Serum thyroxine and thyrotropin level according to the severity of acute pancreatitis in dogs with hypothyroidism

Abstract Background Pancreatitis and hypothyroidism are common diseases in dogs. The hypothalamic-pituitary axis controls the secretion of thyroid hormones and is influenced by various factors, such as non-thyroid diseases and drugs. This study examined whether the serum thyroxine and thyrotropin levels differ according to the severity of acute pancreatitis (AP) in dogs with existing pre-existing hypothyroidism. Results The serum total T4, serum free T4, and serum TSH were measured to diagnose hypothyroidism. Hematological analysis, including specific pancreatic enzyme assays and ultrasonography, was performed to diagnose AP. Forty-four dogs diagnosed concurrent with AP and hypothyroidism were divided into two groups: dogs with mild acute pancreatitis (MAP) and moderate-to-severe acute pancreatitis (MSAP). Logistic regression analysis evaluated the possible risk factors for AP development in dogs with pre-existing hypothyroidism. Receiver operating characteristic (ROC) curve analysis was used to evaluate the total T4 level and predict the AP severity in dogs with pre-existing hypothyroidism. The mean serum total thyroxine was significantly higher in the MAP group than in the MSAP group (p = 0.016). The group with a total thyroxine value of less than 0.4 had a 29.2 times higher risk of MSAP than the group with a total thyroid value between 0.4 and 0.7, and a 192.67 times higher risk of MSAP than the group with a total thyroid value exceeding 0.7. Receiver operating characteristic (ROC) curve analysis was used to evaluate the total thyroxine level and predict the AP severity in dogs with hypothyroidism. Conclusions The serum total thyroxine level correlated with the severity of AP when AP developed in dogs with pre-existing hypothyroidism.