550 Laryngomalacia and obstructive sleep apnea in infants with PWS

Introduction Growth hormone (GH) improves tone, body composition, development, and growth in infants with Prader-Willi Syndrome (PWS). Concerns about sudden death following GH initiation and worsening obstructive sleep apnea (OSA) in children with PWS resulted in guidelines for polysomnography (PSG) evaluation before and after starting GH. We review novel evidence of laryngomalacia as a mechanism for this worsening of OSA and describe the incidence of laryngomalacia in this patient population. Methods A retrospective review of infants and children seen at the Seattle Children’s PWS clinic between October 2014 and May 2020 who had undergone polysomnography (PSG) before and after growth hormone initiation was performed. Findings on otolaryngology evaluation via flexible fiberoptic laryngoscopy (FFL) or drug-induced sleep endoscopy were reviewed to characterize obstruction, diagnosis of laryngomalacia, and response to surgical intervention. Results A total of 28 cases were identified. 12 (41%) were evaluated with FFL between ages 4 and 21 months old (median 5) for noisy breathing, worsening or persistent OSA, or dysphagia. Out of these, 9 (75% of FFL, 31% of total) were diagnosed with laryngomalacia. Children with laryngomalacia were more likely to have worsening of OSA after GH initiation. Surgical interventions including supraglottoplasty or adenotonsillectomy led to improvement in OSA in 86% of children who had worsening after GH initiation. Conclusion Worsening OSA after GH initiation is seen in 38% of patients with PWS. Laryngomalacia is a common comorbid condition and more frequent in those with worsening OSA after GH initiation that is amenable to targeted surgical intervention. Support (if any):