What Are the Different Dermatomyositis Symptoms?
Dermatomyositis is a non-purulent inflammatory lesion that mainly affects striated muscle, mainly lymphocyte infiltration, with or without multiple skin lesions. Clinically, it is characterized by the weakness of symmetrical limb band muscles, cervical muscles, and pharyngeal muscles, which often involve a variety of organs, and can also be accompanied by tumors and other connective tissue diseases.
Basic Information
- English name
- dermatomyositis (DM)
- Visiting department
- Division of Rheumatology
- Common causes
- Unknown, may be related to genetic and viral infections
- Common symptoms
- Morning stiffness, fatigue, loss of appetite, weight loss, fever, joint pain, etc.
- Contagious
- no
Causes of dermatomyositis
- The exact etiology of the disease is unknown and is generally believed to be related to genetic and viral infections. There are significant ethnic differences in the onset of polymyositis and dermatomyositis. African Americans have the highest incidence, with black to white incidence rates ranging from 3 to 4: 1. The incidence of dermatomyositis in children is higher in Asia and Africa than in Europe and America. The presence of this disease in identical twins and first-degree relatives also suggests that it is genetically predisposed.
Dermatomyositis clinical manifestations
- Usually onset, it progresses slowly over weeks, months, and years. Very few patients have acute onset of severe muscle weakness, or even rhabdomyolysis, myosinuria, and renal failure within a few days. Patients may have morning stiffness, fatigue, loss of appetite, weight loss, fever (medium to low fever, or even high fever), joint pain, and a few patients have Raynaud's phenomenon.
- Muscle performance
- Muscle involvement in this disease is usually bilaterally symmetrical. Scapular and pelvic girdle muscle involvement is the most common, followed by neck and throat muscles, respiratory muscle involvement is rare, and orbicular and facial muscle involvement is rare. About half of patients have myalgia and / or muscle tenderness. Myasthenia initially affects the scapular and pelvic girdle muscles. Distal muscle weakness is rare. About half of patients with cervical muscles, especially cervical flexor muscles, are affected by difficulty raising their heads in supine position and weak heads when sitting; throat or upper esophageal striated muscle Difficulty swallowing, hoarseness, and difficulty in pronunciation may occur, which may flow through the nostrils when taking liquid food, causing choking. Gastrointestinal smooth muscle involvement is rare. Weakness of the lower esophageal sphincter can cause gastric acid reflux and esophagitis. Chronic can cause esophageal stricture. When the scapular belt is involved, it may be difficult to raise the arm, and you cannot comb your hair and dress. The weakness of the respiratory muscles can cause chest tightness and dyspnea. In severe cases, you need to use a ventilator to assist in breathing. The steps are difficult. After squatting, it is difficult to stand or stand up from the seat.
- 2. Lung performance
- Dyspnea during exercise is a non-specific but more severe symptom. The involvement of respiratory muscles in polymyositis and dermatomyositis can lead to respiratory muscle weakness. Such patients have difficulty sputum excretion and are susceptible to lung infections. The most serious complication is rapid-type alveolitis, manifested by fever, shortness of breath, severe cough, rapid progress of dyspnea, and severe cases can cause adult respiratory distress syndrome. More common is chronic progressive pulmonary interstitial fibrosis, which is manifested as progressive dyspnea. Due to the hidden attack, its symptoms are easily masked by the symptoms of muscle involvement. There are also many patients without symptoms of pulmonary involvement, only in the Pulmonary interstitial fibrosis was discovered only on radiological and / or pulmonary function tests. On auscultation, the bottom lung twist sounds can be heard. X-ray examination showed frosty glass in the early stage and netted or honeycomb shadow in the late stage. Pulmonary function tests showed restrictive ventilation disorders and reduced diffuse function. Pulmonary hypertension can occur in the advanced stage of the disease, and severe cases can cause right heart hypertrophy and right heart failure. A few patients may have pleurisy and pleural effusion.
- 3. Heart performance
- Heart involvement is common, usually mild, with few clinical symptoms. The most common are heart rhythm disorders, such as palpitations and arrhythmias. Late-stage congestive heart failure can be caused by myocarditis or myocardial fibrosis. Occasionally myocarditis. Myocardial isoenzyme (MB) of creatine kinase (CK) may be increased, but it is not necessarily related to myocardial involvement. Most of it is produced by regenerated myofibrils of damaged muscle.
- 4. Kidney disease
- Renal disease is rare, and proteinuria and nephrotic syndrome are occasionally reported.
- 5. Skin manifestations
- In 55% of patients, the rash appears before myositis, 25% occurs simultaneously with myositis, and 15% occurs after myositis. The type and extent of the rash varies from person to person, and the same patient may have different rashes at different stages. In some patients, the rash and muscle weakness may be parallel, while in other patients the rash and muscle weakness may not be related.
- Dermatomyositis has various skin manifestations. Among them, the diagnostic specificity is Gottron maculopapular or Gottron sign. Common in the metacarpophalangeal joints, interphalangeal joints, elbows, knees and other joints and shoulders, condyles and other vulnerable parts. Characteristic rashes include: dark purple-red rash on the eyelids, especially the upper eyelids, which can be one or both sides, often accompanied by periorbital edema and telangiectasia near the margin of the eyelid. When the edema is severe, both eyelids cover the eyes and cannot be seen. This purplish rash can also appear on the forehead, palate, nose bridge, nasolabial folds, and front of neck, upper chest (V-shaped distribution) and back of neck, upper back, shoulders, and outside of upper arms (Shawl-like distribution). "Technician's hand" -like change: The skin of the finger pad is keratinized, thickened, and cleft. Palms, soles, torso and limbs may also have hyperkeratosis with follicular keratosis; dirt and dark black stripes appear on the palms and sides of the fingers. Because it is similar to the change of the hand of a manual worker, it is named "technician hand". Other skin and mucosal changes: red atrophic plaques may appear on the scalp, upper scales are often misdiagnosed as psoriasis or seborrheic dermatitis; pericypic capillaries are dilated, or acne spots appear. Photosensitivity, itchiness, panniculitis, cutaneous mucin deposition, white spots, multifocal fat atrophy, and Raynaud's phenomenon have also been reported.
Some patients' skin biopsies show typical dermatomyositis changes, with Gottron sign and another skin manifestation of dermatomyositis, but without enzymatic changes and clinical symptoms of dermatomyositis. This condition is called as myositis-free. Dermatomyositis (dermatomyositissinemyositis). It is estimated that it accounts for 10% of all dermatomyositis. Over time, some patients can get partial or complete remission, some have muscle involvement and weakness, and some patients have tumors.
Dermatomyositis examination
- Routine test
- It can be seen that the number of white blood cells is normal or decreased, and 2/3 may have a rapid increase in erythrocyte sedimentation. Blood IgG, IgA, IgM, immune complexes, and a2 and Y globulin can be increased. Complements C3, C4 can be reduced.
- 2. Determination of urine creatine
- Urine creatine excretion can be increased before the muscle enzyme spectrum has been increased, but this change can occur in various muscle lesions and is not specific to the disease.
- 3.Determination of myoglobin
- Myoglobin is only found in the heart muscle and striated muscle. Most patients with myositis have elevated serum myoglobin, and its fluctuations are parallel to the condition. Sometimes the changes appear before the change in CK, but the specificity is poor.
- 4. Autoantibody test
- Autoantibodies can be detected in the serum of most patients. These antibodies can be divided into: myositis-specific autoantibodies that only occur in inflammatory myopathy; often appear in inflammatory myopathy but Non-specific autoantibodies to myositis; autoantibodies that appear in syndromes where myositis and other diseases overlap. Anti-rRNP and anti-Sm antibodies can be detected in patients with SLE, anti-Scl-70 antibodies can be detected in patients with systemic sclerosis, and anti-SSA and anti-SSB antibodies can be detected in patients with Sjogren's syndrome. In addition, non-specific antibodies such as anti-myoglobin antibody, rheumatoid factor, anti-myosin antibody, anti-troponin, and tropomyosin antibody can be detected.
- 5. Muscle Enzyme Examination
- During the course of the disease, muscle-derived enzymes in the serum can increase, and their sensitivities are in order from creatine kinase (CK), aldolase (ALD), aspartate aminotransferase (AST), and alanine aminotransferase. (ALT), lactate dehydrogenase (LDH), etc.
- Carbonic anhydrase U1 is the only isoenzyme that exists in skeletal muscle and is increased in polymyositis and other skeletal muscle lesions, which is more valuable in the diagnosis of muscle lesions.
- 6. EMG examination
- Electromyography is performed by inserting a needle electrode into a skeletal muscle, recording, magnifying it outside the cell, and displaying the electrical activity of the muscle fibers through an oscilloscope. Typical changes include triads: enhanced insertion potential activity, fibrillation potential, and positive sharp waves; spontaneous strange high-frequency discharges; low amplitude, short-term, and multiphase motor unit potentials.
- 7. Histopathological examination < br It is best to choose proximal muscles such as quadriceps and deltoid.
- (1) The main pathological changes of myositis are muscle cell damage, necrosis and inflammation, and the subsequent muscle cell atrophy, regeneration, hypertrophy, and muscle tissue are replaced by fibrosis and fat. 90% of patients with myositis may have abnormal muscle biopsy, showing muscle fiber damage or even necrosis, and at the same time there are different degrees of regeneration phenomenon, muscle fiber thickness varies.
- (2) Skin pathological changes are usually not significantly specific. The main manifestations are: mild thickening or atrophy of the epidermis, and liquefaction and degeneration of basal cells. Superficial dermal edema, infiltration of scattered or focal lymphocytes (mostly CD4 + T cells), plasma cells, and histiocytes. There were fibrin-like substances that were PAS-positive in the true epidermal junction and around the superficial blood vessels of the dermis. Focal mucin accumulation was sometimes seen in the dermis, and Axin blue was positive. Subcutaneous fat manifests as focal panniculitis in the early stages, with mucus-like degeneration of adipocytes, and extensive calcification in the later stages. The pathological characteristics of Gottron lesions are based on the above pathological changes accompanied by hyperkeratosis and thickened spines.
Dermatomyositis diagnosis
- According to the patient's symmetrical proximal muscle weakness, pain and tenderness, with characteristic skin damage such as purplish red edema spots centered around the orbit, Gottron sign and nail root fold stiffness expansion dilated capillary erythema, the general diagnosis is not difficult Combined with the increase of serum sarcozyme and CPK, LDH, AST, ALT and aldolase, if necessary, combined with changes in electromyography and biopsy of the diseased muscle, the disease can be confirmed. The standard diagnostic table proposed by Bohan and Peter in 1975 is still adopted by most clinicians.
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Dermatomyositis Treatment
- The disease is a chronic disease with a long course. The effect of treatment depends on the type of disease, the treatment plan, and the active cooperation of the patient and family.
- Glucocorticoid
- Clinical experience has proven that glucocorticoids are effective in the treatment of idiopathic inflammatory myopathy, so it is considered the first choice for the treatment of polymyositis and dermatomyositis. The lighter can be taken orally once in the morning, and the best should be taken in three divided doses. Once the condition is controlled, the oral administration should be changed to another oral administration. The general course of treatment is not less than 2 years, and the drug can be discontinued at the end. If there is no recurrence in 3 years, there is little possibility of recurrence in the future. If there is no recurrence in 5 years, it is basically a cure.
- 2. Immunosuppressive
- Of these, methotrexate and azathioprine are commonly used. For severe cases, early application of immunosuppressive drugs combined with glucocorticoids is now advocated.
- (1) Methotrexate adult, once a week, increase according to the patient's condition. After the condition is stable, the dose of methotrexate can be reduced, and a small dose of methotrexate can be maintained for several months to one year. Stopping the medicine prematurely can cause relapse. The combination of methotrexate and glucocorticoids can significantly improve muscle strength, and can also reduce the amount of hormones, thereby reducing its side effects, so early application is generally encouraged.
- (2) The combination of azathioprine and glucocorticoids has a significantly better curative effect than hormonal use alone, and can reduce the dose of hormones. But the onset of the drug is slow, usually after 3 months. The main adverse reactions are bone marrow suppression, gastrointestinal reactions and elevated liver enzymes.
- (3) Other cyclophosphamide, leflunomide, low-dose cyclosporin A, antimalarial drugs, and immunoglobulins can all play a role in refractory dermatomyositis.
Dermatomyositis Prognosis
- With the application of immunosuppressive therapy, the prognosis of idiopathic inflammatory myopathy continues to improve. In addition to the use of immunosuppressants, early diagnosis and early treatment, and effective control of complications can also help improve the prognosis.