Etiology

Chylothorax in children occurs most frequently because of thoracic duct injury as a complication of cardiothoracic surgery (Fig. 409-1). Other cases are associated with chest injury (Fig. 409-2) or with primary or metastatic intrathoracic malignancy (Fig. 409-3), particularly lymphoma. In newborns, rapidly increased venous pressure during delivery may lead to thoracic duct rupture. Less common causes include lymphangiomatosis; restrictive pulmonary diseases; thrombosis of the duct, superior vena cava, or subclavian vein; tuberculosis or histoplasmosis; and congenital anomalies of the lymphatic system (Fig. 409-4). Refractory chylothorax in the fetus has been associated with a missense mutation in integrin aα₉. Chylothorax can occur in trauma and child abuse (Chapter 37). It is important to establish the etiology, because treatment varies with the cause. In some patients, no specific cause is identified.

Figure 409-1 Chylothorax (arrows) following cardiac surgery in a 2 wk old infant.

Figure 409-2 Left chylothorax (arrows) following spinal fusion with Harrington rods. It is postulated that the thoracic duct was injured during spine surgery. The pigtail chest tube (arrowhead) needed to be retracted to better drain the effusion.

Figure 409-3 Large right chylous effusion opacifying much of the right thorax in a teenager with pulmonary lymphangiomatosis and hemangiomatosis. Note the associated interstitial lung disease.