Inflammatory versus noninflammatory symptoms
Specific joint symptoms are associated with inflammatory or noninflammatory aetiologies; however, there is much crossover. Both inflammatory and noninflammatory musculoskeletal conditions feature pain, stiffness and restricted range of joint movement, but the nature of the symptoms varies.
Synovitis (inflammation of the synovial membrane) is a hallmark of inflammatory arthritis, whereas other causes of arthritis may be associated with little or no synovitis. Synovitis presents with boggy swelling, warmth, erythema, effusion, pain and stiffness.
In an inflammatory process, such as synovitis, joint stiffness is more pronounced after inactivity. Prolonged morning stiffness that lasts longer than 1 hour is a hallmark. Pain and stiffness can markedly improve or be relieved by activity and nonsteroidal anti-inflammatory drugs (NSAIDs). Associated symptoms of fatigue, weight loss, fever and night sweats suggest systemic inflammation.
In a predominantly noninflammatory process (eg osteoarthritis), joint pain tends to be exacerbated by activity and relieved by rest. Stiffness in the morning or after prolonged rest is usually short-lived.
Diffuse, nonspecific symptoms such as arthralgias, joint tenderness, myalgias and fatigue, in the absence of other clinical signs of inflammatory arthritis, may be associated with central sensitisation syndromes, such as fibromyalgia. Detailed advice on diagnosis and management can be found in the topic on Fibromyalgia.
Other conditions that may be associated with these diffuse, nonspecific symptoms include:
- osteoarthritis
- hypothyroidism
- osteomalacia
- multiple myeloma.
Noninflammatory musculoskeletal symptoms may infrequently be associated with serious conditions, such as malignancy or sepsis.
Any of the above conditions may coexist, particularly fibromyalgia coexisting with rheumatoid arthritis (in 18 to 24%), axial spondyloarthritis (in 14 to 16%) and psoriatic arthritis (in 18%)Zhao, 2019. Osteoarthritis can occur secondary to any inflammatory arthritis. Diagnosis is often difficult in these people.