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Pain is the chief symptom of most musculoskeletal disorders. The pain may be mild or severe, local or widespread (diffuse). Although pain may be acute and short-lived, as is the case with most injuries, pain may be ongoing with chronic illnesses, such as rheumatoid arthritis.
Causes
Musculoskeletal pain can be caused by damage to bones, joints, muscles, tendons, ligaments, bursae, or nerves. Injuries are the most common cause. If no injury has occurred or if pain persists for more than a few days, then another cause is often responsible.
Bone pain is usually deep, penetrating, or dull. It commonly results from injury. Other less common causes of bone pain include bone infection (osteomyelitis) and tumors.
Muscle pain is often less intense than bone pain but can be very unpleasant. For example, a muscle spasm or cramp (a sustained painful muscle contraction) in the calf is an intense pain that is commonly called a charley horse. Pain can occur when a muscle is affected by an injury, an autoimmune reaction (for example, polymyositis or dermatomyositis), loss of blood flow to the muscle, infection, or invasion by a tumor.
Tendon and ligament pain is often less intense than bone pain. It is often worse when the affected tendon or ligament is stretched or moved. Common causes of tendon pain include tendinitis, tenosynovitis, lateral and medial epicondylitis, and tendon injuries. Common causes of ligament pain include injuries (sprains).
Fibromyalgia may cause pain in the muscles, tendons, or ligaments. The pain is usually in multiple locations and may be difficult to describe precisely. Affected people usually have other symptoms.
Virtually all joint injuries and diseases produce a stiff, aching pain, often referred to as "arthritic" pain. The pain is worse when the joint is moved and may range from mild to severe. With some conditions, there may be swelling of the joint along with the pain. Joint inflammation (arthritis) is a common cause of joint pain. There are many types of arthritis, including rheumatoid and other types of inflammatory arthritis, osteoarthritis, infectious arthritis, and arthritis due to gout or pseudogout. Other causes of joint pain include autoimmune and vasculitic disorders (for example, systemic lupus erythematosus, polymyalgia rheumatica, and polyarteritis nodosa), avascular necrosis of bone, and injuries (for example, dislocations, sprains, and fractures affecting the portion of the bone inside the joint). Sometimes, pain originating in structures near the joint, such as tendons and bursae, seems to be coming from the joint.
Some musculoskeletal disorders cause pain by compressing nerves. These conditions include the "tunnel syndromes" (for example, carpal tunnel syndrome, cubital tunnel syndrome, and tarsal tunnel syndrome). The pain tends to radiate along the path supplied by the nerve and may be burning.
Bursal pain can be caused by bursitis or fibromyalgia. Usually, bursal pain is worse with movement involving the bursa. There may be swelling.
Sometimes, pain that seems to be musculoskeletal is actually caused by a disorder in another organ system. For instance, shoulder pain may be caused by a disorder affecting the spleen or gallbladder. Back pain may be caused by an abdominal aortic aneurysm. Arm pain may be caused by a heart attack (myocardial infarction). Additionally, sometimes pain that seems to be coming from one part of the musculoskeletal system actually comes from another part. For instance, knee pain in an adolescent may be caused by a disorder of the hip called slipped capital femoral epiphysis.
Evaluation and Treatment
Sometimes, the type of pain suggests where the pain has originated. For example, pain that worsens with motion suggests a musculoskeletal disorder. Pain with muscle spasm suggests that pain is caused by a muscle disorder. The site of swelling or the location of tenderness when the doctor palpates the area (for example, a joint, ligament, or bursa) often indicates the source of pain. However, often these characteristics of pain do not indicate its origin or cause. Thus, doctors usually base a specific diagnosis on the presence of other symptoms and often on the results of laboratory tests and x-rays. For example, Lyme disease often causes joint pain and a bull's eye—like skin rash; blood tests show antibodies to the bacteria that cause Lyme disease. Gout is characterized by a sudden attack of pain, swelling, and redness in the joint at the base of the big toe or other joints; tests of the joint fluid generally show the presence of uric acid crystals.
Blood tests are useful only in supporting the diagnosis made by the doctor after an examination. A diagnosis is not made or confirmed by a blood test alone. Examples of such blood tests include rheumatoid factor and antinuclear antibodies, which are used to help diagnose many of the common causes of arthritis, such as rheumatoid arthritis and systemic lupus erythematosus. Usually, such tests are recommended only if symptoms specifically suggest such a disorder or are persistent or unusually severe.
X-rays are primarily used to take images of bones; they do not show muscles, tendons and ligaments. X-rays are usually taken if the doctor suspects a fracture or, less commonly, a bone tumor or infection or to look for changes that confirm a person has a certain kind of arthritis (for example, rheumatoid arthritis or osteoarthritis).
A computed tomography (CT) scan is more sensitive than an x-ray and is often used to obtain more detail about a fracture or bone problem that was found with plain x-rays.
Unlike plain x-rays, magnetic resonance imaging (MRI) can identify abnormalities of soft tissues such as muscles, bursae, ligaments, and tendons. Thus, MRI may be used when the doctor suspects damage to a major ligament or tendon or damage to important structures inside a joint.
Pain is usually best relieved by treating its cause. In addition, the doctor may recommend analgesics (see Pain: Treatment of Pain) such as acetaminophen, nonsteroidal anti-inflammatory drugs (NSAIDs), or, if pain is severe, opioids. Depending on the cause, applying cold or heat or immobilizing the joint may help relieve musculoskeletal pain.
Last full review/revision September 2006 by Michael Jacewicz, MD
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