Rheumatologic manifestations of brucellosis

The Potential of a CT-Based Machine Learning Radiomics Analysis to Differentiate Brucella and Pyogenic Spondylitis

Background

Pyogenic spondylitis (PS) and Brucella spondylitis (BS) are common spinal infections with similar manifestations, making their differentiation challenging. This study aimed to explore the potential of CT-based radiomics features combined with machine learning algorithms to differentiate PS from BS.

Methods

This retrospective study involved the collection of clinical and radiological information from 138 patients diagnosed with either PS or BS in our hospital between January 2017 and December 2022, based on histopathology examination and/or germ isolations. The region of interest (ROI) was defined by two radiologists using a 3D Slicer open-source platform, utilizing blind analysis of sagittal CT images against histopathological examination results. PyRadiomics, a Python package, was utilized to extract ROI features. Several methods were performed to reduce the dimensionality of the extracted features. Machine learning algorithms were trained and evaluated using techniques like the area under the receiver operating characteristic curve (AUC; confusion matrix-related metrics, calibration plot, and decision curve analysis to assess their ability to differentiate PS from BS. Additionally, permutation feature importance (PFI; local interpretable model-agnostic explanations (LIME; and Shapley additive explanation (SHAP) techniques were utilized to gain insights into the interpretabilities of the models that are otherwise considered opaque black-boxes.

Results

A total of 15 radiomics features were screened during the analysis. The AUC value and Brier score of best the model were 0.88 and 0.13, respectively. The calibration plot and decision curve analysis displayed higher clinical efficiency in the differential diagnosis. According to the interpretation results, the most impactful features on the model output were wavelet LHL small dependence low gray-level emphasis (GLDN).

Conclusion

The CT-based radiomics models that we developed have proven to be useful in reliably differentiating between PS and BS at an early stage and can provide a reliable explanation for the classification results.

Prevalence and relevant factors of positive RF in brucellosis patients with arthralgia

Background

Brucellosis is a critical zoonotic disease in the world, it is the non-specific arthralgia that make brucellosis patients easily misdiagnosed as rheumatoid arthritis (RA) in endemic regions. Elevated rheumatoid factor (RF) is an essential indicator of RA, and the RF in brucellosis patients is significantly higher than healthy people. Therefore, this study further explored the distribution of RF and the relevant factors of the RF positivity in brucellosis patients with arthralgia, in order to strengthen the recognition of physicians for brucellosis patients with RF positivity, especially in brucellosis-endemic areas, so as to avoid misdiagnosis and untimely treatment that may lead to malignant outcomes.

Methodology and principal findings

The medical records of all 572 brucellosis inpatients were collected in the Sixth People’s Hospital of Shenyang, China from 2015 to 2016. After excluding 106 patients without arthralgia, 5 patients who unwilling to perform RF testing and 16 patients with diseases that may affect RF, 445 brucellosis inpatients with arthralgia were involved in this retrospective cross-sectional study. 143 (32.1%) patients with RF >10 IU/ml were classified into the RF positive group, with an average level of 16.5[12.2, 34.7] IU/ml, of which 45 (10.1%) patients were high-positive with RF >30 IU/ml. Multivariate logistic regression model was used to further analyze the relevant factors of the RF positivity and found that age, wrist joint pain and elevated C-reactive protein (CRP) were positively associated with RF positivity, with OR of 1.02 (P = 0.024), 8.94 (P = 0.008) and 1.79 (P = 0.019), respectively.

Conclusion

The prevalence of positive RF in brucellosis patients with arthralgia was critical, nearly one-third of patients had RF positive. Elderly men brucellosis patients with arthralgia, wrist joint pain and elevated CRP were at high risk of positive RF. It is reminded that physicians should focus on differential diagnosis during clinical diagnosis and treatment, especially in brucellosis-endemic regions.

Brucellosis is a highly contagious zoonosis caused by Brucella spp., which compromises to organs and systems, causing non-specific symptoms such as fever, headache, sweating, fatigue, myalgia and arthralgia. Similarly, patients with rheumatoid arthritis (RA) may also have the above non-specific symptoms. It is precisely because of the non-specificity and similarity of symptoms that brucellosis patients were easily misdiagnosed and failed to receive timely treatment, resulting in neurosis, chronic fatigue syndrome, endocarditis and other adverse outcomes. However, rheumatoid factor (RF) is an essential indicator of RA, and the RF in brucellosis patients is significantly higher than healthy people. In order to strengthen the recognition of physicians for brucellosis patients with RF positivity, we conducted this research and found that the prevalence of positive RF in brucellosis patients with arthralgia was common and critical. Elderly men brucellosis patients with arthralgia, wrist joint pain and elevated CRP were at high risk of positive RF. It is reminded that physicians should pay attention to the possibility of brucellosis during clinical diagnosis and treatment, especially in brucellosis-endemic regions, which had certain clinical significance.

The early diagnostic value of serum neopterin and cartilage oligomeric matrix protein for osteoarticular changes among brucellosis patients at an early period

Background

Brucellosis is an important public health problem in China. Brucellosis can cause many osteoarticular changes, especially chronic brucellosis. Brucellosis presents various diagnostic difficulties because it mimics many other diseases. Because of the poor sensitivity and ability of X-ray image, it is necessary to find a good method of early diagnosis for osteoarticular changes among brucellosis patients at an early period.

The aim of this study was to find early changes biomarkers for osteoarticular changes among brucellosis patients at an early period and provide a better understanding of the osteoarticular changes in this disease at an early stage.

Methods

Sixty-one cases of brucellosis patients at an early period (within 6 months) and 67 cases of volunteers were selected and divided into brucellosis vs. control groups. Serum samples were detected with serological tests for brucellosis, including rose bengal plate test (RBPT), agglutination test (SAT), and IgG and IgM with ELISA. Meanwhile, cartilage oligomeric matrix protein (COMP) and neopterin (NPT) levels in all samples were measured simultaneously with ELISA. The data were analyzed using SPSS 17.0 software.

Results

Together with the clinical examination, epidemiological investigation, and serological tests of RBPT, SAT, and IgG and IgM with ELISA, the patients from brucellosis group all were diagnosed as brucellosis cases at an early period, while the results of RBPT, SAT, and IgG and IgM with ELISA from the healthy control group were negative. Comparing with the healthy control, the medians of serum NPT and COMP in the patients group were 9.26 ng/l, 1.70 ng, respectively, which were higher than that of the healthy control group with significant differences (Z = 5.512, 3.614, all p = 0.000).

Conclusion

The serum NPT and COMP levels of brucellosis patients at an early period were increased. The serum NPT and COMP levels might be the indicator biomarker for osteoarticular changes of human brucellosis at an early stage.

A Rare Form of Brucella Bursitis with Negative Serology: A Case Report and Literature Review

Brucellosis is still endemic in certain parts of the world including the Mediterranean, the Middle East, Latin America, and African regions. Osteoarticular manifestations are common presenting features. Brucellosis presenting as prepatellar bursitis has already been reported. We present a case of seronegative olecranon bursitis with positive blood and aspirate cultures. The patient improved remarkably by treatment with streptomycin and doxycycline with no evidence or relapse.

Human brucellosis mimicking axial spondyloarthritis: a challenge for rheumatologists when applying the 2009 ASAS criteria

Although the development of the 2009 SpA classification criteria by Assessment of SpondyloArthritis international Society (ASAS) represents an important step towards a better definition of the early disease stage particularly in axial spondyloarthritis (axSpA), the specificity of the criteria has been criticized these days. As the commonest zoonotic infection worldwide, human brucellosis can mimic a large number of diseases, including SpA. This study was performed to determine the frequency of rheumatologic manifestations in patients with brucellosis and the chance of misdiagnosing them as having axSpA in central China. The results showed that clinical manifestations of axSpA could be observed in brucellosis. Over half of patients had back pain, and one fifth of the patients with back pain were less than 45 years old at onset and had the symptom for more than 3 months. Two young males were falsely classified as suffering from axSpA according to the ASAS criteria, and one with MRI proved sacroiliitis was once given Etanercept for treatment. Therefore, differential diagnosis including human brucellosis should always be kept in mind when applying the ASAS criteria, even in traditionally non-endemic areas.

Subclinical sacroiliitis in brucellosis. Clinical presentation and MRI findings

PURPOSE

The aim of this work was to detect subclinical sacroiliac joint involvement in patients with brucellosis and study their clinical and laboratory features.

PATIENTS AND METHODS

The study included 100 brucellosis patients being followed-up in the Gastroenterology and Hepatology Unit, Theodor Bilharz Research Institute and Cairo University outpatient clinics. A thorough history, physical examination, routine laboratory tests, and abdominal ultrasound were obtained for all patients. Extended rheumatological examination was performed including clinical testing for sacroiliitis and enthesitis. None of the patients reported a history of back pain or any symptoms suggestive of sacroiliitis during the course of the infection. Plain x-ray and MRI scan of the sacroiliac joints were performed for all patients.

RESULTS

Asymptomatic sacroiliitis was present in 24 % of the brucellosis patients; none of the patients had tenderness over their spine with preserved lumbar spine mobility. Sacroiliitis was mainly unilateral being bilateral in 20.83 %. There was an obvious relationship with animal contact and occupation of the patients. Osteoarticular involvement was common (67 %) including arthralgias, arthritis, myalgias, spondylitis, enthesitis and bursitis, being clearly higher in those with sacroiliitis. The MRI scan showed blurring of the margins in 66.67 %, widening in 25 %, narrowing in 54.17 %, erosions in 20.83 %, and sclerosis in 12.5 %.

CONCLUSION

Osteoarticular manifestations of brucellosis are prevalent and subclinical sacroiliitis is evident, a finding that may classify these patients as having brucellar spondyloarthropathy (BSA). Referring brucellosis patients for rheumatological assessment has the advantage of early assessment of asymptomatic cases with sacroiliitis which is commonly overlooked.

Prevalence of positive autoimmune biomarkers in the brucellosis patients

Brucellosis is a chronic infectious disease with articular involvement. Discrimination between brucellosis and rheumatologic disorders is difficult in regions endemic for brucellosis. There are few studies about the rate of positive autoantibodies as rheumatologic biomarkers in brucellosis, and the prevalence is variable. In this study, the rheumatologic tests were studied in brucellosis patients. This cross sectional study was performed in two teaching hospitals in Tehran, Iran. Forty-nine patients with brucella infection and 42 healthy participants were enrolled in this study. Brucellosis was diagnosed on the basis of the clinical symptoms and positive serology for brucellosis. Rheumatic factor (RF) and antinuclear antibodies (ANA) were evaluated in all patients. Cyclic citrullinated peptides antibody (ACPA) and anti-double strand DNA (anti-dsDNA) were checked in all patients and control groups. Out of 49 patients, 15 (30.6 %) were RF positive and 4 (8.2 %) were ANA positive. Anti-dsDNA was concurrently positive with ANA in 1 patient (2 %) but ACPA titer was positive in 8 patients (16.3 %). None of the patients with positive autoantibody biomarkers fulfilled the criteria for rheumatologic disorders. The rate of positive RF in healthy people was significantly lower than patient group (2.4 vs. 30.6 %), but the positiveness rate of other biomarkers did not have significant difference in two groups. Sixty percent of the patients with positive RF and 75 % with positive ACPA had skeletal involvement (P < 0.05). Autoantibody biomarkers can be positive in brucellosis. Rheumatologists should be aware of brucellosis in patients with musculoskeletal involvement and positive autoantibody biomarkers in endemic regions.