This retrospective study was performed by the two center of medical faculty of university pediatric clinics. The medical records of all patients with BA between November 2011 and January 2014 were obtained from the hospital records. A total of 64 children with BA and 66 age- and gender-matched healthy controls were enrolled in the study.
Healthy subjects were children who applied to hospital for routine check-up or for preoperative evaluation of minor elective surgery such as circumcision or hernia repair. Control group subjects were recruited from hospital records of these children. Children with any sign of infection or systemic illness were excluded from the control group.
Arthritis occurred for the first time in all patients within the week before admission to hospital. The diagnosis of arthritis was made if the subjects had joint pain, restriction of movement, and swelling. Swelling was not essential for the diagnosis of hip, spine, or sacroiliac arthritis. Although encountered in many cases, additional signs such as effusion, redness and increased temperature on joint were not considered essential for the diagnosis of arthritis.
The diagnosis of brucellosis with joint involvement was established according to the presence of all of the following criteria; a clinical picture compatible with arthritis, isolation of Brucella from blood or synovial fluids, positive brucella serology test 1:≥160, using the Standard Agglutination Test (SAT) for patients presenting with symptoms suggestive of brucellosis. For screening and in the absence of clinical indicators of active brucellosis, a titer of 1:320 or higher is more specific for the presence of the disease. Pediatric patients with a synovial fluid culture positive for brucella and available results of the cytological examination of the synovial fluid aspirate were identified. Relevant demographic, clinical and laboratory data, and treatment modalities and outcomes were obtained from patients’ follow-up cards and hospital records.
Hemogram parameters including white blood cell (WBC) count, neutrophil count, lymphocyte count, hemoglobin (Hb), platelet count (PLT), platelet distribution width (PDW), red cell distribution width (RDW), mean platelet volume (MPV), neutrophil to lymphocyte ratio (NLR) and platelet to lymphocyte ratio (PLR) were assessed. C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), agglutination assay and culture for both blood and joint puncture at admission were also recorded.
NLR and PLR were calculated as the ratio of neutrophils to lymphocytes and platelets to lymphocytes, respectively. These hematological variables were measured and recorded in the healthy control subjects as well. Comparison between the study and the control subjects was performed with regards to WBC, neutrophil count, lymphocyte count, PDW, RDW, PLT, MPV, NLR and PLR. Blood samples were obtained using a vacutainer and collected in tubes containing standard EDTA. All blood samples were tested for hematological parameters using the same regularly calibrated analyzer (Abbott CELL-DYN 3700, United States).
Joint fluid was aspirated from the affected joint following a strict sterile technique. Since usually only small amounts of fluid were obtained, the synovial fluid specimens were only sent for cytological and bacteriological examination, and tested for antibrucella antibodies using microagglutination test.
WBC, Hb, neutrophil count, lymphocyte count, PLT, MPV, NLR and PLR values were compared between the study and the control groups.
Patients with a clear-cut underlying pathology like various bone and joint diseases, connective tissue, rheumatic disorders, chronic disorders, anemia or other hematological diseases, acute bacterial infection as well as fever of other etiologies, who were over 18 years old and whose file records were inaccessible, were excluded from the study.
The Non-Interventional Clinical Ethics Committee of Dicle University Medical Faculty approved the study protocol.
The normality of data distribution was determined using the Kolmogorov-Smirnov test. Normally distributed numerical variables were expressed in mean plus/minus standard deviation. Normally distributed numeric variables were compared using the Student’s t-test or One-way ANOVA test. Data corresponding to an abnormal distribution were compared using the non-parametric Mann–Whitney U-test or Kruskal-Wallis test. The Chi-square test was used to compare categorical variables between the groups. Correlations between numerical variables were evaluated using Pearson’s or Spearman’s correlation analysis. P-values of less than 0.05 were considered statistically significant. The data were analyzed using Statistical Package for Social Sciences (SPSS) version 18.0 program for Windows.