Pain in several joints

The cause of polyarticular arthralgias may be arthritis or extra-articular disorders (for example, rheumatic polymyalgia and fibromyalgia).

Arthritis can be inflammatory and non-inflammatory (eg, osteoarthritis). With inflammatory arthritis, only peripheral joints or peripheral joints with axial joints can be involved in the process. Inflammatory arthritis, accompanied by a lesion of not more than 4 joints, is referred to as peripheral oligoarthritis. The involvement of more than 4 joints in the process is called peripheral polyarthritis. Each of them has its own distinctive characteristics.

Often arthritis is transient and resolved by itself or their manifestations may not meet the criteria of any particular pathology; in such cases, treatment can be initiated on the basis of a preliminary diagnosis. For all atypical and unclear

[1], [2], [3], [4], [5]

The most common causes of polyarthritis

Peripheral polyarthritis

• Rheumatoid arthritis
• Systemic lupus erythematosus
• Viral arthritis
• Serum sickness
• Psoriatic arthritis

Peripheral oligoarthritis

• Behcet's disease
• Enteropathic arthritis
• Infective endocarditis
• Gout (or pseudogout)
• Psoriatic arthritis
• Reactive arthritis
• Rheumatic fever
• Arthritis in Lyme disease

Peripheral arthritis with affection of axial joints

• Ankylosing spondylitis
• Enteropathic arthritis
• Psoriatic arthritis
• Reactive arthritis

Diagnosis of pain in several joints

Clinical data, in particular the history of the disease, are the most important for diagnosis.

Anamnesis. The localization of pain allows us to establish the appearance of the affected anatomical structure (joint, bone, tendon, articular bag, muscles, other soft tissue structures, nerves). The inflammatory nature of arthritis may be indicated by the presence of morning stiffness, nontraumatic joint edema, an increase in body temperature, and a decrease in body weight. Diffuse, indeterminate or unstable pain can be associated with fibromyalgia or functional disorders.

Back pain along with the development of arthritis suggests the presence of spondyloarthropathy, for example ankylosing spondylitis. Arthritis, combined with urethritis and disorders of the gastrointestinal tract, most often are reactive. In particular, diarrhea and abdominal pain are characteristic of arthritis associated with inflammatory bowel diseases.

Physical examination. An increase in body temperature, weakness, skin rashes can occur with systemic rheumatic and non-rheumatic diseases. Examination of the musculoskeletal system allows you to determine whether the disorder has an intraarticular character, and if so, whether it is accompanied by inflammation. The prolonged existence of arthritis can lead to a limitation of the amount of passive movements in the joint.

Assessment of the presence of periarticular changes can also be useful in the differential diagnosis of certain diseases. For example, concomitant tendonitis is characteristic of gonococcal arthritis, RA and other systemic diseases; tenderness of bones - for sickle-cell anemia and hypertrophic pulmonary osteoarthropathy, tofusi - for gout, rheumatic nodules - for RA.

Also useful for differential diagnosis of arthritis is a brush examination. Deformations like "swan neck" or "buttonhole" are typical for long-flowing RA. The defeat of the distal interphalangeal joints with erosion of the nails and the asymmetric nature of the lesion is evidence in favor of psoriatic arthritis. Asymmetric lesions of the joints of the fingers can also occur with reactive arthritis; asymmetric lesion of distal interphalangeal joints and the presence of tofusov - with gout. Skin thickening and flexural contractures indicate the presence of systemic sclerosis. The phenomenon of Reynaud can occur with progressive systemic sclerosis, SLE or mixed connective tissue diseases. The clavate thickening of the fingertips and the soreness of the distal sections of the radial and ulnar bones, caused by periostitis, are noted in hypertrophic pulmonary osteoarthropathy. Painfulness with a slight degree of objective changes is characteristic of SLE, but in rare cases can occur with dermatomyositis. At the same time, with these diseases, it is possible to develop a synovitis that resembles that of RA. Erythema, accompanied by peeling of the skin of the extensor surface of the joints, especially the knee, may indicate dermatomyositis.

Examination. If clinical specific diagnostics are not possible, the inflammatory nature of arthritis can be confirmed by evaluating the ESR and the concentration of the C-reactive protein. An increase in the values of these indicators indicates inflammation, but it is very non-specific, especially in adults. In addition, in the presence of an unclear diagnosis, it is possible to conduct other studies.

Differential diagnosis of rheumatoid arthritis and osteoarthritis of the joints of the hand

Criteria	Rheumatoid arthritis	Osteoarthritis
The nature of the edema	Synovial, capsular, soft tissue; dense at palpation - only in the late stages	Bone density with the presence of irregular growths; in rare cases, the formation of soft cysts
Weakness	Always	There is no or slight degree of severity, transient
Defeat of distal interphalangeal joints	Uncharacteristically, except for the thumb	Characteristically
Affection of proximal interphalangeal joints	Characteristically	Often
Lesion of carpometacarpal joints	Characteristically	Uncharacteristically
Wrangling of the wrist joints	Usually or often	Rarely, excluding the carpometacarpal joint of the thumb

[6], [7], [8], [9]