Evaluation of the Relationship Between Thyroid Function Tests and Markers of Infection Severity in Children Presenting with Acute Infections

Aim: In cases of mild to moderate infections, a phenomenon known as non-thyroidal illness syndrome may occur, characterized by reduced thyroid hormone levels despite an intact thyroid gland.This study aimed to investigate the relationship between thyroid function tests and inflammatory markers in children with acute infections. Materials and Methods:Children under the age of 18 years who had previously presented to the Pediatric Outpatient Clinics of University of Health Sciences Trkiye, zmir City Hospital with acute infections and had blood tests performed were included in this study.Data of thyroid functions and infection markers were collected from the records.Results: A total of 50 patients and 112 individuals in a control group under the age of 18 years were included in this study.No statistically significant differences were observed between the groups in terms of demographic or baseline clinical characteristics.Serum triiodothyronine (T3) and thyroid-stimulating hormone levels were significantly lower in the patient group, while levels of C-reactive protein (CRP), procalcitonin, and erythrocyte sedimentation rate, as well as the CRP/lymphocyte ratio (CLR), neutrophil/lymphocyte ratio (NLR), and monocyte/lymphocyte ratio (MLR) were significantly higher in the patient group.The median T3 level was significantly lower in the patient group.A subgroup analysis was performed in order to assess the relationship between T3 levels and complete blood count/infection markers.A negative correlation was observed between T3 levels and CRP, procalcitonin, neutrophil counts, as well as CLR, NLR, MLR, and disease severity. Conclusion:Thyroid function tests, in conjunction with infection markers, may serve as potential predictive tools for clinical outcomes.There is a correlation between infection/inflammation markers and thyroid function in pediatric patients with acute infections.