While there is no definitive test for rheumatoid arthritis, there are ways that providers can accurately assess for and diagnose this disease. These include physical presentation, imaging, and biomarkers. Providers look for specific symptoms and decide which diagnostic test would be most appropriate.
A client with rheumatoid arthritis will likely present with fatigue, malaise, low-grade fever, weight loss, anemia, or anorexia which are all early symptoms of RA. Stiffness of joints (especially after inactivity such as sleeping), paresthesia (tingling) of the hands and feet, or joint pain with swelling and warmth in the joint are common. Inflammatory arthritis will involve three or more joints (Baker, O'Dell & Romain, 2022). Involvement of the musculoskeletal system other than joints (occurs in approximately 40 percent of patients (Matteson & Davis, 2022).
On physical examination, the patient will have reduced or limited joint mobility. Deformities include the presence of rheumatoid nodules, which are subcutaneous, round, non-tender masses. Skin lesions may also be present and are caused by vasculitis. If the spinal cord is involved, the patient may have a positive Babinski's sign indicating compression of the vertebrae. Periodontal bone loss is also seen with lymphocytic infiltration of the salivary glands, which causes bone resorption (Matteson & Davis, 2022).
The goal of imaging the joints in patients with suspected rheumatoid arthritis is to rule out septic arthritis, identify soft tissue swelling and discover early erosions of the joints. Radiography is inexpensive and provides for serial comparison for disease progression (Tsou, 2022). Percutaneous ultrasonography-guided aspiration may help localize and obtain samples of any fluid that can be found.
Image 1: Bilateral hand x-ray of a patient with Rheumatoid Arthritis.
According to the National Institute of Health, a biological marker (biomarker) is "a characteristic that is objectively measured and evaluated as an indicator of normal biological processes, pathogenic processes, or pharmacologic responses to a therapeutic intervention" (Biomarkers Definitions Working Group, 2001). By using biomarkers to identify the disease and the effectiveness of treatment, providers can identify patients at risk for RA and target those patients who are more likely to assume a more rapidly destructive form of the disease with early and aggressive interventions (Taylor & Deleuran, 2022). The primary biological marker used is the rheumatoid factor (RF). RF autoantibodies are found in approximately 80 percent of patients with RA. Citrullinated peptides (ACPA) have relatively high specificity for RA. If both are present, they are predictive of poor functional outcomes (Taylor & Deleuran, 2022). Other blood tests used to rule out and confirm the diagnosis include erythrocyte sedimentation rate (ESR) and serum C-reactive protein (CRP). Both blood tests are typically elevated in RA (Baker, O'Dell & Romain, 2022).