Rare Case of Spontaneous Idiopathic Chylothorax in an Adult With Noonan Syndrome

Document Type

Abstract

Publication Date

5-1-2023

Abstract

Noonan syndrome is a genetic disorder with wide spectrum of symptoms and physical features with variable severity. These include facial abnormalities, skeletal malformations, congenital heart defects, intellectual disabilities, and lymphatic abnormalities including spontaneous chylothorax. Although rare, risk of lymphatic abnormalities can persist into adulthood. We present a case of spontaneous chylothorax in an adult patient with Noonan Syndrome (NS). 45-year-old male with Noonan syndrome (KRAS mutation Y71D) presented with fever, cough, and dyspnea for two days. Physical examination revealed oxygen saturation of 88% of ambient air but otherwise normal vital signs, lung examination showed bibasilar dullness (right > left) and decreased breath sounds over the right middle and lower lung zones. Admission was complicated with PEA cardiac arrest requiring intubation. CT chest revealed a large right pleural effusion and bilateral opacities concerning for multifocal pneumonia. Chest tube was placed in the right pleural cavity yielding 2900cc of milky fluid. Spontaneous chylothorax was diagnosed with triglycerides >1000 mg/dL and cholesterol 107 mg/dL. Bacterial and fungal cultures remained negative. Patient was placed on a low-fat enteral nutrition with medium chain triglycerides (MCT) supplementation. Patient continued to have chylous drainage via the chest tube. Lymphangiogram showed opacification of peribronchial lymphatics suggestive of absence or atresia of the terminal thoracic duct with retrograde flow along the peribronchial lymphatics. MR Lymphangiogram showed MR Lymphangiogram showed abnormal lymphatic flow from the thoracic duct into lung parenchyma. He underwent successful glue embolization of the thoracic duct and collateral channels. Patient was discharged to acute rehab with plan to begin trial of MEK inhibitor as outpatient. Lymphatic abnormalities are one of the major features of Noonan syndrome. Lymphatic dysplasia and hypoplasia lead to development of peripheral lymphedema and rarely chylous ascites and chylothorax due to obstruction, lymphangiectasia, and retrograde flow into tissue. Commonly seen within the first 2 years of life, patients carry a lifelong risk of lymphatic abnormalities with overall prevalence being 20%. Our patient did not have the usual risk factors of trauma or history of cardiothoracic surgery yet developed spontaneous idiopathic chylothorax. As underlying pathophysiology remain unclear, treatments are largely directed towards supportive, and symptoms related. They include dietary modifications to limit fat consumption, MCT oil supplementation, embolization in the event of refractory chylous leak. MEK inhibitors can be considered as possible treatment option for Noonan syndrome with KRAS syndrome. However, there is a paucity of data in this regard and require further research. (Table Presented).

Publication Title

American Journal of Respiratory and Critical Care Medicine

Volume

207

First Page

A3388

Last Page

A3388

Comments

American Thoracic Society International Conference, ATS 2023 held 2023-05-19 to 2023-05-24 in Washington, DC

Link to Full Text

Open Access

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