A clinician can often diagnose a musculoskeletal disorder based on symptoms and the results of a physical examination. Laboratory tests, imaging tests, and other diagnostic procedures are sometimes necessary to help the clinician make or confirm a diagnosis.
Physical examination: When a person complains of muscle weakness, the clinician checks muscles for bulk, texture, and tenderness. Muscles are also checked for twitches and involuntary movements, which may indicate a nerve disease rather than a muscle disease. Clinicians look for wasting away of muscle (atrophy), which can result from damage to the muscle or its nerves or from lack of use, as sometimes occurs with prolonged bed rest. Clinicians look for muscle enlargement (hypertrophy), which normally occurs with exercise such as weight lifting. However, when a person is ill, hypertrophy may result from one muscle working harder to compensate for the weakness of another. Muscles can also become enlarged when normal muscle tissue is replaced by abnormal tissue (increasing the size but not the strength of the muscle), which occurs in certain inherited muscle disorders, such as Duchenne's muscular dystrophy.
Clinicians try to establish which (if any) muscles are weak as well as the degree of weakness involved. The muscles can be tested systematically, usually beginning with the face and neck, then the arms, and finally the legs. Normally, a person should be able to hold the arms extended, palms up, for one minute without them sagging, turning, or shaking. Downward drift of the arm with palms turning inward is one sign of weakness. Strength is tested by pushing or pulling while the clinician pushes and pulls in the opposite direction. Strength is also tested by having the person perform certain maneuvers, such as walking on the heels and tiptoes, rising from a squatting position, or getting up and down from a chair rapidly 10 times. To assess eye muscle strength, the person is asked to look in all directions; if double vision develops, one or more eye muscles may be weak.
The clinician tests a joint's range of motion by moving the limb around a joint while the person is completely relaxed (passive movement). The clinician will check muscle tone by testing passive movement. Resistance to such movement (passive resistance) may be decreased when the nerve leading to the muscle is damaged. Resistance to such movement may be increased when the spinal cord or brain is damaged. If a person is weak, clinicians also tap the person's muscle tendon with a rubber hammer to assess reflexes. Reflexes may be slower than expected when the nerve leading to the muscle is damaged. Reflexes may be more rapid than expected when the spinal cord or brain is damaged.
Laboratory tests: Laboratory tests are often helpful in making the diagnosis of a musculoskeletal disorder. A test called an erythrocyte sedimentation rate (ESR) test measures the rate at which red blood cells settle to the bottom of a test tube containing blood. The ESR is increased when inflammation is present. However, because inflammation occurs in so many conditions, the ESR alone does not establish a diagnosis. The level of creatine kinase (a normal muscle enzyme that leaks out and is released into the bloodstream when muscle is damaged) may also be tested. Levels of creatine kinase are increased when there is widespread and ongoing destruction of muscle. In rheumatoid arthritis, a blood test to identify rheumatoid factor or anti-cyclic citrullinated peptide (anti-CCP) antibody is helpful in making the diagnosis. In systemic lupus erythematosus (lupus), a blood test to identify autoimmune antibodies (antinuclear antibodies) is helpful in making the diagnosis.
Nerve tests: Nerve conduction studies help determine whether the nerves supplying the muscles are functioning normally. Nerve conduction studies, together with electromyography, help indicate whether there is a problem primarily in the muscles (such as myositis or muscular dystrophy); in the nervous system, which supplies the muscles (such as a stroke, spinal cord problem, or polyneuropathy); or with the neuromuscular junction (such as myasthenia gravis). Electromyography, often performed at the same time as nerve conduction studies, is a test in which electrical impulses in the muscles are recorded to help determine how well the impulses from the nerves are reaching the connection between nerves and muscles (neuromuscular junction).
X-rays: X-rays are most valuable for detecting abnormalities in bone and are taken to evaluate painful, deformed, or suspected abnormal areas of bone. Often, X-rays can help to diagnose fractures, tumors, injuries, infections, and deformities (such as congenital hip dysplasia). Also, X-rays may be helpful in showing changes that confirm a person has a certain kind of arthritis (for example, rheumatoid arthritis or osteoarthritis). X-rays do not show soft tissues such as muscles, bursae, ligaments, tendons, or nerves. To help determine whether the joint has been damaged by injury, a clinician may use an ordinary (non-stress) X-ray or one taken with the joint under stress (stress X-ray).
Arthrography is an X-ray procedure in which a dye is injected into a joint space to outline the structures, such as ligaments inside a joint. Arthrography can be used to view torn ligaments and fragmented cartilage in the joint.
Dual-energy X-ray absorptiometry (DEXA): The most accurate way to evaluate bone density, which is necessary when screening for or diagnosing osteoporosis, is with dual-energy X-ray absorptiometry (DEXA). In this test, low-dose X-rays are used to examine bone density at the lower spine, hip, wrist, or entire body. Measurements of bone density are very accurate at these sites. To help differentiate osteoporosis (the most common cause of an abnormal DEXA scan) from other bone disorders, doctors may need to consider the person's symptoms, medical conditions, medication use, and certain blood or urine test results as well as the DEXA results.
Computed tomography (CT) and magnetic resonance imaging (MRI): Computed tomography (CT) and magnetic resonance imaging (MRI) give much more detail than conventional X-rays. CT and MRI may be performed to determine the extent and exact location of musculoskeletal damage. These tests can also be used to detect fractures that are not visible on X-rays. MRI is especially valuable for imaging muscles, ligaments, and tendons. MRI can be used if the cause of pain is thought to be a severe soft-tissue problem (for example, rupture of a major ligament or tendon or damage to important structures inside the knee joint). The amount of time a person spends undergoing CT is much less than for MRI.
Bone scanning: Bone scanning is an imaging procedure that is occasionally used to diagnose a fracture, particularly if other tests, such as plain X-rays and CT or MRI, do not reveal the fracture. Bone scanning involves the use of a radioactive substance (technetium-99m-labeled pyrophosphate) that is absorbed by any healing bone. The technique can also be used when a bone infection or a metastasis (from a cancer elsewhere in the body) is suspected. The radioactive substance is given intravenously and is detected by a bone-scanning device, creating an image of the bone that can be viewed on a computer screen.
Joint aspiration: Joint aspiration is used to diagnose certain joint problems. A needle is inserted into a joint space and fluid (synovial fluid) is drawn out (aspirated) and examined under a microscope. A doctor can often make a diagnosis after analyzing the fluid. For example, a sample of synovial fluid may contain bacteria, which confirms a diagnosis of infection. Joint aspiration is usually performed in a doctor's office and is generally quick, easy, and relatively painless. The risk of joint infection is minimal.
Arthroscopy: Arthroscopy is a procedure in which a small (diameter of a pencil) fiber optic scope is inserted into a joint space, allowing the doctor to look inside the joint and to project the image onto a television screen. The skin incision is very small. A person receives local, spinal, or general anesthesia. During arthroscopy, doctors can take a piece of tissue for analysis (biopsy) and, if necessary, perform surgery to correct the condition. Disorders commonly found during arthroscopy include inflammation of the synovium lining a joint (synovitis); ligament, tendon, or cartilage tears; and loose pieces of bone or cartilage. Such conditions affect people with arthritis or previous joint injuries, as well as athletes. All of these conditions can be repaired or removed during arthroscopy. There is a very small risk of joint infection with this procedure.
signs and symptoms
Pain is the chief symptom of most musculoskeletal disorders. The pain may be dull, sharp, radiating, or local and may be mild or severe. Although pain may be acute (short-lived), as is the case with most injuries, it may become chronic (ongoing) with illnesses such as rheumatoid arthritis. Muscle pain is known as myalgia.
Common symptoms of osteoarthritis include joint pain, swelling and/or stiffness in a joint (especially after use), joint discomfort before or during a change in the weather, bony lumps on the fingers, and loss of joint flexibility. The joints that are most often affected by osteoarthritis include the fingers, spine, and weight-bearing joints, such as the hips, ankles, feet, and knees.
Rheumatoid arthritis often affects many joints at the same time, and the severity of symptoms varies among patients. Symptoms, which may come and go, typically include pain and swelling in the joints (especially in the hands and feet), generalized aching or stiffness of the joints and muscles (especially after periods of rest), loss of motion of the affected joints, weakness in the muscles near the affected joints, low-grade fever, and general feeling of discomfort. Early in the disease, the joints in the hands, wrists, feet, and knees are most frequently affected. Over time, arthritis may develop in the shoulders, elbows, jaw, hips, and neck. In addition to the joints, rheumatoid arthritis may cause swelling in the tear ducts, salivary glands, the lining of the heart, the lungs, and occasionally, blood vessels.
Periarthritis causes swelling and pain in the joints. Most patients develop periarthritis of the shoulder. When the shoulder is affected, the joint's mobility is significantly or completely reduced and aggressive treatment is started.
Signs and symptoms of muscular dystrophy vary according to the type of muscular dystrophy. In general, they may include muscle weakness, apparent lack of coordination, and progressive crippling, resulting in contractures of the muscles around the joints and loss of mobility.
The primary symptoms of fibromyalgia include widespread musculoskeletal pain, severe fatigue (tiredness), and sleep disturbances. Fibromyalgia may cause pain in the muscles, tendons, or ligaments. The pain is usually in multiple locations and may be difficult to describe precisely.
Most individuals with fibromyalgia complain of a total body "ache." Their muscles may feel like they were pulled or overworked or feel as if they are burning. Other symptoms associated with fibromyalgia include irritable bowel syndrome (IBS). Symptoms of IBS include fluctuations between constipation and diarrhea, frequent abdominal pain, abdominal gas, and nausea. Symptoms of IBS are frequently found in roughly 40 to 70% of fibromyalgia patients.
Acid reflux, or gastroesophageal reflux disease (GERD), also occurs with the same high frequency. Recurrent migraine or tension-type headaches are seen in about 70% of fibromyalgia patients and can pose a major problem in coping for this patient group.
Temporomandibular joint disorder (TMJ) causes tremendous jaw-related face and head pain in one-quarter of fibromyalgia patients.
Other common symptoms of fibromyalgia include
premenstrual syndrome (PMS) and painful periods, chest pain, morning stiffness, cognitive or memory impairment, numbness and tingling sensations, muscle twitching, irritable bladder, the feeling of swollen extremities (hands and feet), skin sensitivities, dry eyes and mouth, dizziness, and impaired coordination. Fibromyalgia patients are often sensitive to odors, loud noises, bright lights, and sometimes even the medications they are prescribed.
Temporomandibular joint (TMJ) disorder
Common symptoms of TMJ disorders include pain and soreness of the jaw (which may worsen when the individual chews food, talks, or yawns), pain in and around the ear, facial pain, an uneven bite or change in the way the lower and upper teeth fit together, jaw muscle stiffness, a clicking sound or grating sensation when the mouth is opened and closed (sometimes called jaw clicking), headache, tired facial muscles, and locking of the joint, which may temporarily limit the movement of the jaw.
It is important to note that jaw clicking affects many individuals who do not have TMJ disorders. Individuals who do not experience pain or limited movement of the jaw when the jaw clicks most likely do not have TMJ disorders.
Depression: Some individuals with musculoskeletal problems may suffer from depression. This may happen if the musculoskeletal disorder interferes significantly with the patient's lifestyle, including causing pain. Individuals should consult their healthcare providers if they experience feelings of sadness, low self-esteem, loss of pleasure, apathy, and difficulty functioning for two weeks or longer with no known underlying cause. These may be signs of depression and suicidal thoughts.
Joint damage: In some cases, musculoskeletal disorders can lead to severe joint damage. In such cases, surgery, such as a joint replacement, may be necessary. Individuals should regularly visit their healthcare providers to monitor their conditions.
Limited mobility: Patients with musculoskeletal disorders may have limited mobility in their joints. Joint mobility decreases as the joint becomes more damaged.
causes and risk factors
Individuals who are more susceptible to musculoskeletal problems tend to maintain fixed positions (such as sitting in a chair or standing), perform repetitive movements of the limbs (such as athletes or factory workers), overload particular muscle groups, apply pressure on body parts, and use forceful movements (such as in sports).
Musculoskeletal problems and pain can be caused by damage or injury to bones, joints, muscles, tendons, ligaments, bursae, or nerves. 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, dull, or sharp. It commonly results from injury. Other less common causes of bone pain include bone infection (osteomyelitis), vitamin A toxicity, and tumors.
Muscle pain is often less intense than that of 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, dehydration and resulting electrolyte imbalances, infection, or invasion by a tumor.
Tendon and ligament pain is also often less intense than bone pain. This type of pain is often worse when the affected tendon or ligament is stretched or moved. Common causes of tendon pain include tendonitis, tenosynovitis, lateral and medial epicondylitis, and tendon injuries. Common causes of ligament pain include injuries (sprains).
The exact causes of osteoarthritis and rheumatoid arthritis remain unknown. Most researchers believe that several factors, including obesity, age, joint injury or stress, genetics, and muscle weakness, may contribute to the development of osteoarthritis. Some researchers believe that cartilage damage may occur when too many enzymes that allow for the natural breakdown and regeneration of cartilage are released.
Rheumatoid arthritis is considered an autoimmune disorder because the immune system does not function properly and attacks the body's own cells. Some researchers believe that this autoimmune process is triggered by an infection with a virus or bacterium. Heredity may also play a role in the development of rheumatoid arthritis.
Periarthritis typically occurs after a joint becomes injured, which causes scarring, thickening, and shrinkage of the joint. It may also occur after exposure to cold temperatures. Periarthritis typically affects the shoulder. Individuals who have other types of long-term arthritis that affect the shoulders have an increased risk of developing periarthritis of the shoulder.
Gender: Although fibromyalgia may develop in men or women, statistics indicate that women are seven times more likely to develop the condition than men. Nine out of 10 fibromyalgia patients are women, and an estimated 3.4% of American women have the condition. Women's symptoms also tend to be more severe than men's. Women may be more prone to develop fibromyalgia during menopause.
Age: Individuals between the ages of 20 and 60 are at the highest risk of developing fibromyalgia, although it may occur at any age.
Genetic factors: There is some indication that genetic factors may be involved in the development of fibromyalgia. Studies have shown that individuals with family members who have fibromyalgia are at a higher risk of developing it themselves.
Specific lifestyle factors: People who have recently experienced a traumatic physical or emotional event (such as a divorce, car accident, or death of a family member) may be at a higher risk of developing fibromyalgia.
Psychiatric illness: While the majority of individuals with fibromyalgia report a history of psychiatric symptoms, such as depression or anxiety, many patients do not. There is no clear evidence that psychiatric illness causes fibromyalgia.
Changes in weather, cold or drafty environments, infections, allergies, hormonal fluctuations (premenstrual and menopausal states), stress, depression, and anxiety may all contribute to fibromyalgia.
Muscular dystrophy refers to a number of diseases that are caused by genetic mutations that involve progressive weakness, degeneration, and wasting of muscles. The Duchenne and Becker types of muscular dystrophy (DBMD) have similar signs and symptoms, are caused by the same genetic mutation (dystrophin mutation), and occur more frequently in males than in females.
The particular gene that causes DBMD is found on the X chromosome, and so it is called "X-linked." Females carry two X chromosomes. Males carry one X chromosome and one Y chromosome. Because males have only one X chromosome, a male carrying a copy with a DBMD mutation will have the condition. However, because females have two copies of the X chromosome, a female can have one copy with a DBMD mutation and one functional copy. Because the functional copy is usually enough to compensate, a female with a DBMD mutation usually has few or no symptoms. However, because she can pass the mutation on to her children, she is called a "carrier."
Each son born to a woman with the dystrophin mutation on one of her two X chromosomes has a 50% chance of inheriting the mutated gene and having DBMD. Each of her daughters has a 50% chance of inheriting the mutation and being a carrier. While most cases of DBMD occur by inheritance from the mother, in approximately one-third of boys with DBMD, there is a new mutation that forms in the egg, and so the mother is actually not the carrier of the mutation.
Temporomandibular joint disorder
The cause of most TMJ disorders remains unknown. Some types of temporomandibular joint (TMJ) disorders appear to be caused by injury to the joint from a severe blow to the jaw or arthritis. Many behaviors, including frequently clenching the jaw or grinding the teeth (which may occur during sleep), poor posture that puts strain on the muscles and bones near the jaw, or other habits that overwork the jaw muscles (e.g. constantly chewing gum), may contribute to the development of TMJ disorders. However, further research is needed to definitively determine if these behaviors cause TMJ disorders.