Ultrasonographic appearance and clinical findings in 14 dogs with gallbladder mucocele

Fourteen dogs with enlarged gallbladders and immobile stellate or finely st riated bile patterns on ultrasound are described, Smaller breeds and older dogs were overrepresented, with 4/14 Cocker Spaniels. Most dogs presented f or nonspecific clinical signs such as vomiting, anorexia and lethargy. Abdo minal pain, icterus and hyperthermia were the most common findings on physi cal examination. All dogs except one had serum elevation of total bilirubin and/or alkaline phosphatase, alanine aminotransferase and gamma glutamyl t ransferase. All dogs were diagnosed with a gallbladder mucocele upon histol ogic and/or macroscopic evaluation. Ultrasonographically, mucoceles are cha racterized by the appearance of the stellate or finely striated bile patter ns and differ from biliary sludge by the absence of gravity dependent bile movement. On ultrasound, gallbladder wall thickness and wall appearance wer e variable and nonspecific, The cystic or common bile duct were normal size d in 5 dogs although all 5 had evidence of biliary obstruction at surgery o r necropsy, Loss of gallbladder wall integrity and/or gallbladder rupture m ere present in 50% of the dogs, all located in the fundus, Gallbladder mall discontinuity on ultrasound indicated rupture whereas neither bile pattern s predicted the likelihood of gallbladder rupture. Pericholecystic hyperech oic fat or fluid were suggestive of but not diagnostic for a gallbladder ru pture, Cholecystectomy appears to be an appropriate treatment for mucoceles , if not to treat a gallbladder rupture, at least in most dogs to prevent i t since gallbladder wall necrosis was identified by histology in 9 of 10 do gs. Mucosal hyperplasia was present in all gallbladders examined histologic ally. Positive aerobic bacterial culture was obtained from bile in 6 of 9 d ogs. Cholecystitis was diagnosed histologically in 5 dogs and 4 dogs had si gns of gallbladder infection solely upon bacterial bile culture. Gallbladde r infection was not present with all the mucoceles suggesting that biliary stasis and mucosal hyperplasia may be the primary factors involved in mucoc ele formation. Based on the results of our study, me suggest two alternate courses of action in the presence of a distended gallbladder with an immobi le ultrasonographic stellate or finely striated bile pattern: a cholecystec tomy when clinical or biochemical signs of hepatobiliary disease are presen t or a medical treatment (antibiotics and choleretics) and patient monitori ng by follow-up ultrasound examinations when the patient does not have clin ical or biochemical abnormalities. An aerobic bile culture should be obtain ed in all patients, by ultrasound-guided fine needle aspirate or at surgery .