An extract on #ig_hungary
Renal amyloidosis can occur as a consequence of untreated chronic inflammation. Treatment with penicillamine and gold salts are recognized causes of membranous nephropathy.
The eye can be directly affected in the form of episcleritis or scleritis, which when severe can very rarely progress to perforating scleromalacia. Rather more common is the indirect effect of keratoconjunctivitis sicca, which is a dryness of eyes and mouth caused by lymphocyte infiltration of lacrimal and salivary glands. When severe, dryness of the cornea can lead to keratitis and loss of vision. Preventive treatment of severe dryness with measures such as nasolacrimal duct blockage is important.
Liver problems in people with rheumatoid arthritis may be due to the underlying disease process or as a result of the medications used to treat the disease. A coexisting autoimmune liver disease, such as primary biliary cirrhosis or autoimmune hepatitis may also cause problems.
Peripheral neuropathy and mononeuritis multiplex may occur. The most common problem is carpal tunnel syndrome caused by 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. Clumsiness is initially experienced, but without due care, this can progress to quadriplegia.
Constitutional symptoms including fatigue, low grade fever, malaise, morning stiffness, loss of appetite and loss of weight are common systemic manifestations seen in people with active RA.
Local osteoporosis occurs in RA around inflamed joints. It is postulated to be partially caused by inflammatory cytokines. More general osteoporosis is probably contributed to by immobility, systemic cytokine effects, local cytokine release in bone marrow and corticosteroid therapy.
The incidence of lymphoma is increased, although it is uncommon and associated with the chronic inflammation, not the treatment of RA.
When RA is clinically suspected, a physician may test for rheumatoid factor (RF) and anti-citrullinated protein antibodies (ACPAs measured as anti-CCP antibodies). It is positive in 75-85%, but a negative RF or CCP antibody does not rule out RA, rather, the arthritis is called seronegative, which is in about 15-25% of people with RA. During the first year of illness, rheumatoid factor is more likely to be negative with some individuals becoming seropositive over time. RF is a non-specific antibody and seen in about 10% of healthy people, in many other chronic infections like hepatitis C, and chronic autoimmune diseases such as Sjgren's syndrome and systemic lupus erythematosus. Therefore, the test is not specific for RA.
Hence, new serological tests check for anti-citrullinated protein antibodies ACPAs . These tests are again positive in 61-75% of all RA cases, but with a specificity of around 95%. As with RF, ACPAs are many times present before symptoms have started.
The by far most common clinical test for ACPAs is the anti-cyclic citrullinated peptide (anti CCP) ELISA. In 2008 a serological point-of-care test for the early detection of RA combined the detection of RF and anti-MCV with a sensitivity of 72% and specificity of 99.7%.
Other blood tests are usually done to differentiate from other causes of arthritis, like the erythrocyte sedimentation rate (ESR), C-reactive protein, full blood count, kidney 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 of RA, or be a sign of Still's disease, a seronegative, usually juvenile, variant of rheumatoid arthritis.