What are the symptoms of polymyositis

Polymyositis is an autoimmune disease. Because polymyositis can affect the skin, it is also called dermatomyositis. The symptoms of polymyositis are also quite obvious and are more common in women aged between 20 and 40. The main symptoms of patients include muscle weakness.

1. Muscle

This disease affects the striated muscles, and its clinical characteristics are symmetrical weakness and pain in the proximal muscles of the limbs. There may be muscle swelling and tenderness in the early stage, and muscle atrophy in the late stage. Patients often have Raynaud's phenomenon, and one-third of patients have mild arthritis symptoms.

(1) Muscle weakness: It may occur suddenly and progress over several weeks to months, with different clinical manifestations depending on the location of the affected muscles.

(2) Myalgia: Muscle swelling may occur in the early stages of the disease, and about 25% of patients experience proximal muscle pain or tenderness.

2. Systemic lesions

(1) Digestive tract: The most common symptom is dysphagia and difficulty eating. X-ray barium meal examination shows slow esophageal motility. Dysphagia means a poor prognosis and is an indication for early use of hormones. (2) Lungs: Lung lesions are very common, with 20% to 65% of patients having interstitial lung lesions. Symptoms include cough, sputum, high fever, chills, and difficulty breathing. Chest X-ray shows increased lung markings, followed by pneumonia, pleurisy, pleural thickening, etc. Severely ill patients develop respiratory distress syndrome. It is the most common cause of death in dermatomyositis. The clinical manifestations of interstitial pneumonia are dry cough and dyspnea. Jo-1 antibody is strongly correlated with interstitial lung disease, with a positive rate of 20%.

(3) Heart: manifested as heart failure, pericarditis, conduction block, and arrhythmia. Coronary artery changes, active vasculitis, intimal hyperplasia, occlusive arteritis, and medial sclerosis with calcification.

(4) Bones and joints: The main symptoms are swelling and pain in the metacarpophalangeal joints, proximal interphalangeal joints, wrist joints, and knee joints. X-ray examination shows non-erosive arthritis and joint deformities.

(5) Gastrointestinal tract: nausea, vomiting, abdominal pain. Gastric bleeding or even perforation.

(6) Kidney: Rarely, proteinuria, casts, hematuria, and acute renal failure may occur, but most patients have normal renal function.

(7) Nervous system: rare, peripheral nerve damage, and central nervous system damage in patients with SLE.

3. Malignant tumors

About 15% of adult patients with dermatomyositis have malignant tumors, which are more common in males. Myositis may precede, occur simultaneously with, or occur after malignancy. The most common ones are breast cancer, lung cancer, kidney cancer, and ovarian cancer. Myositis symptoms may improve after tumor resection, but they may also recur after years of relief.

4. Other connective tissue diseases

About 20% of patients may have other connective tissue diseases, such as systemic sclerosis and systemic lupus erythematosus.