Urine concentrations changes of cysteinyl leukotrienes in non-obese children with obstructive sleep apnea undergoing adenotonsillectomy

Objective: The main objective of the study was to compare preoperative to postoperative levels of urine-Cysteinyl leukotrienes (uCysLT) in children undergoing adenotonsillectomy (AT) for obstructive sleep apnea (OSA) in order to investigate whether exaggerated leukotriene activity is the cause or consequence of OSA. Methods and materials: A prospective study was conducted on non-obese children (4-10 years old) referred for overnight PSG. Children with moderate/severe OSA treated with AT were included. A second PSG study performed 2 months postoperatively to confirm OSA resolution, and those with residual OSA were excluded. Morning urine specimens after both PSG studies were obtained and pre-operative uCysLT levels were compared to postoperative levels. Results: 27 children fulfilled the criteria and underwent a post-operative PSG study with three exclusions for residual OSA (postop-AHI > 2), so the study group consisted of 24 children (mean age: 5.7 +/- 2.1 years). Mean preoperative and postoperative AHI was 10.96 +/- 5.93 and 1.44 +/- 0.56 respectively. Mean preop-uCysLT were 21.14 +/- 4.65, while after AT they significantly reduced to 12.62 +/- 2.67 (P < 0.01). Conclusion: uCysLT levels are significantly reduced after AT in non-obese children with moderate/severe OSA, suggesting that exaggerated leukotriene activity is mainly a consequence of OSA.