of progressive dystrophy. As a rule, this disease is difficult to differentiate from neural amiatrophy of Marie-Charcot. To separate these two diseases, an electroencephalogram of the head is required, which gives an understanding of what disease is to be dealt with.

The main symptoms of the disease include atrophy of the muscles of the limbs with their subsequent emaciation. Possible paresis of the feet, hands, etc.

Emery-Dreyfus myodystrophy

This type of disease was not initially singled out as a separate disease, since in its symptoms it was similar to Duchenne dystrophy. However, later, as a result of a long-term study, it was found that Emery-Dreyfus disease has individual symptoms.

The disease is classified as rare. At risk are people under 30, usually a young age. There is evidence of the manifestation of symptoms after 30 years, but they are rare.

The main difference between this type of disease is problems with the muscles of the heart, which can ultimately cause death. Cardiomyopathy in this disease is not the only difference. In addition to heart problems, patients have standard signs for Duchenne dystrophy, but in a more benign mode of development.

Causes

The negative component of diseases of the nervous system is that they are difficult to study. For this reason, it is not fully known about the factors that provoke the development of one form or another of muscular dystrophy.

The main reason for the formation of most subspecies of this disease is a gene mutation, in particular the gene that is responsible for protein synthesis.

For example, Duchenne disease is directly related to the mutation of the sex X chromosome. The main carrier of a bad gene are girls who, despite its presence in their own DNA, do not suffer from this disease.

As for the myotonic form, the culprit of its occurrence is a gene located on chromosome 19.

Main symptoms

The presence of a large number of different subspecies in this ailment indicates differences in symptoms, however, the disease has common symptoms, which include:

Diagnosis of muscular dystrophy

Diagnostic measures for such a disease are extensive, since there are a large number of diseases from which it is necessary to differentiate the disease.

At the initial stage, the doctor will definitely study the patient's history, clarify the symptoms, daily routine, etc. These data are required to draw up a plan for subsequent diagnostic measures, which may include:

It is worth noting that the later the disease manifests itself, the better for the patient, since early symptoms in most cases end in death.

Treatment

The treatment of muscular dystrophy is a complex and lengthy process, however, at the present time, a medicine has not been created that completely heals the patient. All activities are aimed at making life easier for the patient and restoring some of the lost abilities.

To slow down the development of the disease, the following drugs are prescribed:

• corticosteroids;
• vitamins B1;
• adenosine triphosphate (ATP).

In addition, to slow down the development process, fetal stem cells are used, which slow down the process of dystrophy.

In addition, the following are prescribed as preventive measures:

• massage;
• physiotherapy;
• breathing exercises.

In addition to standard treatment options, it is important to constantly be guided by three main components in the process of life:

1. Adequate physical activity.
2. Timely psychological support.
3. Dieting.

Physical activity

The lack of desire in a person to fight the disease has a negative effect on the body. Judge for yourself, passivity, unwillingness to move depresses the already affected muscular system. Muscles need to be given a load, since without a load, dystrophic processes begin to occur faster, thereby progressing at a faster pace.

Moderate physical activity, the use of supportive devices will be an excellent help in the fight against the disease.

In the presence of pain in the muscles, swimming, yoga, stretching exercises are perfect.

Psychological support

Psychological support of the environment is important for a sick person. And if the disease is as serious as this one, even more so. For some, the usual support from friends and family will suffice, while others may need qualified psychological help.

It is important to make it clear to such a person that he was not left alone with his problem. He must understand that he has someone to turn to, there are people who empathize and support him.

Diet

With regard to diet and diet, there is a common belief that following an anti-inflammatory diet can slow the progression of the disease. This diet reduces inflammation, glucose levels, removes toxins from the body and nourishes it with beneficial substances.

The essence of such a diet is as follows:

1. Refusal of products containing "bad" fats and replacing them with "good" ones, introducing unsaturated fats into the diet, which are found in olive, linseed, sesame oil, avocados.
2. The use of meat and fish in food, in the production of which antibiotics or hormones were not used.
3. Complete removal of refined sugar and gluten from the diet.
4. Eating the following foods - Chinese cabbage, broccoli, celery, pineapple, salmon, beets, cucumaria, ginger, turmeric and other foods that have anti-inflammatory properties.
5. Dairy products are allowed only on the basis of sheep and goat milk.
6. It is permissible to use herbal teas, lemonade, kvass, fruit drinks and natural juices.

Prevention

Since muscular dystrophy is quite difficult to predict and detect at an early stage, preventive measures come down to two simple recommendations:

Mandatory examination of a woman at the stage of pregnancy planning for the presence of mutations in the genes

If, for some reason, a genetic examination was not performed before pregnancy, a test is performed already during pregnancy to determine mutations in the X chromosome in the fetus.

Prognosis and complications

Depending on the type of disease, the prognosis may be different, and nevertheless, several possible complications that occur with this ailment can be distinguished.

• cardiac disorders
• rachiocampsis
• decrease in the intellectual abilities of the patient
• decreased motor activity
• respiratory system disorders
• lethal outcome

So, muscular dystrophy is a rather dangerous and incurable disease, so future parents need to be deeply responsible for planning pregnancy. Take care of yourself and your future children!

There are a number of forms of muscular dystrophy. They differ in such characteristics as the age at which the disease begins, the localization of the affected muscles, the severity of muscle weakness, the rate of progression of dystrophy and the type of inheritance. The two most common forms are Duchenne muscular dystrophy and myotonic muscular dystrophy.

Duchenne muscular dystrophy

(pseudohypertrophic muscular dystrophy) is the most common form of this disease in children. The cause of the disease is a genetic defect localized on the X chromosome (one of the two chromosomes that determine the sex of a person). Women with a defective gene pass it on to their children, but they themselves usually do not have symptoms of dystrophy. Boys who receive the defective gene inevitably develop muscle weakness between the ages of two and five.

First of all, the large muscles of the lower extremities and the pelvic girdle suffer. Then the degeneration spreads to the muscles of the upper half of the body, and then gradually to all major muscle groups. A characteristic manifestation of the disease is pseudohypertrophy of the calf muscles, i.e. their increase due to the deposition of fat and the growth of connective tissue. In contrast, with true muscle hypertrophy, the volume of muscle tissue itself increases.

Duchenne muscular dystrophy is one of the most severe and rapidly progressive forms. By the age of 12, patients usually lose the ability to move, and by the age of 20, most of them die.

Myotonic muscular dystrophy

(Steinert's disease) is the most common form of muscular dystrophy in adults. It is caused by a defective gene on the 19th chromosome. Men and women are equally affected and can pass on the genetic defect to their children. The disease manifests itself at any age, including in infancy, but most often between 20 and 40 years. The first symptoms are myotonia (delayed muscle relaxation after contraction) and weakness of facial muscles; it is also possible to damage the muscles of the limbs and other parts of the body. The progression of the disease occurs in most cases slowly, and complete disability can occur no earlier than 15 years later.

The peculiarity of this disease is that in addition to voluntary muscles, it also affects smooth muscles and cardiac muscle.

Pathomorphology.

All forms of muscular dystrophy are characterized by degeneration of the muscles but not of the associated nerves. Various changes are found in the affected muscle tissue, including significant fluctuations in the thickness (diameter) of muscle fibers. Gradually, these fibers lose their ability to contract, disintegrate and are replaced by adipose and connective tissue.

Diagnosis.

According to their clinical manifestations, muscular dystrophies are similar to spinal amyotrophies - hereditary diseases that affect the motor neurons of the spinal cord. These diseases also lead to severe muscle weakness, sometimes life-threatening. To confirm the diagnosis of muscular dystrophy, electromyography may be required, and sometimes muscle biopsy with microscopic examination to identify characteristic dystrophic changes.

Causes.

Experts believe that each form of muscular dystrophy is caused by a separate point genetic defect that disrupts the ability of muscle cells to synthesize the necessary proteins. The efforts of researchers are focused on finding the defects that underlie diseases and the abnormalities in protein composition that these defects lead to. The gene for Duchenne muscular dystrophy has now been identified.

Treatment.

There is no way to prevent or slow the progression of muscle weakness in muscular dystrophy. Therapy is mainly aimed at combating complications, such as spinal deformity due to weakness of the back muscles, or a predisposition to pneumonia due to weakness of the respiratory muscles. Some progress has been made in this direction, and the quality of life of patients with muscular dystrophy has improved. Now many patients, despite their illness, can lead a full and productive life.

They are distinguished by the selective distribution of weakness and the specific nature of the genetic abnormalities.

Becker's dystrophy, although closely related, has a later onset and causes milder symptoms. Other forms include Emery-Dreyfus dystrophy, myotonic dystrophy, limb girdle dystrophy, faciocapulohumeral dystrophy, and congenital dystrophies.

Duchenne muscular dystrophy and Becker muscular dystrophy

Duchenne muscular dystrophy and Becker muscular dystrophy are X-linked recessive disorders characterized by progressive proximal muscle weakness caused by muscle fiber degeneration. Becker's dystrophy has a late onset and causes milder symptoms. Treatment focuses on maintaining function with physical therapy, braces, and orthotics; Prednisolone is prescribed to some patients with severe functional impairment.

In Duchenne dystrophy, this mutation results in a severe absence (<5%) дистрофина, белка мембраны мышечных клеток. При дистрофии Беккера мутация приводит к образованию ненормального дистрофина или малому его количеству. Дистрофия Дюшенна поражает 1/3000 родившихся мужчин. Дистрофию Беккера выявляют у 1/30 000 родившихся мужчин. У женщин-носителей может быть выражено бессимптомное повышение уровня креатинкиназы и, возможно, гипертрофия задней части голени.

Symptoms and signs

Duchenne dystrophy. This disorder usually manifests itself at the age of 2-3 years. Weakness affects the proximal muscles, usually in the lower extremities first. Children often walk on their toes, have a waddling gait and lordosis. The progression of weakness is steady, flexion contractures of the extremities and scoliosis develop. Significant pseudohypertrophy develops. Most children are wheelchair-bound by the age of 12. Heart involvement is usually asymptomatic, although 90% of patients have ECG abnormalities. One-third of them have mild, non-progressive intellectual disabilities that affect verbal ability more than performance.

Becker's dystrophy. This disorder usually presents symptomatically much later and is milder. The ability to move usually lasts until at least 15 years of age, and many children remain mobile into adulthood. Most of those affected live into their 30s and 40s.

Diagnostics

• Dystrophin immunostaining. i Analysis of DNA for mutations.

Diagnosis is suspected based on characteristic clinical features, age of onset, and family history suggesting X-linked recessive inheritance. Myopathic changes are seen on electromyography (motor unit potentials increase rapidly, are of short duration and low amplitude) and on muscle biopsy (necrosis and marked change in the size of muscle fibers not separated from the motor units). Creatine kinase levels exceeded 100 times normal.

Diagnosis is confirmed by dystrophin analysis with immunostaining of biopsy specimens. Dystrophy in patients with Duchenne dystrophy is not detected. Analysis of DNA mutations in peripheral blood leukocytes can also confirm the diagnosis by detecting abnormalities in the dystrophin gene (about 65% of patients have deletions or duplications and about 25% have point mutations).

Treatment

• supporting measures.
• Sometimes prednisone.
• Sometimes corrective surgery.

There is no specific treatment. Moderate exercise is recommended for as long as possible. An ankle brace will help prevent bending during sleep. Orthopedic appliances on the legs can temporarily help maintain the ability to stand and move around. Obesity should be avoided; calorie requirements are likely to be lower than usual. Genetic counseling indicated.

Daily administration of prednisone does not produce significant long-term clinical improvement, but may slow down the course of the disease. There is no consensus on long-term effectiveness. Gene therapy has not yet been developed. Corrective surgery is sometimes necessary. Respiratory failure can sometimes be treated with non-invasive respiratory support (through a nasal mask). Elective tracheotomy is gaining acceptance, allowing children with Duchenne dystrophy to survive into their 20s.

Other forms of muscular dystrophy

Emery-Dreyfus dystrophy. This disease can be inherited in an autosomal dominant, autosomal recessive (the rarest) or X-linked pattern. The overall frequency is unknown. Females can be carriers, but only males are clinically affected with X-linked inheritance. The genes associated with Emery-Dreyfus dystrophy encode the nuclear membrane proteins lamin A/C (autosomal) and emerin (X-linked).

Symptoms of muscle weakness and wasting can appear any time before age 20 and usually affect the biceps, triceps, and less commonly the distal leg muscles. The heart is often involved with atrial fibrillation, conduction disorders (atrioventricular block), cardiomyopathy, and a high likelihood of sudden death.

The diagnosis is indicated by clinical findings, age of onset, and family history. As well as mildly elevated serum creatine kinase levels and myopathic signs on electromyography and muscle biopsy. The diagnosis is confirmed by DNA testing.

Treatment includes therapy aimed at preventing contractures. Pacemakers are sometimes vital in patients with abnormal conduction.

Myotonic dystrophy. Myotonic dystrophy is the most common form of muscular dystrophy in the white population. It occurs with a frequency of about 30/100,000 male and female live births. Inheritance is autosomal dominant with varying penetrance. Two genetic loci - DM 1 and DM 2 - cause abnormalities. Symptoms and signs begin in adolescence or adolescence and include myotonia (delayed relaxation after muscle contraction), weakness and wasting of the distal muscles of the extremities (especially the arms) and facial muscles (ptosis is especially common), and cardiomyopathy. Mental retardation, cataracts, and endocrine disorders may also develop.

Diagnosis is indicated by characteristic clinical findings, age of onset, and family history; The diagnosis is confirmed by DNA testing. Treatment includes the use of an orthotic for drooping foot and drug therapy for myotonia (eg, mexiletine 75–150 mg orally 2–3 times a day).

Dystrophy of the limb belts. There are currently 21 known subtypes of limb girdle dystrophy: 15 autosomal recessive and 6 autosomal dominant. The overall frequency is unknown. Several chromosomal loci have been identified for autosomal dominant (5q [gene product unknown)] and recessive (2q, 4q [, 13q [γ-sarcoglycan], 15Q [calpain, Ca-activated proteases] and 17q [α-sarcoglycan or adhaline] ) forms. Structural (eg, dystrophin-associated glycoproteins) or non-structural (eg, proteases) proteins may be affected.

Symptoms include weakness in the girdle and proximal limbs. The onset of the disease ranges from early childhood to adulthood; onset for autosomal recessive types is usually in childhood, and these types are mostly associated with pelvic girdle involvement.

Diagnosis is indicated by characteristic clinical findings, age of onset, and family history; diagnosis also requires determination of the histological picture of the muscles, immunocytochemistry, Western blotting, and genetic testing for the presence of specific proteins.

Treatment is aimed at preventing contractures.

Facioscapulohumeral dystrophy. The onset of the disease in adolescence or young adulthood is characterized by slow progression: the child has difficulty whistling, closing his eyes and raising his arms (due to weakness of the muscles that stabilize the shoulder blades). Life expectancy is normal. Infantile variations, characterized by weakness of the face, shoulders, and hip girdle, progress rapidly.

Diagnosis is indicated by characteristic clinical findings, age of onset, and family history; The diagnosis is confirmed by DNA analysis.

Treatment consists of physical therapy.

congenital muscular dystrophy. It is not a stand-alone disorder, but is a congenital disorder that is one of several rare forms of muscular dystrophy. The diagnosis is suspected in any flaccid neonate, but should be distinguished from congenital myopathy by muscle biopsy.

Treatment is physical therapy, which can help preserve muscle function.