PM1024: COVID-19 Leading to Chylothorax in the Setting of Noonan Syndrome: Case Report

Introduction: Spontaneous chylothorax associated with Noonan syndrome is a rare complication that typically affects children and is mainly managed with enteric rest. It is largely due to the underlying lymphatic dysplasia where lymphatic vessels are hypoplastic and can cause obstruction, lymphangiectasis, and retrograde flow of lymph into the tissues. Usually, cardiac surgeries can trigger the underlying tendency of developing a chylothorax. We present a unique pediatric case where COVID-19 triggered its development.

Case Description: 11-year-old male with a history of Noonan Syndrome (RIT1 c.246T>A; p.Phe82Leu) and pulmonary valve stenosis s/p pulmonary valvuloplasty and subsequent pulmonary valve replacement presented with seven days of worsening cough, nasal congestion, shortness of breath, fever, and right-sided chest pain. He had a positive COVID-19 home test. He was hemodynamically stable without any respiratory distress. On examination, he had decreased breath sounds at the right lower lobe and a grade 2/6 crescendo-decrescendo murmur at the left upper sternal border. COVID-19 PCR done at the hospital was positive. Pertinent serum labs were: procalcitonin 0.08 ng/mL, 3.2 10*9/L leukocytes, blood culture with no growth, and DIC screen unremarkable. Chest computed tomography (CT) with contrast, done after a concerning chest x-ray, showed a large right pleural effusion, multiple bilateral pulmonary nodular opacities with ill-defined margins, and ground-glass attenuation (Figure 1). A chest tube initially drained blood-tinged cloudy fluid that turned milky over three days. Repeat CT with angiography showed decreased pleural effusion but with loculations for which the patient received pleural tissue plasminogen activator (tPA). Laboratory tests done within a day of chest tube placement showed pleural fluid/serum protein and LDH ratios of 0.98 and 0.64, respectively, and met Light’s criteria for being exudative. Chest fluid had 687 mg/dL of triglycerides and its cytology, AFB smear, and bacterial culture were negative. An echocardiogram was not concerning for an acute etiology, revealing stable mild pulmonary stenosis and regurgitation with normal biventricular size and function. It was determined to be chylothorax given fluid drainage eventually turned milky and had an increased quantity of triglycerides.

Discussion: Lymphatic dysplasia is present in less than 20% of the patients with Noonan syndrome and can rarely lead to chylothorax. Cardiac surgeries can trigger it but interestingly our patient never experienced post-operative chylous drainage following either previous cardiac surgery. COVID-19 infection triggered our patient’s underlying tendency to develop a chylothorax. Few case reports have reported the association of COVID-19 with chylothorax. It is probable that the prothrombotic state due to COVID-19 further led to impaired lymphatic drainage, and eventually chylothorax.

Conclusion: This case highlights that COVID-19 can cause the development of a chylothorax or chylous effusion in children with Noonan syndrome or among populations with a predisposition. Further studies will be required to ascertain the association of COVID-19 with chylothorax.