Arthritis is a disorder of joints causing inflammation, redness, pain and stiffness of joints. There are different types of arthritis such as inflammatory, non-inflammatory, infectious and chronic arthritis. Aging, heredity, previous joint injury, infection and repetitive use of joints are the possible causes of arthritis. If this disease becomes chronic and severe, it can cause friction between the bones and restriction in joint mobility. Hence, accurate diagnosis of arthritis is essential to decide appropriate treatment plan.
Generally, diagnosis of rheumatoid diseases may be difficult because its signs and symptoms resemble other diseases. The diagnosis is made on the basis of medical history and physical examination of the patient as well as some laboratory investigations and imaging tests. Medical history and laboratory tests play a significant role in diagnosis of arthritis and its types.
Medical history covers the information about type of arthritis, severity of symptoms, frequency and location of pain. During physical examination of the patient, the joints are examined for warmth, redness, ease of movement, tenderness and deformity. As some types of arthritis can affect other organs, complete physical examination including lungs, heart, abdomen, eyes, throat and nervous system may be essential.
Some laboratory investigations are suggested to confirm the diagnosis of arthritis. These tests are performed on various samples such as urine, blood and synovial fluid. Some commonly prescribed blood tests are antinuclear antibody, arthrocentesis, complement, complete blood count, determination of serum creatinine, erythrocyte sedimentation rate, hematocrit and rheumatoid factor.
Antinuclear antibody (ANA) test give positive results in people with connective tissue diseases or other autoimmune diseases. This test is positive in about 40-70% of people with Sjogren’s syndrome, about 95% of patients having systemic lupus erythematosus, 30-50% of rheumatoid arthritis patients and approximately 60-80% of patients having scleroderma.
Complete blood count (CBC) is helpful to determine the number of red blood cells, white blood cells and platelets present in the blood sample. Some rheumatic conditions or can cause low red blood count (anemia), low white blood count (leukopenia) or low platelet count (thrombocytopenia).
Determination of rheumatoid arthritis is a significant test in the diagnosis of rheumatoid arthritis. It is most commonly positive in patients with rheumatoid arthritis. Besides this, erythrocyte sedimentation rate (ESR) is useful to detect an inflammation in the body. Elevated levels of ESR indicate presence of inflammation. Raised levels of ESR are found in some forms of arthritis such as ankylosing spondylitis and rheumatoid arthritis. In addition to that, determination of serum uric acid is an important test to diagnose gout.
In addition to these blood tests, urine analysis is performed to detect presence of white blood cells, red blood cells, protein and casts. These abnormalities represent kidney disease which may be found in many rheumatoid diseases such as vasculitis or lupus. Besides this, analysis of synovial fluid is one of the significant laboratory investigations for diagnosis of arthritis. Presence of uric acid crystals in the synovial fluid indicates presence of gout. In patients with septic arthritis, the synovial fluid may contain bacteria or viruses.
The imaging tests like x-ray, MRI and CT scan are also important for the diagnosis of arthritis as they provide the images of joints and bones. Arthroscopy is helpful to determine the joint damage.
