Clinical characteristics of nontraumatic chylothorax in pediatric patients

Abstract

Background: Chylothorax is a condition in which chylous fluid accumulates into the pleural space. The etiologies of chylothorax are various and traumatic or postoperative chylothorax is common. Nontraumatic chylothorax in children is rare and more difficult to treat than traumatic chylothorax. In some cases, they are refractory to conventional treatment, leading to severe morbidity and mortality. Thus, the purpose of this study is to analyze the clinical features of chylothorax in pediatric patients in our hospital and seek appropriate therapeutic management. Method(s): A retrospective review was performed in 63 patients with chylothorax from January 2000 to December 2018 in the Children's Hospital of Seoul National University. Traumatic or postoperative chylothorax was excluded. A total of20 patients with nontraumatic chylothorax were included in our study. Etiology, treatment, and outcome of chylothorax were analyzed. Result(s): Nontraumatic chylothorax was diagnosed in 20 patients. Male patients (14/20 = 70%) were more frequently affected than female (6/ 20 = 30%) patients. Eighteen patients were diagnosed before 1 year of age (90%), only two patients were diagnosed after 1 year of age (6 years old, 12 years old respectively). The most common cause of spontaneous chylothorax was idiopathic factors, constituting 45.5% (13), three cases were related to high central venous pressure due to venous thrombosis and recurrent sepsis, 2 cases were related to Down syndrome, 1 case was Noonan syndrome, and the remaining case was Gorham stout syndrome. Seventeen patients needed a respiratory support device, 6 of the latter received low flow oxygen supplementation, 11 patients received ventilator support. Dietary modification (NPO or MCT base feeding), conventional medication (somatostatin or octreotide), sirolimus, surgical management were administrated to our patients. In the neonate and infant group, three patients who were related to venous thrombosis died because of recurrent septic shock before chylothorax management was administered. Fifteen patients received a dietary modification (NPO or MCT base feeding) and nine patients improved by conservative management. One patient died due to heart failure before medical treatment. Somatostatin or octreotide was used in 5 patients who failed dietary modification, but only one patient improved with octreotide. Among the somatostatin or octreotide failure group, 4 patients received surgical management (pleurodesis or thoracic duct ligation). Three of these patients improved, although one patient died after thoracic duct ligation operation because of post-op ARDS. Two patients who were diagnosed after 1-year of age were refractory to nutritional modification and conventional medication such as somatostatin or octreotide. However, lymphatic intervention and surgical treatment were not suitable for these two patients. Considering that their underlying disorder consisted of Noonan syndrome and Gorham stout syndrome, we used sirolimus to treat the refractory chylothorax. After administration of sirolimus, their chylothorax improved compared to before. Conclusion(s): Most of the nontraumatic spontaneous chylothorax in pediatric patients occur in newborns and the most common cause of chylothorax in the neonatal and infantile period is idiopathic. On the other hand, nontraumatic chylothorax in childhood is rare and tends more to be accompanied by the underlying syndrome. Moreover, the treatment failure rate is higher in the childhood group. In such cases, sirolimus which is an mTOR inhibitor, can be beneficial to patients who tend to be refractory and cannot be treated with lymphatic intervention or operation.