1209 A Case of Morquio Syndrome Presenting as Respiratory Failure Due to Severe OSA and Successful Long-term Treatment

Abstract Introduction Morquio Syndrome is a lysosomal storage disease (mucopolysaccharidosis type 4) characterized by the accumulation of glycosaminoglycans (GAG) and causes craniofacial, skeletal, and soft-tissue abnormalities. The pathophysiology of obstructive sleep apnea (OSA) is multifactorial due to GAG accumulation in upper airways, adenoids, trachea, and bronchi causing narrowing and collapsibility of the airways. Report of case(s) A nine-year-old male with Morquio Syndrome presented to the emergency department with difficulty staying awake for 5 days and an upper respiratory tract infection. He would doze off and wake up every few minutes several times a day. He had no prior history of somnolence. He was admitted to the ICU given the severity of the presentation and was clinically started on BiPAP. There was also a history of loud snoring but no witnessed apneas. An in-laboratory polysomnogram was performed to confirm his diagnosis of severe OSA and sleep-related hypoxemia, with an apnea-hypopnea index of 34.1, minimum oxygen saturation 78%, and time 90% of 74.8 minutes. After a titration study, he was started on noninvasive ventilation (NIV) with bilevel PAP. He remained compliant with outpatient NIV therapy and did not have any hospital admission for respiratory illness. Seven years later, he had a repeat titration study and was switched to NIV with AVAPS. He had one emergency visit for dyspnea and tested positive for influenza. A CT at that time showed severe tracheal stenosis of 8 mm at the thoracic inlet. On direct visualization with laryngoscopy, the stenosis was noted to be around 3 mm, probably due to dynamic airway obstruction. He improved with symptomatic treatment and was discharged the next day. Despite having significant airway abnormalities, he has never required intubation for respiratory failure, likely attributable to consistent use of NIV therapy. Conclusion Symptoms of OSA can be subtle, and if unrecognized, can potentially progress to respiratory failure. It is crucial, particularly in children with airway abnormalities, to actively screen for symptoms of OSA and initiate appropriate treatment. Our case highlights successful long-term treatment spanning more than a decade in an individual with Morquio Syndrome and avoidance of tracheostomy using NIV with bilevel PAP and AVAPS therapy. Support (if any)