Evaluation and Treatment of a Posttraumatic Intrahepatic Biloma in a Dog

Introduction

Bilomas (biliary pseudocysts) are encapsulated extra- or intrahepatic collections of bile that develop following iatrogenic, traumatic, or spontaneous rupture of the biliary tree.¹ Extravasation of bile into the hepatic interstitial tissue generates an intense inflammatory reaction, thereby inducing formation of a well-defined pseudocapsule.² Cholecystectomy and accidental trauma are considered the most common causes of biloma formation in humans.^1,3–5 Ultrasonography, CT and fine-needle aspiration (FNA) are essential for the diagnosis of biloma.^1,6 Two cases of iatrogenic bilomas have appeared in the veterinary literature: one in a dog associated with attenuation of an intrahepatic portosystemic shunt and the other in a cat following an open hepatic biopsy.^6,7 To the authors’ knowledge, no such complication associated with cholecystectomy in the dog has been reported in the veterinary literature. This report describes an intrahepatic biloma that formed following cholecystectomy, which was successfully treated via percutaneous ultrasound-guided aspiration in a dog.

Case Report

A 9 mo old, 7 kg, intact male mixed-breed dog was referred with 1 wk history of depression and vomiting, after being hit by a car 10 days before referral. Clinical examination revealed that the dog was icteric, lethargic, and in poor body condition. Abdominal palpation showed hepatomegaly and abdominal distension. Laboratory abnormalities included a leukocytosis (31,000/μL; reference range, 6–17,000/μL), mildly elevated serum glucose (136 g/dL; reference range, 65–118 g/dL), mildly elevated triglycerides (109.5 g/dL; reference range, 24–102 g/dL), elevated total bilirubin (165 mg/dL; reference range, 0.2–0.6 mg/dL), increased ALP (1076 IU/L; reference range, 32–149 IU/L) and an increased ALT (344 IU/L; reference range, 18–62 IU/L). Abdominal radiography demonstrated decrease of serosal detail. Abdominal ultrasound showed peritoneal effusion, a mildly distended gallbladder with no signs of either intra- or extrahepatic bile duct distention. Ultrasound-guided FNA of the abdominal fluid showed that this was consistent with bile and the diagnosis of biliary effusion was made. Culture and sensitivity tests of the fluid were unremarkable.

An exploratory celiotomy revealed rupture of the cystic duct and cholecystectomy was performed after ligation of the cystic duct with 2–0 polydioxanone^a suture material. The abdominal cavity was copiously lavaged with warm normal saline solution and closed routinely and the dog recovered uneventfully. Postsurgically, the dog received ursodeoxycholic acid^b, metroclopramide^c, enrofloxacin^d, and an intestinal formula diet^e for 10 days. The dog's condition improved significantly.

Clinical examination at the time of representation revealed that the dog was in good body condition with pale mucous membranes and slightly elevated temperature (39.8°). Complete blood count revealed a neutrophilic leukocytosis (20,000/μL; reference range, 6–17,000/μL) and anemia (PCV was 33.6%; reference range, 37%–55%). Serum biochemistry analysis detected an increased ALP (2000 IU/L), an increased ALT (99 IU/L), and low total solids (4 g/dL; reference range, 5.5–8 g/dL).

A 6 cm × 6 cm well-defined, intrahepatic, anechoic, lesion, compatible with an intrahepatic cyst without septa formation was detected on an ultrasonographic examination of the liver through the right hepatic lobes (Figure 1). The remaining hepatic parenchyma was found normal. Ultrasound guided fine needle aspiration of the lesion which was performed under sedation revealed a fluid-filled cyst. Examination of the fluid demonstrated 160 mg/dL cholesterol, 86 mg/dL triglycerids, 3.9 mg/dL total bilirubin, 4 g/dL total solids, and a specific gravity of 1,028. Cytology and culture and sensitivity testing of the fluid were not performed as these findings were consistent with the fluid being bile. Thus, a diagnosis of an intrahepatic biloma was made. The biloma was partially evacuated after removing 60 mL of fluid by placing an 18 gauge catheter percutaneously under ultrasound guidance. Ultrasonographic examination of the evacuated biloma revealed a rough inner wall margin (Figure 2). The dog was discharged from the hospital and was prescribed ursodeoxycholic acid^a at a dose of 15 mg/kg per os q 12 hr for 2 mo and enrofloxacin^c at a dose of 5 mg/kg subcutaneously q 12 hr for six days. Ten days after presentation, ulrasonographic examination of the abdomen showed that the biloma was significantly reduced in size. Two years after referral, the dog was reported to be in good health.

View Figure

• Download as Powerpoint
• Download Figure

View Figure

• Download as Powerpoint
• Download Figure

Discussion

Intrahepatic bile duct disruption may result in bile extravasation allowing accumulation within the hepatic parenchyma. The fluid may follow anatomic planes, accumulate underneath the hepatic capsule, or perforate the capsule to enter the abdominal cavity. The end result of this bile leakage may be either an intra- or extrahepatic biloma.^1,6,7 In the case presented here, it seems possible that that the previous traumatic incident that the dog suffered might have resulted in bile duct disruption and biloma formation. It is also possible, however, that bile duct transection during gallbladder and cystic duct dissection performed during the cholecystectomy, a leak from the cystic duct stump, or vascular compromise and subsequent duct necrosis led to persistent bile leakage and biloma formation.^1,4,5 This intrahepatic cyst was detected 10 days after the cholecystectomy and was located just to right of midline where the gallbladder is usually inspected ultasonographically.

Cholangiectasis has also been reported in humans after extrahepatic bile duct dissection and cholecystectomy because of loss of supportive tissue surrounding the ducts.^8,9 In our case, the large size of the intrahepatic bile cyst and the absence of any cholangiectasis as well as the rough margin of the inner wall of this cyst documented ultrasonographically excluded the presence of bile accumulation within the bile duct. Cytology and culture and sensitivity tests are advisable especially when pyrexia and leukocytosis are present to exclude any infected bile accumulation.

Intrahepatic bilomas in humans occur predominantly in the right upper quadrant or mid-abdomen, close to the porta hepatis or gallbladder.¹⁰ Ultrasonography of bilomas shows an anechoic lesion and, occasionally, sludge-like material with striking distal sonic enhancement.^2,11 On both CT and MRI examinations, a biloma usually appears as a well-defined or slightly irregular cystic mass without septa or calcifications; however, the pseudocapsule is not readily identifiable.¹² Ultrasonographic differential diagnoses for an intrahepatic biloma include choledochal cysts, ectopic gallbladder, hepatic cysts, abscesses, and hematomas.^7,13

The appropriate treatment for most human bilomas is percutaneous drainage; however, major biliary injuries, failure in percutaneous drainage procedures, or even septic bilomas usually require surgical intervention.^1,5 Successful drainage through marsupialization was implemented in an extrahepatic biloma in one dog.⁶ In the case presented here, percutaneous drainage resulted in a significant evacuation of the biloma documented ultrasonographically 10 days after drainage. The clinical significance of this small residual bile collection was not clear since the dog was free of clinical signs 2 yr after drainage. Small intrahepatic bilomas may produce no symptoms and cause no harm in humans.^1,11

Conclusion

This case report describes an unusual complication of either abdominal trauma or cholecystectomy in a dog. The intrahepatic biloma was diagnosed with ultrasound and FNA. Percutaneous drainage of the biloma resulted in complete remission of clinical signs 2 yr after drainage.