Gallstone Ileus: Rare but Serious Complication – Symptoms & Treatment

What is gallstone ileus? (Gallstone bowel obstruction)

Gallstone ileus is a rare but serious complication of gallstones where a large gallstone erodes through the gallbladder wall into the intestine (usually the duodenum), forming a fistula (abnormal connection). The stone then travels down the intestine and becomes lodged, causing a mechanical bowel obstruction. Despite the name “ileus”, it is a true mechanical obstruction, not a functional one. Gallstone ileus accounts for less than 1% of all small bowel obstructions but has a high mortality rate (12‑20%) due to delayed diagnosis and the frailty of affected patients (typically elderly women).

Pathophysiology – cholecystoduodenal fistula and stone migration

The process usually occurs in four steps:

1. Chronic cholecystitis: Long‑standing gallstones cause inflammation and adherence of the gallbladder to the duodenum or colon.
2. Fistula formation: Pressure necrosis from a large stone erodes through the gallbladder wall and into the adjacent bowel, creating a cholecystoduodenal fistula (most common) or cholecystocolonic fistula.
3. Stone migration: The stone passes from the gallbladder into the bowel lumen. The fistula may close spontaneously or remain patent.
4. Obstruction: The stone travels distally and impacts at a narrow point of the small intestine – most commonly the ileum (60‑70%), followed by the jejunum (20‑25%), and rarely the duodenum or colon.

Risk factors: elderly (>65 years), female sex, history of recurrent cholecystitis, large gallstones (>2.5‑3cm).

Symptoms – Rigler’s triad (small bowel obstruction, pneumobilia, ectopic stone)

Symptoms are often intermittent and non‑specific initially, leading to delayed diagnosis. Classic features include:

• Intermittent colicky abdominal pain – stone moves and may temporarily relieve obstruction.
• Nausea and vomiting – may be bilious if obstruction is distal.
• Abdominal distension and constipation (complete obstruction).
• Rigler’s triad (pathognomonic on imaging):
  • Small bowel obstruction (dilated loops).
  • Pneumobilia (air in the biliary tree).
  • Ectopic gallstone (visible stone outside the gallbladder).

Patients may have a history of prior biliary symptoms, but many present with no prior gallbladder issues.

Diagnosis – abdominal X‑ray, CT scan

Imaging is key to diagnosis, as clinical signs are often misleading.

• Abdominal X‑ray (plain film): May show Rigler’s triad in 30‑50% of cases. Dilated small bowel loops, air in the biliary tree (branching radiolucencies over the liver), and an ectopic stone (often calcified).
• CT scan (gold standard): High sensitivity (90‑95%). Shows:
  • Small bowel obstruction with transition point.
  • Pneumobilia.
  • Ectopic stone (hyperdense) in the bowel lumen.
  • Cholecystoduodenal fistula (may be visible).
  • Thickened gallbladder wall.
• Ultrasound: Limited due to bowel gas, but may show pneumobilia, thickened gallbladder, or absence of a previously seen stone.

Treatment – emergency surgery (enterolithotomy, possible cholecystectomy)

Gallstone ileus is a surgical emergency. Treatment involves relieving the obstruction, with debate about whether to address the fistula and gallbladder at the same time.

• Enterolithotomy (stone removal from the bowel): The primary and often only procedure. The surgeon locates the impacted stone, makes an enterotomy, extracts the stone, and closes the bowel. This relieves the obstruction. Most patients are elderly and frail, so a limited procedure is preferred.
• Cholecystectomy and fistula repair (one‑stage procedure): Removing the gallbladder and closing the fistula during the same operation. This is controversial because it adds significant morbidity and mortality. Reserved for young, fit patients with no severe inflammation.
• Two‑stage approach (enterolithotomy first, then interval cholecystectomy): Commonly practised. The patient recovers from the acute obstruction, then undergoes elective cholecystectomy and fistula repair 4‑6 weeks later. However, many patients never have the second stage due to age or comorbidities.

Complications – perforation, sepsis, death

If not treated promptly, gallstone ileus can lead to:

• Bowel perforation due to pressure necrosis from the stone.
• Peritonitis and sepsis.
• Recurrent obstruction if multiple stones pass (rare).
• Post‑operative complications: Wound infection, anastomotic leak, pneumonia, myocardial infarction – common in elderly patients.

Prognosis and mortality

Gallstone ileus has a high mortality rate (12‑20%) despite surgical treatment, mainly due to delayed diagnosis and the advanced age and comorbidities of patients. Early diagnosis and prompt surgery improve outcomes. The recurrence rate after simple enterolithotomy is low (5‑10%).

Interactive FAQ – Gallstone ileus

Disclaimer: This information is for educational purposes. Gallstone ileus is a surgical emergency. If you have symptoms of bowel obstruction (severe abdominal pain, vomiting, constipation), seek immediate medical attention at Vivekananda Hospital.