Gallbladder agenesis in a Maltese dog

Common bile duct perforation due to choledocholithiasis in a cat with gallbladder agenesis

Case summary

An 8-year-old neutered male domestic shorthair cat was presented for further investigation of anorexia, vomiting and lethargy. Abdominal ultrasonography and contrast-enhanced CT revealed choledocholithiasis with suspected bacterial peritonitis and non-visualisation of the gallbladder. During surgery, the common bile duct was noted to be perforated, and a cholelith was found in the abdominal cavity. No gallbladder was confirmed during surgery. Three months postoperatively, the cat underwent CT cholangiography and absence of the gallbladder with a vestigial duplicated gallbladder was diagnosed.

Relevance and novel information

Gallbladder agenesis is extremely rare in cats, with only one previous report, but several dogs have been diagnosed based on CT cholangiography and laparoscopy. This report describes gallbladder agenesis concurrent with choledocholithiasis in an adult cat and represents the first report of CT cholangiography in a cat with gallbladder agenesis.

Canine hepatobiliary anatomy, physiology and congenital disorders

The biliary system is an integral component of normal physiologic homeostasis and essential for survival. It acts as a conduit for the removal of detoxified and catabolised compounds as well as aids in fat digestion and absorption. Derangements in this system can have dangerous sequela that are associated with varying degrees of morbidity and mortality. Moreover, abnormalities in development of the biliary system can have varied and unpredictable changes on function and long-term outcome. The aims of this article were to review canine hepatobiliary anatomy, physiology and cholestasis as well as summarise congenital biliary disorders including human corollaries.

Gallbladder Agenesis in a Dog: Clinicopathological, Histopathology, and Computed Tomography Findings

Three cases of gallbladder agenesis (GA) have been previously reported in the English-speaking veterinary literature. Affected dogs can be either asymptomatic or symptomatic with vomiting, retching, and anorexia previously reported. The previously reported cases and the dog in this report had marked elevations in alanine aminotransferase concentrations, and liver histopathology consistently showed bridging fibrosis and biliary hyperplasia. The condition is most often diagnosed in humans during exploratory surgery, which was also the case in the previous three dogs reported with GA. Computed tomography (CT) or MRI is now recommended for diagnosis of the condition in humans, and this is the first report of CT findings in an affected dog diagnosed without surgery. Bile stasis and cholangiohepatits have been proposed as secondary pathologies in both humans and dogs with GA, and histopathology and CT findings in this case support those theories.

Gallbladder Agenesis in 17 Dogs: 2006-2016

Background

Gallbladder agenesis (GBA) is extremely rare in dogs.

Hypothesis/Objectives

To describe the history, clinical signs, diagnosis, treatment, and outcomes of dogs with GBA.

Animals

Seventeen client‐owned dogs with GBA.

Methods

Medical records from 2006 through 2016 were retrospectively reviewed. Dogs were included when GBA was suspected on abdominal ultrasonography and confirmed by gross evaluation. Signalment, clinical signs, clinicopathological data, diagnostic imaging, histopathology, treatment, and outcome were recorded.

Results

Dogs were of 6 different breeds, and Chihuahuas (10 of 17) were most common. Median age at presentation was 1.9 (range, 0.7–7.4) years. Clinical signs included vomiting (5 of 17), anorexia (2 of 17), ascites (2 of 17), diarrhea (1 of 17), lethargy (1 of 17), and seizures (1 of 17). All dogs had increased serum activity of at least 1 liver enzyme, most commonly alanine aminotransferase (15 of 17). Fifteen dogs underwent computed tomography (CT) cholangiography; common bile duct (CBD) dilatation was confirmed in 12, without evidence of bile duct obstruction. Gross evaluation confirmed malformation of the liver lobes in 14 of 17 dogs and acquired portosystemic collaterals in 5 of 17. Ductal plate malformation was confirmed histologically in 16 of 17 dogs. During follow‐up (range, 4–3,379 days), 16 of 17 dogs remained alive.

Conclusions and Clinical Importance

Dogs with GBA exhibit clinicopathological signs of hepatobiliary injury and hepatic histopathological changes consistent with a ductal plate abnormality. Computed tomography cholangiography was superior to ultrasound examination in identifying accompanying nonobstructive CBD distention. Computed tomography cholangiography combined with laparoscopic liver biopsy is the preferable approach to characterize the full disease spectrum accompanying GBA in dogs.

Gallbladder agenesis in a Chihuahua

A 4-year-old neutered male Chihuahua was presented with a history of anorexia and vomiting. Continuous elevation of liver enzymes was found on repeated blood examinations and the dog was referred to us for further evaluation. The absence of gallbladder was suspected on ultrasonography. Exploratory laparotomy and retrograde cholangiography confirmed gallbladder agenesis and a possible hypoplasia of the right medial and lateral liver lobes. Histologically, proliferation of bile ductules associated with portal fibrosis and pseudolobular formation were apparent in the liver lobes.