Canis ISSN: 2398-2942

Biliary system: disease (cholestatic disease)

Contributor(s): Ben Harris, James Simpson

Introduction

  • Cholestasis is not a diagnosis but a reflection of biliary tract dysfunction.
  • Cause: either intrahepatic or extrahepatic conditions, eg:
    • Trauma, rupture of the gall bladder or bile duct.
    • Neoplasia.
    • Cholelithiasis.
    • Hepatic disease.
  • Signs: jaundice (icterus).
  • Diagnosis: history, signs, hematology, biochemistry, radiography, ultrasonography.
  • Treatment: depends on cause.
  • Prognosis: depends on cause - fair to guarded.

Pathogenesis

Etiology

  • Extrahepatic disease:
    • Severe red cell destruction must be considered in the jaundiced patient.
    • Cholelithiasis.
    • Neoplasia obstructing the bile duct:
      • Within the gall bladder.
      • Within the biliary tree.
      • At the duodenal papilla.
      • Pancreatic.
    • Duodenal foreign body obstruction.
    • Trauma - rupture of the bile duct/gall bladder (most frequently after a road traffic accident).
    • Cholestasis of sepsis.
  • Intrahepatic disease:

Predisposing factors

General
  • Hepatic disease → stagnation of bile flow, functional obstruction.
  • Trauma → gall bladder or bile duct rupture.
  • Ascending biliary tract infection.
  • Cholangitis.
  • Sepsis, endotoxemia.

Pathophysiology

  • Jaundice represents an accumulation of bilirubin within the blood and subsequently deposition within various body tissues - mucous membranes and skin are most obviously involved.
  • Hyperbilirubinemia is associated with:
    • Excessive red cell destruction (pre-hepatic).
    • Hepatic disease.
    • Post-hepatic obstruction (bile duct obstruction).
  • Rupture of the bile duct → bile peritonitis, resorption of bilirubin into the circulation and hyperbilirubinemia. Obvious staining of omentum seen at laparotomy.
  • Cholelith formation is uncommon in dogs Gallbladder: cholelith. Choleliths may obstruct the bile duct, cause inflammation of the gallbladder and bile ducts and eventually cause bile duct perforation.
  • Hepatic disease may result in stasis of bile flow, stagnation of bile and failure of bilirubin excretion.
  • Neoplasms of the bile duct epithelium, liver or pancreas may obstruct bile flow.
  • Endotoxin and other bacterial products may directly, or via cytokine stimulation, inhibit bile flow by acting on hepatic signaling pathways.

Timecourse

  • Days or weeks.

Diagnosis

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Treatment

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Outcomes

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Further Reading

Publications

Refereed papers

Other sources of information

  • Center S A (2009)diseases of the gallbladder and biliary tree.Vet Clin North Am Sm Anim Pract39(3), 543-598PubMed.
  • Thrall D E (2007)Textbook of Veterinary Diagnostic Radiology.Saunders, Elsevier, St Louis.
  • Thomas D, Simpson J W & Hall E J (1996)Manual of canine and feline gastroenterology.Eds. BSAVA, Cheltenham.


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