Rheumatoid arthritis (RA) is a chronic, systemic autoimmune disorder that causes the immune system to attack the joints, where it causes inflammation (arthritis) and destruction. It can also damage some organs, such as the lungs and skin. It can be a disabling and painful condition, which can lead to substantial loss of functioning and mobility. It is diagnosed with blood tests (especially a test called rheumatoid factor) and X-rays. Diagnosis and long-term management are typically performed by a rheumatologist, an expert in the diseases of joints and connective tissues.
Various treatments are available. Non-pharmacological treatment includes physical therapy and occupational therapy. Analgesia (painkillers) and anti-inflammatory drugs, as well as steroids, are used to suppress the symptoms, while disease-modifying antirheumatic drugs (DMARDs) are often required to reverse the disease process and prevent long-term damage. In recent times, the newer group of biologics has increased treatment options.
The name is based on the term "rheumatic fever", an illness which includes joint pain and is derived from the Greek word rheumatos ("flowing"). The suffix -oid ("resembling") gives the translation as joint inflammation that resembles rheumatic fever. The first recognized description of rheumatoid arthritis was made in 1800 by Dr Augustin Jacob Landré-Beauvais (1772-1840) of Paris.
Inflammation in the joints manifests itself as a soft, "doughy" swelling, causing pain and tenderness to palpation and movement, a sensation of localized warmth, and restricted movement. Increased stiffness upon waking is often a prominent feature and may last for more than an hour. These signs help distinguish rheumatoid from non-inflammatory diseases of the joints such as osteoarthritis (sometimes referred to as the "wear-and-tear" of the joints). In RA, the joints are usually affected in a fairly symmetrical fashion although the initial presentation may be asymmetrical.
As the pathology progresses the inflammatory activity leads to erosion and destruction of the joint surface, which impairs their range of movement and leads to deformity. The fingers are typically deviated towards the little finger (ulnar deviation) and can assume unnatural shapes. Common deformities in rheumatoid arthritis are the Boutonniere deformity (Hyperflexion at the proximal interphalangeal joint with hyperextension at the distal interphalangeal joint), swan neck deformity (Hyperextension at the proximal interphalangeal joint, hyperflexion at the distal interphalangeal joint). The thumb may develop a "Z-thumb" deformity with fixed flexion and subluxation at the metacarpophalangeal joint, and hyperextension at the IP joint.
Several forms of vasculitis are also cutaneous manifestations associated with rheumatoid arthritis. A benign form occurs as microinfarcts around the nailfolds. More severe forms include livedo reticularis, which is a network (reticulum) of erythematous to purplish discoloration of the skin due to the presence of an obliterative cutaneous capillaropathy.
Other, rather rare, skin associated symtoms include:
X-rays of the hands and feet are generally performed in people with a polyarthritis. In rheumatoid arthritis, these may not show any changes in the early stages of the disease, but in more advanced cases demonstrates erosions and bone resorption. X-rays of other joints may be taken if symptoms of pain or swelling occur in those joints.
Because of this low specificity, a new serological test has been developed, which tests for the presence of so called anti-citrullinated protein antibodies (ACPAs). Like RF, this test is positive in only a proportion (67%) of all RA cases, but is rarely positive if RA is not present, giving it a specificity of around 95%. In addition, ACPAs can sometimes be detected in early stages of the disease, even before onset of clinical disease. Currently, the most common test for ACPAs is the anti-CCP (cyclic citrullinated peptide) test.
Also, several other blood tests are usually done to allow for other causes of arthritis, such as lupus erythematosus. The erythrocyte sedimentation rate (ESR), C-reactive protein, full blood count, renal function, liver enzymes and other immunological tests (e.g. antinuclear antibody/ANA) are all performed at this stage. Elevated ferritin levels can reveal hemochromatosis, a mimic RA, or be a sign of Still's disease a seronegative, usually juvenile, variant of rheumatoid.
At least four criteria have to be met for classification as RA. These criteria are not intended for the diagnosis for routine clinical care; they were primarily intended to categorize research. For example: one of the criteria is the presence of bone erosion on X-Ray. Prevention of bone erosion is one of the main aims of treatment because it is generally irreversible. To wait until all of the ACR criteria for rheumatoid arthritis are met may sometimes result in a worse outcome. Most sufferers and rheumatologists would agree that it would be better to treat the condition as early as possible and prevent bone erosion from occurring, even if this means treating people who don't fulfill the ACR criteria. The ACR criteria are, however, very useful for categorising established rheumatoid arthritis, for example for epidemiological purposes.
Rarer causes that usually behave differently but may cause joint pains:
Rheumatoid arthritis is an autoimmune disease, the cause for which is still unknown. It is a systemic (whole body) disorder principally affecting synovial joints.
Cytokines (chemical mediators) give rise to inflammation of joint synovium. Constitutional symptoms such as fever, malaise, loss of appetite and weight loss are also due to cytokines released in to the blood stream. Blood vessel inflammation (vasculitis) affecting many other organ systems can give rise to systemic complications.
As with most autoimmune disease, it is important to distinguish between the cause(s) that trigger the inflammatory process, and those that permit it to persist and progress.
It has long been suspected that certain infections could be triggers for this disease. The "mistaken identity" theory suggests that an infection triggers an immune response, leaving behind antibodies that should be specific to that organism. The antibodies are not sufficiently specific, though, and set off an immune attack against part of the host. Because the normal host molecule "looks like" a molecule on the offending organism that triggered the initial immune reaction - this phenomenon is called molecular mimicry. Some infectious organisms suspected of triggering rheumatoid arthritis include Mycoplasma, Erysipelothrix, parvovirus B19 and rubella, but these associations have never been supported in epidemiological studies. Nor has convincing evidence been presented for other types of triggers such as food allergies. There is also no clear evidence that physical and emotional effects, stress and improper diet could be a trigger for the disease. The many negative findings suggest that either the trigger varies, or that it might in fact be a chance event, as suggested by Edwards et al .
Epidemiological studies have confirmed a potential association between RA and two herpesvirus infections: Epstein-Barr virus (EBV) and Human Herpes Virus 6 (HHV-6). Individuals with RA are more likely to exhibit an abnormal immune response to the Epstein-Barr virus. The allele HLA-DRB1*0404 is associated with low frequencies of T cells specific for the EBV glycoprotein 110 and predisposes one to develop RA.
The factors that allow the inflammation, once initiated, to become permanent and chronic, are much more clearly understood. The genetic association with HLA-DR4 is believed to play a major role in this, as well as the newly discovered associations with the gene PTPN22 and with two additional genes , all involved in regulating immune responses. It has also become clear from recent studies that these genetic factors may interact with the most clearly defined environmental risk factor for rheumatoid arthritis, namely cigarette smoking Other environmental factors also appear to modulate the risk of acquiring RA, and hormonal factors in the individual may explain some features of the disease, such as the higher occurrence in women, the not-infrequent onset after child-birth, and the (slight) modulation of disease risk by hormonal medications.
Autoimmune diseases require that the affected individual have a defect in the ability to distinguish foreign molecules from the body's own. There are markers on many cells that confer this self-identifying feature. However, some classes of markers allow for RA to happen. 90% of individuals with RA have the cluster of markers known as the HLA-DR4/DR1 cluster, whereas only 40% of unaffected controls do. Thus, in theory, RA requires susceptibility to the disease through genetic endowment with specific markers and an infectious event that triggers an autoimmune response.
Once triggered, B lymphocytes produce immunoglobins and rheumatoid factors of the IgG and IgM classes that are deposited in the tissue. This subsequently leads to the activation of the serum complement cascade and the recruitment of the phagocytic arm of the immune response, which further exacerbates the inflammation of the synovium, leading to edema, vasodilation and infiltration by activated T-cells (mainly CD4 in nodular aggregates and CD8 in diffuse infiltrates). Early and intermediate molecular mediators of inflammation include tumor necrosis factor alpha (TNF-α), interleukins IL-1, IL-6, IL-8 and IL-15, transforming growth factor beta, fibroblast growth factor and platelet-derived growth factor. Synovial macrophages and dendritic cells further function as antigen presenting cells by expressing MHC class II molecules, leading to an established local immune reaction in the tissue. The disease progresses in concert with formation of granulation tissue at the edges of the synovial lining (pannus) with extensive angiogenesis and production of enzymes that cause tissue damage. Modern pharmacological treatments of RA target these mediators. Once the inflammatory reaction is established, the synovium thickens, the cartilage and the underlying bone begins to disintegrate and evidence of joint destruction accrues.
The goal of treatment is two-fold: alleviating the current symptoms, and preventing the future destruction of the joints with the resulting handicap if the disease is left unchecked. These two goals may not always coincide: while pain relievers may achieve the first goal, they do not have any impact on the long-term consequences. For these reasons, most authorities believe that most RA should be treated by at least one specific anti-rheumatic medication, also named DMARD (see below), to which other medications and non-medical interventions can be added as needed.
Cortisone therapy has offered relief in the past, but its long-term effects have been deemed undesirable.. However, cortisone injections can be valuable adjuncts to a long-term treatment plan, and using low dosages of daily cortisone (e.g., prednisone or prednisolone, 5-7.5 mg daily) can also have an important benefit if added to a proper specific anti-rheumatic treatment.
There is an increasing recognition amongst rheumatologists that permanent damage to the joints occurs at a very early stage in the disease. In the past the strategy used was to start with just an anti-inflammatory drug, and assess progression clinically and using X-rays. If there was evidence that joint damage was starting to occur then a more potent DMARD would be prescribed. Tools such as ultrasound and MRI are more sensitive methods of imaging the joints and have demonstrated that joint damage occurs much earlier and in more sufferers than was previously thought. People with normal X-rays will often have erosions detectable by ultrasound that X ray could not demonstrate.
There may be other reasons why starting DMARDs early is beneficial as well as prevention of structural joint damage. In the early stage of the disease, the joints are increasingly infiltrated by cells of the immune system that signal to one another and are thought to set up self-perpetuating chronic inflammation. Interrupting this process as early as possible with an effective DMARD (such as methotrexate) appears to improve the outcome from the RA for years afterwards. Delaying therapy for as little as a few months after the onset of symptoms can result in worse outcomes in the long term. There is therefore considerable interest in establishing the most effective therapy with early arthritis, when they are most responsive to therapy and have the most to gain.
The most important and most common adverse events relate to liver and bone marrow toxicity (MTX, SSZ, leflunomide, azathioprine, gold compounds, D-penicillamine), renal toxicity (cyclosporine A, parenteral gold salts, D-penicillamine), pneumonitis (MTX), allergic skin reactions (gold compounds, SSZ), autoimmunity (D-penicillamine, SSZ, minocycline) and infections (azathioprine, cyclosporine A). Hydroxychloroquine may cause ocular toxicity, although this is rare, and because hydroxychloroquine does not affect the bone marrow or liver it is often considered to be the DMARD with the least toxicity. Unfortunately hydroxychloroquine is not very potent, and is usually insufficient to control symptoms on its own.
Many rheumatologists consider methotrexate to be the most important and useful DMARD, largely because of lower drop-out rates for reasons of toxicity. Nevertheless, methotrexate is often considered as a very 'toxic' drug. This reputation is not entirely justified, and at times can result in people being denied the most effective treatment for their arthritis. Although methotrexate does have the potential to suppress bone marrow or cause hepatitis, these effects can be monitored using regular blood tests, and the drug withdrawn at an early stage if the tests are abnormal before any serious harm is done (typically the blood tests return to normal after stopping the drug). In clinical trials, where one of a range of different DMARDs were used, people who were prescribed methotrexate stayed on their medication the longest (the others stopped because of either side-effects or failure of the drug to control the arthritis). Methotrexate is often preferred by rheumatologists because if it does not control arthritis on its own then it works well in combination with many other drugs, especially the biological agents. Other DMARDs may not be as effective or as safe in combination with biological agents.
The Prosorba column blood filtering device was approved by the FDA for treatment of RA in 1999 However, the results have been very modest.
Historic treatments for RA have also included: rest, ice , compression and elevation, acupuncture, apple diet, nutmeg, some light exercise every now and then, nettles, bee venom, copper bracelets, rhubarb diet, rest, extractions of teeth, fasting, honey, vitamins, insulin, magnets, and electroconvulsive therapy (ECT).. Most of these have either had no effect at all, or their effects have been modest and transient, while not being generalizable.
Radon therapy, popular in Germany and Eastern Europe, can induce beneficial long-term effects for rheumatoid arthritis.
A survey in the United Kingdom between 1998 and 2002 found arthritis to be reported among the five most common reasons for the medicinal use of cannabis.
Severely affected joints may require joint replacement surgery, such as knee replacement.
Rheumatoid arthritis affects women three times more often than men, and it can first develop at any age. The risk of first developing the disease (the disease incidence) appears to be greatest for women between 40 and 50 years of age, and for men somewhat later. RA is a chronic disease, and although rarely, a spontaneous remission may occur, the natural course is almost invariably one of persistent symptoms, waxing and waning in intensity, and a progressive deterioration of joint structures leading to deformations and disability.
An anomaly has been noticed from investigation of Precolumbian bones. The bones from the Tennessee site show no signs of tuberculosis even though it was prevalent at the time throughout the Americas. Jim Mobley, at Pfizer, has discovered a historical pattern of epidemics of tuberculosis followed by a surge in the number of rheumatoid arthritis cases a few generations later. Mobley attributes the spikes in arthritis to selective pressure caused by tuberculosis. A hypervigilant immune system is protective against tuberculosis at the cost of an increased risk of autoimmune disease.
The art of Peter Paul Rubens may depict the effects of rheumatoid arthritis, for it is presumed that he used his own hands as a model. In his later paintings, his rendered hands show increasing deformity consistent with the symptoms of the disease.
Rheumatoid arthritis appears to have been depicted in 16th century paintings.
The first recognized description of rheumatoid arthritis was in 1800 by the French physician Dr Augustin Jacob Landré-Beauvais (1772-1840) who was based in the famed Salpêtrière Hospital in Paris. The name "rheumatoid arthritis" itself was coined in 1859 by British rheumatologist Dr Alfred Baring Garrod.