Polyarthritis

Polyarthritis is an inflammation of four or more joints. It can be the main manifestation of diseases of the joints themselves, primarily RA and psoriatic arthritis, but it also occurs as one of the symptoms of various rheumatic and non-rheumatic diseases. In the first days and weeks of polyarthritis, it is first necessary to exclude diseases that require urgent medical action.

Urgent treatment, often intensive, is required for such systemic rheumatic diseases accompanied by polyarthritis as systemic lupus erythematosus, mixed connective tissue disease, relapsing polychondritis, acute rheumatic fever. In addition to polyarthritis, all these diseases usually have extra-articular manifestations that suggest a diagnosis. However, they are not always obvious and are detected only by targeted search. To diagnose systemic rheumatic diseases, additional examination is usually necessary, the nature and scope of which depend on the preliminary diagnosis.

[ 1 ], [ 2 ], [ 3 ]

What causes polyarthritic?

Systemic lupus erythematosus

It is characterized by:

• unstable, asymmetric, migratory polyarthritis or oligoarthritis of any localization;
• severe pain syndrome with moderate exudative phenomena;
• non-inflammatory nature of changes in cerebrospinal fluid is often noted
• polyarthritis with persistent or frequently recurring damage to the joints of the hands (“rheumatoid-like” arthritis), the peculiarity of which is the predominant damage to the tendon apparatus with the gradual development of finger deformities (Jaccoud syndrome);
• ineffectiveness of NSAIDs and the absence of radiological signs of joint destruction even in the case of long-term polyarthritis.

Mixed connective tissue disease

Polyarthritis with frequent damage to the joints of the hands ("rheumatoid-like" arthritis) is typical, accompanied by diffuse swelling of the hands due to tenosynovitis. Chronic polyarthritis with the development of destructive changes and deformations of the joints characteristic of RA is possible. Almost all patients have a high titer of ANA (speckled glow) in the blood serum, which can be used as a screening test.

Systemic vasculitis

Polyarthritis is possible with all systemic vasculitis, but it most naturally develops with hemorrhagic vasculitis (Schonlein-Henoch disease): it is characterized by an attack-like course, predominant damage to the knee and ankle joints, the presence of skin purpura, which is often palpable (“palpable purpura”).

Relapsing polychondritis

Predominantly migrating, paroxysmal polyarthritis with damage to the knee, ankle joints and small joints of the hands and feet is possible. In some cases, persistent damage to large joints with gradual loss of cartilage develops. Damage to the costosternal joints is known.

Acute rheumatic fever

It is characterized by oligo- and polyarthritis of large and medium joints, symmetrical lesions, significant pain intensity (“immobilizing” pain), the migratory nature of arthritis, and its spontaneous reverse development.

If the above-mentioned emergency situations are absent or excluded, a consistent, systematic examination of the patient is necessary with a careful, targeted study of complaints, anamnesis and results of direct examination. The age of onset of the disease and the patient's gender are of certain importance. For example, it is known that systemic lupus erythematosus and mixed connective tissue diseases develop predominantly in young women, RA in women in general, and Bechterew's disease in young men. In some diseases (Behcet's disease), an ethnic predisposition is noted.

[ 4 ], [ 5 ], [ 6 ], [ 7 ], [ 8 ], [ 9 ]

How to recognize polyarthritis?

The anamnesis is especially important in the diagnosis of a number of acute infections preceding polyarthritis, such as infections that occur with typical exanthemas (rubella, parvovirus infection) or manifested by acute intestinal or urogenital disorders (salmonellosis, dysentery, chlamydia). The epidemiological anamnesis should be taken into account, especially in the case of a recent stay of the patient in regions unfavorable for arthritogenic infections. Sometimes, mainly in the case of spondyloarthritis, the family anamnesis is of diagnostic value. Valuable information can be obtained from the analysis of concomitant diseases and methods of their treatment (allergic reactions to drugs, vaccines and serums). The localization of polyarthritis, the characteristics of pain sensations (night pain indicates significantly pronounced arthritis and/or damage to bone structures), and other possible complaints, such as paresthesia (associated damage to the peripheral nervous system) or muscle weakness (in this case, tests should be performed to objectively assess the strength of individual muscles) should be clarified.

Direct examination of a patient with polyarthritis

The localization of polyarthritis, its combination with damage to other anatomical structures of the musculoskeletal system, as well as with extra-articular changes have a certain diagnostic and differential diagnostic value.

• Polyarthritis with symmetrical (or close to symmetrical) lesions of the wrist and finger joints (metacarpophalangeal and proximal interphalangeal). The most common causes are RA, psoriasis, acute viral infections (parvovirus B19, rubella, hepatitis B), allergic and anaphylactic reactions. It can also occur with SLE, CTD, systemic vasculitis, hyperparathyroidism.
• Polyarthritis with damage to the distal interphalangeal joints of the hands. The most common cause is psoriatic, in some cases - ReA. Similar changes can be noted in multicentric reticulohistiocytosis and erosive osteoarthrosis.
• Polyarthritis with "axial" involvement of finger joints (simultaneous involvement of all three joints of one finger). The most common causes are seronegative spondyloarthritis and sarcoidosis.
• Polyarthritis with damage to the joints of the hands and pronounced diffuse soft edema (tenosynovitis). The most common causes are remitting seronegative symmetrical synovitis, accompanied by soft edema: RA (in elderly patients), rheumatic polymyalgia, polyarthritis palmar aponeurosis syndrome, CTD.
• Polyarthritis with damage to the joints of the axial skeleton (sternoclavicular joints, sternal joints, sternocostal joints, pubic symphysis, sacroiliac joints). The most common causes are seronegative spondyloarthritis, SAPHO syndrome, brucellosis.
• Polyarthritis of large and medium joints, mainly of the lower extremities, combined with enthesitis (especially of the heel areas) and/or tenosynovitis of the finger tendons (dactylitis). The most common causes are seronegative spondyloarthritis; sarcoidosis.
• Polyarthritis in combination with damage to the lumbar spine and/or sacroiliac joints. The most common cause is seronegative spondyloarthritis.

The detection of certain “extra-articular” manifestations during an objective examination of patients is of valuable importance for establishing the nosological affiliation of polyarthritis.

[ 10 ], [ 11 ], [ 12 ], [ 13 ], [ 14 ], [ 15 ], [ 16 ], [ 17 ]

Changes in the skin, mucous membranes, nails and periarticular soft tissues

Psoriasis of the skin and nails. It is necessary to examine "hidden" localizations (scalp, armpits, perineum, gluteal folds, navel). The most typical types of psoriatic nail lesions are multiple point defects (thimble-shaped nails) and subungual hyperkeratosis.

Keratoderma of the soles and palms is characteristic of ReA, SAPHO syndrome (erythematous spots transforming into pustules, and then into cone-shaped horny papules or into thick, crusted plaques).

Morbilliform macular erythematous rash on the chest, abdomen, and proximal extremities in patients with fever and polyarthritis. Typical of Still's syndrome. The rash "blooms" during the peak of fever. The Koebner phenomenon is characteristic: rubbing the skin in a "suspicious" place leads to the formation of a persistent area of redness, erythematous rash on the cheeks and nose ("butterfly") is characteristic of SLE, and is also typical of acute parvovirus infection.

Persistent erythematous macular rash or erythematous papules with scales located over the joints. Characteristic of dermatomyositis (often combined with periorbital edema and erythematous changes of the eyelids), it can also be observed in SLE, CTD. Violet-red raised lesions on the face ("chill lupus"): brownish-bluish nodules, small or larger. Characteristic of sarcoidosis. Sarcoid nodules are characterized by the presence of "specks of dust" on diascopy.

Reticular (dendritic) livedo is a typical manifestation of APS, SLE, and some types of systemic vasculitis (nodular polyarteritis).

Palpable purpura (slightly elevated hemorrhagic rash not associated with thrombocytopenia) is characteristic primarily of hemorrhagic vasculitis, but can also occur in other vasculitides involving small-caliber vessels: cryoglobulinemic vasculitis, Wegener's granulomatosis, Churg-Strauss syndrome, and microscopic polyangiitis.

Point painless skin necrosis in the area of the pulp of the fingers and around the nail bed (digital arteritis) is typical for RA. They can be noted in systemic vasculitis.

Annular erythema is observed in SLE, Lyme disease. In acute rheumatic fever, annular erythema (usually in the form of multiple elements) appears on the skin of the trunk and proximal parts of the extremities, on the face. It can disappear within a few hours, but recur or "persist stably after the other manifestations of the disease have subsided. Annular erythema can be one of the types of skin manifestations in the so-called subacute lupus erythematosus. In Lyme disease, annular erythema (single element) is a stage in the development of a diffuse erythematous spot that appears at the site of a tick bite.

Xanthelasmas, xanthomas over joints and tendons are observed in hypercholesterolemia.

Ulcers and skin necrosis in the shin area are characteristic of RA, Crohn's disease, systemic vasculitis, especially cryoglobulinemic vasculitis.

Painful, recurrent, self-healing ulcers in the area of the external genitalia and scrotum are typical of Behcet's disease.

Diffuse hyperpigmentation of the skin with a bronze tint is a sign of hemichromatosis.

Bluish-violet, slate-gray coloration of the auricles and nasal cartilages is pathognomonic for ochronosis (also characterized by dark coloration of urine, sweat and tears).

Localized thickening of the skin and soft tissues in the area of the proximal interphalangeal joints of the hands. There are two variants:

• "fibrous fingertips" (thickening is noted only over the back of the joint);
• pachydactyly (thickening is noted around the entire perimeter of the joint).

Erythema nodosum is observed in many diseases, but in combination with polyarthritis it is characteristic primarily of sarcoidosis. It is rarely observed in rheumatic diseases.

Gouty subcutaneous tophi, usually located in the area of the elbow joints, on the auricles, on the fingers, are painless. Whitish crumbly contents can be seen through the skin. The most convenient object for confirming the diagnosis of gout (examination of the contents in a polarizing microscope to detect urate crystals).

Rheumatoid nodules are usually located in the elbow joints, on the extensor surface of the forearms, on the fingers. They are painless and are detected in patients with a seropositive variant of RA. They can be located subperiosteally, in which case they are immobile. Externally similar nodules can be found in amyloidosis, gout, hypercholesterolemia, SLE, soft tissue calcification, annular granuloma (a skin disease), and multicentric reticulohistiocytosis.

Recurrent aphthous stomatitis is typical for Behcet's disease. It can be diagnosed in SLE, Crohn's disease.

Painless erosions of the oral mucosa are characteristic of ReA. Focal changes in the oral mucosa are possible with psoriasis.

Circinate (ring-shaped) balanitis (vesicles with subsequent formation of painless erosions) is characteristic of ReA.

Single or multiple painless hemorrhagic macules or papules are characteristic of gonorrhea. A similar rash may also be seen in meningococcal sepsis.

[ 18 ], [ 19 ], [ 20 ]

Eye changes

• Iridocyclitis (anterior uveitis) is characteristic of seronegative spondyloarthritis, juvenile arthritis, and Behcet's disease.
• Dry keratoconjunctivitis is typical for Sjögren's syndrome and disease.
• Acute conjunctivitis is characteristic of ReA.
• Episcleritis and scleritis can be observed in RA and systemic vasculitis.

[ 21 ], [ 22 ], [ 23 ]

Laboratory research

The minimum necessary laboratory tests used for diagnostics and differential diagnostics of inflammatory joint diseases whose main symptom is polyarthritis include a complete blood count, cytological analysis of cerebrospinal fluid, biochemical blood test (concentration of uric acid, cholesterol, creatinine, calcium, phosphorus, iron, transaminase activity, alkaline phosphatase, creatine kinase, etc.), determination of CRP, rheumatoid and ANF in the blood serum. Other tests (microbiological, immunological, cerebrospinal fluid analysis for crystals, etc.) are performed as indicated.