Clinical measures in rheumatoid arthritis and ankylosing spondylitis.

Except for morning stiffness, the clinical symptoms and the history of patients with rheumatoid arthritis (RA) and ankylosing spondylitis (AS) usually differ: the location in RA is mostly the hands and feet, and in AS rather the back. Patients with RA tend to be older (>50 years) and female, while in AS there are somewhat more often male and younger (<30 years) at onset of inflammatory back pain, the leading clinical symptom. The clinical examination of patients in the early phase of the disease is usually easier in RA, although arthralgia and arthritis may be difficult to differentiate. Joint counts are useful in states of high disease activity with polyarticular flares and more established disease. In comparison, in AS, young patients with back pain frequently show normal physical examens, a reduction of lateral spinal flexion and chest expansion are often the earliest signs which are also sensitive to change on therapy with biologics. The cervical spine may be affected in RA and AS - more frequently in advanced disease stages but rather early cases have been reported.