Constant Thirst, Hunger and Weight Gain in a Young Heeler
by A reader
Drinking a lot since puppyhood, constant hunger and fast weight gain do point toward a hormone or metabolic problem, so you are right to keep pushing. Cushing's disease is rare in a 2-year-old, and Addison's disease usually causes weight loss rather than gain, though an abnormal sodium-to-potassium ratio is a reason to look at the adrenal glands. Other possibilities include a problem with the hormone that controls urine concentration (diabetes insipidus), kidney or liver problems, diabetes, and simply drinking out of habit.
Some useful tests need only a urine sample, which can be caught at home in a clean container: a urine concentration test, a check for sugar and infection, and a urine cortisol test that can help rule Cushing's in or out. Ask your vet if they will run these from a sample you bring in.
For the fear, ask your vet about medicine to give at home before the visit. Many very fearful dogs do much better with a pre-visit calming medicine, a muzzle trained at home with treats, and a quiet room or exam in the car. A veterinary behaviorist or a clinic with fear-free training can help a lot.
Meanwhile, don't restrict his water, and measure how much he drinks in 24 hours, which helps the vet. See adrenal gland problems in dogs, Cushing's disease and Addison's disease.
This is general information, not a diagnosis. Please follow your own vet's advice.
