Hepatic Failure/GI/Endocrine Emergencies

Lateral fistulas divert off the intestines while maintaining the continuity of the intestinal tract.

With lateral fistulas, intestinal contents follow normal progression beyond the fistula.

ii.

End fistulas disrupt the continuity of the intestinal tract beyond the fistula.

Postoperative fistulas

Most fistulas are formed after surgery (about 80%), most commonly after operations for cancer.

Postoperative fistulas form because of either infection or breakdown at intestinal anastomoses.

Postoperative fistulas are more commonly external, often because of the presence of a drain.

15%–25% of GI fistulas occur spontaneously.

Crohn disease and inflammatory bowel disease are the leading cause of spontaneous fistula

formation, though pancreatitis and cancer (particularly if radiation therapy is involved) can also

lead to spontaneous fistulas.

Spontaneous fistulas often form because of local inflammatory processes that can cause local

abscess formation or perforation.

Trauma-induced fistulas

Some fistulas are caused by trauma (abdominal wounds or blunt trauma).

Trauma may lead to fistula formation by causing vascular injury.

Common presenting symptoms include pain, abdominal tenderness, leukocytosis, and fever. External

fistulas are generally easier to recognize because of the presence of effluent at the drainage sites. Patients

with internal fistulas may present with nonspecific symptoms such as diarrhea, dyspnea, or SIRS.

within the first week after surgery.

Diagnostic workup should include fistula output volume, fistula output description (e.g., color,

consistency), biochemical evaluation of fistula content (e.g., water-electrolyte balance, amylase, lipase,

pH), microbiological evaluation of fistula content, and markers of nutritional status.

Radiographic contrast studies using CT or MRI are necessary to determine the anatomic aspects of the

fistula (e.g., origin, length of fistula, presence of obstruction or abscesses). Barium is generally used for

contrast because of its ability to show mucosal surfaces.

Fluid resuscitation and electrolyte management

GI fistula fluid is typically iso-osmotic and rich in sodium, potassium, chloride, and bicarbonate.

High-output fistulas can result in large fluid and electrolyte imbalances leading to dehydration,

hypokalemia, hyponatremia, and metabolic acidosis.

Fistula output from the upper GI tract is generally more acidic and rich in potassium. Replacement

fluid should include a maintenance infusion of 0.9% sodium chloride with potassium and frequent

reassessments for potassium corrections.

Pancreatic and duodenal fistulas result in bicarbonate losses and may require bicarbonate

replacement.