Cholelithiasis

From Dog
Multiple small choleliths extracted from a Keeshond with cholelithiasis and cholecystitis[1]

Cholelithiasis is a common form of extrahepatic biliary obstruction in dogs but is essentially rare in canine medicine.

Choleliths are frequently an incidental finding on ultrasonography or at postmortem and three types are recognized in dogs: pure cholesterol choleliths, mixed choleliths (cholesterol mixed with bile acids, pigment, calcium and protein) and pigment choleliths (calcium bilirubinate).

Choleliths usually develop when bile becomes saturated with cholesterol, often due to persistent hypercholesterolemia. This results in delayed gall bladder emptying and mucosal secretion of mucin which may induce cystic duct occlusion[2]. Other causes of cholelith formation include nidus formation around bile pigments, mucoproteins, bacteria and refluxed intestinal contents[3].

This disorder is more frequently observed in older, female, small-breed dogs[4], where complicating diseases such as hepatitis, cholangitis and biliary peritonitis[5] may also be observed.

Clinical signs include vomiting, icterus, abdominal pain and fever. Unlike gallstones in humans, which primarily contain cholesterol, choleliths in dogs and cats contain bilirubin pigments[6].

Blood tests usually show leukocytosis, hypoalbuminemia, hypercholesterolemia, and markedly elevated bilirubinemia, γ-glutamyl transferase, ALT and AST.

Diagnosis is usually based on clinical history and supportive imaging studies (usually ultrasonography). A common finding is the appearance of a porcelain gallbladder due to chronic distension and calcification of teh gall bladder mucosa[7].

A differential diagnosis would include primary bile duct carcinoma, pancreatitis, cholangiohepatitis, cholecystitis with or without cholelithiasis and neoplasia[8].

Treatment consists of removal of the stones by cholecystotomy or cholecystoduodenostomy, jejunostomy or choledochal tube stenting[9].

Appropriate broad-spectrum antibiotic therapy is usually indicated such as enrofloxacin and metronidazole[10].

References

  1. Ward R (2006) Obstructive cholelithiasis and cholecystitis in a keeshond. Can Vet J 47(11):1119-1121
  2. Church EM & Matthiesen DT (1988) Surgical treatment of 23 dogs with necrotizing cholecystitis. J Am Anim Hosp Assoc 24:305–310
  3. Strombeck DR & Guilford WG (1990) Small Animal Gastroenterology, 2nd ed. Davis, California: Stonegate Publ. pp:686–689
  4. Baker SG et al (2011) Choledochotomy and primary repair of extrahepatic biliary duct rupture in seven dogs and two cats. J Small Anim Pract 52(1):32-37
  5. Brömel C et al (1998) Gallbladder perforation associated with cholelithiasis and cholecystitis in a dog. J Small Anim Pract 39(11):541-544
  6. Merck Veterinary Manual
  7. Brömel C et al (1998) Porcelain gallbladder associated with primary biliary adenocarcinoma in a dog. J Am Vet Med Assoc 213(8):1137-1139
  8. Center SA (2009) Diseases of the gallbladder and biliary tree. Vet Clin North Am Small Anim Pract 39(3):543-598
  9. Mayhew PD et al (2006) Choledochal tube stenting for decompression of the extrahepatic portion of the biliary tract in dogs: 13 cases (2002-2005). J Am Vet Med Assoc 228(8):1209-1214
  10. Harris, SJ et al (2008) Obstructive cholelithiasis and gall bladder rupture in a dog. Journal of Small Animal Practice 25(11):661-667