Chylothorax in a 3-month-old boy with respiratory syncytial virus infection

Chylothorax is a condition in which chyle leaks into the thoracic cavity. The causes of chylothorax can be nontraumatic, traumatic or idiopathic. The most common cause of nontraumatic chylothorax is obstruction of the thoracic duct by tumor. Traumatic chylothorax is caused by disruption of the thoracic duct, most often due to cardiac surgery or a thoracic surgical procedure, although in rare cases by cough or vomiting. We report the case of a 3-month-old boy with respiratory syncytial (RS) virus infection who presented with right chylothorax. No obstructive tumor mass was identified in the thoracic duct. Clinical symptoms of Noonan syndrome and Down syndrome, which often accompany lymphatic anomaly, were not found. Therefore, we speculate that his severe cough caused a high thoracic pressure and a disruption of the thoracic duct. He was treated by thoracocentesis and MCT milk. One month later, pleural effusion disappeared and did not recur. RS virus infection might be a rare cause of chylothorax in infants.