GI21 - Comparison of Gallbladder Volume and Emptying Between Treated Hypothyroid Dogs and Healthy Dogs

Abstract: Background - Endocrine disorders are risk factors for gallbladder diseases, including bile sludge, mucocele, and cholelithiasis. Objectives - To compare gallbladder volume (GBV) and emptying between controlled hypothyroid dogs and healthy dogs of the same age and diet. Animals - Nine treated and controlled hypothyroid dogs without comorbidities (body condition score: 4–7, nine-point scale) and 21 healthy age-matched dogs. Methods - All dogs were fed the same extruded diet for 60 days. After a 12-hour fast, initial GBV (V0) was measured via ultrasonography. Dogs then received levothyroxine sodium and 50% of their daily food intake. GBV was reassessed at 30, 60, and 120 minutes postprandially (Vx), using the formula: GBV = 0.52 × Length(cm) × Height(cm) × Width(cm), indexed to body weight (kg). Gallbladder ejection fraction (GBEF) was calculated as GBEF = [(V0–Vx) / V0] × 100. All measurements were performed in triplicate. Statistical analysis was conducted using T-tests, Wilcoxon, and Mann-Whitney tests (p < 0.05). Results - No significant differences were observed in GBV and GBEF between groups at any time point (p < 0.05). However, hypothyroid dogs exhibited slower emptying postprandially compared to the fasted state, whereas healthy dogs showed a more rapid response (Table 1). Conclusions and Clinical Importance - Hypothyroid dogs have similar GBV but exhibit delayed GBEF compared to healthy dogs, suggesting an altered postprandial gallbladder response in hypothyroid dogs.