Clinical variables determining the success of adenotonsillectomy in children with Down syndrome
Introduction
Down syndrome (DS) is the most common chromosomal disorder, with an estimated incidence of 1: 1000 live births worldwide and 1.13: 1000 live births in Brazil [1], [2], [3].
Obstructive sleep apnea syndrome (OSAS) may prevent these patients from reaching their full developmental capacity. The prevalence of OSAS in children with Down syndrome has been estimated at 57%–66.4% in studies that evaluated data obtained from full-night polysomnography assessment [4], [5], [6].
The possible causes for the high prevalence of OSAS in these patients with DS are the craniofacial anatomical alterations found in this specific population, such as middle-third facial hypoplasia, micrognathia, flaccid supraglottis, narrow nasal fossae and oropharynx [7], [8]. Hypertrophy of the pharyngeal and palatine tonsils, reduced-volume oral cavity, narrow palate, glossoptosis, relative macroglossia, increased secretion production, cervical fat deposition, hypothyroidism and generalized muscular hypotonia are also contributing factors [7], [9], [10], [11].
In healthy children, OSAS results in growth deficit, developmental impairment, behavioral problems, low academic performance, systemic and pulmonary arterial hypertension. In children with DS, OSAS also impairs executive function and is associated with poor verbal fluency and lack of inhibition, which may hinder the ability of these patients to function independently [9], [10], [12].
Polysomnography (PSG) is the gold standard for the diagnosis of sleep-disordered breathing and it helps therapeutic decision-making and surgical indication [13]. PSG prior to adenotonsillectomy (AT) in DS patients is crucial, as it defines OSAS severity and predicts the need for postoperative monitoring. Postoperatively, the PSG is also indicated in these patients, as it identifies children with residual OSAS who may require further treatment [13], [14]. Although it is not curative in all patients with DS, the adenotonsillectomy (AT) is the treatment of choice for OSAS in these patients [7].
The aim of this study was to evaluate the evolution of clinical complaints and polysomnographic parameters in children with OSAS and DS submitted to adenotonsillectomy. We also planned to verify the interaction of comorbidities (heart disease and hypothyroidism) in the therapeutic outcome.
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Material and methods
A longitudinal study of a historical cohort of children with DS and habitual snoring, treated at the Pediatric Otorhinolaryngology Outpatient Clinic of Universidade Federal de São Paulo, São Paulo, SP, Brazil, was carried out from 2005 to 2015. The patient's files were identified in a database based on the diagnosis according to the International Classification of Diseases (ICD 10) codes Q90.9 for DS, G47.3 for sleep apnea and J35.3 for pharyngeal and palatine tonsil hypertrophy. The
Results
Ninety patients with DS and habitual snoring were identified. Sixty-three patients were excluded: 23 were on surgical planning, 25 were not submitted to preoperative or postoperative PSG, 3 had total sleep time <180 min, and 12 had primary snoring.
The characteristics of the final sample, consisting of 27 patients with OSAS, can be seen in Table 1. The mean age at the date of surgery was 6.7 ± 3.6 and ranged from 1.5 to 16 years. Data of excluded patients were similar to data of patients
Discussion
The main findings of this study were: 70.4% of the children with Down syndrome persisted with OSAS after tonsillectomy. However, there was a decrease in arousal index, and an increase in the minimal oxygen saturation. Patients with severe OSAS had a significant improvement in polysomnographic variables after adenotonsillectomy. As for the comorbidities, we observed that the central apnea index of children with heart disease worsened after AT, as well as the apnea-hypopnea index and central
Conclusion
The adenotonsillectomy was able to cure OSAS in 29.6% of the children with DS and 44.4% showed a reduction of at least 50% in O-AHI. Patients with severe OSAS were the ones most likely to show improved respiratory data in the polysomnography. Congenital heart disease and hypothyroidism may interfere with the polysomnographic parameter improvement.
Acknowledgments
To the statistician, Jimmy Adans Costa Palandi, who performed the statistical analysis of the collected data.
To Sonia Strong, who provided language help.
This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
Polysomnographies were funded by the Associação Fundo de Incetivo à Pesquisa - AFIP.
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