Pituitary Apoplexy-Like Disease in 4 Dogs

Background: Pituitary apoplexy in humans is a clinical syndrome resulting from sudden infarction, hemorrhage, or both in a normal or an adenomatous pituitary gland. Objective: Describe a clinical syndrome in dogs similar to pituitary apoplexy in humans. Animals: Four dogs exhibiting a sudden onset of neurologic signs. Methods: A retrospective study was used, including clinical examination, computed tomography (CT), postmortem examination, and histopathology of the brain. Pituitary tissue from 3 of the dogs was subjected to immunocytochemistry. Results: Four dogs (2 Mongrels, 1 Bordeaux Dog, and 1 Cocker Spaniel; median age, 11 years; median body weight, 20.5 kg) presented with acute neurologic signs including depression (n = 3), behavioral changes (n = 1), vision loss (n = 1), seizures (n = 1), and collapse (n = 1). CT disclosed suprasellar infarction, hemorrhage, or both associated with a pituitary macroadenoma in 3 dogs and a frank hemorrhage in a nonadenomatous pituitary gland in 1 dog. CT findings were correlated with postmortem findings, and pituitary apoplexy was confirmed by histopathology and immunocytochemistry of the pituitary tissue. Conclusions and Clinical Importance: This study provides histopathologic evidence of pituitary apoplexy in dogs. The results are relevant for future diagnosis and treatment of pituitary disease in dogs.