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SMALL BOWEL FISTULAE

Small Bowel Fistulae

  • Mortality from Enterocutaneous Fistula (ECF) remains at 10%.
  • Spontaneous fistulas occur in 15% - 25% of cases.
  • Iatrogenic fistulas (due to surgical intervention) account for 75% - 85% of cases.
  • Most common (MC) site of origin for enterocutaneous fistula: Ileum.

Duodenal Fistulas

  • Prone to volume and electrolyte loss.

High-Output Fistulas

  • Mortality rate: 35%.
  • Most common abnormalities include:
    • Hypovolemia.
    • Hypokalemia.
    • Metabolic acidosis.

Types of Fistulas

  • Proximal fistulas:
    • Higher output.
    • Greater fluid and electrolyte loss.
    • Greater loss of digestive capacity.
  • Distal fistulas:
    • Lower output.
    • Easier to manage.
    • More likely to close spontaneously.

Complications

  • Sepsis is the most common cause of death in patients with fistulas.

Factors Preventing Spontaneous Fistula Closure [BOX 49.5 Sabi]

  • High output (>500 mL/24 hr)
  • Severe disruption of intestinal continuity (>50% of bowel circumference)
  • Active inflammatory bowel disease of the bowel segment
  • Cancer
  • Radiation enteritis
  • Distal obstruction
  • Undrained abscess cavity
  • Foreign body in the fistula tract
  • Fistula tract <2.5 cm long
  • Epithelialization of the fistula tract

These factors can prevent spontaneous closure of a fistula, increasing the need for medical or surgical intervention.

MCQs for Revision

1. Most common site of origin of enterocutaneous fistula is?

A) Duodenum

B) Jejunum

C) Ileum

D) Colon

Correct Answer: C) Ileum

(The ileum is the most common site of origin for enterocutaneous fistulas)

2. Most common cause for enterocutaneous fistula (ECF)?

A) Sepsis

B) Iatrogenic

C) Malignancy

D) Trauma

Correct Answer: B) Iatrogenic

(Iatrogenic causes, particularly due to surgical intervention, are the most common causes of ECF)

3. All of the following factors are responsible for preventing spontaneous closure of ECF, except?

A) Fistula tract >2.5 cm long

B) Fistula output >500 ml/24 hr

C) Epithelialization of fistula tract

D) Disruption of >50% bowel circumference

Correct Answer: A) Fistula tract >2.5 cm long

(Fistula tracts longer than 2.5 cm are more likely to close spontaneously, whereas the other factors prevent closure)

4. An ECF is considered as high output when the output is?

A) >500 ml/day

B) >200 ml/day

C) >1000 ml/day

D) >400 ml/day

Correct Answer: A) >500 ml/day

(An ECF is considered high output when it exceeds 500 ml/day)