Retrospective Study of Children with Brucellosis and the Role of Blood Markers in Diagnosis

Objective Brucellosis is a zoonotic infection that spreads to humans via direct contact with infected animals, eating unpasteurized dairy products, or inhaling contaminated aerosols. After transmission, it replicates in regional lymph nodes and can affect multiple systems by entering the bloodstream. Although hematological laboratory findings such as leukocytosis/leukopenia, lymphocytopenia, anemia, and thrombocytopenia may be present in brucellosis patients, it is mainly an inflammatory disease that leads to elevated acute phase reactants. Our study examined whether inflammatory markers like platelet indices, neutrophil-to-lymphocyte ratio (NLR), and platelet-to-lymphocyte ratio (PLR) can help diagnose brucellosis. Materials and Methods The study included 42 children diagnosed with brucellosis and 44 healthy children as a control group, treated at the Pediatric Infectious Diseases Clinic of Erzurum Regional Training and Research Hospital between September 2018 and February 2019. Demographic data, presenting complaints, and physical examination findings on admission were retrospectively obtained from patient records. Laboratory parameters included complete blood count results—such as hemoglobin, red cell distribution width (RDW), mean corpuscular volume (MCV), platelet count, mean platelet volume (MPV), platelet distribution width (PDW), plateletcrit (PCT), and platelet-large cell ratio (P-LCR). Additionally, absolute counts of neutrophils, lymphocytes, and monocytes, inflammatory ratios (NLR, PLR, monocyte-to-lymphocyte ratio [MLR]), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and liver enzymes including alanine transaminase (ALT) and aspartate transaminase (AST) were recorded. Information on diagnostic methods and treatment regimens was also collected. Results Of the patients diagnosed with brucellosis, 30 were male and 12 were female. The mean age was 12.4 years (SD ± 3.7), ranging from 6 to 17 years. The most common complaints and physical examination findings on admission were weakness, arthralgia, and fever. Brucella agglutination test was positive in 35 patients (83.3%), blood culture was positive in 4 patients (9.5%), and brucella Coombs test was positive in 40 patients (95.2%). Most patients (42.9%) received a combination therapy including rifampicin, sulfamethoxazole/trimethoprim, and streptomycin. Significant differences in RDW, platelet count, and PCT values were observed between the patient group and the controls (p < 0.05). Discussion The study results show that RDW, platelet count, and PCT values could be helpful inflammatory markers for identifying brucellosis in children. However, markers such as MPV, PDW, P-LRC, NLR, PLR, and MLR were found to have no prognostic value. Further comprehensive studies are needed in this regard.