Gallbladder Sludge in Dogs: Ultrasonographic and Clinical Findings in 200 Patients

Echogenic luminal contents are often noted during ultrasonographic examination of the gallbladder (GB) in canine patients, but the significance of biliary sludge is not well understood. GB contents were evaluated during 200 sequential ultrasonographic scans performed at a veterinary school, and sludge was quantified using a 1-5 scale. GB volume was retrospectively estimated from stored images. Medical records were used to determine patient demographics, clinicopathologic findings, and diagnoses/disorders. The majority of dogs (66.5%) had some hyperechoic material within the GB. Four dogs were diagnosed with a mucocele. For statistical purposes, dogs with uniformly nonechogenic bile or minimal sludge (80.5%) were compared to those with >25% sludge (17.5%). Dogs with >25% sludge were significantly older than those with minimal sludge (8 versus 11 yr). Serum cholesterol and bilirubin concentrations and activities of both alkaline phosphatase and gamma-glutamyl transferase were not correlated with the presence of GB sludge. Dogs with spontaneous hyperadrenocorticism or hypothyroidism were more likely to have >25% sludge (odds ratio: 5.04). In addition, >25% sludge was associated with increased GB volume, suggesting that changes in GB function or contractility may impact the formation of biliary sludge in dogs.