Polymyositis is a rare, but serious phenomenon. This pathology belongs to the group of systemic diseases. The disease is characterized by damage to the smooth and skeletal muscles, often combined with damage to the skin (in this case, the disease is called dermatomyositis). The symptoms of polymyositis, the diagnosis and treatment of this pathology are devoted to this article.
Causes of the disease
The etiology of the disease has been little studied. Until now, the main cause of polymyositis, unfortunately, remains unknown.
It is believed that the main trigger factor is any past viral infection. The likelihood of polymyositis (the symptoms of which are described in this article) is much higher if the patient has ailments caused by parasites. It is believed that one of the "causal" factors is the indirect reaction of the body's immune defense to viral antigens.
In addition, provoke manifestations of the disease can:
- Various injuries.
- Allergies to medicines.
- Subcooling / overheating.
- Prolonged exposure to intense solar radiation.
- Pregnancy.
In about a third of patients, the disease is accompanied by the formation of a variety of neoplasms and may be a consequence of the toxic effects of cancer cells on the muscles. Another variant of the onset of the disease is the result of immunopathological reactions due to the commonality of myocytes and tumor antigens, which the body perceives the same and tries to destroy.
Risk groups
Theoretically, anyone can become infected with polymyositis, regardless of gender or age. However, according to statistics, women are more likely to experience pathologies than men. It has been established that the majority of cases are children 5-15 years old and adults 40-60 years old.
Classification
In accordance with the location of the process and the symptoms present, polymyositis is divided into the following types:
- The primary (ideopathic) form of polymyositis. It develops slowly, more characteristic of women. In this case, the proximal muscles of the neck and limbs are damaged. Patients complain of difficulty moving up the stairs, combing, muscle tension and soreness. Arthralgia is sometimes present. In severe cases, the muscles atrophy and dysphagia develops.
- Myositis with inclusion. This variety is rarely diagnosed. It is accompanied by damage to the distal segments of the limbs.
- Juvenile (children's) form. The main manifestation is calcification (deposition of calcium salts) in and under the skin. With the progression of the process, atrophy and contractures appear, vessels (up to vasculitis and thrombosis) and the gastrointestinal tract are affected, there is a pronounced pain syndrome, ulceration, perforation and bleeding.
- In combination with autoimmune systemic pathologies. In this case, polymyositis acts as a complication of SLE, RA, Sjogren’s disease or scleroderma.
- Primary dermatomyositis (ideopathic). Symptoms of this form are represented by the appearance of a variety of rashes (dermatitis, erythema) on the face, in the joints of the fingers, back and limbs. Often there are stomatitis, conjunctivitis and pharyngitis.
- Polymyositis in malignant neoplasms. Most often detected two years after the malignancy of the process. This form is typical for elderly patients with cancer of the testicles, prostate or mammary glands, lungs, intestines, and also suffering from lymphomas.
Clinical picture
For this pathology (both for adults and for children), a subacute onset of the process is characteristic. In this case, the first symptoms of polymyositis are considered manifestations of damage to the muscles of the shoulders and pelvis.
Next, the symptoms of lesions of the internal organs (lungs, gastrointestinal tract and heart) join. Approximately 15% of patients have articular syndrome.
Patients are often interested in what symptom is most characteristic of polymyositis. As a rule, the manifestations of muscle syndrome come to the fore in this disease. Let's talk about it in more detail.
Muscle syndrome
It is characterized by muscle pain that occurs during movements, palpation, and in some cases at rest. Along with soreness, muscle weakness is growing, which does not allow the patient to carry out elementary movements actively and in full. The patient is not able to sit down, hold objects in his hands, stand up, tear his head off the pillow, and so on.
Affected muscles become denser and swollen. Later they undergo atrophy, myofibrosis, and in some forms - calcification. Such changes can lead to complete immobilization of the patient.
Muscle syndrome involves the presence of lesions and smooth muscles of the esophagus, larynx, pharynx. In this case, there are violations of swallowing (dysphagia) and changes in speech (dysarthria). If the process spreads to the facial muscles, the patient’s face becomes similar to a mask, and ptosis, strabismus, and diplopia appear on the muscles of the eyes.
Joint syndrome
Implies damage to the joints of the hand and wrist.
Ankle, shoulder, knee and elbow joints are much less likely to be damaged. In this case, there are obvious characteristic signs of the inflammatory process in the joint: hyperemia and swelling of the skin (sometimes calcifications are found in it), restriction in movements. However, joint deformation with polymyositis does not occur.
Changes in the internal organs
In polymyositis, lesions of the gastrointestinal tract most often occur, manifested by the following symptoms: anorexia, bowel obstruction, diarrhea / constipation, abdominal pain, erosion with bleeding, perforation or ulcers.
The result of insolvency of the respiratory muscles and throwing food into the airways during choking is hypoventilation and, as a result, the development of pneumonia.
Damage to the organs of the cardiovascular system is manifested in the form of arrhythmia, hypotension, Raynaud's syndrome, heart failure and myocarditis.
Course of the disease
The course of polymyositis can be acute, subacute (more often) and chronic.
In the case of an acute course, the disease manifests itself in intoxication and fever, muscle lesions quickly progress, dysarthria and dysphagia occur. In a short time, the patient becomes immobilized. If therapy is not performed, the condition rapidly worsens. There is a fatal outcome.
Polymyositis with an acute course is characterized by wave-like changes in the patient's condition: periods of deterioration alternate with improvements. Despite the apparent periodic improvement, muscle weakness increases and damage to the internal organs joins.
The chronic course of the disease is considered the most favorable and is characterized by damage to only certain muscle groups, due to which patients remain able-bodied for a long time.
Diagnostic measures
If polymyositis is suspected (in the presence of the symptoms described above), the patient should consult a rheumatologist, neurologist, gastroenterologist, pulmonologist and cardiologist.
The results of a clinical blood test indicate the presence of inflammation (leukocytosis and accelerated ESR). Blood biochemistry detects signs of damaged muscle tissue (increased levels of aldolase, CPK, ALT, AST). With polymyositis, these data are used to determine the degree of activity of inflammation in muscle tissue. Approximately 20% of patients have antinuclear antibodies. Even less often, rheumatoid factor is found in the blood of patients.
In order to exclude the presence of other neuromuscular pathologies, electromyography is prescribed. Confirmation of pathological changes in muscle tissue will be:
- Low amplitude action potential.
- Spontaneous fibrillation.
- Increased excitability.
The most informative technique confirming the presence of polymyositis is the histology of muscle fibers. A biopsy of the quadriceps or biceps of the shoulder is used to collect the material. In this case, changes characteristic of polymyositis are detected: infiltration of muscle tissue and vascular walls by lymphocytes, the presence of vacuoles (cavities) between the fibers, degenerative or necrotic changes.
To diagnose the condition of somatic organs, lung x-rays, ultrasound of the heart and gastrointestinal tract, gastroscopy and ECG are prescribed.
Pathology therapy
Treatment of polymyositis is to eliminate the inflammatory process and maintain a stable remission.
Basic therapy is glucocorticosteroid drugs. At the beginning of treatment, the dosage of Prednisolone is 40-60 mg / day. Then it decreases to 10-20 mg / day.
In cases where treatment does not bring the desired effect (that is, an improvement in the condition and blood counts does not occur), immunosuppressants are prescribed (for example, Methotrexate). These drugs can be administered both orally and intramuscularly. Contraindications to the use of Methotrexate are: renal / liver failure, pathological changes in blood coagulation.
The immunosuppressants Cyclophosphamide, Cyclosporin, Azathioprine, and Chlorambucil are less popular with polymyositis, but they are also prescribed in some cases.
Before the attenuation of inflammatory reactions, the physical activity of the patient is sharply limited.
If polymyositis is combined with vasculitis, lymphocyte and plasmapheresis are prescribed to the patient.
Forecasts
The most unfavorable in the prognostic plan is the acute form of polymyositis, the causes and symptoms of which we examined above. Aspiration pneumonia or cardiopulmonary failure, which occurs in this case, most often causes death.
Children's age of the patient worsens prognosis of polymyositis (symptoms and treatment for this category of patients are the same as for adults). The difference is in the dosage of drugs, which should be determined by the attending physician. The steady and rapid progression of pathology almost always leads to immobilization of the child.
The chronic course is most favorable for life, and for further disability.