Ingested foreign body in the common bile duct.

We report a case of a 5-year-old boy who accidentally ingested a metal pin which was found inside the common bile duct on surgical exploration of duodenum and was removed through the ampulla of Vater. This is the first instance that an ingested metal pin in the common bile duct has been reported in the world literature.

INTRODUCTION

Common bile duct (CBD) is a rare site for foreign bodies (FB). Most reported cases in the literature are on sutures, surgical clips and stents found in the CBD, after previous surgical procedures. There are few reports of fish bones and worms found in the CBD. Some fish bones were believed to have entered the CBD retrogradely, whereas others had evidence of penetration through the walls of duodenum and CBD. Shrapnel and bullets have been found inside the CBD in patients who had sustained blast injuries and gunshot injuries.

However, an ingested metal pin in the CBD has never been reported previously.

CASE REPORT

A 5-year-old boy was admitted with a history of accidental ingestion of a metal pin 2 weeks ago. On admission he was asymptomatic and found to be normal on clinical examination. The plain abdominal radiograph done on the day of admission showed the presence of a pin with its head pointing downward in the right upper quadrant of the abdomen [Figure 1].

Figure 1

Plain abdominal radiograph taken before the upper GI endoscopy

An upper gastrointestinal (GI) endoscopy did not show the metal pin inside the lumen of bowel up to the second part of duodenum. Plain radiograph done after the endoscopy showed the pin to be in the same position. A spiral computed tomogram (CT) scan of the abdomen done on the following day reported, “Metal pin in the second part of duodenum with evidence of mild dilatation of CBD. No free fluid was seen in the abdomen.” A repeat upper GI endoscopy was performed which confirmed the absence of pin inside the duodenal lumen up to the third part.

Even though the child remained asymptomatic, an exploratory laparotomy was performed on the following day as penetration of the pin into an adjacent structure was considered a probability.

At laparotomy, mild redness was observed over the CBD area above the duodenum. The metal pin was palpable deeply on the medial side of the second part of the duodenum. However, when the duodenotomy was done, there was no pin inside the lumen. Through the lumen, the pin was located just outside the posteromedial aspect of the second part of duodenum. Further palpation led to the head of the pin appearing through the ampulla of Vater through which it was extracted from the CBD. There was some biliary sludge loosely adhering to the pin [Figure 2].

Figure 2

Picture of the metal pin with biliary sludge

The child made an uneventful recovery.

DISCUSSION

Most of the ingested FB including metal pins pass through the GI tract uneventfully within a week. Rarely, perforation of bowel or penetration in to an adjacent structure can occur, especially with sharp or pointed FB. Orda et al.[1] reported a case of CBD stone caused by a fish bone, where a choledochoduodenal fistula was demonstrated by endoscopic retrograde cholangiopancreaticography (ERCP) as the possible route of migration of the fish bone from duodenum to the CBD. Retrograde migration of fish bones, food material and round worms from duodenum to CBD have been reported.[2] Prochazka et al.[3] reported two cases of gallstones caused by foreign material, which had not undergone any previous operations, and concluded that the presence of foreign material within stones in the CBD in patients without previous surgery could be explained by possible reflux from the duodenum.

CONCLUSIONS

As there was no choledocho-enteral fistula in our case, we postulate that the metal pin entered the CBD through the ampulla of Vater, associated with reflux from duodenum.

Although metal FB's are clearly seen on plain radiographs and CT scans, these techniques could be unreliable in exactly locating the FB in biliary tract, as in our case. Therefore, metal FB seen on plain radiographs in the region of the second part of duodenum with or without abdominal signs should arouse the suspicion of it being in the CBD.