Survey of owners on population characteristics, diagnosis, and environmental, health, and disease associations in dogs with megaesophagus.

Megaesophagus affects dogs worldwide but limited information is available regarding its characteristics in the general population of dogs. The objectives of this study were to provide information on a large population of dogs diagnosed with megaesophagus in regards to population characteristics, medical and family history, diagnosis, concurrent disease, and predisposing factors. A link to a web-based survey was provided on megaesophagus support websites and 838 eligible surveys were evaluated. Breeds most frequently associated with congenital megaesophagus were German shepherds, mixed breed "goldendoodles", Labrador retrievers, great Danes, and dachshunds. Breeds most often associated with acquired megaesophagus were Labrador and golden retrievers, Chihuahuas, boxers, German shepherds, dachshunds, and Rottweilers. Diagnosis was most often by a general practitioner (63.6%) via plain radiographs (63.3%) and/or barium study (45%). Congenital megaesophagus was diagnosed in 41.3% of dogs and persistent right aortic arch in 4.3%. Diseases most commonly associated with acquired megaesophagus were myasthenia gravis (19.3%), esophagitis (10.8%), hypothyroidism (8.8%). Survey results support previous breed predilections and identified dachshunds, boxers, Chihuahuas, Rottweilers, and "goldendoodles" as additional at risk breeds. Myasthenia gravis was found at lower rates than previous described and contrary to recent studies, hypothyroidism was found in relatively high prevalence. Most dogs were diagnosed by a general practitioner suggesting previous studies at referral facilities may be biased towards dogs with more severe disease and worse outcomes.