Myopathy refers to a broad range of diseases of skeletal muscle that lead to dysfunction of skeletal muscle. It includes but is not limited to myositis 1.
Pathology
Etiology
Inflammatory myopathies include infectious myositis as well as idiopathic inflammatory, drug-related, or post-traumatic entities. See the separate article: myositis.
In addition, non-inflammatory myopathies include the following:
- drug-related myopathy
- steroid myopathy
- hereditary/congenital myopathy, including muscular dystrophy 2
- dystrophinopathies such as Duchenne muscular dystrophy
- facioscapulohumeral muscular dystrophy
- inborn errors of metabolism (e.g. glycogen storage disease)
- endocrine myopathy 3
- thyroid myopathy (hypothyroidism or hyperthyroidism; including thyroid ophthalmopathy)
- parathyroid dysfunction (e.g. hyperparathyroidism)
- adrenal axis dysfunction (e.g. Cushing syndrome)
- pituitary dysfunction (e.g. acromegaly)
- diabetic myonecrosis
- denervation myopathy, such as due to peripheral neuropathy
Radiographic features
The imaging findings vary by chronicity 1. Chronic myopathies appears as fat replacement and atrophy (sarcopenia), sometimes with mineralization or ossification.