Polymyositis, Inclusion Body Myositis, and Related Myopathies
Polymyositis
Definition
Polymyositis: acute or subacute onset; sometimes spontaneous improvement; infiltration of muscle by lymphocytes. Occurs alone or as part of systemic disease (including collagen-vascular disease, HIV infection).
Clinical Features
Symptoms of proximal limb myopathy: difficulty climbing stairs, rising from low seats, lifting packages or dishes, working with arms overhead.
Difficulty holding head erect (“dropped head” syndrome) due to neck muscle weakness. Cranial muscles spared except for dysphagia.
Usually subacute, nadir in months. Rare before puberty. Often seen with collagen vascular diseases: systemic lupus erythematosus, rheumatoid arthritis, Sjögren disease, systemic sclerosis.
Investigations
EMG: myopathic pattern fibrillations, positive waves may be present.Stay updated, free articles. Join our Telegram channel
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