The nocturnal intermittent hypoxia caused by obstructive sleep apnea syndrome (OSAS) can provoke the sympathetic nervous activity (SNA). Salivary alpha-amylase (sAA) is a sensitive, non-invasive biomarker for reflecting the SNA, and a useful marker for pediatric OSAS subjects. Adenotonsillar hypertrophy (ATH) is the most commonly identified risk factor in OSAS childhood, therefore, several studies showed that the adenotonsillectomy (T&A) may alleviate nocturnal enuresis (NE) in children with OSAS.
The present study was to investigate the effect of T&A on NE, the change of sAA value in ATH and OSAS children, with/without NE, and with/without the operation.
37 children (Group A) were admitted for ATH and NE. The saliva samples were taken before and after polysomnography for the measure of sAA. After the T&A, the children were followed-up for 1 year. 35 OSAS children with NE but no T&A were as a NE watchful-waiting group (Group B), 32 subjects without OSAS or NE were as non-OSAS control (Group C), 42 cases who underwent T&A but did not have NE were admitted to evaluate the SNA (Group D). Follow-up included evaluations for NE, sAA and urinary catecholamine after the T&A or at the equivalent time points.
The observational results in the present study showed a significant rate of the disappearance of NE 1 month after the T&A and had an almost complete resolution 1 year later. OSAS may irritate oxidative stress and increase SNA in pediatric subjects, which reflected by increased levels of sAA and urinary catecholamine, while the T&A can decrease enuresis and the SNA in children with OSAS (Figure).
Little research has previously focused on the relationship between childhood OSAS and the SNA. No data are currently available regarding comparisons of sAA levels before and after the T&A in children with OSAS and enuresis. Our findings in this present study showed that there was a resolution or decrease in enuresis events and drops in sAA levels following T&A, which were consistent with earlier study. However, there was no significant difference in the urinary catecholamine levels was found between OSAS groups with or without NE. Furthermore, there was no correlation between the urinary catecholamine and polysomnography parameters.
T&A has a favorable therapeutic effect on NE and may decrease SNA in children with OSAS. sAA might be associated with instability of ANS by OSAS and have a consistent relationship with the apnea-hypopnea index. Our studying aims had been met.