What is arthritis?

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A group of more than one hundred inflammatory diseases that damage joints and their surrounding structures, resulting in symptomatic pain, disability, and systemwide inflammation.
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Causes and Symptoms

Approximately one in six people (more than 15 percent) suffers from one of approximately one hundred varieties of arthritis, and 2.6 percent of the population suffers from arthritis that limits their activities. Although many people over seventy-five years of age experience arthritis, the disease can occur in the young as a result of infections, rheumatic conditions, or genetic conditions. Young and middle-aged adults experience the disease as a result of trauma, infections, and rheumatic or autoimmune reactions. Arthritis may be located in joints, joint capsules, the surrounding muscles, or diffusely throughout the body. Inflammation of the joint lining (synovium) can similarly afflict the linings of other organs: the skin, colon, eyes, heart, and urinary passage. In addition to the characteristic symptoms of joint pain and stiffness, individuals suffering from arthritis may also experience psoriasis and rashes, spastic colitis, dryness of the eyes, inflammations of the conjunctiva or iris, frequent urination, discharge and burning upon urination, and other symptoms.

Arthritis has many causes. Infectious causes of arthritis include septic arthritis, tuberculous arthritis, viral arthritis (potentially caused by the hepatitis virus, parvovirus B19, or human immunodeficiency virus), acute rheumatic fever, and Lyme disease. Primary arthritic syndromes include rheumatoid arthritis and juvenile rheumatoid arthritis, which are systemic inflammatory diseases characterized by chronic destructive synovitis. Seronegative spondyloarthropathy—such as reactive arthritis, psoriatic arthritis, and ankylosing spondylitis—is another primary arthritic syndrome. Reactive arthritis is a systemic inflammatory disorder that arises one to six weeks after an infection, most often gastrointestinal or urogenital infections. A form of reactive arthritis called Reiter’s syndrome affects the eyes and urethra as well as the joints. Psoriatic arthritis is associated with mild to severe psoriasis and joint pain. Osteoarthritis is brought on by wear-and-tear degeneration of the joints and is associated with older age. Such wear and tear can occur in the joints after years of trauma, repetitive use, and (especially in the obese) weight-bearing. Osteoarthritis and rheumatoid arthritis are the most common forms of arthritis.

Additionally, uric acid crystals associated with gout can build up in the joints, causing arthritis. Gout sufferers experience painful, hot, tender, and swollen joints—with symptoms often beginning in the big toe. Calcium pyrophosphate dihydrate deposition disease is also associated with crystal-induced arthritis. Arthritis is also associated with a number of other medical conditions. Autoimmune causes of arthritis include systemic lupus erythematosus (SLE), Sjögren’s syndrome, and dermatomyositis (also known as idiopathic inflammatory myopathy). Endocrine and metabolic disorders such as thyroid disease, Gaucher’s disease, Wilson disease, and hemochromatosis can also cause arthritis. Arthritis may also be associated with tumors that grow from cartilage cells, blood vessels, synovial tissue, and nerve tissue. Blood abnormalities may give rise to hemorrhages into joints (a side effect of sickle cell disease and hemophilia), causing joint conditions that can be disabling and very painful and that may require surgery. Traumatic and mechanical derangements—sports and occupational injuries, leg-length disparity, and obesity—may elicit acute synovial inflammation with subsequent degenerative arthritis.

The inflammatory reactions in response to injury or disease consist of fluid changes—the dilation of blood vessels accompanied by an increase in the permeability of the blood vessel walls and consequent outflow of fluids and proteins. Injurious substances are immobilized with immune reactions and removed by the cellular responses of phagocytosis and digestion of foreign materials, resulting in the proliferation of fibrous cells to wall off the injurious substances and, in turn, leading to scar formation and deformities. The chemical reactions to injury commence with a degradation of phospholipids when enzymes are released by injured tissue. Phospholipids—fatty material that is normally present—break down into arachidonic acid, which is further broken down by other enzymes, lipoxygenase and cycloxygenase, resulting in prostaglandins and eicosanoid acids. Most anti-inflammatory medications attempt to interfere with the enzymatic degradation process of phospholipids and could be damaging to the liver and kidneys and to the body’s blood-clotting ability.

A physician bases the diagnosis of arthritic disease on the patient’s medical history and a physical examination. Specific procedures such as joint aspiration, laboratory studies, and X-ray or magnetic resonance imaging (MRI) may help to establish the diagnosis and the treatment. The history will elicit the onset of pain and its relation to time of day and difficulties performing the activities of daily living. A functional classification has evolved that is similar to the cardiac functional classification: Class 1 patients perform all usual activities without a handicap; class 2 patients perform normal activities adequately with occasional symptoms and signs in one or more joints but still do not need to limit their activities; class 3 patients find that they must limit some activities and may require assistive devices; and class 4 patients are unable to perform activities, are largely or wholly incapacitated, and are bedridden or confined to a wheelchair, requiring assistance in self-care.

A person’s medical history or surgical conditions and the medications that he or she is taking can influence the physician’s diagnosis and prescription for treatment. Patients may present a picture of the body to the physician showing the joints involved in their symmetry (whether distal or proximal, and whether weight-bearing or posttraumatic in distribution). Physicians may ask (verbally or by questionnaire) for a history of other system complaints, which can then be checked more thoroughly. During a physical examination, the physician will check the joints, skin, eyes, abdomen, heart, and urinary tract. The neuromuscular evaluation may reveal localized tenderness of the joints or muscles, swelling, wasting, weakness, and abnormal motions. Joints may have weakened ligamentous, muscular, and tendinous supports that could give rise to instability or grinding of joints, with subsequent roughening of cartilage surfaces.

Joint pathology is generally associated with some limitation in the range of motion. Sensation testing, muscle strength, and reflex changes may also indicate nerve tissue damage. Nerves occasionally pass close to joints and may be pinched when the joint swelling encroaches upon the passage opening. This condition may result in carpal tunnel syndrome, in which the median nerve at the wrist becomes pinched, causing pain, numbness, and weakness in the hand. Pinched nerves may also be associated with tarsal tunnel syndrome, in which the nerve at the inner side of the ankle joint may be compressed and cause similar complaints in the feet. Other nerves may be constricted in exiting from the spine and when passing through muscles in spasm.

Arthritis of the spine can lead to a progressive loss in motion. The amount lost can be measured by comparing the normal motion with the restricted motion of the patient. The neck may be limited in all directions, rotation of the head to the sides can restrict driving ability, and the head may gradually tilt forward. The lower back may also exhibit restriction in all directions; for example, it may be limited in forward bending because of spasms in the muscles in the back. Tilting backward of the trunk may be limited and painful when the vertebral body overgrowth of degenerative arthritis restricts the space for the spinal cord. The nerves pinched in their passage from the vertebrae may thus cause radiculitis, irritation of the nerves as they exit from the spine that leads to pain and muscle involvement. Circumferential measurements of the involved joints and the structures above and below can confirm swelling, atrophy from disuse or inaction, or atrophy from a damaged nerve supply. When measurements are repeated, they can indicate improvement or deterioration. One type of arthritis that most often affects the spine, ankylosing spondylitis, occurs predominantly in males in their late teenage and early adult years.

Testing of blood for cells, chemicals, or enzymes is helpful. One test—the erythrocyte sedimentation test (EST)—measures the inflammatory markers in the blood. When the sedimentation rate exceeds the normal range, active inflammation in the body is indicated. Comparisons of results from ESTs performed at different stages can reveal the disease’s rate of progression or improvement. Blood tests may also measure uric acid for gout and rheumatoid factor (RF) for rheumatoid arthritis. Blood tests for immune substances and antibodies are also possible. The joint fluid can be aspirated and analyzed, particularly for appearance, density, number of blood cells, and levels of sugar. Cloudy fluid, the tendency to form clots, a high cell count, and lower-than-normal levels of sugar in the joint fluid (compared to the overall blood sugar level) indicate abnormalities. With inflammatory arthritides, the X-rays will show the results of synovial fluid and cellular overabundance. Clumps of pannus break off and may destroy the cartilage and bone. Bones about these joints, because of increased vascularity and blood flow, have less minerals and will appear less dense, a condition known as osteoporosis.

Deformities in inflammatory arthritis may be the result of unequal muscle pulls or the destruction or scarring of tissues; such deformities can occasionally be prevented by the use of resting splints, which is most important for the hands.

Degenerative and posttraumatic arthritis show joint narrowing, thinning of the cartilage layer, hardening of the underlying bone (called eburnation), and marginal overgrowth of the underlying bone (called osteophytes), resulting in osteoarthritis. Osteophytes, or marginal lipping in the back, may enhance symptoms of lower back pain. The cushions between the vertebrae, called discs, are more than 80 percent water, a figure which diminishes with aging, bringing the joints in the back (the facets) closer together and compressing the facet joints between the vertebrae. Irritation and arthritis of these joints are the result. Other organ structures may be involved as well.

Treatment and Therapy

Treatment of arthritis depends on the type and the severity of the arthritis and may vary from home treatment to outpatient treatment to hospitalization for surgical and/or rehabilitative care. Education regarding the patient's condition, prognosis, treatment goals, and methods of treatment is necessary. Patients must be made aware of warning signs of progression, drug effects, and local and systemic side effects of drug therapy. Surgical treatment such as joint replacement, may be considered for the treatment of severe joint damage or if symptoms are unsatisfactorily controlled with medical management. Postoperative restrictions in the range of motion must be given prior to surgery; in hip replacement, for example, hip bending should not exceed ninety degrees. The rotation and overlapping of legs must be limited initially after surgery.

Some physicians provide a questionnaire that outlines the activities of daily living and recommends how a patient should perform such activities and how much time should be spent at rest. The goals generally are to maintain function, to alleviate pain, to limit the progression of deformities, to prevent complications, and to treat associated and secondary disease states. In patients with degenerative arthritis—most often the elderly, who are at risk for other organ failures—arthritides associated with systemic diseases and other organ involvements may require care.

Medication is used for symptom control. Nonsteroidal anti-inflammatory drugs (NSAIDs), such as aspirin and ibuprofen, are often used to ease pain and reduce swelling. Short-term use of oral corticosteroids may also be prescribed to reduce joint tenderness and pain. Topical capsaicin cream also reduces discomfort. Disease-modifying antirheumatic drug (DMARDs), such as abatacept and tocilizumab, are recommended as the first-line therapy for rheumatoid arthritis. Cyclooxygenase 2 (COX-2) inhibitors may also be used in the medical management of osteoarthritis.

Other therapies can include assistive devices, counseling patients and their families regarding home management, heat therapy, range-of-motion and strengthening exercises, and biofeedback. The aim is to reduce the need for and frequency of medical care, through a balance between rest and activity and between effective drug dose and physical modalities. To protect joints and allow function, various braces and assistive devices may be needed. Posture training may alleviate postural muscle fatigue. In acute stages of inflammation, the treatment choices are rest, ice, compression, and proper positioning and medicinals for pain and inflammation.

Physicians may offer physical therapy, occupational therapy, assistive devices for self-care, ambulation, or home and automobile modifications. Assistive devices may include reachers, an elongated shoehorn handle, thickened handles for utensils, walkers, canes, crutches, and wheelchairs. Homes may require ramps for easier access, widened doors to allow wheelchair passage, grab bars in bathtubs, or raised toilet seats for easier transference from a wheelchair.

Heat therapy may reduce the pain, loosening tightened tissues. Patients frequently will be stiffer after protracted rest periods (for example, on waking) and feel better after some activity and exercise. Heated pools offer an excellent heating and exercise modality. The type of heat modality used will depend upon the depth of heating desired. Hot packs and infrared lamps will heat predominantly the skin surface areas and some underlying muscles. Diathermy units heat the muscular layers, and ultrasound treatments heat the deepest bony layers. Ultrasound (but not diathermy) can even be used in patients who have metallic implants such as joint replacements.

Perspective and Prospects

Historically, arthritis was treated with warm baths or sands. Some experimental treatments presently being tried include transcutaneous electrical nerve stimulation (TENS) to bring about reductions in intra-articular pressures and in the fluid and cellular content in joints. Exercises continue to maintain and improve strength, dexterity, the range of motion, and endurance. Good health habits—including adequate rest, good nutrition, nutritional supplements, and weight management—can be beneficial.


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