Chylothorax Flashcards

1
Q

Anatomy of thoracic duct

A
  • 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%)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Lymphatic drainage of right head, neck, chest wall, right lung, right heart, dome of liver, right diaphragm

A

Right lymphatic duct that drains into posterior junction of RIGHT jugular-SC junction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Primary physiologic role of the thoracic duct

A

Deliver digestive fat (60% of ingested fat) to the venous system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Main cellular component of thoracic duct lymph

A

T-lymphocytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Properties of chyle

A
  • Bacteriostatic
  • alkaline pH
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Normal rate of lymph flow

A

30-190 ml/hr

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Mechanics of normal lymph flow

A
  • Negative transdiaphragmatic pressure gradient
  • Thoracic duct valves
  • Normal intraductal pressure: 10-25 cmH2O
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

MCC of pleural effusion in neonatal period

A

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)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

MC non-penetrating traumatic MOA of thoracic duct injury

A

Hyperextension of the spine with rupture of thoracic duct just above the diaphragm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

MC operations associated with surgical injuries to the thoracic duct

A
  • Esophagectomy
  • Aortic operations
  • PDA ligation
  • Left pneumonectomy
  • Resection of posterior mediastinal tumors
  • Sympathectomy
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Laterality of duct injuries above (and below) T6

A
  • Right side: below T6
  • Left side above T6
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Incidence of chylothorax after esophagectomy

A

0.5-3.5%

*no assocation with approach

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

MOA of neoplastic chylothorax

MC neoplasm associated with chylothorax

A

Invasion, compression or tumor embolism of thoracic duct

Lymphoma (50% of cases)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Most postoperative chylothoracies drain how much

A

Excess of 1L/day

*If persists for > 1 week, mortality and morbidity increased

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Spontaneous healing of non-surgical thoracic duct fistula occurs __ %

A

< 50%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Laboratory (diagnostic) characteristics of chylothorax

A

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
17
Q

Pseudochylothorax

A

Accumulation of cholesterol in long-standing pleural effusion.

Cholesterol > 200 mg/dL with cholesterol crystals (no chylomicrons)

18
Q

Medical managment of chylothorax

A
  • 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
19
Q

Surgical treatment options for chylothorax

A
  • 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
20
Q

Indications for thoracic duct ligation

A
  • 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
21
Q

Surgical techniques to address thoracic duct

A
  • 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
22
Q

Visualization of thoracic duct can be enhanced by what measures

A

Ingestion of 6-8 oz of cream or olive oil 2-3 hours prior to surgery

23
Q

Effect of thoracic duct ligation on mortality

A

Reduction in mortality from >50% to ~ 10%

Prophylactic thoracic duct ligation advocated during esophagectomy