Juvenile rheumatoid arthritis

Introduction to juvenile rheumatoid arthritis Juveniler heumatoidarthritis (JRA) is a group of diseases characterized by chronic arthritis. The International Rheumatology Alliance Pediatric Standing Committee expert group has fixed the unexplained joint swelling in children for more than 6 weeks. It is juvenile idiopathic arthritis (JIA), which replaces two classification criteria for juvenile rheumatoid arthritis and juvenile chronic arthritis. basic knowledge The proportion of illness: 0.03% Susceptible people: children Mode of infection: non-infectious Complications: pericarditis pleurisy anemia diffuse intravascular coagulation peritonitis dry syndrome iridocyclitis glaucoma cataract ankylosing spondylitis

The cause of juvenile rheumatoid arthritis

(1) Causes of the disease

1. The cause of the cause of JRA is unclear. The data accumulated over the years is related to the abnormal immune response caused by infection-inducing people.

Infection factor (30%):

About 35% of JRA patients have rubella virus isolated from synovial cells. Some patients with systemic JRA have evidence of Coxsackie or adenovirus infection. The researchers also found that a considerable number of JRA patients have parvovirus B19 (HPV-B19). The clue of infection, Hoffman et al. confirmed that there is evidence of mycoplasma infection in JRA patients, but failed to confirm the presence of mycoplasma DNA in the joint fluid. Therefore, it is believed that mycoplasma infection is not the direct cause of arthritis. Some people think that some antibodies rise after infection. High is the basis of post-infection injury. Infection is only a trigger for abnormal immune response. Many observations have found that active arthritis is associated with Chlamydia trachomatis, Yersinia, Salmonella, Shigella, and Campylobacter jejuni infection. The data show that there are T cells activated by pathogens in the blood or joint synovial fluid of patients with active arthritis. Of course, chronic arthritis can only occur after infection in susceptible populations.

Genetic factors (15%):

There is a lot of data to confirm that the major histocompatibility complex (MHC) characteristics determine whether an individual has an abnormal immune response under certain conditions, what type of occurrence, and what degree of immune response determines whether the individual occurs. Immune injury, so people are particularly interested in whether there is a specific MHC site to determine whether autoimmune diseases occur. Some people have confirmed that single-oval twins and siblings share the case of JRA, suggesting that genetic factors may play a role in susceptible to JRA. Important role, but genetic studies did not achieve the results of a single genotype and JRA incidence, although HLA-A2, DR8, DR5 and DPw2 are more common in the oligoarticular type, but the detection of these genetic markers for the diagnosis of JRA oligoarticular type Sex, sensitivity is not ideal, it has been found that HLA-DR4 is common in rheumatoid factor-positive polyarthritis, but Barron and Bedford et al (1992) also found that HLA-DR4 is also more common in systemic JRA, and other data are also It indicates that HLA-A2 is associated with early childhood JRA; HLA-DRB1*0405 is associated with adult rheumatoid arthritis and is positive with RF. Destruction and other closely related, the exact role of genetic factors in the JRA yet in-depth study.

Immunological factors (35%):

There are many studies on the overall and local immune response abnormalities in JRA patients. Different dominant T cell clones can be detected in different stages of JRA disease. The most common are CD4 positive T cells, which may be stimulated by different antigens. Excessive activation of cells and macrophages will produce excessive cytokines such as interleukin (IL-1, 6, 8), tumor necrosis factor (TNF), granulocyte-single colony-stimulating factor (GM-CSF), etc. IL-1 can induce synovial fibroblasts and articular chondrocytes to synthesize prostaglandin E2 and synthetic protease, which mediate joint tissue damage. It is found that IL-6 and IL-8 concentrations are positively correlated with rheumatoid arthritis activities, IL- 1 and TNF can also stimulate the synthesis or secretion of other cytokines.

Autoantibodies may play a role in the pathogenesis of some JRA, 10% to 15% of children with RF positive, 80% of patients with chronic iridoinitis JRA can measure ANA, and AO positive in patients with polyarticular and oligoarticular types As a result, only ANA patients with systemic and oligoarticular type II were rarely positive.

2. Clinical classification JRA classification standards are constantly changing in various countries. Most rheumatologists believe that arthritis in childhood is a heterogeneous disease. At present, there is no uniform classification standard for this type of disease. In the United States, it is called "juvenile rheumatoid arthritis (JRA)" (Table 1), and in Europe it is called "juvenile chronic arthritis" (JCA), which includes different contents. : American classification criteria include systemic arthritis, polyarthritis (rheumatoid-positive group, rheumatoid factor-negative group) and oligoarthritis and extended oligoarthritis, although it is called rheumatoid arthritis, but only 15% rheumatoid factor is positive, so the name is not exact, and this classification does not include ankylosing spondylitis in childhood; and the European classification criteria include a wide range, in addition to the above several types of arthritis, juvenile ankylosing spondylitis Inflammatory bowel arthritis and other arthritis caused by connective tissue diseases are included. Chronic arthritis in childhood is a group of diseases, its onset, duration and outcome. Different from each other, the presumed cause is also inconsistent. In order to facilitate the international collaborative group to conduct research on immunology, epidemiology, outcomes and treatment plan implementation of such diseases, the International Rheumatology Alliance Pediatric Standing Committee expert group (Classification) Taskforce of Pediatric Standing Committee of International League of Association for Rheumatology (ILAR) has been discussed many times [Durhan, Chile, 1997, Durhan, South Africa, 1997, Edmonton, Canada], swelling of unexplained joints in childhood This type of arthritis, which lasted for more than 6 weeks, was uniformly defined as juvenile idiopathic arthritis.

(1) Classification of the American Rheumatology Association: The classification of the American Rheumatology Association in the past 20 years, see Table 1 Clinical Classification of Juvenile Rheumatoid Arthritis (US), according to the clinical features within 6 months after the onset of JRA, JRA is divided into 3 types: systemic type, arthritis type, polyarthritis type, according to age, gender, lower extremity joint involvement, sacroiliitis, family history and HLA type, oligoarthritis type is divided into 2 types According to the rheumatoid factor test results, the polyarthritis type is divided into rheumatoid factor negative (type I) and rheumatoid factor positive (type II) type 2, rheumatoid factor positive type polyarthritis is very similar to adult rheumatoid arthritis The arthritis type with ankle arthritis is similar to the early manifestation of adult ankylosing spondylitis, while systemic and oligoarthritis type I are rare in adults, so although collectively known as JRA, they are not actually the same disease. It may also be a clinical type with the same basic lesions but one performance, and further scientific classification will help guide diagnosis and treatment.

(2) Zhuhai Proposed Classification in 1998: The 5th Pediatric Immunology Conference (Zhuhai) recommended to divide JRA into 4 types, namely systemic type, less joint type, polyarticular type and tendon attachment inflammatory arthritis type The oligo-articular cases classified by the American College of Rheumatology are divided into two types. The following conditions are met for children with ankylosing spondylitis (JAS): boys; older children (8 years old); lower extremity joints Mainly inflammation, early invasion of the hip joint; HLA-B27 positive; a family history of positive ankylosing spondylitis in children; inflammation of the tendon attachment; ankle arthritis, if no ankle arthritis is diagnosed as early ankylosing spondylitis In this classification, considering the American JRA classification method commonly used in domestic textbooks, it is still divided into systemic disease type, arthritis type and polyarthritis type, and its characteristics are described in clinical manifestations.

(3) International Rheumatology Alliance 2001 Classification Standards Discussion Paper: Discussion Paper on Classification Standards for Juvenile Idiopathic Arthritis (Edmonton, Canada): The total definition is for children under 16 years of age who have unexplained joint swelling for more than 6 weeks. , called juvenile idiopathic arthritis, classified as follows:

1 systemic juvenile idiopathic arthritis (systemic JIA) definition:

A. Fever for at least 2 weeks, accompanied by arthritis, accompanied by one or more of the following symptoms:

a. Short-lived, unfixed erythematous rash.

b. The swelling of the whole body lymph nodes.

c. Hepatosplenomegaly.

d. serositis.

B. The following should be excluded:

a. Children with psoriasis.

b. Children over 8 years old with HLA-B27 positive male arthritis.

c. First-degree relatives in family history have HLA-B27-related diseases (ankylosing spondylitis, arthritis associated with inflammation of the attachment point, acute anterior uveitis or ankle arthritis).

d. Two times tested for rheumatoid factor positive, the interval between detection is at least 3 months.

2 oligoarticular JIA definition:

A. 1 to 4 joints involved in the first 6 months of onset, including two subtypes:

a. Persistent less joint type JIA: The number of joints involved in the whole disease process is 4.

b. Expandable less joint type JIA: The number of joints affected after 6 months of disease is 5.

B should exclude the following:

a. Children with psoriasis.

b. Children over 8 years old with HLA-B27 positive male arthritis.

c. First-degree relatives in family history have HLA-B27-related diseases (ankylosing spondylitis, arthritis associated with inflammation of the attachment point, acute anterior uveitis or ankle arthritis).

d. Two times tested for rheumatoid factor positive, the interval between detection is at least 3 months.

e. Systemic JIA.

3 polyarticular arthritis (polyarticularJIA) (negative rheumatoid factor): Definition: More than 5 joints involved in the first 6 months of onset, rheumatoid factor negative.

The following should be excluded:

A. Children with psoriasis.

B. Children over 8 years old with HLA-B27 positive male arthritis.

C. First-degree relatives in family history have HLA-B27-related diseases (ankylosing spondylitis, arthritis associated with point of attachment inflammation, acute anterior uveitis or sacroiliitis).

D. 2 times detected rheumatoid factor positive, detection interval of at least 3 months.

E. Systemic JIA.

4 polyarticular arthritis (polyarticular JIA) (rheumatoid-positive): Definition: More than 5 joints involved in the first 6 months of onset, rheumatoid factor positive.

The following should be excluded:

A. Children with psoriasis.

B. Children over 8 years old with HLA-B27 positive male arthritis.

C. First-degree relatives in family history have HLA-B27-related diseases (ankylosing spondylitis, arthritis associated with point of attachment inflammation, acute anterior uveitis or sacroiliitis).

D. Systemic JIA.

5 Psoriasis juvenile idiopathic arthritis (psoriatic JIA): Definition:

A. 1 or more arthritis combined with psoriasis.

B. Arthritis combines the following two items: finger inflammation; nail depression or nail detachment; family history has psoriasis patients.

C. The following should be excluded:

a. Children over 8 years old with HLA-B27 positive male arthritis.

b. First-degree relatives in family history have HLA-B27-related diseases (ankylosing spondylitis, arthritis associated with inflammation of the attachment point, acute anterior uveitis or sacroiliitis).

c. 2 tests for rheumatoid factor positive, at least 3 months between tests.

d. Systemic JIA.

6 arthritis associated with inflammation of the point of attachment (enthesitis related JIA): Definition:

A. Arthritis combined with inflammation of the attachment point.

B. Arthritis or attachment point inflammation, with at least 2 of the following conditions: ankle tenderness or inflammatory lumbosacral and spinal pain, but not limited to the cervical spine; HLA-B27 positive; male arthritis over 8 years of age Children; first-degree relatives in family history have HLA-B27-related diseases (ankylosing spondylitis, arthritis associated with inflammation of the attachment point, acute anterior uveitis or sacroiliitis).

C. The following should be excluded:

a. Psoriasis patients.

b. 2 times rheumatoid factor positive, 2 intervals of 3 months.

c. Systemic JIA.

7 Undetermined juvenile idiopathic arthritis (undefined JIA): Definition: Arthritis that does not meet any of the above or meets the above two categories.

(two) pathogenesis

1. Pathogenesis In summary, the pathogenesis of JRA may be that various infectious microorganisms act as foreign antigens, activate immune cells, trigger abnormal immune responses by direct action or secretion of cytokines and autoantibodies, causing autoimmune tissue damage or Denaturation, especially mentioned bacteria, a special component of the virus as a superantigen, its structure has homology with human MHCII antigen, and can be directly processed with a special variable region chain without antigen-presenting cell processing. (V) structure of T cell receptor (TCR) binds to activate T cells, VT cells are over-activated under the stimulation of superantigen, resulting in immune damage caused by cells or cytokines, self-denatured tissue components (endogenous antigens) For example, denatured IgG or denatured collagen can also act as an antigen to elicit an immune response against its own tissue components, further aggravating immune damage.

2. Pathological changes Typical changes in JRA lesions are chronic inflammation characterized by lymphocyte and plasma cell infiltration in synovial tissue. There is no significant difference between JRA types and pathology of adult rheumatoid arthritis. Early lesions showed non-specific edema, hyperemia, fibrin exudation, lymphocyte and plasma cell infiltration. After recurrent episodes, the synovial tissue thickened and fluffy to the joint cavity, attached to the cartilage and extended to the cartilage to form blood vessels. Destruction of articular cartilage; neutrophil proteases also play a role in lysing proteins. Lymphoid cells accumulate in the synovium during the pathological process, and locally activated T cells accumulate, causing a large increase in inflammatory cytokines, repeated, continuous The inflammation erodes the articular cartilage, causing the articular surface to adhere to the fusion, and is replaced by fibrous or ossicular connective tissue, resulting in joint stiffness, deformation, can occur around the affected joints, tendonitis, myositis, osteoporosis, periostitis, diseased tissue The middle lymph nodes are non-specific follicular hyperplasia and increased germinal center, secreting immunoglobulin and rheumatoid factor Increased plasma cells.

Fibrous serositis of the pleura, pericardium and peritoneum, inflammatory cell infiltration in the capillaries of the rash, and granulomatous infiltration of the iris ciliary body in the eye lesions.

Juvenile rheumatoid arthritis prevention

The etiology of this disease is unclear, and it is related to the abnormal immune response induced by infection. It should actively prevent and treat various infectious diseases, pay attention to nutrition, enhance physical fitness and do vaccination work.

Juvenile rheumatoid arthritis complications Complications pericarditis pleurisy anemia diffuse intravascular coagulation peritonitis dry syndrome iridocyclitis glaucoma cataract ankylosing spondylitis

Children with Sys-JRA may be associated with splenomegaly, lymphadenopathy, pericarditis, pleurisy, anemia, disseminated intravascular coagulation, mesenteric lymphadenopathy or peritonitis, convulsions, etc. Repeated episodes may cause developmental delay.

Children with rheumatoid factor-negative polyarticular type JRA may be associated with vocal dumbness, laryngeal wheezing and difficulty eating. Rheumatoid factor-positive multi-articular JRA may be associated with rheumatoid vasculitis, with Sjogren's syndrome and Fetly syndrome.

Children with oligoarticular JRA may contract due to contracture of the tissues surrounding the joints, resulting in flexion disorders, and the length of the legs may be different, which may be complicated by chronic iridocyclitis, secondary glaucoma, cataract, severe visual impairment or blindness. May be associated with ankylosing spondylitis, inflammatory bowel disease and Reiter disease.

Symptoms of juvenile rheumatoid arthritis Common symptoms Rheumatic polymyalgia leukocytosis inflammatory joint swelling periostitis relaxation heat lumbosacral pain morning stiffness peritonitis sepsis

1. Systemic onset juvenile rheumatoid arthritis (Sys-JRA) is about 20% of patients with JRA, with prominent extra-articular symptoms and arthritic symptoms. Systemic symptoms include relaxation heat, rash, splenomegaly, swollen lymph nodes, pericarditis, pleurisy, abdominal pain, leukocytosis, anemia, and occasionally diffuse intravascular coagulation.

(1) Fever is a prominent feature of systemic disease type. The body temperature rises from 1 to 2 times a day, reaching 39 to 40 °C. The body temperature can be reduced to normal or near normal every day. The sick child shows a serious illness when he has a fever. As usual, the condition changes dramatically, and fever can last for weeks or even months.

(2) The rash is another characteristic of Sys-JRA. It usually appears in high heat, disappears after heat retreat, and is often obvious at night. The next morning subsides, leaving no traces. Local heating can also induce rash. The rash is mostly reddish-colored or Ring erythema, found in any part of the body including the hands and feet, occasionally itching, visible scratches.

(3) Most patients have mild pericarditis and pleurisy lesions, although some patients report chest pain, and most people are often asymptomatic, occasionally a large amount of pericardial effusion, need decompression treatment, liver, spleen, lymph node enlargement can be very obvious, even Similar to malignant diseases.

(4) Most of the changes in liver function tests are mild, and chronic liver disease does not occur. When liver function is abnormal, it is necessary to pay attention to whether it is caused by hepatotoxic drugs, especially non-steroidal anti-inflammatory drugs and methotrexate. A small number of sick children have hepatotoxicity symptoms such as liver pain, liver enzymes, and abnormal blood coagulation after high-dose salicylic acid preparations.

(5) Diffuse intravascular coagulation (DIC) syndrome is a potentially fatal complication of systemic JRA. Glucocorticoid should be used as soon as possible. It has been reported that intramuscular injection of gold-containing preparations for systemic JRA has occurred. This syndrome.

(6) Systemic JRA can cause severe abdominal pain, which may be caused by mesenteric lymphadenopathy or peritonitis. Central neuropathy can be characterized by convulsions, abnormal behavior, and sometimes EEG abnormalities. Repeated episodes of long-term disease can cause developmental delay. The mechanism is still unclear and may be related to active inflammation affecting metabolism, inadequate nutrient intake, and glucocorticoid application.

(7) This type of joint performance can be typical arthritis or only myalgia, joint pain; sick children are susceptible to irritability, refuse to stand or move, looks like systemic damage, generally more pain in high fever, and When the heat is retreating, the joint symptoms are improved. When the systemic symptoms are prominent, the joint symptoms are often neglected. Most of the joint symptoms gradually improve within a few weeks. Occasionally, some cases appear in the systemic symptoms for several weeks, even months or more. No obvious joint symptoms were observed, but statistics showed that most of the children had joint involvement.

Systemic symptoms may recur, the interval is difficult to predict, but it is rare to relapse after puberty, the type of death is very rare, the prognosis depends on the severity of arthritis, 10 to 20 years follow-up statistics, about 25% The patient progresses gradually and the joint function is disabled.

2. Rheumatoid factor-negative polyarticular type JRA rheumatoid factor-negative multi-articular type JRA (seronegative polyarticular juvenile rheumatoid arthritis) JRA patients 20% to 30% of the sick children involved multiple joints within a few months of onset, no significant Systemic performance, and RF detection is negative, at least 4 lesions and joints, almost all joints except the spinal joint can be involved, even the small joints of the palms of the hands, the cervical vertebrae, hip joint involvement is not uncommon, the joint symptoms are mostly swollen , pain, fever, tenderness, movement disorder, finger-to-toe joint involvement, showing typical fusiform swelling; involving the temporomandibular joint manifested as difficulty in opening the mouth, children can complain of earache, the elderly with the disease, can affect the local development of small jaw deformity Involvement of the throat (ring cartilage - sacral cartilage) can cause dumbness, throat wheezing and eating difficulties, some children with morning joint movement disorders are particularly obvious, called morning stiffness, the lesions are generally not red, the joint cavity can be There is a large amount of exudation, and obvious periosteal inflammation makes the joint symptoms very prominent.

This type of extra-articular manifestations have no systemic JRA prominence, but may also have low-grade fever, general malaise, irritation, growth retardation, mild anemia, and rare rheumatoid nodules during disease activity.

The prognosis of this type is related to the severity of arthritis, duration and degree of joint destruction. Active arthritis can last for several months, several years, and can be re-emerged after almost complete remission. Fortunately, there are 80% to 90% of cases. The child eventually relieves or only has a slight chronic disease. Occasionally, individual children develop jaw disease and cause oral activity disorder. The face is asymmetrical and needs surgery to correct it.

3. Rheumatoid factor-positive polyarthritis type JRA seropositive polyarticular juvenile rheumatoid arthritis (JRA) is characterized by polyarthritis (>4 joints) with rheumatoid factor (RF) positive, accounting for JRA is 5% to 10%, and the age is more than 8 years old. Most of them are women. RF is often high-price positive during disease activity. The form of joint disease is similar to RF-negative polyarthritis and human rheumatoid arthritis. At least 50% of patients develop severe arthritis, and the response to current commonly used medications is poor. This type is easy to find subcutaneous rheumatoid nodules, which is the same as that of human rheumatoid arthritis. A few people also have rheumatoid arthritis. In vasculitis, the HLA type of this type of child has a great degree of consistency with adult rheumatoid arthritis. For example, the positive rate of HLA-DR4 is high. This type of patient has occasional reports of Sjogren's syndrome and Fetly syndrome. Symptoms can be seen with low fever, discomfort, weight loss, and delayed growth.

4. About 50% of patients with oligoarticular JRA (pauciarticular juvenile rheumatoid arthritis) are limited to one or a few ( 4) joints during the first 6 months of the disease or even the entire course of the disease, and Common joint lesions usually occur in an asymmetrical distribution. The less than 4 joints involved in the JRA were defined as oligoarticular. There was no difference between arthritic and oligoarticular types in terms of arthritis. Histological changes were observed. Based on synovial inflammation, clinically less articulated can be further divided into 2 types:

(1) Less joint type I JRA: This type is more common in young girls, accounting for 40% to 50% of JRA patients. It is more common in knee, ankle and elbow joint diseases. Finger joint lesions often appear in an asymmetrical form. Hip joint involvement is rare, and no arthritis occurs. The duration of arthritis is long, but the degree is generally mild. 80% of the children have only 4 joints involved in the whole course of the disease, and the joint function is always good. About 20% of the children develop multi-joint involvement after several years, and joint destruction occurs. The bone tissue around the affected joint is hyperplasia after stimulation, resulting in the length of the legs being different. If you do not pay attention to the treatment, it may be due to The tissue around the joint collapses and a flexion disorder occurs.

The main complication of this type is chronic iridocyclitis. Occasionally, iridocyclitis occurs in patients with systemic and RF-positive polyarthritis. Iris often hides onset. In the early stage, only slit lamp examination can be used to diagnose The lesion may involve unilateral or bilateral eyes. If the condition is not controlled in time, anterior chamber scar, secondary glaucoma, cataract, severe visual impairment or blindness may occur, although the incidence of severe iriditis seems to have decreased in recent years. Boone has been screened for 12% of patients with asymptomatic iridocyclitis, so regular ophthalmic follow-up should be emphasized, although Sailer has reported that 2 patients with RF-positive oligoarthritis have poor prognosis and severe joint destruction. However, most RF-negative oligoarticular patients have a good prognosis.

(2) Arthritis type II JRA: This type of boy is mostly, the age is more than 8 years old, about 15% of the total number of children with JARA is less arthritis type II. This type of characteristics includes hips, knees, ankles, etc. Major joint involvement, easy hip syndrome, tendon attachment lesions, HLA-B27 antigen positive and positive family history; with the development of lesions, some patients will involve the spine, ankylosing spondylitis, while other patients may only involve Peripheral joints, so the domestic recommendations for the following limb joint lesions, a positive family history, HLA-B27 positive with lumbosacral pain, but no evidence of hip arthritis of the genital joint type II disease was first diagnosed as ankylosing spine In the early stage of inflammation, in order to help people to be vigilant and prevent missed diagnosis, in addition to ankylosing spondylitis, inflammatory bowel disease and Reiter disease may have clinical manifestations of oligoarticular type II at an early stage.

The reason why ankylosing spondylitis is difficult to distinguish from type II type JRA in early stage is that in the early stage of ankylosing spondylitis, although there is waist and ankle pain, common examination can not diagnose early ankle arthritis. In recent years, magnetic resonance imaging (MRI) has been used. With a more sensitive detection rate, combined with medical history, HLA identification, lumbosacral pain, inflammation of tendon attachment, family history and MRI, differential diagnosis of early and less-articular JRA can be performed in ankylosing spondylitis.

The course of type II JR has a large difference. In the course of several years, the joint symptoms are light and heavy, and the final results are various. Some patients have self-limited iridocyclitis, but rarely occur permanently. Sexual visual impairment, if the joint disease is not ankylosing spondylitis, the early manifestations of Reiter disease and inflammatory bowel disease are rarely accompanied by other systemic symptoms.

Examination of juvenile rheumatoid arthritis

The diagnosis of JRA relies mainly on its clinical features. The key is to exclude some diseases with arthritis and joint disease. Any item in the laboratory examination does not have the value of diagnosis, but it may help to eliminate other diseases.

1. Rheumatoid factor: The rheumatoid factor (RF) of human rheumatoid arthritis detected by standard agglutination test method is almost positive, but the positive rate of RF positive in JRA patients is extremely low, only the older girls are easy to see positive. As a result, if the disease occurs in childhood, RF will not be positive even if the lesion continues to be active until the elderly, RF-positive patients are often accompanied by severe joint disease and rheumatoid nodules, and systemic and oligoarticular patients are negative for RF testing. Why is it that the majority of JRA patients have a negative RF agglutination test? It is not clear that in recent years, about 75% of children with negative RA in general RF agglutination test can detect occult RF, but the pathological effect of occult RF is far from enough. figure out.

2. Antinuclear antibodies: 20% to 30% of children with juvenile rheumatoid arthritis have positive antinuclear antibody (ANA), but the difference in ANA positive rate among different subtypes of JRA is large.

About 25% of patients with RF-negative polyarthritis type JRA are positive for ANA, and nearly 75% of patients with RF-positive polyarthritis JRA are positive for ANA. About 50% of patients with arthritis type I are positive for ANA, while those with less joint type II and systemic disease Type IRA patients have very few ANA positives. In general, positive girls are mostly positive, especially in young children with less joint type. ANA may be associated with chronic iridocyclitis in patients with oligoarticular JRA. ANA can predict whether a child will develop. The risk of this disease, the lack of information on the positive distribution of some specific types of autoantibodies in JRA: Some studies have found that anti-rheumatoid arthritis 54kD and 36kD autoantibodies have some value in the diagnosis of rheumatoid arthritis, but failed in JRA It was confirmed that a survey showed that the anti-cardiolipin antibody positive rate was 59.3%, 28.6% and 9.1% in the systemic, polyarthritis and arthritis-type JRA, respectively. The antibody type was mainly IgG, IgM type. Therefore, this test may be beneficial for the diagnosis of systemic-onset JRA.

3. Neutrophil cytoplasmic antibody (ANCA): Muderl et al. (1997) reported that the positive rate of anti-neutrophil cytoplasmic antibody (ANCA) in serum of JRA patients was 35%, of which polyarthritis type was 44% positive. The arthritis type was 36% positive, and the systemic type was only 16% positive.

4. Synovial fluid analysis: Synovial fluid analysis can not confirm JRA, but can identify septic arthritis and crystalline arthritis (gout is rare in children), septic arthritis fluid looks cloudy green, yellow, with a lot of white blood cells, Polymorphonuclear cells are predominant, and HalLiday et al. (1998) found that nerve growth factor (NGF) in synovial fluids was significantly increased in patients with rheumatoid arthritis. Therefore, activation of inflammatory cells is considered to be a major cause of joint damage.

5. Synovial histology: Histological changes are very similar to other rheumatic diseases. Synovial biopsy can sometimes exclude chronic septic arthritis, tuberculous arthritis and other rare diseases such as sarcoma and synovial tumors.

6. Acute phase reactants: Most patients with JRA have an increased phase of acute phase reactions, in which erythrocyte sedimentation rate is significantly accelerated, but patients with oligoarticular type are often exceptional, and erythrocyte sedimentation results are mostly normal. Acute phase reactants in multi-articular and systemic patients (C The detection of reactive protein, erythrocyte sedimentation rate, etc.) has no diagnostic value, and its limited significance may be due to follow-up during the course of the disease.

7. Blood routine: JRA patients often have mild anemia. Occasionally, systemic JRA is heavier and heavier. The cause of anemia is unclear. It may be related to hematopoietic inhibition, iron deficiency, drug-induced gastrointestinal bleeding, increased red blood cell destruction, and increased peripheral blood leukocytes. Especially prominent in the whole body type JRA.

8. X-ray examination: X-ray and other imaging techniques can help to determine the extent of joint damage in patients. Early stage of disease (about 1 year of disease) X-ray only shows soft tissue swelling, osteoporosis around the joint, and periostitis near the joint. In the late stage, joint bone destruction can be seen. When the joint is severely damaged, adjacent bone tissue may also be eroded. Especially in RF-positive cases, the wrist joint is more common. The chest X-ray can also show that the systemic JRA has pleurisy or pericarditis. Caused by heart enlargement, as well as rheumatic lung disease.

9. Bone radionuclide scanning and MRI ultrasound images: It is helpful for diagnosing joint lesions. Bone scan can help identify infections or find malignant tumors. Ultrasound can detect joint cavity exudation and synovial thickening in children with arthritis. MRI can More sensitive to cartilage destruction and bone erosion than ordinary X-ray examination, joint synovitis can be more clearly understood after sputum dye injection.

Diagnosis and diagnosis of juvenile rheumatoid arthritis

Diagnostic criteria

1. Exclusion diagnosis: JRA diagnosis uses exclusion diagnosis. For example, patients with oligoarthritis should pay attention to septic arthritis, tuberculous arthritis, osteomyelitis, Lyme arthritis, and JRA patients with systemic symptoms. Should pay attention to systemic lupus erythematosus, rheumatic fever, infectious mononucleosis, leukemia and sepsis and other diseases, patients with waist, ankle pain should pay attention to children with ankylosing spondylitis, inflammatory bowel disease, Rut disease Isotopic identification, in particular, is that when individual JRA patients have severe lung disease, attention should be paid to the identification of bacterial and viral pneumonia in various types of children. It is necessary to observe at least 6 weeks of diagnosis of JRA, especially arthritis symptoms. There should be a chronic, persistent feature that is diagnosed with the exclusion of other diseases.

2. The main diagnosis basis: The diagnosis of this disease is mainly based on clinical manifestations. Any systemic symptoms or joint lesions lasting more than 6 weeks, can exclude other diseases, may consider this disease.

3. Diagnostic criteria of the American College of Rheumatology: The diagnostic criteria revised by the American College of Rheumatology in 1989 are as follows (Cassidy etal):

(1) Age of onset: under 16 years of age.

(2) Arthritis: Inflammation of one or several joints, manifested as joint swelling or effusion and possessing the following two or more signs: limited joint activity, pain or tenderness during activity, and elevated local temperature of the joint.

(3) Course of disease: more than 6 weeks.

(4) Clinical type: The clinical type was determined based on the clinical manifestations of the first 6 months of onset.

1 multi-joint type: 5 or more affected joints.

2 less joint type: 4 or less affected joints.

3 systemic type: intermittent fever, rheumatoid rash, arthritis, liver and spleen and lymphadenopathy and serositis.

(5) Excluding other diseases.

Differential diagnosis

Patients with systemic symptoms such as high fever and rash should be differentiated from systemic infections (such as sepsis, tuberculosis and viral infections), malignant diseases (such as leukemia, lymphoma and malignant reticulosis, and other malignant tumors). Involved in the main, in addition to rheumatic fever, septic arthritis, joint tuberculosis, traumatic arthritis, etc., should also be associated with systemic lupus erythematosus, mixed connective tissue disease, inflammatory bowel disease (Inflammatory Bowel Disease) It is differentiated from psoriasis and vasculitis syndrome (allergic purpura, serum disease, Kawasaki disease) with arthritis.

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