Rheumatoid arthritis (RA) is a chronic, systemic autoimmune disorder that causes the immune system to attack the joints, causing inflammation (arthritis), and some organs, such as the lungs and skin. It can be a disabling and painful condition, which can lead to substantial loss of functioning mobility due to pain and joint destruction. 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.
Subscribe in a reader 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. Classic DMARDs are methotrexate and sulfasalazine, but also the newer group of biologics which includes highly-effective agents such as infliximab (Remicade), etanercept (Embrel), adalimumab (Humira), abatacept (Orencia) and rituximab (Rituxan/Mabthera).
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.
Signs and symptoms
While rheumatoid arthritis primarily affects joints, problems involving all other organs of the body are known to occur. Extra-articular ("outside the joints") manifestations occur in about 15% of individuals with rheumatoid arthritis. It can be difficult to determine whether disease manifestations are directly caused by the rheumatoid process itself, or from side effects of the medications commonly used to treat it - for example, lung fibrosis from methotrexate, or osteoporosis from corticosteroids.
Joints
The arthritis of rheumatoid arthritis is due to synovitis, which is inflammation of the synovial membrane that covers the joint. Joints become red, swollen, tender and warm, and stiffness prevents their use. By definition, RA affects multiple joints (it is a polyarthritis). Most commonly, small joints of the hands, feet and cervical spine are affected, but larger joints like the shoulder and knee can also be involved, differing per individual. Eventually, synovitis leads to erosion of the joint surface, causing deformity and loss of function.
Inflammation in the joints manifests itself as a soft, "doughy" swelling, causing pain and tenderness to palpation and movement, a sensation of localised 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.
Skin
The rheumatoid nodule is the cutaneous (strictly speaking subcutaneous) feature most characteristic of rheumatoid arthritis. The initial pathologic process in nodule formation is unknown but is thought to be related to small-vessel inflammation. The mature lesion(a part of an organ or tissue which has been damaged) is defined by an area of central necrosis surrounded by palisading macrophages and fibroblasts and a cuff of cellular connective tissue and chronic inflammatory cells. The typical rheumatoid nodule may be a few millimetres to a few centimetres in diameter and is usually found over bony prominences, such as the olecranon, the calcaneal tuberosity, the metacarpophalangeal joints, or other areas that sustain repeated mechanical stress. Nodules are associated with a positive RF titer and severe erosive arthritis. Rarely, they can occur in internal organs.
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. (This rash is also otherwise associated with the antiphospholipid-antibody syndrome, a hypercoagulable state linked to antiphospholipid antibodies and characterized by recurrent vascular thrombosis and second trimester miscarriages.)
Other, rather rare, skin associated symtoms include:
* pyoderma gangrenosum, a necrotizing, ulcerative, noninfectious neutrophilic dermatosis.
* Sweet's syndrome, a neutrophilic dermatosis usually associated with myeloproliferative disorders
* drug reactions
* erythema nodosum
* lobular panniculitis
* atrophy of digital skin
* palmar erythema
* diffuse thinning (rice paper skin), and skin fragility (often worsened by corticosteroid use).
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