Seronegative spondyloarthropathy is a large class of diseases, including ankylosing spondylitis (AS), Reid syndrome, psoriatic arthritis and so on. The clinical manifestations of these diseases are varied, the symptoms overlap greatly, the severity of the lesions is different, and the prognosis is far from the same. Especially in the early stage of the disease, it is difficult for atypical or partial female patients to be classified as a certain disease according to the usual classification standards of the above diseases (such as new york's AS standard). They actually account for a large part of seronegative spondyloarthropathy. With the progress of the disease, some patients showed typical AS or psoriatic arthritis in different periods. In recent years, people have classified this kind of disease as undifferentiated spondyloarthropathy (uSpAs), and this view has been accepted more and more. In order to expand the classification range of seronegative spondyloarthropathy, uSpAs, European Research Group on Spinal Arthropathy (ESSG) and Amor were included. There is no mention of their diagnostic criteria [1, 2]. The domestic understanding of uSpAs is still insufficient, which leads to a high misdiagnosis rate of such diseases. This paper summarizes the clinical characteristics and incidence of uSpAs patients diagnosed and treated in our hospital.

Objects and methods

First, case selection.

1July 1998 to1June 1999, there were 147 patients with seronegative spondyloarthropathy who came to our hospital for treatment, including 25 AS patients, 3 psoriatic arthritis patients, 3 reactive arthritis patients and the rest 1 16 us patients. The clinical manifestations, treatment, family history, physical examination and HLA-B27 results of all patients were recorded. In uSpAs group, 6 1 cases were examined by X-ray and CT at the same time, and 14 cases were examined by X-ray and CT only. In AS group, 17 patients only received X-ray examination, and 5 patients received both examinations at the same time.

Second, the method

The clinical manifestations and auxiliary examination indexes of patients were summarized, and the results were analyzed by four diagnostic criteria: new york standard, modified new york standard, Amor standard and ESSG standard, and the results were tested by T test and χ2 test.

fructification

First, most patients were uSpAs, accounting for 78.9%. Compared with AS conforming to new york standards, it has the following characteristics:

1. The proportion of females is greater than that of AS group, and the ratio of males to females in this group is1.4:1(the ratio of males to females in AS group is 12: 1).

2. The course of the disease is short, with an average of 3. 1 year (as group has an average of 1 1.8 years), and the disease is mild, with slight involvement of sacroiliac joints and spine.

3.3. Not all inflammatory spinal pain in USPAS started from low back pain, 4 cases of thoracic pain (3.4%) and 2 cases of cervical pain (65,438 0.7%).

4. The main complaints were buttock and buttock, accounting for 49.65438 0% and 37.65438 0% respectively (56% and 60% respectively in AS group).

5.5. None of the patients with 5.5.uSpAs had limited lumbar motion, and not all of them showed sacroiliitis changes on ordinary X-ray films. In this group, 34.4% patients were diagnosed by X-ray and 56 patients were diagnosed by CT, accounting for 73.2%. The resolution of CT is obviously higher than that of X-ray plain film, and the diagnostic coincidence rate of the two examinations is 46%. However, the coincidence rate of imaging diagnosis of sacroiliitis between radiologists and rheumatologists is not high, and the consistency between the two departments needs to be improved.

6.6. The positive rate of HLA-B27 in USPAs patients was lower than that in AS group, which were 59.5% and 80% respectively.

7. There are 4 cases of late-onset AS, which are characterized by onset after 50 years old, many systemic symptoms, mild spinal symptoms and mild arthritis, all of which do not meet the diagnostic criteria of new york, but they also belong to uSpAs, which is similar to foreign reports.

Second, the compliance of diagnostic criteria for uSpAs patients.

All patients with uSpAs did not meet the diagnostic criteria of ankylosing spondylitis in new york and revised new york, 98 cases (84.5%) met the criteria of Amor, with a score of > 6, and 99 cases (85.3%) met the criteria of ESSG. All 25 patients with AS met the above four diagnostic criteria.

Thirdly, compare the frequency of different symptoms of uSpAs with the literature reports [3 ~ 5], as shown in the attached table.

Frequency of different symptoms of undifferentiated spondyloarthropathy

Project (%) Report on Patients' Literature in Our Hospital (%)

Male 58.6 62.0 ~ 68.0

The average age of onset was 28.616.0 ~ 23.0.

Lumbago 90.0 52.0 ~ 80.0

Peripheral arthritis 72.7 60.0 ~ 100.0

Polyarthritis 45.5 40.0

Attachment point inflammation 63.0 56.0

Heel pain 45.7 20.0 ~ 28.0

Mucosal dermatosis 9.2 16.0

Conjunctivitis/Wax Membranitis 7.6 33.0

Rheumatoid factor negative 94.8 100.0

HLA-B27(+) 59.5 80.0~84.0

Ordinary x-ray film of sacroiliitis 36. 1. 16.0 ~ 30.0

Positive or suspicious family history 25.9 32.0

discuss

1.uSpAs is a common group of seronegative spondyloarthropathy in our hospital. A multi-center survey abroad also found that most of the out-patients with seronegative spondyloarthropathy were diagnosed as uSpAs. According to the standard of new york, the prevalence rate of AS in China is only 0. 1 1% ~ 0.26% (in other places) [6], but it has been reported recently that the prevalence rate of seronegative spondyloarthropathy in the United States is 1.6%. The main reason for the far difference in prevalence rates between the two countries is that the United States Pharmacopoeia is not included in the new york standard used in epidemiological investigation in China. The name uSpAs was first put forward by Burns in 1982, and the related reports are increasing day by day. At present, this term can be considered to refer to patients with clinical and/or radiological manifestations suggesting that they are spondyloarthropathy, but they do not meet any diagnostic criteria of spondyloarthropathy (such as AS, Wright syndrome, psoriatic arthritis, enteropathic arthritis and reactive arthritis). This is not an independent disease, but a set of symptom spectrum, which can exist alone or in combination, with different severity and different course of disease. The meaning of undifferentiated can refer to: ① Spinal arthropathy is diagnosed at an early stage, and then it will differentiate into a certain disease. ② A certain "abortion-type" spondyloarthropathy will not develop into a typical spondyloarthropathy in the future. ③ It belongs to overlap syndrome and has not developed into definite spondyloarthropathy. ④ It belongs to an unknown subtype of spondyloarthropathy and gradually has different differentiation. There are different names in the literature due to the wide naming meaning and different personal emphases of doctors, all of which belong to this field, such as B27-related arthritis, HLA-B27-positive arthritis, HLA-B27-related seronegative arthritis, SEA syndrome (S= seronegative, E= attachment inflammation, A= arthritis), late-onset spondyloarthropathy and BASE syndrome.

2. Compared with AS patients, the clinical manifestations of uSpAs have the following characteristics: ① Symptoms are mild and atypical; ② No spinal motion limitation; ③ Sacroiliac arthritis does not necessarily exist; ④HLA-B27 is not necessarily positive, and the positive rate in this group is lower than that in AS group; ⑤ The proportion of female patients is significantly higher than that of AS patients, indicating that female patients are mild, and even though the course of disease is long, they are still undifferentiated. Because the symptoms of uSpAs are diverse and atypical, the misdiagnosis rate in other hospitals is high, and most of them are misdiagnosed as disc herniation, rheumatoid arthritis, sciatica and so on. Therefore, we should improve our vigilance against the disease, pay attention to hip pain, inner thigh pain, hip pain, heel pain, sole pain and knee pain, and carefully check whether there is attached inflammation. Although the low back pain of uSpAs patients is not significant or even non-existent, sacroiliac joint examination is still very important when the disease is suspected, and HLA-B27 and sacroiliac joint imaging examination should also be done. CT of sacroiliac joint is more sensitive than ordinary X-ray, and CT can be added when the latter is suspicious. The analysis in this paper shows that most patients with early seronegative spondyloarthropathy do not meet the new york criteria commonly used in China. For AS, new york criteria is not an early diagnosis criterion, nor can it be used as a classification criterion for all seronegative spondyloarthropathy. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of ESSG and Amor standards compared by foreign multi-center studies are good [8, 9], which are similar to the results in this paper. Therefore, we suggest that Amor or ESSG standard diagnosis should be adopted for patients with early seronegative spondyloarthropathy, and its sensitivity and specificity are more applicable.

Thirdly, in terms of treatment, more than half of the patients in this group have no obvious effect by using non-steroidal anti-inflammatory drugs. After combined use of sulfASalazine (SASP) for 2 ~ 3g/d, the symptoms of peripheral joints and axis are relieved, which is somewhat different from the foreign reports that SASP is effective for peripheral arthritis as but ineffective for axis lesions. However, due to the lack of long-term follow-up observation results, treatment without control group and no ideal AS activity index at present, it is difficult to draw a conclusion in this paper, and the long-term prognosis of this disease needs further observation. Because most patients with uSpAs progress slowly, the prognosis of each case is not bad, and early use of sulfasalazine may also be beneficial, so we think that it seems too active to give SASP plus immunosuppressant once diagnosed. From the perspective of cost/benefit ratio, it may not be the best choice.

Zhang Wen (Department of Rheumatology and Immunology, Peking Union Medical College Hospital, postal code 100730)

Zhang Naizheng (Department of Rheumatology and Immunology, Peking Union Medical College Hospital, postal code 100730)

Sun (Chaozhou Central Hospital of Guangdong Province)

Zhang Fan (Jixi Mining General Hospital of Heilongjiang Province)