Rare case of extrahepatic biliary obstruction caused by a duodenal foreign body in a cat

Abstract

Case summary

A spayed female British Shorthair cat aged 1 year and weighing 2.6 kg presented with a 5-day history of vomiting and anorexia. Physical examination revealed icterus, and serum biochemistry showed markedly elevated bilirubin and liver enzyme levels. Abdominal ultrasonography revealed a dilated common bile duct (4 mm), mild gallbladder wall thickening and a round, hyperechoic foreign body located at the major duodenal papilla. A contrast-enhanced CT scan confirmed the presence of a 1.9 cm doughnut-shaped foreign body in the proximal descending duodenum, causing extramural compression of the common bile duct. Exploratory laparotomy and enterotomy were performed to remove the object. The cat recovered uneventfully, with normalisation of biliary parameters within 48 h and resolution of clinical signs by postoperative day 4.

Relevance and novel information

This case highlights a rare but surgically treatable cause of extrahepatic biliary obstruction (EHBO) in cats caused by a duodenal foreign body exerting extraluminal compression without intraluminal migration or mucosal invasion. It emphasises the value of cross-sectional imaging and timely surgical intervention in achieving favourable outcomes. To the authors’ knowledge, this is the first peer-reviewed report of feline EHBO caused by extramural duodenal compression that was successfully resolved without biliary tract incision.

Introduction

Extrahepatic biliary obstruction (EHBO) in cats is a relatively rare but clinically significant condition. Common causes include cholangitis, pancreatitis, neoplasia, cholelithiasis and, less frequently, parasitic or mechanical obstructions such as foreign material impaction.^1,2 Among mechanical causes, duodenal foreign bodies leading to extraluminal biliary compression at the major duodenal papilla are exceedingly uncommon.^3,4

Bile duct obstruction can result in cholestasis, hepatocellular damage and secondary pancreatitis due to the anatomical convergence of the biliary and pancreatic ducts.^1,5 In feline practice, ultrasonography remains the first-line diagnostic modality for evaluating biliary dilation, gallbladder wall changes and obstructive lesions.^4,6

This report describes a young cat with obstructive jaundice caused by a duodenal foreign body. It focuses on clinical features, diagnostic evaluation, surgical management and comparison with previously reported feline EHBO cases.

Case description

A spayed female British Shorthair cat aged 1 year and weighing 2.6 kg was presented with persistent vomiting and anorexia that had been ongoing for 5 days. The cat had initially received symptomatic treatment at a local clinic without improvement, prompting referral. On physical examination, the patient was lethargic, icteric and showed discomfort on abdominal palpation. Serum biochemistry revealed hyperbilirubinemia (4.2 mg/dl; reference interval [RI] 0.1–0.5) and elevated liver enzymes (alanine transaminase 1000 U/l, aspartate trans-aminase 288 U/l, alkaline phosphatase 112 U/l, gamma-glutamyl transferase 12 U/l). Other hematologic examinations, including serum biochemistry, complete blood count and blood gas analysis, were performed and found to be within normal limits.

Abdominal ultrasonography demonstrated a 4 mm dilated common bile duct extending to the cystic duct, mild thickening of the gallbladder wall and a 1.9 cm round hyperechoic foreign body with a central acoustic void, located within the proximal descending duodenum at the level of the major duodenal papilla, suggestive of a duodenal foreign body. The adjacent duodenal segment showed mild focal distension, raising the possibility of partial luminal obstruction caused by the impacted foreign body. The pancreas exhibited bilateral lobar thickening with hyperechoic peripancreatic fat, suggestive of concurrent pancreatitis. ⁵

To better characterise the lesion, contrast-enhanced CT was performed, which revealed a 1.9 cm doughnut-shaped object in the proximal descending duodenum at the level of the major papilla, resulting in extraluminal compression of the common bile duct. In addition, there was no evidence of mural thickening, mass lesions or other intra-abdominal pathology. These imaging findings are shown in Figure 1.

Figure 1

Preoperative imaging findings in a cat with extrahepatic biliary obstruction: (a) abdominal ultrasonography showing a dilated common bile duct measuring 4 mm in diameter (arrow); (b) hyperechoic, duodenal foreign body (arrowhead) detected at the level of the major duodenal papilla; (c) axial contrast-enhanced CT image showing extraluminal compression of the dilated common bile duct (arrow) caused by a duodenal foreign body (arrowhead); and (d) coronal CT image depicting a doughnut-shaped object (arrowhead) lodged in the proximal descending duodenum

Upon referral, the patient underwent a complete diagnostic work-up including blood tests and abdominal ultrasonography, which raised suspicion of EHBO secondary to a duodenal foreign body. On the same day, contrast-enhanced CT was performed under a single anaesthetic episode, immediately followed by exploratory laparotomy. Supportive treatment included amoxicillin-clavulanate (12.5 mg/kg IV q12h), maropitant (1 mg/kg SC q24h) and omeprazole (1 mg/kg IV q24h). The patient was stabilised with intravenous fluid therapy using normal saline supplemented with hepatic support before surgery.

Exploratory laparotomy confirmed a foreign body lodged within the proximal duodenum adjacent to the papilla. The duodenum was visibly distended, and both the common bile and pancreatic ducts were dilated. A longitudinal antimesenteric enterotomy was performed to extract the foreign body, followed by routine closure of the intestinal wall. Figure 2 illustrates the distended bile duct and duodenum, the foreign body within the intestinal lumen and the excised object.

Figure 2

Intraoperative findings in a cat with duodenal foreign body-induced extrahepatic biliary obstruction: (a) gross appearance of the markedly dilated common bile duct (arrow) observed during abdominal exploration; (b) intraoperative view of the distended proximal duodenum (asterisk), consistent with mechanical obstruction; (c) a circular foreign body (arrowhead) visualised within the duodenal lumen after a longitudinal antimesenteric enterotomy; and (d) excised doughnut-shaped foreign body measuring approximately 1.9 cm in diameter

Postoperative care included prophylactic administration of amoxicillin-clavulanate (12.5 mg/kg IV q12h), maropitant (1 mg/kg SC q24h) and omeprazole (1 mg/kg IV q24h), all of which were continued for 3 days. Analgesia was provided via butorphanol continuous rate infusion (0.2 mg/kg/h IV) for 72 h postoperatively. Beginning on postoperative day 1, a highly digestible gastrointestinal wet food was offered, and the patient resumed voluntary intake. Vital parameters, including body temperature, heart rate, respiratory rate and body weight, were monitored four times daily during hospitalisation.

Postoperatively, serum bilirubin decreased to 0.5 mg/dl within 48 h, and liver enzyme levels improved. The patient resumed normal appetite and activity and was discharged on postoperative day 4. At the 2-week recheck, the patient was clinically normal, with resolution of laboratory abnormalities. Postoperative ultrasonography showed resolution of bile duct dilation with a normalised diameter of 2 mm (Figure 3).

Figure 3

Postoperative abdominal ultrasonography (48 h postoperatively) showing a reduction of the common bile duct diameter to 2 mm (arrow), consistent with resolution of extrahepatic biliary obstruction

Discussion

This case illustrates a rare but surgically correctable form of EHBO in cats. Although cholangitis, pancreatitis and neoplasia are more common causes of biliary obstruction, mechanical compression from a duodenal foreign body should be considered when imaging findings are suggestive, particularly near the major papilla.^{1 –4} Cholangitis may also contribute to obstructive patterns in feline EHBO, either as a primary pathology or in conjunction with mechanical causes. ⁷

Ultrasonography was instrumental in initial identification, but cross-sectional CT imaging enabled precise three-dimensional localisation of the obstruction and clarified the spatial relationship between the duodenal foreign body and the dilated common bile duct. The ability of CT to distinguish extramural compression from intramural or intraluminal lesions enabled accurate preoperative planning and supported the decision to avoid biliary tract incision. Such detailed anatomic resolution allowed confident yet minimally invasive surgical planning. To the authors’ knowledge, this is the first report in which CT clearly demonstrated extramural biliary compression caused by a duodenal foreign body, without intraluminal involvement. CT was uniquely able to confirm the absence of ductal invasion, allowing precise planning for a less invasive surgical approach.

In previously reported cases, choledochotomy was often necessary because of intraductal foreign bodies or mucosal damage.^3,4 However, in this case, enterotomy alone was sufficient, thereby minimising surgical trauma and associated risks. This approach aligns with recent surgical decision-making principles that emphasise lesion accessibility and anatomic clarity. ⁸

The transient pancreatic changes observed were likely secondary to papillary obstruction and resolved with removal of the compressive lesion. This is consistent with the inflammatory reflux theory described in feline hepatobiliary and pancreatic disorders.^1,2,9

Rapid postoperative normalisation of bilirubin, as seen in this case, has been associated with favourable prognosis in EHBO patients.^10,11 Timely recognition and intervention thus remain essential for improved outcomes.

Only one other peer-reviewed case has described feline EHBO due to extramural duodenal compression. In that case, a peach stone lodged at the papilla caused mucosal damage, necessitating choledochotomy for resolution. ⁴ In contrast, the present case involved a non-invasive, ring-shaped object inducing reversible mechanical compression. This case was managed successfully via enterotomy alone, with full recovery without biliary tract intervention. It adds a distinct clinical and surgical perspective to the limited literature on feline EHBO of mechanical origin.

The distinct anatomical and procedural features of this case, particularly the absence of ductal invasion and the ability to avoid choledochotomy, underscore a rare opportunity for curative management through a minimally invasive surgical approach. Compared with previous reports, this case underscores the importance of advanced imaging in recognising rare anatomical obstructions and guiding optimal surgical strategy in feline EHBO.

Conclusions

This case highlights duodenal foreign body impaction as a rare but important differential diagnosis in feline EHBO. Abdominal ultrasonography and CT enabled accurate diagnosis and surgical planning. CT, in particular, allowed for detailed spatial assessment of the obstructive lesion relative to the biliary tract, supporting a minimally invasive surgical strategy. Prompt surgical removal of the obstruction led to rapid clinical and biochemical recovery. Although uncommon, mechanical EHBO remains an important differential diagnosis in jaundiced cats with biliary dilation, particularly when imaging findings suggest duodenal involvement. This case demonstrates how early identification of extramural compression can allow for less invasive yet curative intervention in select feline patients.