Myopathy refers to a group of disorders affecting muscle function, leading to decreased effectiveness. The primary symptom is muscle weakness. Myopathies can be either inherited or acquired, with symptoms appearing at
birth or developing later. In acquired cases, potential causes include medication, inflammation, or electrolyte imbalances.
Inherited myopathies arise from genetic abnormalities. One type, mitochondrial myopathy, is caused by irregularities in the mitochondria of cells, which may be due to genetic mutations or spontaneous gene mutations in individuals without a family history. Another type, metabolic myopathy, results from irregularities in the muscle’s metabolic pathway and affects the genes coding for enzymes responsible for muscle function.
The primary symptom of myopathy is muscle weakness, typically more pronounced in the legs and arms than in the hands or feet. This disorder can also affect respiratory muscles, causing breathing difficulties, and may impair muscle support for bones, leading to bone deformities. Additional symptoms of myopathy include:
Some myopathy symptoms are present at birth, while others develop later in life. Typically, a primary care doctor will refer a person with myopathy symptoms to a neurologist or rheumatologist. The doctor will take a comprehensive medical history and conduct a physical evaluation, which may include assessing muscle tenderness, strength, balance, reflexes, and sensation. Additional tests may be required, including blood,
metabolic, thyroid, and other endocrine tests. Genetic tests, a muscle biopsy, and tests for specific muscle autoantibodies may also be requested. To assess muscle function, the doctor might suggest an electromyography test. Imaging tests like MRI and ultrasound can help determine the location of affected muscles and the severity of the disorder.
