What is arthritis?

Pain, one of the cardinal features of arthritis, is the result of the action of numerous inflammatory mediators and inflammatory cell-derived products on local nerves. Although pain is a subjective feeling, it is one of the criteria that are used in clinical practice to assess patients overall functioning, disease activity, and response to therapy. Musculoskeletal disorders affect 20 to 45% of the population.

Pain, soreness, aches, stiffness, swelling, weakness, and fatigue account for more than 95% of all initial muscloskeletal presentations. Chronic disability from muscloskeletal disorders affects 6.1 to 10% of the population.  Arthritis is a general term that describes more than 100 conditions. Specific management of pain in arthritic conditions requires differentiation of the type of arthritis. The primary goals of the patients evaluation are to discern if the complaint is:

• Inflammatory or noninflammatory
• Articular or periarticular in origin
• Acute or chronic
• Mono/oligoarticular or polyarticular

Muscloskeletal conditions are often classified as having inflammatory or noninflammatory symptoms or signs that reflect the nature of the underlying pathologic process.

Arthritis Evalution

While evaluating the patient, the physician should determine whether the complaint originates from articular or periarticular structures. Periarticular structures include tendon, bursa, ligament, muscle, bone, fascia, nerve, or overlying skin. Periarticular joint pain is usually focal and pain is experienced on active motion in a few, specific planes. Pain in arthritic conditions is present on both active and passive motion of the joint in all planes and it is diffuse and produces deep tenderness. On presentation, the clinician should also determine if the arthritis is acute or chronic, based on whether the complaint has been present 6 weeks or less (acute) or longer than 6 weeks (chronic).

The extent of articular involvement is defined as monoarticular (one joint), oligoarticular or pauciarticular (two to four joints), or polyarticular (more than four joints). These approaches can help the physician categorize the complaint as:

• Acute inflammatory mono/oligoarthritis (eg, septic arthritis, gout, pseudogout, viral arthritis, Reiters syndrome, Lyme disease, acute rheumatic fever, hemarthrosis, palindromic rheumatism)
• Chronic inflammatory mono/oligoarthritis (eg, tuberculous arthritis, fungal arthritis, psoriatic arthritis, spondyloarthropathy, pseudogout, sarcoidosis, juvenile chronic arthritis) Acute noninflammatory mono/oligoarthritis (eg, mechanical derangement, trauma)
• Chronic noninflammatory mono/oligoarthritis (eg, osteoathritis, osteonecrosis, neuropathic arthritis, hemarthrosis, pigmented villonodular synovitis, oreign body synovitis)
• Acute inflammatory polyarthritis (eg, viral arthritis, septic arthritis, acute rheumatic fever, Reiters syndrome)
• Chronic inflammatory polyarthritis (eg, rheumatoid arthritis, psoriatic arthritis, enteropathic arthritis, crystal-induced arthritis, juvenile arthritis, Lyme disease, systemic lupus erythematosus (SLE), scleroderma, mixed connective tissue disease, polymyalgia rheumatica, polymyositis)
• Chronic noninflammatory polyarthritis (eg, osteoarthritis, hemochromatosis, etc)