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Why has this 70-year-old woman with gallstones had abdominal pain, nausea, and vomiting for the past 3 days? That is the diagnostic dilemma faced by Francesco Pata, MD, PhD, of Università della Calabria in Rende, Italy, and colleagues.

As they explained in , the patient had not undergone any abdominal surgery, and her medical history included high blood pressure, atrial fibrillation, and congestive heart failure.

On presenting to the emergency department, she told clinicians that she had not been vomiting blood; likewise she had no blood in her stools, nor were they black and tarry.

On physical examination, she was afebrile, her blood pressure was 80/60 mm Hg, and her heart rate was 122/min. Her abdomen was distended and tympanic, with diffuse tenderness to palpation.

Lab tests revealed the following:

• White blood cell count: 10,450/μL (84% neutrophils)

• C-reactive protein: 9.5 mg/dL

• Potassium: 3.0 mEq/L (reference 3.6-5.2 mEq/L)

• Creatinine: 5.57 mg/dL (429.39 μmol/L, increased from a baseline of 0.80 mg/dL [70.72 μmol/L])

• Sodium and liver function values were unremarkable

The medical team administered a 500 mL bolus of intravenous crystalloid fluid and 1 g of intravenous ceftriaxone, and placed a nasogastric tube, which produced initial drainage of 300 mL of biliary fluid.

The team also performed a non-contrast-enhanced abdominal CT scan, which showed a thickened gallbladder with intraluminal air and gallstones adherent to the duodenum, with a suspected fistula tract. Axial section imaging revealed a 2.7 cm gallstone in the middle ileum and proximal bowel distension, prompting a diagnosis of gallstone ileus.

Pata and co-authors explained that the observed combination of an ectopic gallstone in the small bowel and a thickening of the gallbladder wall with intraluminal air adherent to the duodenum is characteristic of a cholecystoenteric fistula. The team therefore planned to perform a surgical intervention when the patient's condition stabilized.

The case authors noted that the team did not order magnetic resonance cholangiopancreatography, since the CT scan had confirmed the diagnosis of gallstone ileus. The team also did not administer nasogastric barium, due to the risk of worsening the bowel obstruction and inducing barium peritonitis in a patient with a perforated bowel. Finally, given the patient's hemodynamic instability, the team did not consider emergency exploratory laparotomy as an option.

The patient was admitted to the intensive care unit (ICU), where she received 3 L of intravenous fluid resuscitation over 12 hours.

The case authors noted that the patient's vital signs returned to normal by the following day. The team performed a midline laparotomy and enterolithotomy and removed a 2.7 cm gallstone that had been obstructing the middle ileum.

"A 3-cm ileal resection with a hand-sewn side-to-side anastomosis was performed due to evidence of mild ischemic changes in the posterior wall of the ileum," Pata and co-authors said.

After 3 days in the ICU for monitoring, the patient was discharged to home on postoperative day 8. A follow-up appointment 1 month later showed the patient to be free of symptoms, with a normal serum creatinine level. Clinicians referred her to a hepatobiliary surgical specialist for follow-up and care management.

Discussion

"Gallstone ileus is a mechanical obstruction caused by migration of a gallstone from the gallbladder through a biliary-enteric fistula into the gastrointestinal tract," Pata and co-authors wrote.

A fistula usually develops when inflammation from repeated episodes of cholecystitis cause the gallbladder to adhere to surrounding organs, the team explained. "In 85% of patients with gallstone ileus, gallstones travel through a cholecystoduodenal fistula into the duodenum, and 15% have a fistula that involves the stomach, small bowel, or transverse colon."

Gallstones generally advance from the gastrointestinal tract, and small stones are expelled through the rectum, but gallstones larger than 2 cm may obstruct the intestine. In 50% to 60.5% of cases, this occurs in the ileum; the jejunum, duodenum, colon, or stomach are involved less frequently.

The presenting symptoms of gallstone ileus tend to include nausea, vomiting, abdominal pain, and distension, and may occur sporadically as the gallstones move along the gastrointestinal tract. Rarely, an impacted gallstone can lead to intestinal perforation.

Although the percentage of bowel obstructions due to gallstone ileus overall is 1-4%, the rate in patients is approximately 25%. Indeed, older patients (mean age of 74) are most likely to develop gallstone ileus, and 80-90% have several comorbidities, including hypertension, diabetes, and ischemic heart disease, the case authors noted. About half of patients with gallstone ileus have no history of gallbladder disease, and women account for 72-90% of cases of gallstone ileus.

Regarding diagnostic imaging, Pata and co-authors noted that an abdominal CT scan has a 93% sensitivity and 100% specificity and is recommended for the diagnosis of gallstone ileus.

The condition is typically treated with because the intestinal obstruction rarely resolves spontaneously. "Potential surgical procedures, performed using an open or laparoscopic approach, include extraction of the gallstone through an enterotomy (enterolithotomy) or enterolithotomy plus cholecystectomy and fistula closure performed in a single operation (one-step procedure) or in sequential operations (two-step procedure)," the case authors wrote.

They noted that while there are no data from randomized clinical trials to indicate an optimal surgical approach, gallstone ileus is most often managed with enterolithotomy alone; this procedure seems to have lower rates of mortality and complications immediately following surgery compared with other surgical options.

However, patients at low risk of surgical complications may benefit from a one-step procedure, to decrease the likelihood of gallstone recurrence, retrograde cholecystitis, or gallbladder cancer, the authors said.

They added that approximately 5% of patients who undergo enterolithotomy for gallstone ileus have a recurrence, with about 85% occurring within the first 6 months after surgery.

"Despite surgical treatment, gallstone ileus is associated with a rate of 7% to 30%, in part due to the advanced age and multiple medical comorbidities of most patients," the team cautioned.

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