What is gallstone ileus?

What is Gallstone Ileus?

Gallstone ileus is a rare but serious complication of cholelithiasis where a gallstone passes through an abnormal fistula (cholecystoenteric fistula) from the inflamed gallbladder into the gastrointestinal tract, causing mechanical bowel obstruction. 1, 2

Pathophysiology

The condition develops through a specific sequence of events:

• Chronic cholecystitis causes the gallbladder to adhere to adjacent intestinal structures
• Persistent inflammation and pressure from the gallstone erodes through the gallbladder wall
• A bilioenteric fistula forms, most commonly between the gallbladder and duodenum
• The gallstone migrates into the intestinal lumen and becomes impacted, typically in the terminal ileum (the narrowest part of the small bowel) 2, 3

Clinical Presentation

This condition predominantly affects elderly female patients (median age 83 years, 90% female in one cohort), though rare cases occur in younger patients 3, 4. Key clinical features include:

• Symptoms: Abdominal pain, distension, and vomiting (classic bowel obstruction presentation)
• Timeline: Symptom onset typically 2-7 days before presentation 3
• History: More than half of patients have no prior history of biliary disease, making diagnosis challenging 4
• Laboratory findings: 50-60% show deranged liver function tests, acute kidney injury, and elevated inflammatory markers 3

Diagnostic Findings

CT scan is the diagnostic imaging modality of choice, revealing Rigler's Triad 5:

1. Small bowel obstruction (most commonly in the ileum)
2. Pneumobilia (air in the biliary tree)
3. Ectopic gallstone visible in the intestinal lumen (typically 2.5-4 cm in size) 3

Critical diagnostic pearl: The presence of pneumobilia in a patient without prior biliary surgery should immediately raise suspicion for a bilioenteric fistula 1.

Clinical Significance and Mortality Risk

This is a surgical emergency with high morbidity and mortality, particularly in elderly patients 2. The vague and non-specific symptoms commonly lead to delayed diagnosis, which increases mortality risk 1. Despite being an uncommon cause of bowel obstruction overall, gallstone ileus accounts for a significant proportion of small bowel obstructions in elderly populations.

Management Approach

Enterolithotomy (surgical removal of the impacted stone) is the primary treatment, with mortality of 4.2% and readmission rates of 4.8% 6. The surgical approach can be:

• Open enterolithotomy (most common): Mean postoperative stay 10 days
• Laparoscopic enterolithotomy: Mean postoperative stay 5 days (when surgeon expertise permits) 3
• Conservative management: Reserved for select cases only 3

Important management controversy: Single-stage procedures (enterolithotomy plus cholecystectomy and fistula repair) versus enterolithotomy alone show no difference in complications, readmissions, or mortality, but single-stage procedures result in significantly longer hospital stays (10 vs 8 days) and higher costs ($70,959 vs $52,147) 6. Therefore, enterolithotomy alone is the preferred initial approach for most patients, reserving definitive biliary surgery for a later elective setting if needed.

Key Clinical Pitfalls

• Recurrence risk: A small proportion develop recurrent gallstone ileus within weeks; extremely rare cases can recur during the same admission 2
• Intraoperative vigilance: Surgeons must carefully palpate the entire small bowel proximally to identify additional migrating stones 2
• Age-related considerations: Increasing age and higher mortality risk scores predict lower likelihood of undergoing definitive single-stage procedures 6