Abstract: Title: Suspected Autoimmune Polyglandular Syndrome Type II in 51 Dogs
Background: Autoimmune polyglandular syndrome type II (APS-II) is characterized by the co-occurrence of two or three of the following: adrenal insufficiency, hypothyroidism, and diabetes mellitus (DM). While its clinicopathological features are well-documented in humans, reports on APS-II in dogs remain limited to individual case reports.
Objectives: To describe the clinical course of APS-II in dogs. Animals: Fifty-one client-owned dogs diagnosed with APS-II based on clinicopathological criteria were included in this retrospective, observational cohort study.
Methods: Medical records from five university referral hospitals in Europe, from 2000 to 2024, were reviewed. Data included signalment, clinical signs, endocrine testing, and outcomes. Diagnosis was based on compatible clinical signs and confirmatory endocrine tests.
Results: Of 51 dogs, 19 (37%) had hypothyroidism and hypoadrenocorticism, 24 (47%) had hypothyroidism and DM, 7 (14%) had hypoadrenocorticism and DM, and 1 dog was diagnosed with all three. The most common initial diagnosis was DM (43%), followed by hypoadrenocorticism (33%) and hypothyroidism (23%). Median interval between the first and second diagnoses was 122 days (range 0-1636). Median age at first endocrinopathy diagnosis was 7 years (range 1-13). Median survival time was 41 months (range 1 - 145) from initial diagnosis with a median age of death of 12 years (range 1–15). Conclusions and Clinical Importance: This study highlights the importance of recognizing polyendocrinopathies in dogs. Further research is needed to identify risk factors associated with APS-II and how if differs from single endocrinopathies.
