Myalgia

Myalgia means "muscle pain" and is a symptom of many diseases and disorders. The most common causes are the overuse or over-stretching of a muscle or group of muscles. Myalgia without a traumatic history is often due to viral infections. Longer-term myalgias may be indicative of a metabolic myopathy, some nutritional deficiencies or chronic fatigue syndrome.

Causes
The most common causes of myalgia are overuse, injury or strain. However, myalgia can also be caused by diseases, disorders, medications, or as a response to a vaccination. It is also a sign of acute rejection after heart transplant surgery.

The most common causes are: Muscle pain occurs with:
 * Injury or trauma, including sprains, hematoma
 * Overuse: using a muscle too much, too often, including protecting a separate injury
 * Chronic tension
 * Rhabdomyolysis, associated with:
 * Viral
 * Compression injury
 * Drug-related, esp fibrates and statins, occ ACE inhibitors, cocaine, some retro-viral drugs
 * Severe potassium deficiency
 * Fibromyalgia
 * Infections, including:
 * Influenza (the flu)
 * Lyme disease
 * Malaria
 * Dengue Fever
 * Hemorrhagic fever
 * Muscle abscess
 * Polio
 * Rocky Mountain spotted fever
 * Trichinosis (roundworm)
 * Auto-immune disorders, including
 * Systemic lupus erythematosus
 * Polymyalgia rheumatica
 * Polymyositis
 * Dermatomyositis
 * Multiple Sclerosis (this is neurologic pain localised to myotome)

Overuse
Overuse of a muscle is using it too much, too soon and/or too often. Examples are:
 * Repetitive strain injury.

Injury
The most common causes of myalgia by injury are: sprains and strain (injury).

Autoimmune
Multiple sclerosis(neurologic pain interpreted as muscular), Myalgic Encephalomyelitis, Myositis, Lupus erythematosus, Familial Mediterranean fever, Polyarteritis nodosa, Devic's disease, Morphea

Metabolic defect
Carnitine palmitoyltransferase II deficiency, Conn's syndrome, Adrenal insufficiency, Hyperthyroidism, Hypothyroidism

Other
Chronic fatigue syndrome, Ehlers Danlos Syndrome, Hypokalemia, Exercise intolerance, Mastocytosis, Peripheral neuropathy, Eosinophilia myalgia syndrome, Fibromyalgia, Barcoo Fever, Herpes, Delayed onset muscle soreness, AIDS, HIV, Tumor-induced osteomalacia, Post Orgasmic Illness Syndrome

Medications
Acrylamide, Aspirin, colesevelam, darbepoetin, darunavir, daptomycin, ezetimibe, ibandronate sodium, ibuprofen, imiquimod, interferons, isotretinoin, procainamide, quinupristin/dalfopristin, statins, sumatriptan, tasigna, tiotropium, vardenafil, zolmitriptan, zocor.

Withdrawal syndromes
Sudden cessation of high-dose corticosteroids, opioids, barbiturates, benzodiazepines, or alcohol can induce myalgia.