Cushing’s disease (hyperadrenocorticism) is the overproduction of the hormone cortisol by the adrenal glands that are located in near the kidneys. Cushing’s disease occurs commonly in dogs, but is rare in cats. Most dogs with Cushing’s disease are about 6 years old or older but sometimes Cushing’s disease occurs in younger dogs. Cortisol affects the function of many organs in the body, so the signs of Cushing’s disease may be varied.
Symptoms in dogs include increased thirst and urination, increased appetite, reduced activity, excessive panting, hair loss, thin or fragile skin, recurrent skin infections and enlarged abdomen.
Most canine Cushing’s disease occurs naturally and is either pituitary-dependent or adrenal-dependent. About 80–85 percent of Cushing’s is pituitary-dependent, meaning it’s triggered by a tumor on the pituitary, a pea-sized gland at the base of the brain.
The pituitary makes a number of hormones, including adrenocorticotropic hormone (ACTH). The pituitary tumor causes overproduction of ACTH, which travels through the bloodstream to the adrenal glands, stimulating them to produce more cortisol than the body needs. In the other 15–20 percent of Cushing’s dogs, a tumor in one or both adrenal glands produces excess cortisol.
The type of Cushing’s may determine what kind of treatment is prescribed. Veterinarians use blood tests to diagnose Cushing’s and to differentiate between disease caused by the pituitary or the adrenals. They may also use an ultrasound to help detect a tumor on an adrenal gland.
Most veterinarians treat both adrenal- and pituitary-dependent Cushing’s disease with medication. The only way to “cure” Cushing’s disease is to remove the adrenal tumor if the disease is adrenal-dependent and the tumor hasn’t spread. However, because of the complexity and risks of the surgery, most cases are treated with medication. Surgical techniques to remove pituitary tumors in dogs are being studied, but surgery is not a widely available option.
Although Cushing’s is typically a lifelong condition, the disease usually can be managed with medications. It’s important for a veterinarian to see the dog regularly and do blood tests. Monitoring the blood helps determine the right dose, which may need to be adjusted periodically.
Why am I writing about Cushing’s? Because Kirby has just been diagnosed and is having the ultrasound tomorrow to determine which form he has and then we will proceed with treatment.
It was a difficult case to diagnose as Kirby did not gain weight, rather had a dramatic weight loss over a few weeks, in addition to several other symptoms. He was first tested for Addison’s disease, the opposite of Cushing’s and everyone was surprised with the outcome after the first round of tests.
But Cushing’s it is and now we will take this new journey together. Kirby is a very strong dog who has been through a lot in his life and everything that can be done to keep him happy and comfortable, pain free, and as active as possible, will be done.
The important thing is for him to get the light back in his eyes and the pep in his step.