polymyarian

例句：

1. 1. The patient was diagnosed with polymyoarthritis, which is a type of arthritis affecting the muscles and joints.
   患者被诊断出患有多发肌炎，这是一种影响肌肉和关节的关节炎类型。
2. 2. Myasthenia gravis is a rare autoimmune disorder that affects the nerves and muscles.
   重症肌无力是一种罕见的自身免疫疾病，影响神经和肌肉。
3. 3. Polymyoarthritis can cause pain, stiffness, and swelling in the affected areas, making daily activities difficult.
   多发肌炎可以导致受影响区域疼痛、僵硬和肿胀，使日常活动变得困难。