chylous fistula of the neck
TRANSCRIPT
CHYLOUS FISTULA OF THE NECK
Abhilash
OVERVIEW
Introduction Anatomy Pathophysiology Complications Etiology Investigation
Management› Medical› Surgical
What is Chyle? Alkaline,milky, odourless fluid 2-4L produced everyday
PROBLEM
Chylous fistulas are known to lead to prolonged hospitalization.
Clinically, chylous fistulas may be difficult to manage because of significant electrolyte, fluid, and protein imbalance.
FREQUENCY
Complication rate 1 - 2.5% of neck dissection involving level IV.
predilection for the left side of the neck, but up to 25% of cases involve the right side of the neck.
ETIOLOGY
Post operative complication› Radical neck
dissection› Selective neck
dissection› Anterior neck surgery
Penetrating trauma Node biopsy Cervical rib excision
ETIOLOGY
• Other potential causes of Chyle Leak– Lymphoma– Tuberculosis– Lymphangioleiomyomatosis– Liver cirrhosis– Congenital chylothorax (neonates)– Central venous cannulation– Idiopathic
PATHOPHYSIOLOGY
The thoracic duct is the conduit for lymph and dietary fat to reach the venous bloodstream.
The flow of chyle is around 2-4 L per day
Consists of fat 1-3% composed of TG (70% long chain), protein(3%), electrolytes content is the same as plasma except of lower calcium concentration, and lymphocytes (T lymphocyte).
Its daily production is dependent on the diet and daily dietary intake.
PATHOPHYSIOLOGY
Chemical composition of chyle is similar to that of tissue lymph, with higher concentration of cholesterol, phospholipids, and fat particles, particularly triglyceride rich chylomicrons and long-chain (>10 carbon atoms) esterified fats. .
PATHOPHYSIOLOGY
The flow of chyle against gravity is supported by the interplay of› thoracic and abdominal pressures,› transmission of peristaltic bowel contractions,› contraction of the lymphatic vessels walls› Venturi effect at the junction of the thoracic duct
and the subclavian vein
FAT METABOLISM
• 95% of ingested fats are triglycerides with long chain fatty acids (LCT).
• These fats are re-esterified in the mucosal cells of the bowel wall, combined with an apolipoprotein and phospholipid and transported into the lymphatic system as chylomicrons.
• Middle chain fatty acids (MCTs), length C12 or less, are absorbed directly into the portal system without the formation of chylomicrons, bypassing the lymphatics; this is important in dietary therapy of chylous fistulas.
The challenges in patient with chyle leak
Hypoproteinemia Hyponatremia Hypochloremia Dehydration Emaciation Lymphocytopenia and immunosupression Pleural effusion - chylothorax Wound problems - infection, suture breakdown,
hemorrhage Chylopharyngeal fistula Peripheral edema Secondary sepsis
INVESTIGATION
– Excessive drainage, >500ml/ day for more than 3 days
– Milky white appearance on enteral feeding– Clear fluid on withholding enteral feeding
• Biochemical– Triglycerides > 100mg/dL and chylomicrons>4%Dyes– Sudan III stains chylomicrons
(No quantitative criteria have been established)
- Ether
Imaging
Plain radiograph CT scan Lymphangiography Lymphoscintigraphy
MANAGEMENT OF CHYLE FISTULA
Outline of management › Prevention› Nutritional modification› Medical management› Surgical management
PREVENTION AND INTRAOP RECOGNITION
Meticulous surgical technique and knowledge of anatomy.
PPV/Raise IAP to detect small leaks. Trendenlenburg position ? Role of ingesting high fat content
preoperatively. Posterior approach of dissection
All chyle leaked discovered intraoperatively should be identified and ligated with non-absorable suture material [3/0 or 4/0]
The needle should not pass directly through the duct
Over sewing the duct continuously with the fascia attached to the duct stump using black silk.
If a chylous fistula was treated intra-operatively, medical management strategies should be initiated post-operatively without delay.
Suction drains in wound beds.
Local and regional flaps.
Scalenus anterior muscle flap. Sternocleidomastoid flap. Pectoralis major flap.
Other adjuncts
Sclerosing agents – OK 432 or tetracyclines. Induce inflammatory reaction in the wound
bed. Intraoperative or postoperatively through
drain. - report of phrenic nerve paralysis Cynaoacrylate adhesives Fibrin glue adhesives.
Postoperative recognition of chyle leak
High drain outputs after resuming feeding. Greasy white fluid in the drains. Confirmation by biochemical tests.
Medical management of chyle leaks.
Bed rest. ?Pressure dressings avoided in setting of flaps. Negative pressure wound therapy and
aspirations I/O charts, s.urea and electrolytes daily. Liver function tests including albumin.
Nutritional Management
Goals of therapy
› Reduce chyle fluid production› Replace fluid and electrolytes› Maintain replete nutritional status and prevent
malnutrition
Nutrition intervention Fat free diet (< 0.5g fat per serving)
Fat free diet supplemented with MCT
TPN
MCT vs TPN No clear consensus. Reports of increase output with MCT.
Enteral nutrition – if <1L per day Low fat, semi elemental if <500ml/day (MCT
diet – Lucente et al Elemental diet for 500ml to 1L TPN if > 1 L per day Addition of intralipids to TPN.
Patients who are only on fat free/MCT diet as the only fat source for any duration of time will have to supplement essential fatty acids (EFA)
EFA cannot be produced endogenously and must be taken in form of diet.› Linoliec acid› -linolenic acidἀ
Other important unsaturated fatty acids can be made from these EFA.› Arachidonic acid is synthesized from linolenic acid and
is the precursor molecule for prostaglandins, leukotrienes and thromboxane molecule
EFA deficiency can occur within 5 days of fat free diet.› Eczema › Impaired wound healing › Thrombocytopenia
Guideline in the Nutritional Management of Chyle Leak
Adequate protein intake› Chyle contains significant amounts of protein (22–60
g/L)› Recommendations for protein intake should account
for such losses if an external drain is present or with repeated chylous fluid “taps”
› Adequate intake may be a challenge for patients on a fat free oral diet
Essential fatty acid deficiency (EFAD)› 2%–4% of total calories from EFA required to avoid
EFAD› May occur within 1-3 weeks of a fat free diet› Diagnosis: triene to tetraene ratio of >0.4 &/or
physical signs of EFAD (see section on MCT oil for more details)
› IV fat emulsion may be required if a patient is unable to tolerate any oral/enteral fat or if it is unwise to try adding oral/enteral fat
› MCT oil does not provide significant EFA
Fat soluble vitamins› Fat soluble vitamins are also carried by the lymphatic
system› A multivitamin with minerals is generally
recommended for patients on a restricted oral or enteral regimen
› Water soluble forms of vitamins A, D, E, and K may be better utilized
Practical Gastroenterology,2004University of Virginia Health System Nutrition Support Traineeship Syllabus
Somatostatin It decreases the intestinal
absorption of fats, therefore TG concentration in the thoracic duct is lowered.
Somatostatin › reduces gastric, pancreatic and
intestinal secretion.› It inhibit the motor activity of the
intestine › slows the process of intestinal
absorption › reduces splanchnic blood flow › decreases hepatic venous pressure
DECREASES THE THORACIC DUCT LYMPH FLOW RATE
Orlistat – blocks the enzyme responsible for breakdown of fat and intestinal absorption
? SURGICAL MANAGEMENT
High output fistulas >500ml per day Usually after 5 -7 days of no reduction in chyle. Most surgeons recommend thoracoscopic
approach
SURGICAL MANAGEMENT
LOCAL PROCEDURES – › reexploration of wound site after fat rich diet.› And suturing with non absorbable suture or clips
and local flap.› Vicryl mesh overlay has been described.
SURGICAL MANAGEMENT
DISTANT PROCEDURE Transabdominal cannulation of thoracic
duct following lympgangiography Embolisation coils and cyanoacrylate glue
› 60% success Thoracoscipic ligation of TD. Right sided
approach