Pneumobilia with Multiple Air-Fluid Levels on Abdominal Radiography: A Clincher

Sir,

A 47-year-old female patient was admitted with abdominal pain and distension. Pain started 2 days before presentation and was sudden in onset, crampy, initially localized in the right hypochondrium and later progressed to involve the whole abdomen. Abdominal distension was also progressive, associated with vomiting and bloating. With suspicion of intestinal obstruction, plain radiograph of the abdomen was performed. Erect abdominal radiograph revealed multiple air-fluid levels and air in the biliary tree (pneumobilia) [Figure 1]. Multidetector computed tomography (MDCT) of the abdomen was performed after administrating intravenous and oral iodinated contrast media. MDCT revealed contracted gallbladder with evidence of air and contrast material in the common bile duct and the intrahepatic biliary radicals with dilatation of small bowel loops. A round-to-oval hyperdense lesion was seen in the lumen of distal ileal loop at transition point. Distal to the transition point, small bowel loops were collapsed [Figure 2]. Radiological findings were in favor of cholecystoenteric fistula with gallstone ileus. Explorative laparotomy was done with extraction of a 3 cm × 2 cm-sized gallstone from the distal ileal loop [Figure 3]. Enterolithotomy, cholecystectomy, and fistula closure were done as one-stage procedure.

Figure 1.

Plain radiograph of abdomen in erect posture showing evidence of pneumobilia (solid yellow arrow) with multiple air-fluid level (yellow arrow) suggestive of small bowel obstruction

Figure 2.

(a) Contrast-enhanced computed tomography of abdomen (with oral and intravenous iodinated contrast media) showing evidence of air and contrast material in the common bile duct shown in axial (arrows in a and b) and coronal sections (arrow in c). (d and e) Coronal and sagittal sections showing dilatation of small bowel loops with air-fluid levels and a round-to-oval hyperdense lesion (arrows) in the distal ileal loop is noted at the transition point. Distal to the transition point, small bowel loops are collapsed

Figure 3.

Postoperative image of gallstone extracted from the distal ileal loop

DISCUSSION

Gallstone ileus is a rare complication of cholelithiasis accounting for only 0.5% of cases, and it is also a rare cause of small bowel obstruction. Subacute-to-chronic cholecystitis due to gallstones causes erosion of the wall of gallbladder and adjacent small bowel with migration of gallstone into the bowel lumen. The stone may also enter the bowel through dilated ampulla of Vater. Most frequent site of fistula formation is duodenum followed by stomach, jejunum, and transverse colon. The gallstone may further pass unobstructed to rectum or may get impacted in the terminal ileum and cause small bowel obstruction. Bouveret's syndrome is a subtype of gallstone ileus, caused by impacted gallstone in the duodenal bulb, leading to gastric outlet obstruction. Size and morphology are important parameters which determine whether gallstone will cause obstruction or not. A size of 2.5 cm is at least required for the same. If gallstone is in the stomach, proximal migration may cause stone to be vomited out.[1,2]

As there is predominance of female patients in gallstone diseases, the majority of cases of gallstone ileus are encountered in the female gender. It has been observed with higher frequency among the elderly. It is frequently preceded by biliary colic. Physical examination findings include abdominal distension, tenderness and signs of dehydration, increased bowel sounds, and rarely obstructive jaundice. If perforation occurs, signs of toxicity and peritonitis may be present. If an elderly female patient with previous gallstone disease presents with abdominal distension and tenderness, a high index of suspicion is required to make diagnosis of gallstone ileus. Clinical differential diagnosis includes other causes of small bowel obstructions such as adhesions and bowel strictures due to chronic inflammations such as intestinal tuberculosis and foreign body impaction.[1,2]

The role of diagnostic radiology includes evaluation with plain radiograph of abdomen in erect posture followed by ultrasonography and MDCT. The Rigler's triad of small bowel obstruction, pneumobilia, and stone in the bowel lumen can be recognized on plain radiographs; however, identifying the complete Rigler's triad is infrequent as most of the stones are radiolucent. Upper gastrointestinal series may identify contrast material in gallbladder and biliary tree. Ultrasonography may be helpful in identifying contracted gallbladder with remnant stones if present; however, its utility is limited by gaseous distension of abdomen frequently present in these patients. Combination of radiography and ultrasonography increases the sensitivity of diagnosing this condition.[3,4]

MDCT is better in demonstrating the abnormality, making a rapid diagnosis, and aiding in making decision of surgery. MDCT is helpful in localizing the endoluminal gallstone, measuring the size of stone in all orthogonal planes, counting multiple other stones, and detecting changes of bowel necrosis and perforation. Carefully searching the entire gastrointestinal tract is important as multiple stones can be present in 3%–44% of all patients with gallstone ileus.[3,4]

In cases of gallstone ileus, the prime objective is to relieve obstruction. Correction of metabolic derangement and electrolyte imbalances is also required. Moreover, delay in treatment can lead to serious complications such as bowel necrosis and perforation peritonitis.

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Conflicts of interest

There are no conflicts of interest.