Cushing's disease in dogs occurs when dogs produce too much of the cortisol hormone, and it causes many of the dog's organs to have a difficult time working properly. The disease occurs in the adrenal glands of the dog, and there is not one test that can diagnose the disease so veterinarians must diagnose by first ruling out other possibilities.
There are two different types of Cushing's disease: pituitary-dependent Cushing's disease and adrenal-dependent Cushing's disease. In pituitary-dependent Cushing's disease, it is the brain that sends the signal to produce too much of the cortisol hormone. In adrenal-dependent Cushing's disease, the dog has a tumor in the adrenal gland that causes the overproduction of the cortisol hormone, as stated by the College of Veterinary Medicine at Washington State University.
Dogs that have Cushing's disease have many different symptoms, all of which can be attributed to other illnesses. This is what makes Cushing's disease so difficult to diagnose. The symptoms include a ravenous appetite, excessive drinking, additional urination, stiff walking, hair loss, panting, thinner skin, weakness and a pot-bellied appearance, as noted by WebMD. Some dogs may even experience trouble breathing due to a blood clot in the lung. It is always best to take a dog with any of these symptoms into a veterinarian for an accurate diagnosis. Early treatment in Cushing's disease is important because Cushing's erodes many of the body's organs.