GASTRO INTESTINAL FISTULA

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GASTRO INTESTINAL FISTULA
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Introduction
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• A fistula is an abnormal transmural communication
  between two epithelised surfaces
• When it involves gut on on or both sides it is a
  gastrointestinal fistula
• Leads to volume,electrolyte and nutritional
  defecits
• Sepsis malnutrition and electrolyte disturbances
  are the principal causes of death
• Overall mortality is 6-20
• Malignancy accounts for 5-30 of thers deaths

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Classification
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Internal /external

• Internal-communicate with other portions of GIT
  or other organs
• External-with the skin and drainage of enteric
  contents to skin or vagina

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Anatomic classification

• Internal/external anatomic course
• Suggests etiology
• Prognosticates spontaneous closure
• Assists planning operative timing and approach

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Physiologic classification

• Based on output
• Low(lt200ml/24 hrs)
• Moderate(200-500ml/24 hrs)
• High(gt500ml/24 hrs)
• Prognosticates mortalities

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Etiologic classification

• Based on underlying disease process
• Prognosticates spontaneous closure prognosticates
  mortality

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Etiology

• Spontaneous (15-25)of EC fistulas
• Iatrogenic (75-80)

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Spontaneous

• Radiation, IBD, diverticular disease,
  appendicitis, ischemic bowel, indwelling tubes,
  perforation of duodenal ulcer, malignancies, TB,
  actinomycosis
• Radiation ,recurrent cancer and IBD fistulas
  often require surgical closure

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Iatrogenic

• Cancer operations, operations for IBD, operations
  for adhesions

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Anatomy of fistula

• Predicts chance of closure

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Oral and pharyngeal fistulas

• Spontaneous advanced head and neck cancer
• Fistulas resulting from surgical treatment(more
  common now)
• Non operative treatment usually will result in
  spontaneous closure

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Oesophageal fistulas

• Cervical
• Post operative leaks of cervical anastomosis
• Undetected or inadequate repair
• Usually close spontaneously

• Occurring in chest
• Leak,tumor,instrumentation,postemetic
  perforations
• Empyema mediastinitis and sepsis
• Usually mandates operative intervention

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Gastric fistulas

• Post operative in 85-90cases
• Gastric resection for ca, peptic ulcer Sx,
  bariatric Sx,ischeamia, cancer and radiation
• Avg time from diagnosis to closure40 days
• Mortality 15-25
• Outputgt200 increases to 40
• Associated sepsis-60
• 30-50spontaneous closure rates

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Duodenal fistulas

• 5-85 post operative
• spontaneous closure rates vary from 30-80
• Mortality 28
• When spontaneous closure occurs mean time is
  30-40

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Small intestinal fistulas

• Most common type of GI fistulas
• 70-90 post operative
• Disruption of anastomosis,unrecognised
  injury,inadverent suturing,less than adequate
  prepration,less adequate blood supply,per-op-hypot
  ension,tension at sutures,abscess adjacent to
  anastomosis,poor nutritional status
• Spontaneous closure rates of ilieal(32) and
  jejunal (higher)

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Pouch fistulas

• Follows total procto colectomy with iliealpouch
  and pouch anal anastomoses
• Poor blood supply
• Crohns pathology

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Colonic fistulas

• Diverticulitis, cancer, IBD, Pancreatitis,
  appendicitis, radiation therapy, post operative
• Low output
• Post op has spontaneous closure rates of 80-90
• Post appendicectomy- most close spontaneously

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Internal fistulas

• Crohns disease and diverticulitis account for
  most internal fistulas
• Crohns (enteroenteric,enterovesical,enterocolonic,
  colovaginal0
• Diverticulitis(colovesical in males and
  colovaginal in females)
• Malabsorption,intractable diarrhea,infections,obst
  ruction,short bowel syndrome

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Prevention

• Guidelines to be followed per operatively

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• Tension free anastomosis in well perfused bowel
• Accurately plased sutures/stapling to prevent
  unrecognised intra op leak
• Perform careful sharp adhesiolysis in bright
  light
• Resection with end to end anastomosis of small
  bowel defects gt half diameter
• Administer pre op oral bowel preprationalong with
  luminal and systemic antibiotics

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• Careful hemostasis
• Place soft drains and tubes
• Avoid perioperative hypotension steroid therapy
  and malnutrition
• Fresh anastomosis be covered withfat/omentum
• The greater omentum should be laid back to
  position

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• Dead space should be covered with live tissue or
  drained with suction drain
• Drains should be kept away from anastomosis
• Pre op nutritional prepration is important
• Whenever in dobut proximal diverting ostomies
  will help

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Pathophysiology
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• Physiologic classification based on output
• Fluid elecdtrolytes and trace mineral loses occur
• More in proximal high output and less in distal
  low output fistulas
• Predicts mortality,assists in preventing and
  treating metabolic defects
• No correlation between static measurement of
  spontaneous fistula output and closure
• Chance of spontaneous closure is three times more
  in low outpt than high output fistulas(CST)
• Anatomic and etiologic factors are more imp
  predictors of closure

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Low output

• lt200ml/24hrs
• K,Cl,Mg
• 1-1.2REE
• Protien 1-1.5gm/kg/day
• RDAwater soluble vitamins
• 2-5RDA of vitC
• Vit-k 10 mg/wk

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Moderate output

• 200-500ml/24hrs
• Na,K,Cl,Hco3,Zn
• 1.2-1.3-REE
• Protien 1.2-1.8 gm/kg/day
• 2RDAwater soluble vitamins
• 5-10RDA of vitC
• Vit-k 10 mg/wk

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High output

• gt500ml/24hrs
• Na,K,Cl,Hco3,Mg,Zn,Cu
• 1.2-1.5-REE
• Protien 1.5-2.5 gm/kg/day
• 2RDAwater soluble vitamins
• 5-10RDA of vitC
• Vit-k 10 mg/wk

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Fluid and electrolyte imbalances

• Abnormalities in SE ofgt48 hrs duration
• K,Na,Mg,Posp,Zn
• Fluid lost is metabolically expensive(enzymatic
  protiens and critical electrolytes)

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Malnutrition

• Most severe and refractory in high output
  fistulas
• Lack of adequate intake
• Hypercatabolism associated with sepsis
• Loss of protien rich energy requiring secretions
  from fistula
• Control of sepsis is an early singular goal in
  nutritional stabilisation

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Sepsis

• Most common complication
• Most common cause of death
• Ct,MRI or indium scans should be used liberally
  to localize sepsis

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Natural history

• Factors that predicts incidence of spontaneous
  closure and the time it takes

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• Likely to close
• Oropharyngeal ,oesophageal,duodenal
  stump,pancreatobiliary jejunal and colonic
• Well nourished
• Sepsis absent
• Appenticitis ,diverticulitis,post op
• Healthy boweland adjacent tissue,small
  leak,quiescent disease,no abscess

• Unlikely to close
• Gastric, ligament of teitz,ilieal
• Poorly nouriashed
• Present
• Cancer FB,Radiation
• Total anastomotic disruption,abscess,distal
  obstruction,active disease

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• Tract gt2cm length
• Defectlt1cm size in bowel
• Transferringt200mg/dl

• lt2cm
• gt1cm
• lt200mg/dl
• Epithelisation of tract
• FB

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Time for spontaneous closure

• Pharyngeal and oesophageal-15-25days
• Duodenal 21days
• Colonic 30-40 days
• Small bowel especially ilieal-40-60 days if they
  heal
• Of fistulas closing spontamneously91close in
  first month
• Remaining 9 in next two months
• On an avg 38 of all fistula close on TPN alone
  in 50(-14 days)

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Diagnosis,evaluation and management

• Ultimate aim is closure of fistula and restoring
  intestinal continuity

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Five phases of management

• Stabilisation (24-48hrs)
• Investigation (after 7-10 days)
• Decision (7-10 days-4-6 wks)
• Definitive therapy (when spontaneous closure is
  unlikely or after 4-6 wks)
• Healing (5-10 days after closure)

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Stabilisation

• Rehydration
• Correction of anaemia
• Drainage of sepsis
• Electrolyte replenetion
• Oncotic pr restoration
• Control of fistula drainage
• Local skin care

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Recognition

• 5-6 days after operation
• Wound abscess appears which is drained resulting
  in enteric contents appearing on dressing

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Resuscitation

• Crystalloid 3-4l
• Anaemia correction (pcv 35)
• Serum albumin to atleast 3mg/dl
• Exogenous albumin is helpful

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Local control

• Wound care assumes high priority
• Place red rubber catheters on low continuous
  suction next to fistulous tracts
• Karya powder ,ilieostomy seal,glycerine ion
  exchange resins
• Stoma adhesive (most effective)
• An enterostomal therapist should be involved

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Nutritional management(central role)

• TPN with bowel rest
• Dramatically decreases the output of fistula and
  simplifies fluid and electrolyte management
• Feeding rates 1.3-1.5 BEE
• Protien is more imp than calories
• Weight gain is not the priority
• Restoration of N balance is imp

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• 1.2-2g of protien/kg/day
• Fluids 30ml/kg or 1500ml/m2
• Fistula loses must be added to it
• 500-800ml/day for each deg of fever
• Water sol vit-twice rda
• Vit c 5-10 times rda
• Monitor serum mg biweekly
• 10mg/day of elemental zinc (high output)

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Role of enteral feeding

• Give atleast a part of nutritional needs
  enterally
• Restore hepatic protien synthesis,gut mucosal
  integrity and immunological competence
• Lipid based enteral formulas with oligopeptides
• Atleast 4 feet of functional bowel should be
  there proximal or distal to bowel

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Antibiotics

• Only if sepsis is present
• Coliforms,bacteroids,enterococcus and strep
• CT to r/o any abscess and percutaneous drainage
• Still sepsis not controlled-operative therapy

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Nasogastric tubes

• Little evidence that its helpful unless intestine
  is obstructed
• Unless fistula is high NG tube can be removed
  without much increase in drainage
• Long term NG tube-impaired cough,serous otitis
  media,Pharyngitis,esophageal stricture

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Decreasing volume of secretion

• Does no improve closure rates
• Decrease time for spontaneous closure
• Proton pump inhibitors
• Somatostatin (can achieve upto 55reduction in
  fistula output)
• Long acting analouge SMS201-995 100-600mic gm
  /day in 4 divided doses)

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Investigations

• Fistulogram
• CT

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Fistulogram

• To define anatomy and patho physiology
• After 7-10 days
• Water soluble contrast media is injected into
  fistulous tract
• Aim is to define those charecteristics of fistula
  which determine whether spontaneous closure is
  likely
• An entire Gi contrast study may also be combined
  with it

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• Is the bowel in continuity/totally disrupted
• End fistula/lateral bowel fistula
• Is there an associated abscess cavity/size/does
  fistula drain into it
• Adjacent bowel-normal/strictured or inflamed
• Distal obstruction
• Etiology
• Length of track
• Size of bowel wall defect

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CT

• In a septic patient to identify abscess
• Evaluation of a reccurent tumor

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Decision

• When to shift to surgical management

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• No signs of imminent closure after 4-5 wks of
  sepsis free nutritional support
• Uncontrolled sepsis at any time
• Anatomical features pleclude closure
• Early operative intervention is indicated in
  transplant patients and malignant fistulas

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General surgical considerations
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• Meticulous skin care and control of fistula
  drainage should make sure that operation is
  carried on a healthy abdominal wall
• Abdominal wall should be re evaluted loculations
  drained cellulitis treated
• Fistula drainage should be cultured
• Enteric tube feeds should be stopped 2 days prior
  to surgery
• Mechanical bowel preparation given
• Enteric and iv antibiotics given
• Wash abd wall with antibacterial solutions
• Coagulation profile and nutritional status
  optimized

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• New incision
• Any abscesses present should be drained through
  separate stab incisions
• Dissection should proceed from ligament of treitz
  to rectum and all adhesions freed
• Sharp dissection with knife is preferred
• Resection along with excision of fistulous tract
  and end to end anastomosis gives best results

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• Anastomosis carried in a clean field away from
  previous abscess cavities
• Omentum should be placed back in anatomic
  position covering anastomosis
• A secure abdominal wall closure is important
• If difficult plastic surgeons are incorporated
• Prosthetic reconstructions contraindicated(recurre
  nt fistula and infection)
• Myocutaneous flaps preffered
• A gastrostomy for decompression and feeding
  jejunostomy placed

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Duodenal fistulas

• An exception to rule of resection and end to end
  anastomosis
• Duodenal repair reinforced with omental or
  jejunal patch
• Gastrojejunostomy
• Duodenostomy for decompression
• Gastrostomy and feeding jejunostomy

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Post op healing

• Continuing nutritional support is important
• Antibiotics should be given
• Provide appropriate proteins and calories
  parentrally
• Early enteral nutrition is beneficial
• But should be supplemented by parental till
  atleast 1500 k cal can be taken eternally
• It is often difficult to persuade these persons
  to eat

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Complications

• Reccurent fistula(10)
• Post op mortality due to sepsis
• Short bowel syndrome
• Oesophageal stricture
• Post partum cramping abdominal pain

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Conclusion

• Enterocutaneous fistula is a common and
  embarrassing complication after bowel surgeries
• Many can be avoided by proper surgical techniques
• Once it occurs depending on natural history many
  heal conservatively
• One technically superior and complete operation
  is better for patient and surgeon than many
  incomplete and inferior operations

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References

• Maingots abdominal operations 10th edition
• Current surgical therapy 7th edition