OVERVIEW
Infection associated rheumatism is a group of rheumatic diseases caused directly by infectious factors or indirectly through immune-mediated joint and muscle tissue lesions, including reactive arthritis, rheumatic fever, microvirus B19 infectious rheumatism, hepatitis virus-associated rheumatism and so on, which is a kind of rheumatic disease.
Classification
Rheumatic diseases are divided into more than ten types and more than one hundred diseases, mainly including: diffuse connective tissue diseases, such as rheumatoid arthritis, systemic lupus erythematosus, primary dry syndrome, polymyositis/dermatomyositis, systemic sclerosis, and systemic vasculitis, etc.; spondyloarthropathies, such as ankylosing spondylitis, psoriatic arthritis, inflammatory bowel disease arthritis, and undifferentiated spondyloarthropathies, etc.; degenerative changes, such as osteoarthritis; crystal related arthritis, e.g. gout, pseudogout. Infection-associated rheumatism, e.g. reactive arthritis, rheumatic fever; Tumor-associated rheumatism, which is subdivided into primary, e.g. synovial tumors, synovial sarcomas. Secondary, such as multiple myeloma, metastatic tumors, and so on. There are other categories, such as gyratory rheumatism, osteoporosis, fibromyalgia syndrome, etc.
Etiology
Rheumatic diseases are caused by a variety of reasons such as infectious, immune, metabolic, endocrine, hereditary, degenerative, neoplastic, endemic, and toxic. Infection-associated rheumatic diseases can be directly or indirectly stimulated or initiated by group A group B hemolytic streptococcal infection, multiple infectious factors, antigens or super antigens produced by microorganisms, and other immune responses.
Symptoms
The majority of patients have joint lesions and symptoms, which can be as high as 70% to 80%, and about 50% have only pain, while severe cases have full inflammatory manifestations such as redness, swelling, heat, pain and functional impairment; often multiple joints are involved. The size of the invaded joints varies depending on the type of disease.
Infection-associated rheumatic diseases may invade multiple systems, with overlapping pathology and similar symptoms in many diseases, such as MCTD (Mixed Connective Tissue Disease), which is a typical example of this presentation.
Multiple antibodies and immune complexes (CIC) appear in the serum and may be deposited in tissues (skin, synovial membranes) or organs (kidneys, liver), leading to different manifestations, often with Raynaud’s phenomenon.
Examination
1. Comprehensive examination
(1) Routine examination: blood, urine, stool; blood sedimentation; C-reactive protein (CRP), comprehensive biochemical examination (liver function, renal function, myosin profile, etc.).
(2) Serologic examination
(1) General tests: rheumatoid factor (RF), C3, C4, CH50, CIC, IgG, IgA, IgM, IgE.
(2) Special examination: ① antinuclear antibody spectrum is of great significance in the diagnosis and differential diagnosis of rheumatic diseases. Generally do anti-nuclear antibody (ANA), if the potency>1:40, further check other items; ② other: such as anti-keratin antibody (AKA), anti-histone antibody (Anti-histoneantibody), anti-phospholipid antibody, anti-nuclear peripheral factor (ANCA) and so on.
(3) Joint fluid examination: fresh joint fluid for routine culture, serologic and immunologic examination.
2. Imaging examination
(1) X-ray film: generally used in front and side position, both large and small joints, limbs, shoulder, spine, sacroiliac joints; according to the different diseases and parts of the body, the damaged or hyperplastic lesions of the bones are usually shown clearly, but due to the overlap of the images, it is not easy to see the small lesions in the early stage; synovial membrane, joint capsule, cartilage, meniscus, ligaments are not shown.
(2) Computed tomography (CT): it can accurately display the small differences in density of different tissues in a cross-section, which is an ideal examination method to observe the small lesions of bone, joint and soft tissue.
(3) Magnetic resonance imaging (MRI): for bone, joint and soft tissue lesions, it has higher resolution than X-ray and CT, and its soft tissue imaging is better than CT. it is mostly used for observing bone, cartilage, meniscus and fascia.
(4) Imaging: ①Arthrography: Generally use filtered air or organic iodine solution, or both can be used at the same time. It can show the structures of articular cartilage, meniscus, synovium and ligaments. It is helpful for the diagnosis of intra-articular lesions, mostly used in large joints of the limbs, and is now rarely used; ② angiography: divided into arteriography and venography, used when necessary.
(5) arthroscopy: can directly observe the lesions of various tissues in the joints, especially meaningful for the diagnosis and differential diagnosis of synovitis. Synovial biopsy and surgical treatment can be taken when necessary.
(6) Biopsy: In cases where diagnosis is difficult, it can help to confirm the diagnosis. Sometimes immunohistochemical staining is also required.
(7) Radionuclide bone scan: it is helpful to identify osteoma (primary or secondary) and myeloma.
(8) Ultrasonography: It can determine the thickness of the joint capsule, cartilage, synovium, and fluid accumulation.
Diagnosis
Diagnosis is made on the basis of history, clinical manifestations, specific serologic tests, and imaging tests.
Treatment
1. Drug treatment
Choose non-steroidal anti-inflammatory drugs, such as diclofenac diethylamide emulsion, meloxicam, loxoprofen, diclofenac sodium, celecoxib.
2. Etiologic treatment
Immunoglobulin is effective in the treatment of microvirus B19-infected rheumatic diseases. Interferon alpha 2b is effective in some cases of hepatitis C virus-associated cryoglobulinemia, and treatment-failed cryoglobulinemia can be treated with immunosuppressive agents.