Polyarticular Arthritis

Background

• Arthritis is one of the most common causes of disability in the United States and may affect a single joint (monoarticular) or many joints (polyarticular).
• Polyarticular involvement does not rule out septic arthritis, a medical emergency.
• Polyarticular arthritis may be caused by a variety of disorders and nearly 50% of patients may not have a definitive diagnosis.
• Common causes include systemic autoimmune diseases such as rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE); vasculitides such as polymyalgia rheumatica (PMR) and polyarteritis nodosa; and viral infections such as parvovirus B19, disseminated gonococcal infection, Sjogren syndrome, relapsing polychondritis, juvenile idiopathic arthritis (JIA), acute rheumatic fever, drug-induced lupus, and sarcoidosis.
• Less commonly, spondyloarthropathies and crystal arthropathies may present with polyarticular arthritis.
• Arthritis may be generally classified as inflammatory or noninflammatory based on general appearance, history of pain and stiffness, synovial fluid analysis, and blood tests.
• Common inflammatory causes of polyarticular arthritis include RA, SLE, JIA, PMR, and sarcoidosis while noninflammatory causes include osteoarthritis and trauma.

Evaluation

• A critical part of any evaluation is to determine if the patient has septic arthritis, which is a medical emergency.
• History of joint involvement including the number of joints affected and the pattern and type of joints involved, the onset, duration, and chronicity of pain and stiffness, and syndromic features may help narrow the differential.
• Arthrocentesis may be helpful and should be performed for all patients with suspected infectious arthritis. Synovial fluid may be assessed for appearance, white blood cell count and differential, polarizing light microscopy, Gram stain, and culture.
• Tissue or synovial biopsy may be helpful for establishing some causes of polyarticular arthritis.
• Imaging may have a limited role in establishing most causes of arthritis.

Management

• Because septic arthritis may be rapidly destructive, patients with a suspected infection should receive empiric antibiotics.
• Pain management and supportive care including ice, immobilization, and/or elevation is often warranted in patients with arthritis.
• Definitive treatment is dependent on the underlying cause. Patients with septic arthritis should receive parenteral antibiotics, drainage as necessary, and pain control.