Editing Enterocutaneous fistula

Fistula: an abnormal communication between two epithelialised surfaces, one of which is a hollow organ.

* Enterocutaneous fistula:     between the lumen of the GIT and the skin
* Enteroatmospheric fistula:     between the lumen of the GIT and the wound of an open abdomen.
* Can be congenital or acquired     but most commonly iatrogenic (75-85% post-op)
** Anastomotic breakdown
** Dehiscence of surgically      closed segment of stomach/bowel
** Unrecognised enterotomy
* Predispositions:
** Intrinsic intestinal disease      (Crohn's)
** Radiation enteritis
** Distal obstruction
** Hostile abdo
** Malnourished
* Spontaneous enteric fistula: '''FRIEND'''
** Foreign body
** Radiation
** Inflammation/infection (TB,      actinoycosis)
** Epithelialisation
** Neoplasia
** Distal obstruction

== '''Presentation''' ==

* Mostly occur in the     post-operative setting
* Triad:
** Sepsis
** Fluid/electrolyte imbalance
** Malnutrition
* Often not progressing well     post-op, with first abdominal symptoms then signs of bowel obstruction,     then a wound infection will be seen 7-10 days post-op, which will     eventually show enteric contents in the wound.
* Enteroatmospheric fistulas     will present with an exposed segment of bowel seen through a large fascial     defect

== '''Classification''' ==

* Output
** High output: >500ml/24hrs
*** Commonly coming from the       ileum
** Medium: 200-500
** Low <200
* Location
** Proximal fistulas generally      have higher output, greater fluid and electrolyte losses, and greater      loss of digestive capacity
** Distal fistulas have lower      output and are therefore easier to manage and more likely to close      spontaneously

== '''Considerations:''' ==

* Hypersecretory gastric state
* Intra-hepatic cholestasis -     related to loss of bile salts
* Malnutrition
** Bypass
** Loss of protein-rich      secretions
** Lack of nutrient intake
** Sepsis
* Skin and surgical wound     complications


== '''Management''' ==

* Early surgical intervention     is ineffective
* Three phases:
** Stabilisation
** Staging and supportive care
*** Try and get it to close       spontaneously, by reducing output
** Definitive management
* Need MDT approach
** Surgeon
** Nutritionist
** Enterostomal therapist
*** Consider VAC
** Interventional radiologist
** Gastroenterologist

== '''Overall approach mnemonic: SNAPS''' (a bit simplistic - see below for full process) ==

* Sepsis
** Obtain adequate drainage
** May involve defunctioning of      the bowel
* Nutrition
** Often parenteral nutritional      support
* Anatomy (define fistula     tract)
** Image the site of leak
** CT with contrast
* Procedure
** Ultimately aim for      reparative procedure
** Delay until patient is well      enough that success is likely
* Skin care
** Determine what is coming out      of the fistula and protect the skin accordingly

== '''Natural history with best management:''' ==

* 54% closed spontaneously, and     18% needed definitive surgery
* >90% of fistulas that     closed did so within 1 month, <10% of fistulas closed after 2 months,     and no fistulas closed spontaneously after 3 months
* Uncomplicated proximal     fistulas have higher spontaneous closure rates

=== '''Stabilisation / initial medical treatment''' ===

#* Resus + antibiotics - halt      catabolism
#** Aggressive fluid therapy
#** Cease antibiotics 5-7 days       after source control has been obtained and sepsis has resolved.
#** Antibiotics in non-septic       patients with ECF is controversial, and there is no evidence of improved       outcomes, so probably shouldn't be done routinely.
#* CT. If evidence of free GIT      perforation or diffuse peritonitis, need urgent exploration. Focus on      infection drainage and exteriorisation of any leaking bowel. Don't redo      the anastomosis in the infected field in order to create a stoma, but you      could divert the faecal stream higher up.
#* Infected wounds, abscesses,      etc are opened and drained. Perc drainage of intra-abdo collections      (allows changing a complex fistula to a simple one) - generally done      through anterior abdominal wall, but can be done transgastric/transrectal      etc.
#* Fix electrolytes
#* Involve MDT - consistent      messaging
#* Set realistic expectations      with patient and family

=== '''Staging and supportive care''' ===

#* Nutrition:
#** Allow 500mL/24 hours clear       fluids
#** Low-output fistulas       (<200mL/day):
#*** In general, aim for        enteral feeding, if they are able to absorb enough
#*** First, try a short period        of bowel rest after the patient has been stabilised to see if fistula        will close (?TPN)
#*** If fistula continues,        start on oral diet
#*** If fistula output does not        increase substantially with oral diet, can continue; but if output        increases >1.5L per day, need to stop oral diet and start TPN
#** Moderate or high-output       fistulas
#*** May be intolerant to        nutrition secondary to sepsis, poor absorption, greater fluid and        nutrient loss from fistula, or difficulty with infection/excoriation of        skin
#** TPN - trace elements,       multivitamins, vitamin K +/- octreotide (reduces GI secretion - yet to       be proven, and come with side effects)
#*** Indications:
#**** Fistula output >1.5L         per day
#**** <75cm of intestinal         length prior to the fistula
#**** Intestinal discontinuity
#*** Can be given either        exclusively or as an adjunct
#** Feeding down distal limb -       Starkey says more trouble than it is worth
#* Fluid status - needs to be      carefully maintained, taking into account the fistula losses. Can use St      Mark's Intestinal Failure Unit worksheet to establish necessary      electrolyte replacement.
#** Duodenal or pancreatic       fistulas may require bicarbonate to prevent metabolic acidosis.
#* NGT only if obstructed
#* PPI - decreases risk of PUD
#* Wound care
#** The real challenge is       management of high-output and enteroatmospheric fistulas
#** Most low-output fistulas       can be managed with gauze and an ostomy appliance
#** NPWT has become widespread,       but is not really proven to improve healing
#** Sometimes can simply put a       drain down the tract
#** Skin care - prevent       excoriation using a stomahesive product (zinc oxide, aluminium paste,       karaya powder)
#* Fistula output reduction
#** Anticathartics (loperamide)       - give loperamide up to 16mg daily
#** Somatostatin - useful in       high-output fistulae
#*** Dosage given in most        studies seems to be octreotide 100microg subcut q8h
#** Antisecretories - PPI       generally given
#** Cholestyramine - for       bilioenteric fistulae
#* Once initial resus and      medical treatment is progressing, define the fistula tract (origin,      course, length) with a fistulogram/CT/endoscopy
#** Can check for       bilirubin/amylase
#** Methylene blue may be       helpful

=== '''Definitive management''' ===

#* Definitive surgery for      patients whose fistulae have failed to heal (about 50%)
#** Simple fistula - wait 3/12
#** Complex - wait 6-12 months
#** May also require abdo wall       reconstruction
#*** Botox or component        separation
#** But you don't HAVE to wait       more than 6 weeks if all other criteria are optimised
#* Optimal criteria for      surgery:
#** Clinically stable
#** Psychologically stable and       willing
#** Albumin > 25
#** Period of convalescence       >6 weeks since insult
#** Output controlled at skin -       should look basically like an odd stoma, without sepsis
#* Surgery
#** One-stage procedure
#** Incision in a clean area
#** Careful adhesiolysis
#** Fistula tract excision and       segmental resection of the involved segment of intestine and       reanastomosis
#*** Simple closure of fistula        tract almost always results in recurrence
#** Bail-out option is       exteriorisation of both ends of bowel
#** Resect bowel as necessary,       but limit anastomosis to minimum
#** 2 layers permanent suture       for anastamosis with omental covering
#* Likely need TPN and slow      rehab post-op too

[[Category:Colorectal]]