Pain that seems to be coming from joints can sometimes be coming from structures outside the joints, such as ligaments, tendons, or muscles (see Introduction to the Biology of the Musculoskeletal System). Examples of such disorders are bursitis and tendinitis.
 
True joint pain (arthralgia) may or not be accompanied by joint inflammation (arthritis). The most common symptom of joint inflammation is pain. Inflamed joints may also be warm and swollen, and less often the overlying skin may be red. Arthritis may involve only joints of the limbs or also joints of the central part of the skeleton, such as the spine or pelvis. Pain may occur only when a joint is moved or may be present at rest. Other symptoms, such as rash, fever, eye pain, or mouth sores, may be present depending on the cause of the joint pain.
 
Different disorders tend to affect different numbers of joints. Because of this, doctors consider different causes of pain when the pain affects one joint (see Joint Pain: Single Joint) than when it affects more than one joint. When multiple joints are involved, some disorders are more likely to affect the same joint on both sides of the body (for example, both knees or both hands) than other disorders. This is termed symmetric arthritis. Also, in some disorders, an attack of arthritis remains in the same joints throughout the attack. In other disorders, the arthritis moves from joint to joint (migratory arthritis).
 
Causes
In most cases, the cause of pain originating inside multiple joints is arthritis. Disorders that cause arthritis may differ from each other in certain tendencies, such as the following:
 
How many and which joints they usually involve
Whether the central part of the skeleton, such as the spine or pelvis, is typically involved
Whether arthritis is sudden (acute) or longstanding (chronic)
Acute arthritis affecting multiple joints is most often due to
 
Viral infection
The beginning of a joint disorder or a flare up of an existing chronic joint disorder (such as rheumatoid arthritis or psoriatic arthritis)
Gout or calcium pyrophosphate arthritis (previously called pseudogout)
Less common causes of acute arthritis in multiple joints include Lyme disease (which also may affect only one joint), gonorrhea and streptococcal bacterial infections, reactive arthritis (arthritis that develops after an infection of the digestive or urinary tract), and gout.
 
Chronic arthritis affecting multiple joints is most often due to
 
Inflammatory disorders such as rheumatoid arthritis, psoriatic arthritis, or systemic lupus erythematosus (in adults)
The noninflammatory disorder osteoarthritis (in adults)
Juvenile idiopathic arthritis (in children)
Some chronic inflammatory disorders can affect the spine as well as the limb joints (called the peripheral joints). Some affect certain parts of the spine more frequently. For example, ankylosing spondylitis more commonly affects the lower (lumbar) part of the spine, whereas rheumatoid arthritis more typically affects the upper (cervical) part of the spine in the neck.
 
The most common disorders outside the joints that cause pain around the joints are
 
Fibromyalgia
Polymyalgia rheumatica
Bursitis or tendinitis
Bursitis and tendinitis often result from injury, usually affecting only one joint. However, certain disorders cause bursitis or tendinitis in many joints.
 
Evaluation
In evaluating joint pain, doctors first try to decide whether joint pain is caused by a disorder of the joints or a serious bodywide (systemic) illness. Serious bodywide disorders may need specific immediate treatment. The following information can help people decide when to see a doctor and know what to expect during the evaluation.
 
Warning signs
 
In people with pain in more than one joint, symptoms that should prompt rapid evaluation include
 
Joint swelling, warmth, and redness
New rashes, spots, or purple blotches
Sores in the mouth or nose or on the genitals
Chest pain, shortness of breath, or new or severe cough
Abdominal pain
Fever, sweats, weight loss, or chills
Eye redness or pain
When to see a doctor
 
People with warning signs should see a doctor right away. People without warning signs should call a doctor. The doctor decides how quickly they need to be seen based on the severity and location of pain, whether joints are swollen, whether the cause has been diagnosed previously, and other factors. Typically, a delay of several days or so is not harmful for people without warning signs.
 
What the doctor does
 
Doctors first ask questions about the person’s symptoms and medical history. Then they do a physical examination. What doctors find during the history and physical examination often suggests a cause for joint pain and guides the tests that may need to be done (see table Some Causes and Features of Pain in More Than One Joint).
 
Doctors ask about pain severity, onset (sudden or gradual), how symptoms vary over time, and what increases or decreases pain (for example, rest or movement or time of day when the symptoms worsen or abate). They ask about joint stiffness and swelling, previously diagnosed joint disorders, and risk of exposure to sexually transmitted diseases and Lyme disease.
 
Doctors then do a complete physical examination. They check all joints (including those of the spine) for swelling, redness, warmth, tenderness, and noises that are made when the joints are moved (called crepitus). The joints are moved through their full range of motion, first by the person without assistance (called active range of motion) and then by the doctor (called passive range of motion). This examination helps determine which structure is causing the pain and if inflammation is present. They also check the eyes, mouth, nose, and genital area for sores or other signs of inflammation. The skin is examined for rashes. Lymph nodes are felt and the lungs and heart examined. Doctors usually test function of the nervous system so that they can detect disorders of the muscles or nerves.
 
Some findings give helpful clues as to the cause. For example, if the tenderness is around the joint but not over the joint, bursitis or tendinitis is likely the cause. If tenderness is present all over, fibromyalgia is possible. If the spine is tender as well as the joints, possible causes include osteoarthritis, reactive arthritis, ankylosing spondylitis, and psoriatic arthritis. Findings in the hand can help doctors differentiate between rheumatoid arthritis and osteoarthritis, two particularly common types of arthritis. For example, rheumatoid arthritis is more likely to involve the large knuckle joints (those that join the fingers with the hand) and wrist. Osteoarthritis is more likely to involve the finger joint near the fingernail. The wrist is unlikely to be affected in osteoarthritis, except at the base of the thumb.
 
TABLE
Some Causes and Features of Pain in More Than One Joint
Testing
 
The following tests are the most important overall:
 
Tests of joint fluid
Blood tests for autoantibodies
Erythrocyte sedimentation rate (ESR) and C-reactive protein
If joints are swollen, doctors usually insert a needle into the joint to take a sample of the fluid in the joint for testing (a procedure called joint aspiration or arthrocentesis). Doctors numb the area before taking a sample, so people experience little or no pain during the procedure. Doctors generally do a culture on the fluid to see whether infection is present. They look under a microscope for crystals in the fluid, which indicate gout or related disorders. The numbers of white blood cells in the fluid indicate whether the joint is inflamed.
 
Doctors also often do blood tests for autoantibodies. Examples of such tests are antinuclear antibodies, anti–double-stranded DNA, anticyclic citrullinated peptide, and rheumatoid factor. Autoantibodies in the blood may indicate an autoimmune disorder such as rheumatoid arthritis or systemic lupus erythematosus.
 
LAB TEST
Antinuclear Antibody (ANA)
LAB TEST
Anti-dsDNA
The ESR is a test that measures the rate at which red blood cells settle to the bottom of a test tube containing a blood sample. Blood that settles quickly typically means that bodywide (systemic) inflammation is likely, but many factors can affect the ESR test including age and anemia, so the test is sometimes inaccurate. To help determine whether bodywide inflammation is present, doctors sometimes do another blood test called C-reactive protein (a protein that circulates in the blood and dramatically increases in level when there is inflammation).
 
Imaging tests are sometimes necessary, especially if there is a possibility of bone or joint tumors. X-rays are done first, but sometimes computed tomography (CT) or magnetic resonance imaging (MRI) is needed.
 
If a particular disorder is suspected, other tests may be required (see table Some Causes and Features of Pain in More Than One Joint).
 
Treatment
The underlying disorder is treated. For example, people with an autoimmune disorder (such as systemic lupus erythematosus) may need a drug that suppresses the immune system. People with a gonorrhea infection in the joint need antibiotics.
 
Symptoms can usually be relieved before the diagnosis is known. Inflammation can usually be relieved with nonsteroidal anti-inflammatory drugs (NSAIDs). Pain without inflammation is usually treated more safely with acetaminophen. Immobilizing the joint with a splint or sling can sometimes relieve pain. Applying heat (for example, with a heating pad) may decrease pain by relieving spasm in the muscles around joints (for example, after an injury). Applying cold (for example, with ice) may help relieve pain caused by joint inflammation. Heat or cold should be applied for at least 15 minutes at a time to allow deep penetration. The skin must be protected from extremes of heat and cold. For example, ice should be put in a plastic bag and wrapped in a towel.
 
After the acute pain and inflammation have lessened, physical therapy may be useful to regain or maintain range of motion and strengthen surrounding muscles. In people with chronic arthritis, continued physical activity is important to prevent permanent joint stiffness (contractures) and muscle loss (atrophy).
 
Essentials for Older People
Osteoarthritis is the most common cause of multiple joint pains in the elderly. Although more common among younger adults (those aged 30 to 40), rheumatoid arthritis can also begin later in life (after age 60). Older adults who may have rheumatoid arthritis may also have cancer. People over age 55 who have hip and shoulder stiffness and pain that is usually worse in the morning may have polymyalgia rheumatica. Recognizing polymyalgia rheumatica is important because treating it can help prevent other problems.