Dermatomyositis (polymyositis-Hepp-Unferrihta, polymyositis) - a severe systemic disease that causes damage to the smooth and skeletal muscle, leading to a violation of the motor function, the defeat connective tissueand the skin in the form of redness (with a purple tinge) and edema.
first dermatomyositis described E. Wagner in 1863.And in the early twentieth century.They were studied various forms of the disease.The researchers, based on the severe course and high mortality (over 50%), dermatomyositis attributed to the group of malignant connective tissue.
Dermatomyositis is a rare disease that can affect both adults and children alike.The incidence among children 1.2-2.5: 1, adult 2-6,1: 1, more common in women and girls.The predominance of women and an increase in the incidence of puberty (teenage dermatomyositis) suggests the influence of sex hormones on the development of the disease.
It is believed that the incidence is associated with age-peak it accounted for 5-15
Causes of dermatomyositis is currently not sufficiently explored.It is considered a multifactorial disease dermatomyositis.Great importance is attached to the development of infectious agents.Studies have shown that frequent infections within 3 months, predispose to the development of dermatomyositis.
Another lot of important etiologic factor is a viral disease caused mainly picornaviruses, parvoviruses, influenza viruses.
Other etiologic factors include bacterial pathogens (β-hemolytic streptococcus group A) vaccine (against measles, typhoid) and drugs (growth hormone).
as a pathogenic factor of dermatomyositis performs an autoimmune reaction with the formation of autoantibodies that are directed against cytoplasmic proteins and ribonucleic acids, which are part of the muscle tissue.These reactions give rise to imbalances in the T - and B cells and inhibition of T-suppressor function.
There are a number of so-called predisposing (trigger) factors, which include: hypothermia, giperinsolyatsiya, overheating, physical and mental trauma, heredity, exacerbation of focal infection, drug allergy.
Based on the causes of the disease, and the nature of the current classification was proposed (by A. Bohan and Y. Peter):
- primary (or idiopathic) polymyositis
- primary (or idiopathic) dermatomyositis
- Dermatoziozit with neoplasm(or polymyositis)
- Children (juvenile) dermatomyositis with vasculitis (or polymyositis)
- Dermatomyositis and polymyositis with other connective tissue diseases
Depending on the course of the disease: acute, subacute, chronic.
From Origin: idiopathic (primary), paraneoplastic (secondary).
According to the degree of activity are distinguished: I, II, III.
Dermatomyositis proceeds periods:
1. prodromal period, the duration varies from a few days to a month.
2. symptomatic period, muscle, skin and common syndromes.
3. Dystrophic (cachectic, Terminal), the period of complications.
main symptoms are systemic dermatomyositis:
- rapidly progressive muscle weakness.At the beginning of the disease can occur locally or diffuse edema of muscle tissue, which leads to their rapid atrophy.The most frequent lesion of the neck muscles, shoulders, hips.This is manifested in restricted activity, possible difficulty in standing and inability to lift his head from the pillow, comb, brush your teeth.
- The second important symptom is a rash on the skin that have a purple hue and a little tower over her.The most commonly affected areas around the eyes, eyelids, chest, back, shoulders, knees, legs, nails and knuckles.Often the rash is the first sign of the disease.
- Symptom Gottron characterized by the appearance of pink, scaly plaques and nodules on the extensor surfaces of the joints.
- Sore muscles.
- The defeat of the joints, symmetric swelling, pain in the joint.
- itching, peeling at the site of lesions.
- Dysphagia (difficulty swallowing), cough, shortness of breath.
- Children found calcium deposits under the skin and around the muscle.
Many patients do not die because of the disease itself, but because of the complications that it causes:
- Aspiration pneumonia (by ingestion of food into the airway).
- respiratory and heart failure (weakness of the heart muscle and respiratory).It occupies the first place in mortality from complications of dermatomyositis.
- difficulty swallowing leads to weight loss, lack of nutrients and vitamins, is developing a common dystrophy.
- Gastrointestinal bleeding, ulceration due to gastrointestinal mucosa.
- Education bedsores and venous ulcers.
Chronic proceeds latent and general condition of the patient for a long time can remain satisfactory.In the course of the disease is the deposition of calcium in the skin and subcutaneous tissue, resulting in contractures and limited mobility.
subacute characterized by cycles of development.If the correct and timely treatment may cure or transition into a chronic form of the disease.And with delayed treatment can be fatal.
In acute course of the disease there is a rapid increase in muscle weakness (patient immobility and inability to swallow).In this current death occurs within 3-6 months from the onset of the disease.Death occurs due to cardiac and respiratory failure or aspiration pneumonia.
Juvenile (children) dermatomyositis, appears in early childhood.It is characterized by inflammation of the muscles and the growth of muscle weakness, which further leads to reduced mobility.Most often suffer from dermatomyositis girls.
distinctive feature of adult dermatomyositis is that the disease is not associated with the appearance of tumors.
cause of childhood dermatomyositis
main cause of child dermatomyositis is considered to be the impact of infectious agents.Many patients within a few months transferred to any infectious disease.
Argued that juvenile dermatomyositis has a genetic predisposition, which appear to confirm cases of the family of dermatomyositis.An important role in the development of the disease is the solar radiation (insolation).
The main symptoms of child (juvenile) dermatomyositis include: muscle inflammation, muscular weakness, skin rashes, skin and muscle calcification, seizures, fever, inflammation of the blood vessels in the skin, lungs and intestines.
diagnosis of juvenile dermatomyositis
inspect, collect complaints and medical history, and a number of laboratory and diagnostic tests:
- CBC (ESR acceleration)
- urinalysis (presence of myoglobin in the urine)
-biochemical blood tests (increase aldolase serum contents of CK, creatinine)
- ECG (conduction disturbances, arrhythmias)
- X-ray diagnostics (possible formation of calcifications in the soft tissues)
- Muscle biopsy (all signs of inflammation)
-Elektomiografiya (increased muscle excitability)
The differential diagnosis is carried out with the following diseases: reactive arthritis, atopic dermatitis, myopathic syndrome of unknown etiology, lymphadenitis, SLE, JRA and other myositis (juvenile polymyositis, infectious myositis, DMD, myotonia, illness Myunhmeyera, medicinaland toxic myopathies and others.), inflammatory diseases of the skin (erythema multiforme, contact dermatitis, rash predbulleznye).
outlook is less favorable than that of adults, deaths recorded in the first years of the disease, due to the high activity of the process and the rapid progression of the disease.The five-year survival rate of children in juvenile dermatomyositis is approximately 90%.With early detection and diagnosis of properly chosen therapy achieved long-term remission.Then you need to take a second course of treatment.The average treatment duration of 2-3 years, but in some cases it can last up to 15 years.
Before treatment is necessary to conduct a full examination of patients to eliminate the tumor and infectious diseases (especially in children).
basis in the treatment of systemic dermatomyositis are steroids in high dosages.The drug of choice is prednisone.
Depending on the course of the disease are assigned different dosages of the drug.
In the case of an acute course of dermatomyositis initial dose of prednisolone is 80-100 mg / day, with subacute 60 mg / d, the chronic course of 30-40 mg / day.When properly selected dose prednisolone after a week start to disappear symptoms of intoxication, but after 10-14 days fade swelling, pale erythema, myalgia, a decrease kreatinurii and transaminases.
If there is no effect, the prednisolone dose should be gradually increased.The maximum dose of patients given at least two months, and then gradually reduce it to maintenance.Treatment dermatomyositis approximately 2-3 years.
When dermatomyositis resistant to glucocorticosteroids administered cytostatic drugs (methotrexate, azathioprine).
dermatomyositis initial dose methotrexate 7.5 mg / week and then gradually increase it to 0.25 mg / week, until a positive effect, but the maximum dose should not exceed 25 mg / week.The clinical effect usually develops within 5-6 weeks, and the maximum - in 5-6 months.Upon reaching the positive dynamics of the dose of methotrexate is gradually reduced by ¼ per week.
There are several contraindications to methotrexate treatment: pregnancy, kidney and liver disease of the bone marrow.
was also found incompatible with methotrexate anticoagulants, salicylates, with drugs, oppressive blood.Therefore, their combined use is strictly prohibited.
with contraindications to treatment with methotrexate is used azathioprine, albeit a less effective drug.The initial dose of 2-3 mg / kg / day.When azathioprine treatment effect is 7-9 months.Then it is necessary to gradually reduce the dose every 4-8 weeks to 0.5 mg / kg, up to the minimum effective.
In acute and subacute during dose reduction of glucocorticoids, prescribers quinoline series (delagil, plakvinil) and the chronic course - from the outset.
For the treatment of dermatomyositis by indications may be used: B vitamins, ATP, kokarboksilaza, nonsteroidal anti-inflammatory agents, salicylates.
Prevention of dermatomyositis is: hypothermia avoidance of frequent, timely treatment of infectious diseases, with the exception of the uncontrolled use of drugs and physiotherapy.
forecast dermatomyositis poor despite treatment, mortality remains high, especially in parneoplasticheskih processes.There is a connection with the age of the patients prognosis and early detection of the disease, as well as timely initiation of therapy.