They will vomit often

Cases of dogs suffering from diabetes that are properly treated by the veterinarian don’t lead to complications, but those that don’t receive specific treatment can have severe effects, such as excessive vomiting without an apparent cause.

 “If diabetes goes untreated, the dog can go into diabetic ketoacidosis (DKA), where you see vomiting, lethargy and a poor appetite. At this point, it’s an emergency situation that requires hospitalization,” said Dr. Behrend. 

DKA will occur when the blood sugar is very high and no insulin to stimulate glucose. “The body will start to produce ketones for energy, but this is not a sustainable pattern; the blood becomes acidic, and the body’s enzymes start to malfunction,” said Dr. Romine.