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Articular (joints)
Rheumatoid arthritis and osteoarthritis
Rheumatoid arthritis is a chronic, inflammatory, multisystem, autoimmune disorder. It is commonly polyarticular, i.e. it affects many joints. The symptoms that distinguish rheumatoid arthritis from other forms of arthritis are inflammation and soft-tissue swelling of many joints at the same time (polyarthritis). The joints are usually affected initially asymmetrically and then in a symmetrical fashion as the disease progresses. The pain generally improves with use of the affected joints, and there is usually stiffness of all joints in the morning that lasts over 1 hour. Thus, the pain of rheumatoid arthritis is usually worse in the morning compared to the classic pain of osteoarthritis where the pain worsens over the day as the joints are used.
Extra-articular manifestations also distinguish this disease from osteoarthritis (hence it is a multisystemic disease). For example, most patients also suffer with anemia, either as a consequence of the disease itself (anaemia of chronic disease) or as a consequence of gastrointestinal bleeding as a side effect of drugs used in treatment, especially NSAIDs (non-steroidal anti-inflammatory drugs) used for analgesia. Hepatosplenomegaly may occur with concurrent leukopaenia (Felty's syndrome), and lymphocytic infiltration may affect the salivary and lacrimal glands (Sjo"gren's syndrome). Pericarditis, pleurisy, alveolitis, scleritis and subcutaneous nodules are other features.
Deformities
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. Classical 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.
Cutaneous manifestations
1. The cutaneous (strictly speaking subcutaneous) feature most characteristic of rheumatoid arthritis is the rheumatoid nodule. The initial pathologic process in nodule formation is unknown but is thought to be related to small-vessel inflammation. The mature lesion 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 calcaneum at the Achilles tendon insertion, the metacarpophalangeal joints, or other areas that sustain repeated mechanical stress. Nodules are associated with a positive RF titer and severe erosive arthritis. They can rarely occur throughout the body in internal organs.
2. Rheumatoid arthritis is associated with a variety of forms of vasculitis. 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.
Rheumatoid arthritis is rarely associated with pyoderma gangrenosum, a necrotizing, ulcerative, noninfectious neutrophilic dermatosis. Sweet's syndrome, a neutrophilic dermatosis usually associated with myeloproliferative disorders, viral infections, and drug reactions, also occurs in rheumatoid arthritis. Other complications include erythema nodosum, lobular panniculitis, atrophy of digital skin, palmar erythema, diffuse thinning (rice paper skin), and skin fragility.
Extra-articular (elsewhere)
Pulmonary
The lungs may become involved as a part of the primary disease process or as a consequence of therapy. Fibrosis may occur spontaneously or as a consequence of therapy (for example methotrexate). Caplan's nodules are found as are pulmonary effusions.
Renal
Amyloidosis can occur.
Cardiovascular
Pericarditis, endocarditis, left ventricular failure, valvulitis and fibrosis.
Ocular
Keratoconjunctivitis sicca (dry eyes), episcleritis and scleromalacia.
Neurological
Peripheral neuropathy and mononeuritis multiplex may occur. Much the commonest probem is carpal tunnel syndrome due to compression of the median nerve by swelling around the wrist. Atlanto-axial subluxation can occur, owing to erosion of the odontoid process and or/transverse ligaments in the cervical spine's connection to the skull. Such an erosion (>3mm) can give rise to vertebrae slipping over one another and compressing the spinal cord. At first the patient experiences clumsiness but without due care this can progress to quadriplegia.
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Important notice:
The content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other
qualified health provider with any questions you may have regarding a medical condition.
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