Chylothorax Flashcards
Anatomy of thoracic duct
- originates from cisterna chyli (T10-L3)
- enters thorax through aortic hiatus (T12)
- Course
- anterior to vertebral bodies (between Ao and azygous vein)
- posterior to esophagus
- Crosses midline to left: T4-5 (coursing to left of esophagus)
- Arches laterally at C7 (anteiror to SC artery, superficial to phrenic/anterior scalene)
- Passes behind carotid sheath and terminates into jugular-SC vein junction
- Single branch (80%)
- Multiple branches (20%)
Lymphatic drainage of right head, neck, chest wall, right lung, right heart, dome of liver, right diaphragm
Right lymphatic duct that drains into posterior junction of RIGHT jugular-SC junction
Primary physiologic role of the thoracic duct
Deliver digestive fat (60% of ingested fat) to the venous system
Main cellular component of thoracic duct lymph
T-lymphocytes
Properties of chyle
- Bacteriostatic
- alkaline pH
Normal rate of lymph flow
30-190 ml/hr
Mechanics of normal lymph flow
- Negative transdiaphragmatic pressure gradient
- Thoracic duct valves
- Normal intraductal pressure: 10-25 cmH2O
MCC of pleural effusion in neonatal period
Congenital Chylothorax
- Respiratory distress at birh or 1st weeks of life
- MOA:
- atretic thoracic duct
- multiple dilated lymphatic channels of fistulas
- Tx: conservative (self limited)
- Breastfeeding ok
- Thoracocentesis for inital relief
- Pleuroperitoneal shunting for persistent chylothorax (in absence of ascites)
MC non-penetrating traumatic MOA of thoracic duct injury
Hyperextension of the spine with rupture of thoracic duct just above the diaphragm
MC operations associated with surgical injuries to the thoracic duct
- Esophagectomy
- Aortic operations
- PDA ligation
- Left pneumonectomy
- Resection of posterior mediastinal tumors
- Sympathectomy
Laterality of duct injuries above (and below) T6
- Right side: below T6
- Left side above T6
Incidence of chylothorax after esophagectomy
0.5-3.5%
*no assocation with approach
MOA of neoplastic chylothorax
MC neoplasm associated with chylothorax
Invasion, compression or tumor embolism of thoracic duct
Lymphoma (50% of cases)
Most postoperative chylothoracies drain how much
Excess of 1L/day
*If persists for > 1 week, mortality and morbidity increased
Spontaneous healing of non-surgical thoracic duct fistula occurs __ %
< 50%
Laboratory (diagnostic) characteristics of chylothorax
Pleural fluid with:
- Triglyceride level > 110 mg/dL (99% diagnostic)
- <50 ml/dL excludes chylothorax with 95% probability
- 50-110 ml/dL: check chylomicrons
- Chylomicrons: very specific finding for chylothorax
- Fat staining with Sudan-3
- Cholesterol : Triglyceride ratio < 1
Pseudochylothorax
Accumulation of cholesterol in long-standing pleural effusion.
Cholesterol > 200 mg/dL with cholesterol crystals (no chylomicrons)
Medical managment of chylothorax
- Drainage of pleural space
- Reduction of chyle flow (somatostatin)
- Hydration
- Nutrition (medium-chain triglycerides)
- Reduction in dietary intake and long-chain f.a.
- TPN may be preferred
- ~ 25-50% spontaneous closure rate
- Infection rare as chyle is bacteriostatic
Surgical treatment options for chylothorax
- Pleurodesis (chemical)
- fistula healing likely due to obliteration of pleural space rather than vessel closure
- Pleuroperitoneal shunting (no ascites)
- malignant chylothorax
- thoracotomy contraindicated
- Percutaneous transabdominal duct catheterization and embolization
- frail pateints not able to tolerate duct ligation
- Thoracic duct ligation
Indications for thoracic duct ligation
- Thoracic duct drainage > 1500 ml/day (adults) or > 100 ml/day (children) over 5 day period despite medical managment
- Persistent leak > 2 weeks
- Nutritional or metabolic complicaitons
- Entrapped lung with inability to drain collection with thoracostomy
- Post-esophagectomy chylothorax
- high morbidity and mortality due to immunologic and metaboic imbalances
Surgical techniques to address thoracic duct
- Direct ligation of thorcic duct
- Mass ligation
- all tissue between Ao, spine, esophagus and azygous vein
- performed above diaphragmatic hiatus (right pleural space)
- VATS ligation
- Pleurectomy
- Fibrin glue
- Pleuroperitonal shunt
Visualization of thoracic duct can be enhanced by what measures
Ingestion of 6-8 oz of cream or olive oil 2-3 hours prior to surgery
Effect of thoracic duct ligation on mortality
Reduction in mortality from >50% to ~ 10%
Prophylactic thoracic duct ligation advocated during esophagectomy
