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118 Bile Duct Obstruction, Extrahepatic

Bile Duct Obstruction, Extrahepatic Client Education
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content may predispose cats to ascending
BASIC INFORMATION
obstruction: > 5 mm in cats, varies in
cholangitis and pancreatitis after vomit- ○ Common bile duct dilation signifying
Definition ing associated with inflammatory bowel dogs
Obstruction of the extrahepatic bile duct system disease. ○ Stellate or kiwi fruit pattern if GB
Dogs and cats: mucocele
Synonym • Other possible causes include neoplasia, ○ Visible contraction of the GB is not
Extrahepatic bile duct obstruction, EHBDO, stricture in biliary system, duodenal obstruc- expected in healthy or diseased states
biliary obstruction tion by a foreign body, diaphragmatic hernia, • Peritoneal fluid analysis obtained during
and parasitic infection. abdominal ultrasound examination (p. 1343)
Epidemiology • Lack of bile entering intestinal tract ○ Elevated bilirubin concentration: bile
SPECIES, AGE, SEX ○ Decreases absorption of fat and fat-soluble peritonitis
• Dogs (middle-aged to older adults): gallblad- vitamins, notably vitamin K: potential ○ Cytologic analysis and microbiological
der (GB) mucocele, pancreatitis; less com- coagulopathy. May also result in increased (aerobic and anaerobic) culture and
monly, neoplasia absorption of endotoxin from the gut. sensitivity testing: septic peritonitis
• Cats (middle-aged to older adults): neoplasia Paradoxically, dogs with EHBDO recently • Coagulation profile (p. 1325)
have been shown to be hypercoagulable. • Thromboelastography
RISK FACTORS
• Dogs: pancreatitis, hyperadrenocorticism, DIAGNOSIS TREATMENT
hypothyroidism, neoplasia
• Cats: pancreatitis, cholangitis/cholangiohepatitis, Diagnostic Overview Treatment Overview
inflammatory bowel disease, eosinophilic The diagnosis is suspected based on present- Patients require surgical correction of the
sclerosing fibroplasia, neoplasia ing history and physical examination find- problem along with appropriate intensive and
ings. Confirmation requires demonstration supportive postoperative care. A crucial excep-
ASSOCIATED DISORDERS by abdominal ultrasound exam that the tion is transient biliary obstruction caused by
Dogs: icterus is caused by an obstructed common acute pancreatitis, which often improves with
• Cholecystitis bile duct. medical therapy alone.
• GB mucocele
• Hypercoagulability (in contrast to hypoco- Differential Diagnosis Acute General Treatment
agulability, as previously believed) Hyperbilirubinemia (p. 528): • Rehydration by intravenous administration
Dogs and cats: • Rule out hemolysis (pp. 59 and 60) of balanced electrolyte solution
• Cholangitis/cholangiohepatitis • Rule out hepatic disease (pp. 174, 442, 452, • Parenteral antibiotics effective against gram-
• Cholelithiasis and 458) negative bacteria and anaerobes:
• Bile peritonitis ○ Empirical therapy
• Neoplasia Initial Database ■ Cefoxitin 30 mg/kg IV q 2h periop-
• CBC eratively, then q 6h (dogs and cats), or
Clinical Presentation ○ Possible mild anemia (unless concurrent ■ Metronidazole 7.5-15 mg/kg IV q 12h
HISTORY, CHIEF COMPLAINT gastrointestinal ulceration). In contrast, with
• Dogs: anorexia, lethargy, vomiting, diarrhea hyperbilirubinemia/icterus caused by ■ Enrofloxacin 2.5-5 mg/kg IV q 12h
• Cats: anorexia, lethargy, weight loss, vomiting hemolysis generally produces moderate to (dogs only)
marked anemia. ■ Ampicillin 22 mg/kg IV q 6-8h can
PHYSICAL EXAM FINDINGS ○ Inflammatory leukogram be added to cefoxitin to add gram-
• Dogs: icterus, fever, tachycardia, ± abdominal • Serum biochemistry profile positive coverage
pain ○ Increased bilirubin concentration ○ Specific long-term therapy based on
• Cats: icterus, dehydration, fever or hypo- ○ Increased liver enzyme concentrations culture and sensitivity test results
thermia (proportional alkaline phosphatase [ALP] • Sometimes, fresh-frozen plasma may be
> alanine aminotransferase [ALT]) beneficial
Etiology and Pathophysiology ○ Possible increased amylase and lipase ○ Hypoproteinemia
Dogs: concentrations ○ Coagulopathy
• Pancreatitis: pancreatic swelling compresses ○ Hypokalemia • Vitamin K administration: 2.5 mg/kg SQ
common bile duct (p. 742) • Urinalysis: bilirubinuria is common in both q 12h × 3-5 days, then once weekly
• Mucocele: biliary sludge or gelatinous species, but mild bilirubinuria is also normal • Surgical intervention for relief of extrahepatic
mucous obstruct biliary outflow (p. 374) in healthy dogs. biliary obstruction
• Cholelithiasis: choleliths (stones) obstructing • Survey abdominal radiographs ○ Duodenotomy and retrograde and ante-
biliary outflow; cause poorly understood ○ Cranial abdominal detail may be decreased grade flushing of biliary system: all cases
(p. 162) in cases with biliary leakage and peritonitis. ○ Common bile duct stenting: if tem-
Cats: ○ May delineate radiopaque choleliths porary or dynamic obstruction likely
• Extrahepatic biliary obstruction often associ- • Survey thoracic radiographs: rule out meta- (i.e., pancreatitis) and severe persistent
ated with a triad of diseases: cholangitis, static disease if neoplasia is suspected. hyperbilirubinemia
pancreatitis, and inflammatory bowel disease ○ Cholecystoduodenostomy/jejunostomy:
(pp. 160, 543 and 740) Advanced or Confirmatory Testing if advanced or permanent obstruction
○ Common opening of the pancreatic and • Abdominal ultrasound examination ○ Tube cholecystostomy
common bile ducts into the duodenum ○ Normal diameter of common bile duct ○ Cholecystectomy: for GB mucoceles, cho-
and the increased duodenal bacterial in dogs and cats: 3-4 mm lecystolithiasis, or if GB wall is devitalized

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