Mitochondrial myopathy is a term that unites a group of diseases that mostly affect muscles (less commonly, eyes, brain, and other parts of the body).
What factors provoke the development of such pathologies? What are the reasons? What symptoms indicate a person has myopathy? And, most importantly, how to treat this condition? This and much more will now be discussed.
Types of mitochondrial diseases
I would like to start with their consideration. Each ailment of this nature is caused by biochemical, structural or genetic defects of the mitochondria. They lead to the same consequence - a violation of tissue respiration.
The predisposition is transmitted exclusively along the female line, but to children of both sexes. Pathological disorders usually manifest themselves in defects of different links in the respiratory chain, the Krebs cycle, or beta oxidation processes.
It should be noted that not all regulators and enzymes that are necessary for the full functioning of mitochondria pass encoding through mitochondrial DNA. In some cases, nuclear DNA is involved in this process.
And before moving on to a detailed story about what it is - mitochondrial myopathy, one should consider the groups of diseases of this origin. There are two of them:
- Hereditary syndromes that are caused by gene mutations. These are the Kearns-Sayre, Pearson, Bart, MELAS, MERRF syndromes, etc.
- Secondary diseases that include impaired cellular energy metabolism. This includes glycogenosis, liver failure, rickets, diabetes, hypoparathyroidism, pancytopenia, migraines, and chronic fatigue syndrome.
There are many more types of mitochondrial hereditary diseases. The list includes the following ailments:
- Diabetes mellitus accompanied by deafness.
- Wolf-Parkinson-White Syndrome. Cardiac pathology characterized by abnormal excitation of the ventricles.
- Optical neuropathy of Leber. Almost always fraught with loss of vision, which occurs in the early puberty.
- Encephalopathy of a neurogastrointestinal nature.
- Multiple sclerosis.
- Ataxia, neuropathy.
- Tunnel vision, blindness, dementia, ptosis.
- Leia's syndrome. Also known as subacute necrotizing encephalomyopathy.
It should be noted that initially mutations of this kind were considered rare. But as a result of a study on 10 known genetic abnormalities, in which 3,000 newborns took part, those were found in quite a large number - in 1 out of 200 babies.
Etiology
Mitochondrial myopathy is formed due to disorders that occur in the mitochondria. They are sources of energy that are located in almost all cells of the body.
What is the pathogenesis? The so-called base of an ordinary cell are hundreds of mitochondria. Their total energy is enough for her to develop and maintain vital functions.
However, some mitochondria may be defective. Due to their presence, the cell is deprived of adenosine triphosphate, a substance of great importance in the metabolic process. The result is the accumulation of an excessive amount of fuel molecules and destructive forms of oxygen.
Why are some mitochondria mutated? The reason is genetic mutations. After all, genes are hereditary instructions. They are involved in the process of “making” proteins. And those genes that give rise to pathologies of this nature are responsible for proteins that act precisely inside the mitochondria.
Pathogenesis
What happens as a result of the above? The body begins to use excess fuel molecules, although this is not necessary. As a result, by-products that are potentially dangerous (lactic acid, for example) are generated. The same thing happens when the cell lacks oxygen. This, incidentally, happens at the time of performing heavy exercises.
What is the result? The level of lactic acid in blood lactic acidosis increases. Because of this, muscle fatigue occurs. And this phenomenon often causes damage to muscle and nerve tissue.
In other words, the combined effects of energy deprivation, as well as the accumulation of toxins in the cells, lead to the appearance of neurological and muscle symptoms. The latter indicate a formed mitochondrial myopathy.
Symptoms
Now we should talk about the signs by which we can find out about the presence of a disease belonging to the group of pathologies under consideration.
Key symptoms of mitochondrial myopathy are identified in the following list:
- Extreme muscle fatigue.
- Intolerance to physical exercises that do not even require a special load.
- Weakness.
- Cramps and paresis.
- Dyspnea.
- Urine discoloration.
- Headaches that are reminiscent of a migraine in nature.
The muscles of the extremities are affected, damage to the fibers of the eyeball is often diagnosed (this is manifested by ophthalmoplegia and ptosis). The central nervous system may be involved in the pathological process, in such cases, dementia, myoclonus, epilepsy, cerebellar ataxia, etc. are diagnosed.
Often, the lesion extends to the kidneys (tubulopathy), heart (cardiomyopathy), auditory analyzer, liver.
It is still important to make a reservation that mitochondrial myopathy usually occurs in children. However, pathology can “debut” at an older age.
Be that as it may, muscle weakness is usually widespread in nature, according to which most patients learn about their ailment. Limited manifestations are less common - local lesions of the muscles of the face, limbs, and the eyeball.
Diagnostics
After talking about the symptoms of mitochondrial myopathy, we can proceed to the study of the features of diagnosis. Typically, doctors suspect this pathology after detecting ptosis (omission of the upper eyelid) or impaired eyeball movements.
In such cases, the patient is sent for blood for analysis. Results typically show increased levels of lactic acid. But this, too, cannot be the basis for making an accurate diagnosis. All doubts are dispelled by the results of a sample of a muscle biopsy.
Having studied a fragment of muscle tissue in the laboratory, much can be found. Mitochondria of people with this pathology differ from healthy ones that are not mutated. They gather at the edges of the muscle tissue, due to which it acquires a reddish, ragged appearance.
Still often prescribed a measurement of the functionality of the respiratory chain. This is necessary to establish a defective area. And only in some cases it is possible to diagnose a mutation in the genetic code.
In general, it is impossible to diagnose mitochondrial myopathy in children or adults without collecting a complete medical history and a detailed clinical examination. The main difficulty is the lack of complaints in patients at rest. Therefore, the number of diagnostic procedures shown is large. It includes:
- The study of enzymatic activity (blood donation for the enzymes LDH, CPK, ALT, AST, adolases, etc.).
- Electroneurography (an alternative is electromyography).
- An ischemic forearm test required to detect glycogenosis.
- Tomography of internal organs.
- CT or MRI of the brain.
- A muscle biopsy with microscopic, histochemical, and morphological examination.
In addition to all of the above, for the accurate diagnosis of mitochondrial myopathy, it is often necessary to consult a nephrologist, cardiologist, neurologist, geneticist and ophthalmologist.
Complications
Mitochondrial myopathy is a very serious disorder, fraught with serious consequences. Why is it important not to neglect therapy, even if the prognosis is unpleasant? Because if you start the disease, you can allow the development of complications. These include the following conditions:
- Hearing loss.
- Dementia
- Lactic acidosis.
- Dramatic weight loss.
- Myoclonic epilepsy of a progressive type.
- Limited eye mobility.
- Violations of the nervous system.
- Vomiting
- Skeletal muscle abnormalities.
- Gastrointestinal Disorders.
- Difficulty swallowing.
- Heart failure or irregular rhythm.
- Cramps.
- Dementia.
And this is not all the possible consequences of mitochondrial myopathy. Does disability give in this condition? The logical question. Since this pathology leaves a significant imprint on human performance, yes. A disease with damage to the neuromuscular system, confirmed by a medical institution, is the basis for disability.
Therapy
Unfortunately, treatment of mitochondrial myopathy is not possible. Because the problem is a congenital metabolic disorder. In simple terms, there is a malfunction in the system that cannot be fixed.
However, there is no way to do without therapy. Symptomatic relief should be. What drugs the patient will have to take is determined by the doctor after the diagnosis of mitochondrial diseases.
Also an integral component of the patient's life is diet therapy. It is very important to eat foods high in fructose and protein. Combining such a diet with multivitamins, you can improve the condition, especially with glycogenosis.
If the patient is diagnosed with myoglobinuria, then the introduction of an additional amount of fluid into the body is prescribed. This is necessary for the prevention of renal failure and urine output.
And without fail, mitochondrial myopathy is prescribed medication, the purpose of which is to improve energy metabolism. These are riboflavin, L-carnitine, vitamins E and C, thiamine and ubiquinone.
It is important to make a reservation that the use of glucocorticosteroids shows excellent results. Orthopedic correction is often prescribed.
Individual cases are patients with acquired and secondary myopathies. Here, I am focusing on therapy to eliminate the cause of mitochondrial diseases - they correct systemic diseases, endocrine pathologies, intoxications, etc. In simple terms, in such cases they treat the disease that triggered the appearance of myopathy. It will leave - this consequence will be eliminated.
Physical education and massage
These are two key components of therapy for myopathy. A person suffering from this ailment should not lead a sedentary or sedentary lifestyle. This will only aggravate his condition.
But physiotherapy exercises can prevent muscle atrophy and the further development of contracture. A nice bonus is an improvement in muscle tone.
It is especially important to start such treatment in time with Duchenne myopathy. It is useful to perform exercises in the water (in the pool, for example, and preferably in the sea), it is worth focusing on the limbs.
Typically, the patient is prescribed an individual course of physiotherapy exercises. The load, of course, is minimal - feasible for the patient. When a person completes the course, then stopping is not recommended. On the contrary, you need to perform daily exercises at home, at least slightly increasing the load.
If a very young child is faced with myopathy, then he needs to actively maintain the tone of the ankle muscles, since this section affects the quality of walking.
This is normal when a person is unable to cope with physical education. Therefore, at first the dosage of general developmental exercises is minimal - 4 times for each, no more. And the use of improvised means for their implementation is allowed.
As for massage, it is selective, the specialist intensively affects the most affected muscles. The recommended course is 1.5 months with daily sessions.
In addition to the above, it is strongly recommended that you go to classes in the pool at least 2 times a week. Still positive on the state of health are breathing exercises.
What else do you need to know?
When it comes to myopathy, it is very important to realize that the treatment of a genetic anomaly or hereditary gene disease has not yet been developed. The only option is symptomatic therapy that can improve the quality of life. Its goal is to restore and strengthen the metabolic processes that occur in muscle tissue.
Be sure to use vitamins of group B. They are widely known for their antineuritic effect. It is these drugs that can enhance and then restore neuromuscular impulses in damaged structures. But they need to be taken only in parallel with adenosine triphosphoric acid. It is an element that modulates energy metabolic reactions at the cellular level.
Another therapy involves taking anticholinesterase drugs. These include galantamine and ambenonium. They have a number of positive actions:
- Accumulation of acetylcholine.
- Strengthening Stamina.
- Improving neuromuscular transmission.
- Increased activity.
In addition, glutamic acid and hydrolysates are indicated for use. The use of these funds helps to replenish the body’s reserves necessary for building the notorious muscle fibers.
And, of course, not without the use of trace elements. In simple terms, drug therapy is multi-component, combined. Duration ranges from one to two months, but in a year the patient goes through at least three such courses.
Diet
Since we are talking about the peculiarities of mitochondrial diseases and their treatment, we need to talk separately about the diet shown for compliance with people who have experienced myopathy.
The main goal of the diet is to improve health, rebuild the metabolism, and also replace the main "fuel" of the body with fats.
What are the main points of the diet? It should contain high-quality fats in large quantities, a small amount of carbohydrates and moderate - protein. Compliance with such a diet is aimed at optimizing the ability of mitochondria to produce ketones - organic substances that are best suited for the "role" of the body’s main fuel.
However, for the body to start burning them, it is necessary to increase the amount of healthy fats consumed and to minimize the amount of carbohydrates eaten.
Forecast
Much has been said above about mitochondrial myopathy. That it is clear. What are the forecasts? Unfortunately, unfavorable. Especially when it comes to infant forms and those diseases that make themselves felt from the very early weeks of a child’s life. Such patients often die at the beginning of the newborn period.
In late and adult forms, the prognosis is more favorable. But how the pathological process will proceed, and also what the outcome will be, also depends on the involvement of other systems and organs in it. If, for example, the heart, kidneys and liver are affected, then the prognosis will also be unfavorable.
The chances of improving the quality of life are patients with acquired mitochondrial myopathy. This can not but rejoice. Symptoms of their pathological process can be mitigated by correcting the causative disease.
It should be noted that the prevention of primary metabolic pathologies cannot be neglected. What does it consist of? In genetic medical counseling, men and women who decide to conceive. It will need to be done before planning a pregnancy, and then in the first trimester.
What is it for? Timely detection of the notorious secondary myopathies allows you to quickly start therapy, due to which you can avoid the development of disorders in muscle tissue.