Sleep disordered breathing and growth hormone therapy in children with Prader Willi syndrome

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Introduction Children with Prader Willi Syndrome (PWS) have several sleep abnormalities, including reduced REM sleep, altered sleep structure, oxygen desaturation and both central and obstructive apnea. PWS is now widely accepted as an indication for Growth Hormone (GH) treatment. GH may worsen sleep disordered breathing (SDB) presumably due to an IGF-1 mediated lymphoid tissue hypertrophy. Our study aims to evaluate the role of polysomnography (PSG) and non- invasive ventilation in children with PWS undergoing GH treatment. Materials and methods Descriptive observational study by review of medical charts and PSG reports in all children with PWS undergoing GH, at a tertiary hospital. Obstructive sleep apnea (OSA) was defined as an apnea–hypopnea index (AHI) > 1/h. Statistic descriptive analysis was done. Results A total of 11 children were identified, with a median age of 13 years (5;17), 6 (55%) were male and the median Body Mass Index (BMI) Z-score was 2,4 (1,1;2,8). All children underwent PSG, 9 of them before GH treatment, 1 soon after, and 1 before and after that therapy. Reduced REM sleep was found in all cases, and in 3 children was associated with reduced slow-wave sleep. Median AHI was 0,2/h (0;9,7) and median desaturation index (DSI) was 4,2 (0;50). Two children were already on non-invasive ventilation (NIV) when GH treatment was begun and performed PSG with ventilation. OSA was diagnosed in four children who initiated NIV before GH treatment, with elimination of respiratory events. The OSA group had a median BMI Z-score of 2,5 (2,3;2,8) versus 2,2 (1,1;2,4) in the non-OSA group. After treatment sleep respiratory symptoms were reported only in one child; she repeated PSG that didn’t reveal significant alterations. All children are still in treatment, without respiratory sleep complaints. Adenotonsillectomy (AT) was performed in three patients before GH treatment and in one afterwards. Conclusion As others, we have shown that children with PWS have altered sleep architecture with reduced REM and slow-wave sleep. The group with OSA had higher BMI Z-score, although the small dimension of the samples prevents a significant statistic analysis. When OSA is diagnosed and AT is not indicated, NIV is a successful therapeutic option, allowing GH treatment. Acknowledgements Raquel Firme Irina Carvalheiro.