Добре дошли в сайта на д-р Севдалина Ламбова, дм, ревматолог





            The idiopathic inflammatory myopathies (IIM) of unknown cause are termed myositis and are characterized clinically with progressive symmetrical muscle weakness, decreased muscle endurance, fatigue and histologically with mononuclear inflammatory cell infiltrates in muscle tissues. They are infrequent autoimmune diseases, that affect striated muscles, and are frequently accompanied by extramuscular manifestations from skin, joints, lungs, heart, oesophagus. The IIM are а heterogeneous group of disease. The main subgroups are polymyositis (PM); dermatomyositis (DM) – in the presence of the characteristic skin rashes; PM and DM associated with neoplasia; overlap syndromes, etc. They are rare diseases with yearly incidence 2-7 per 1 million. PM and DM are more frequent in women with female-to-male ratio 3:1. The peak age at onset is 50-60 years, although PM and DM may start at any age.


            The classic clinical presentation includes symmetric proximal muscular weakness, decreased muscle endurance and muscle fatigue. The characteristic features of the muscle weakness is that it is most pronounced in proximal muscle groups, has a symmetrical distribution and often is with subacute or insidious onset. Patients have difficulties when rising from chairs, walking uphill and upstairs. In most severe cases, muscle weakness may progress and the patient may be confined to the bed. In contrast to the muscular dystrophies, muscle weakness in myositis progresses over weeks to months rather than years, and tends to show spontaneous exacerbations and remissions.


            Dysphagia, problems with swallowing and nutrition may occur due to involvement of throat and oesophagus muscles. Vasculitis of blood vessels of gastrointestinal tract may develop. Weakness of thoracic muscles and diaphragm may lead to dyspnea. Dyspnoea and cough are common symptoms in patients with PM and DM in the context of lung involvement whose prevalence varies between 5 and 65% depending on the diagnostic methods used and the patient population. The skin rashес may precede the muscle symptoms by months to years and in some patients the skin manifestations may be the only clinical sign – the state that is termed “amyopathic DM”. Some of the characteristic localizations of skin rashes are over the dorsal side of metacarpophalangeal and interphalangeal hand joints, eyelids, neck. The skin of the hands may be affected with hyperkeratosis, scaling and fissuring (the so-called “mechanic’s hands”). Arthralgia and arthritis are common in patients with myositis. The arthritis affects mainly hand and feet joints. Raynaud’s phenomenon (RP) is present in over 20% of myositis patients e. g., those with antisynthetase syndrome, which is characterized with symmetric nonerosive arthritis, interstitial lung disease, fever, mechanic’s hands, RP, antisynthetase antibodies (anti-Jo-1). Clinical manifestations of heart involvement are rare in patients with IIM, while subclinical features, detected by electrocardiogram are frequent findings and include conduction abnormalities and arrhythmias. Taking into account that cardiovascular disease is among the leading causes of mortality in myositis patients, heart involvement should not be overlooked.


             Laboratory and instrumental methods

            The elevated serum skeletal-muscle enzymes are main laboratory markers, which are used for diagnosis and assessment of disease activity in patients with idiopathic myopathies e. g., creatine phosphokinase (CK), serum glutamate oxaloacetate and pyruvate transaminases, lactate dehydrogenase. CK is considered to be the most useful serum enzyme marker among them, which is increased in over 95% of adult patients with myositis at presentation or during the disease course. Markers of inflammation e. g., leucocytosis, elevated platelet count, CRP and ESR may be also found in myositis patients.


            Autoantibodies are present in approximately 60-70% of patients with myositis. Antinuclear antibodies (ANA) are detected most frequently. Among myositis-specific autoantibodies, currently routinely is investigated anti-Jo-1 antibodies.


            Electromiographic signs and specific findings from histological muscle examination are diagnostic.


            High  resolution computed tomography, pulmonary function tests with diffusion capacity, electrocardiography may be indicated for detection of the respective organ involvement in PM/DM.


             The pharmacological therapy includes corticosteroids, immunosuppressive drugs (methotrexate, azathioprine, etc.), intravenous immunoglobulins, etc. Non-pharmacological treatments such as appropriate exercise programmes should also be considered for optimal improvement of muscle function. The precise therapeutic regimen should be chosen according to the form of the disease and the degree of disease activity.


                                                                                   Dr Sevdalina Lambova, MD, PhD