RESUMEN
Chylothorax is the accumulation of chyle-containing lymphatic fluid within the pleural space. It is mainly caused by injury or obstruction of the thoracic duct due to neoplasm or trauma. There have been several reports of chylothorax associated with chromosomal anomaly such as Down syndrome. Most cases are congenital, and development of chylothorax in an adult with Down syndrome is rare. Here, we report a case of chylothorax in an adult with Down syndrome who had been treated with mechanical ventilation. A 31-year-old woman with Down syndrome was admitted with urosepsis. She was treated with mechanical ventilation due to severe respiratory acidosis. Four days after mechanical ventilation, she developed unilateral pleural effusion, and analysis indicated chylothorax. After conservative treatment, including fasting and total parenteral nutritional support, the chylous formation completely disappeared.