Rheumatoid Arthritis

Introduction

Rheumatoid arthritis (RA) is a persistent, systemic autoimmune disorder that prompts the immune system to launch an assault on the joints, causing inflammation (arthritis) and destruction. It can also harm various organs, including the lungs and skin. RA is a debilitating and painful condition, often resulting in significant loss of mobility and function. Diagnosis typically involves blood tests, especially the rheumatoid factor test, as well as X-rays. Diagnosis and long-term management are usually overseen by a rheumatologist, a specialist in joint and connective tissue diseases.

Various treatment options are available. Non-pharmacological approaches encompass physical therapy and occupational therapy. Pain relievers (analgesics), anti-inflammatory medications, and steroids are used to alleviate symptoms, while disease-modifying antirheumatic drugs (DMARDs) are often required to halt disease progression and prevent long-term damage. In recent years, a new class of medications called biologics has expanded the treatment arsenal.

Signs and Symptoms

While rheumatoid arthritis primarily targets the joints, it can also affect other parts of the body. Extra-articular (outside the joints) manifestations occur in approximately 15% of individuals with rheumatoid arthritis. Distinguishing whether these manifestations result from the rheumatoid process itself or from side effects of medications used for treatment can be challenging. For example, lung fibrosis may develop due to methotrexate, and corticosteroids can lead to osteoporosis.

Joints

Rheumatoid arthritis-related joint inflammation, known as synovitis, causes joints to become red, swollen, tender, and warm, impeding their mobility. RA typically affects multiple joints, with the small joints of the hands, feet, and cervical spine being commonly affected. However, larger joints such as the shoulder and knee can also be involved, varying from person to person. Synovitis eventually leads to joint surface erosion, resulting in deformity and loss of function.

Inflamed joints exhibit soft, doughy swelling, accompanied by pain, tenderness to touch and movement, localized warmth, and restricted mobility. Increased morning stiffness, lasting more than an hour, is a prominent feature. These signs distinguish rheumatoid arthritis from non-inflammatory joint conditions like osteoarthritis. In RA, joint involvement is typically symmetrical, although the initial presentation may be asymmetrical.

As the disease progresses, inflammation causes joint surface erosion, leading to deformities. Common deformities include the Boutonniere deformity (hyperflexion at the proximal interphalangeal joint with hyperextension at the distal interphalangeal joint) and swan neck deformity (hyperextension at the proximal interphalangeal joint, hyperflexion at the distal interphalangeal joint). The thumb may develop a "Z-thumb" deformity, characterized by fixed flexion and subluxation at the metacarpophalangeal joint and hyperextension at the IP joint.

Skin

The most distinctive cutaneous feature of rheumatoid arthritis is the rheumatoid nodule, which forms beneath the skin. The exact cause of nodule formation is unknown but is believed to be related to inflammation of small blood vessels. A mature rheumatoid nodule consists of central necrosis, surrounded by palisading macrophages and fibroblasts, encased in cellular connective tissue and chronic inflammatory cells. These nodules can vary in size from millimeters to centimeters and are often found over bony prominences, such as the olecranon, the calcaneal tuberosity, and the metacarpophalangeal joints, or other areas subject to repeated mechanical stress. Nodules are associated with a positive rheumatoid factor (RF) titer and severe erosive arthritis. In rare cases, they may also occur in internal organs.

Rheumatoid arthritis can also lead to various forms of vasculitis with cutaneous manifestations, including microinfarcts around the nailfolds and more severe forms like livedo reticularis, characterized by erythematous to purplish discoloration of the skin due to an obstructed cutaneous capillaropathy. Other rare skin-related symptoms include pyoderma gangrenosum, Sweet's syndrome, drug reactions, erythema nodosum, lobular panniculitis, atrophy of digital skin, palmar erythema, and skin fragility, which can be exacerbated by corticosteroid use.

Lungs

Lung fibrosis is a recognized response to rheumatoid disease, and it can also be a rare but established consequence of certain therapies, such as methotrexate and leflunomide. Caplan's syndrome refers to the presence of lung nodules in individuals with rheumatoid arthritis who have had additional exposure to coal dust. Pleural effusions are also associated with rheumatoid arthritis.

Kidneys

Chronic inflammation can lead to renal amyloidosis as a consequence of rheumatoid arthritis. Rheumatoid vasculitis, although rare, can cause glomerular kidney disease. Additionally, the use of penicillamine and gold salts for treatment can lead to membranous nephropathy.

Heart and Blood Vessels

Individuals with rheumatoid arthritis have an increased risk of atherosclerosis, myocardial infarction (heart attack), and stroke. Other potential complications include pericarditis, endocarditis, left ventricular failure, valvulitis, and fibrosis.

Other

Dry eyes (keratoconjunctivitis sicca), scleritis, episcleritis, and scleromalacia can affect individuals with rheumatoid arthritis.

Additional manifestations include Felty syndrome, anemia, and thrombocytosis.

Neurological complications may encompass peripheral neuropathy, mononeuritis multiplex, and carpal tunnel syndrome due to median nerve compression around the wrist. Atlanto-axial subluxation, resulting from erosion of the odontoid process and transverse ligaments connecting the cervical spine to the skull, can Next