Overview and Causes of Muscle Pain

Distinguishing Overuse From Diseases and Conditions

Muscle Pain
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Most people will experience muscle pain at some point. Muscle pain, or myalgia, can range from mild to severe. It can resolve quickly after a brief episode or persist for a longer duration. Any muscle in the body can be affected but most commonly the muscles in the neck, back, and legs are involved.

Causes of Muscle Pain

Whether the muscle pain is less extensive or more extensive depends largely on the cause.

The most common causes of muscle pain and muscle aches are overuse, stress, and minor injuries. In such cases, the muscle pain is usually localized and limited to one muscle or a specific group of muscles. Systemic muscle pain, which is felt all over your body, generally is related to a more complicated cause, such as illness, infection, or medication side effects. Specifically, the following are possible causes of muscle pain.

Medications that can cause muscle pain:

ACE inhibitors (for blood pressure)
Statins (to lower cholesterol)

Infections that can cause muscle pain:

Abscess of a muscle
Lyme disease
Polio or post-polio syndrome
Rocky Mountain Spotted Fever

Diseases and Conditions:

Chronic fatigue syndrome
Electrolyte imbalance
Myofascial pain syndrome
Polymyalgia rheumatica
Rheumatoid arthritis

Treating Muscle Pain

When muscle pain is related to overuse, repetitive stress, or strain, it can usually be treated at home. The resulting minor injury will usually respond to R.I.C.E. -- rest, ice, compression, and elevation.

If muscle pain persists and you suspect that it is due to something other than a minor strain or injury, consult your doctor.

Treating the underlying condition would be the obvious priority.

You should not delay medical care if you have muscle pain along with any of the following problems: trouble breathing, dizziness, pronounced muscle weakness, stiff neck, high fever, tick bite, rash, localized redness and swelling that might signal infection, muscle pain that started after taking a new medication. Seek medical care immediately in such cases.

Inflammatory Diseases of Muscle

Inflammatory muscle diseases are systemic autoimmune disorders which are characterized by chronic muscle weakness, muscle fatigue, and the infiltration of mononuclear cells into skeletal muscle. Polymyositis and dermatomyositis are the two primary types of inflammatory diseases of muscle. Another type, called inclusion body myositis, is considered by some to be an idiopathic inflammatory myopathy as well.

Inflammatory myopathies can exist on their own or secondary to another rheumatic disease. The rheumatic diseases most often associated with inflammatory myopathies include scleroderma, mixed connective tissue disease, Sjogren's syndrome, and systemic lupus erythematosus.

An inflammatory myopathy can co-exist with rheumatoid arthritis, too.

The main symptoms associated with polymyositis and dermatomyositis are muscle weakness and low muscle endurance. The weakness usually occurs symmetrically in the neck, pelvic, thigh, and shoulder muscles. If untreated, the muscle weakness progresses and in severe cases, the patient may require mobility aids -- possibly even a wheelchair. If there is impaired contractility of the throat muscles, there can be issues related to swallowing and nutrition. If there is weakness of the diaphragm or thoracic muscles, breathing difficulties may develop. If the lower esophagus is involved, there can be acid reflux problems that develop. If the sphincter ani is affected, there may be incontinence. Dermatomyositis, unlike polymyositis, has a characteristic rash associated with it. Usually, the inflammatory myopathies are treated with corticosteroids and immunosuppressant drugs to help slow progression.


Kelley's Textbook of Rheumatology. Ninth Edition. Inflammatory Diseases of Muscle and Other Myopathies. Nagaraju K. and Lundberg, I.E. Chapter 85. P.1404.

Muscle Aches. MedlinePlus. Update 5/1/2011.

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