Chylothorax results from accumulation of chyle in the pleural space following injury to the thoracic duct. Initial management is conservative and is often successful, but surgical ligation may be necessary for a persistent leakage.
Surgical anatomy of the thoracic duct:
(1) There are many anatomic patterns, with minor variations.
(2) There is a rich collateral network.
(3) Most often the thoracic duct arises at the cisterna chyle in the midline at the level of L2.
(4) The duct enters the thorax through the aortic hiatus to the right of midline and is covered by the aorta.
(5) In the lower thorax it lies between the azygous vein and the aorta and is covered by the esophagus. The thoracic duct is essentially a single structure on the right between the T8-T12.
(6) The duct crosses to the left side at the level of T4-T5. It lies beneath the aortic arch and then the left subclavian artery.
(7) In the neck it curves ventrally to cross the anterior scalene muscle and phrenic nerve, then empties into the junction between the left internal jugular and subclavian veins.
Causes of chylothorax:
(1) idiopathic in neonate
(2) nontraumatic, usually due to compression of the thoracic duct by mediastinal involvement by tumor or lymphadenopathy
(3) following surgery (often cardiothoracic)
(4) following placement of a catheter in the subclavian vein (if the needle is directed too far superiorly during insertion)
(5) following physical trauma (after vertebral fracture, penetrating injury, etc.)
Nutritional complications can arise because of the volume and composition:
(1) The volume can reach 2.5 liters per day
(2) The fluid is rich in protein and electrolyte, approximating serum levels.
(3) Quantitative measurements may be difficult if drainage is incomplete or chest tubes become blocked..
Conservative management:
(1) reduction of oral intake to reduce chyle
(2) chest tube drainage if chylous effusion present (thoracentesis in the neonate)
(3) nutritional support
(2a) enteral nutrition with concentrated medium-chain essential fatty acids
(2b) total parenteral nutrition
(4) positive end-expiratory ventilation (PEEP) can compress the thoracic duct against the pleura with healing
Indications for surgical intervention – all of the following:
(1) failure of conservative management after 14-28 days
(2) average loss of chyle of >= 1,500 mL per day in the adult, or >= 100 mL per year of age in children, for >= 5 days
(3) development of nutritional or metabolic complications with clinical deterioration
Relative contraindications to early surgical ligation of the thoracic duct:
(1) idiopathic neonatal chylothorax (usually respond to conservative therapy)
(2) nontraumatic chylothorax (requires control of underlying disease process)
Surgical management:
(1) closure of fistula if identifiable, or ligation of the right thoracic duct at the level of the diaphragm on the right side
(2) pleurectomy or decortication to prevent reaccumulation
Specialty: Pulmonology
