Definition

A muscle disorder causes patterns of weakness, loss of muscle tissue, electromyogram (EMG) findings, or biopsy results that suggest a muscle problem. The muscle disorder can be inherited, such as muscular dystrophy, or acquired, such as alcoholic or steroid myopathy.

The medical name for muscle disorder is myopathy.

Alternative Names

Myopathic changes; Myopathy; Muscle problem

Symptoms

The main symptom is weakness.

Other symptoms include cramps and stiffness.

Exams and Tests

Your health care provider will take your medical history and perform a neurological exam. Tests that may be ordered include:

• Blood and urine tests
• Electromyography (EMG) and nerve conduction studies (NCS)
• Muscle biopsy
• Genetic tests to look for conditions that run in families. This can be tested with blood work or sometimes saliva testing.

A muscle biopsy examines a tissue sample under a microscope to confirm disease. Sometimes, a blood or saliva test to check for a genetic disorder is all that is needed based on someone's symptoms and family history.

Treatment

Treatment depends on the cause. It usually includes:

• Bracing
• Medicines (such as corticosteroids in some cases)
• Enzyme replacement therapy
• Gene replacement therapy
• Physical, respiratory, and occupational therapies
• Preventing the condition from getting worse by treating the underlying condition causing the muscle weakness
• Surgery (sometimes)

Your health care provider can tell you more about your condition and treatment options.

References

Borg K, Ensrud E. Myopathies. In: Frontera WR, Silver JK, Rizzo TD Jr, eds. Essentials of Physical Medicine and Rehabilitation: Musculoskeletal Disorders, Pain, and Rehabilitation. 4th ed. Philadelphia, PA: Elsevier; 2019:chap 136.

Doughty CT, Amato AA. In: Jankovic J, Mazziotta JC, Pomeroy SL, Newman NJ, eds. Bradley and Daroff's Neurology in Clinical Practice. 8th ed. Philadelphia, PA: Elsevier; 2022:chap 109.

Selcen D. Muscle diseases. In: Goldman L, Cooney K, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 389.