Philadelphia College of Osteopathic Medicine Conyers, Georgia, United States
Introduction/Purpose: Gallstone ileus is an uncommon complication of cholelithiasis and has been described as a mechanical intestinal obstruction due to the impaction of a gallstone in the gastrointestinal tract. It is caused by the passing of a gallstone from the bile ducts into the intestinal lumen through a fistula. The incidence of gallstone ileus remains rare in the general population, accounting for up to 5% of small bowel obstructions (SBO) but accounts for 25% of non-strangulated SBO in the elderly over the age of 65. Female patients are about three times more likely to be affected than male patients. Impaction of gallstones most commonly occurs in the ileum, at a frequency of 50-65%, and is usually secondary to a cholecystoduodenal fistula. We are reporting a case of a 78-year-old female who presented with abdominal pain and vomiting secondary to gallstone ileus due to a rare cholecystogastric fistula tract and treated with endoscopic colonoscopy with electrohydraulic lithotripsy.
Methods or Case Description: A 78-year-old female presented to the emergency department with periumbilical abdominal pain and bilious emesis for 3 days. Symptoms included poor oral intake, weakness, and oliguria. She denied fever, diarrhea, or constipation. No reports of recent sick contacts, uncooked food consumption, or post prandial right upper quadrant pain. Her past medical history included diverticulitis, osteoarthritis, and hypertension. Past surgical history included hysterectomy.
On physical examination, the abdomen was soft, mildly distended, and tender in the periumbilical abdomen. No abdominal rigidity or rebound tenderness. Her physical examination was otherwise unremarkable. Baseline total bilirubin was 2.6 mg/dL and her other liver tests within normal limits. Her serum creatinine was at 4.1 mg/dL, elevated from her baseline of 1.5 mg/dL.
Diagnostic imaging with a CT of the abdomen/pelvis without contrast demonstrated dilated loops of the small bowel with colonic diverticula. An intraluminal gallstone was seen in the distal small bowel measuring 2.4 x 1.4 cm. The gallbladder demonstrated mild pericholecystic stranding with a calcified gallstone measuring 1.4 cm in the lumen. Given her radiological and laboratory findings, there was additional concern for possible choledocholithiasis. An MRI of the abdomen without contrast and magnetic resonance cholangiopancreatography (MRCP) was performed with no evidence of choledocolethiasis. However, the previously suspected cholecysto-enteric fistula was now classified as cholecystogastric fistula after a fistulous tract was visualized on MRCP.
The patient was admitted for possible surgical intervention. Gastroenterology was consulted and with joint decision-making with general surgery, the patient was selected for colonoscopy with electrohydraulic lithotripsy for stone extraction. The patient tolerated the procedure and post-operative CT abdomen/pelvis with oral contrast did not demonstrate complications. The patient was discharged home on hospitalization day 5.
Outcomes: Cholecystogastric fistulas can be difficult to diagnose due to the non-specific symptoms patients present with. Fistula formation can be caused by vascular insufficiency or chronic inflammation caused by the gallstone(s) against the biliary wall leading to pressure necrosis and erosion. Only about 50% of patients with gallstone ileus has had history of gallbladder disease. Biliary-enteric fistula formation at the duodenum has an incidence of 77-90% compared to fistulas at the stomach, which has an incidence of 2%.
Abdominal radiography and CT are used but CT is more sensitive and specific and has become the gold standard for detection of chole-enteric fistulas. Rigler’s triad of pneumobilia, dilated bowel loops, and ectopic gallstones on imaging is pathognomonic for gallstone ileus. The presence of 2 of the 3 signs is diagnostic. Our patient’s CT demonstrated Rigler’s triad. The additional MRI/MRCP imaging allowed further characterization of her fistula and ruled out choledocholithiasis. This allowed for further definitive preoperative management to ensure no other underlying causes contributed to the patient’s status.
Gallstone ileus has a poor prognosis that worsens with age, with a mortality rate that ranges from 7.5-15%. Surgery is the mainstay treatment for gallstone ileus. Management includes removal of the obstructing stone, cholecystectomy, and transection of the fistula tract. We decided to use an endoscopic as the first-line approach for our patient due to her advanced age and the patient was hemodynamically stable. Due to the most likely patient population and their likely co-morbidities, the endoscopic approach offers a safe and judicious option that can be considered before surgery. Previous cases with cholecysto-gastric fistulas have utilized this approach and found success except in patients with certain risk factors.
Conclusion: This case illustrates that endoscopic treatment is a viable and safe treatment option for stable patients that are poor surgical candidates in patients with SBO secondary to gallstone ileus due to cholecystogastric fistulas. Furthermore, CT imaging with the presence of Rigler’s triad remain the gold standard for diagnosis of gallstone ileus but MRI/MRCP may offer more insight if pathogenesis needs to be elucidated.
