Cohort study on neonatal course and long-term outcome in children with congenital chylothorax

<bold>Background:</bold> Congenital chylothorax is a rare pulmonary developmental disorder with high associated morbidity and mortality. Limited number of cases have been described and clinical manifestations and treatment outcomes vary. <bold>Methods:</bold> This study aims to delineate the neonatal and long-term outcome of patients with congenital chylothorax by retro- and prospective datacollection at the tertiary care hospital of Ghent, Belgium between 1992 and 2022. <bold>Results:</bold> 18 patients with congenital chylothorax were included, 7 of which had an anatomopathologic diagnosis of congenital pulmonary lymphangiectasia. 13 patients were born prematurely and male-female ratio was 2:1. Of 16 patients with prenatal diagnosis, 4 underwent an intra-uterine intervention. The most common comorbidities were hydrops (8/18), pulmonary hypertension (3/18) and reflux disease (6/18). One patient was diagnosed with Noonan syndrome. The majority of patients (14/18) required mechanical ventilation for an average of 16 days. Treatment included pleural drainage (15/18), total parenteral nutrition (14/18), medium-chain triglyceride diet (11/18), somatostatin (8/18) and surgical intervention (3/18), with an average hospital stay of 64 days. 3 patients died during or after the neonatal period. Follow-up ranged from 1 to 30 years, with most patients having good general health but variable respiratory complaints. More than 50% of performed lung function tests showed mild abnormalities. Overall quality of life was similar to a healthy control. <bold>Conclusion:</bold> Congenital chylothorax demonstrates a complex neonatal course. Long-term outcome is excellent in patients whitout comorbidities, although mild pulmonary function abnormalities may occur.