The impact of adenotonsillectomy on monosymptomatic primary nocturnal enuresis in children with obstructive sleep apnea syndrome

Objectives: To analyze the outcome of monosymptomatic primary nocturnal enuresis (MPNE) after adenotonsillectomy in children with obstructive sleep apnea syndrome (OSAS). Methods: The study included 74 MPNE children with OSAS qualified for an adenotonsillectomy procedure. MPNE was assessed prior to surgical procedure as well as 3 and 6 months after surgery. In addition to polysomnographic parameters, serum antidiuretic hormone (ADH) and brain natriuretic peptide (BNP) levels were measured preoperatively and 3 months postoperatively. Results: The mean age was 9.8 years and the mean number of nocturnal wetting weekly was 4.1. Thirty-eight percent of patients had family history of MPNE. All the patients underwent a successful adenotonsillectomy. Nocturnal enuresis was still reported in 18% of children 6 months after adenotonsillectomy. An increased risk of MPNE was significantly demonstrated in children with high obstructive apnea-hypopnea index (O-AHI), high oxygen desaturation index (ODI), high frequent nocturnal enuresis and family history. After surgery, ADH levels were significantly lower, whereas BNP levels were significantly higher in non-resolution children. Univariate analysis showed that higher O-AHI, higher ODI, severe enuresis, low serum ADH and higher serum BNP levels were indicative of persistent nocturnal enuresis. Multivariate analysis showed that higher ODI and higher BNP levels are independent prognostic markers for MPNE. Conclusions: Adenotonsillectomy in MPNE children with OSAS is an effective treatment for resolution of MPNE. Also, higher ODI caused by apnea and elevated serum BNP levels are the most important factors affecting the outcome of MPNE patients.