Chylous ascites following repair of total anomalous pulmonary venous connection coexisting with a persistent left superior vena cava in a neonate: a case report

Chylous ascites refers to the accumulation of lymphatic fluid in the peritoneal cavity. The causes of chylous ascites are various, and commonly include traumatic injury and obstruction, which disrupt the lymphatic system. In addition, cardiothoracic surgery may injure the thoracic duct and lead to chylothorax. However, there are very few reported cases of isolated chylous ascites developing following cardiothoracic surgery. In this paper, we report a case of postoperative chylous ascites in a full-term neonate. The infant underwent cardiothoracic surgery via thoracotomy to repair total anomalous pulmonary venous connection coexisting with a persistent left superior vena cava on day of life 17, and there was a significant increase in abdominal girth on postoperative day 12 (day of life 29). Abdominal ultrasound revealed an 8 mm thick ascites without pleural effusion. Abdominal paracentesis was performed and the milky-white peritoneal fluid was positive for Sudan III staining and the chylous test. The triglyceride concentration of the ascitic fluid was 691 mg/dL and the concentration of protein was 39.4 g/L. Additionally, the ascitic fluid also contained 6 360×106/L of white blood cells, predominantly lymphocytes. These results suggested the infant developed chylous ascites. Conservative management with fasting and medium-chain triglycerides-based formula successfully resolved the chylous ascites without reoccurrence. We present our experience of this rare condition and discuss the possible causes of chylous ascites in this case.