Cushing’s disease (or Cushing’s syndrome) refers to the condition caused by hyperadrenocorticism, which is when the adrenal glands produce too much of the hormone cortisol. It’s one of the most common endocrine disorders affecting dogs, and it causes symptoms that easily interfere with an assistance dog’s health, comfort, energy, and general ability to perform her duties.
Cortisol is often called the “stress hormone,” as one of its main jobs is to help manage the effects of stress on the body. But it also helps your guide, hearing, or service dog regulate her weight and blood sugar levels, stave off infections, and more. An excess in cortisol can throw off important systems.
What Causes Canine Cushing’s Disease?
Cushing’s disease has three different causes, and determining the correct one is important to successful treatment. As many as 90 percent of cases are caused by a benign or malignant tumor on a pituitary gland or overgrowth of a pituitary gland. This causes the gland to overproduce the hormone ACTH, which in turn triggers increased cortisol production in the adrenal glands.
Other causes include a benign or malignant tumor on the adrenal gland and prolonged use of oral or injected steroids. The latter can become an issue in dogs with medical conditions managed by steroid use, but dogs with such conditions would not be expected to be working as assistance dogs, of course.
What Are the Main Signs and Symptoms of Cushing’s Syndrome?
The primary symptoms of Cushing’s disease in dogs are the same, regardless of the cause. These include:
- Increased appetite, thirst, and urination are the most common
- Decreased energy or lethargy are also common
- Developing a potbelly is a hallmark symptom (but not always present)
- Hair loss or darkening of the skin
- Developing blackheads or white scaly patches
- Increased skin infections/poor skin healing
- Persistent bladder infection
- Weigh gain and fat pads on the shoulders/neck
- Muscle weakness
- Excessive panting
- Thinning of the skin
- Easy bruising
- Difficulty sleeping
How Is Cushing’s Disease Diagnosed in an Assistance Dog?
Cushing’s disease is a somewhat tricky diagnosis, simply because the main clinical signs can point to a variety of possible problems. When you notice symptoms or changes to your assistance dog, schedule a veterinary appointment. It’s helpful for your vet if you have a record of the symptoms you’ve observed, when you started seeing them, whether they’re intermittent or chronic, whether they’ve gotten better or worse, and other details.
Your vet will probably begin with a thorough physical examination, blood work, and urinalysis to gather clues. Two types of blood test and one type of urinalysis can check for elevated cortisol levels. Once they’re found, the cause needs to be identified. Testing for excess ACTH or administering drugs to suppress pituitary function can confirm or rule out the most common type of Cushing’s disease. X-ray or ultrasound imaging is used to detect tumors.
How is Canine Cushing’s Syndrome Treated?
Again, treatment depends on the underlying cause. Tumors can often be surgically removed, and this resolves the excess cortisol production. If surgery isn’t an option, the drug trilostane is usually prescribed. It must be given daily for the dog’s life, but it is highly effective at managing the condition. Periodic, ongoing blood tests are necessary to ensure the dosage is working well and that hormone production stays at desired levels.
Cushing’s disease caused by prolonged steroid use can be treated by stopping the steroids, though another treatment strategy is then needed for the condition the steroids were being used for.
Obviously, surgery will prevent your assistance dog from performing her tasks; you’ll need to consult your vet and possibly your trainer to determine if and when she can resume work, or whether it would be best to retire her. If the tumor cannot be removed but doesn’t cause other complications, and you eliminate all the disease symptoms with medication, your guide, hearing, or service dog may very well be able to continue working.
Disclaimer: The information contained in this article is general information only. Please consult a qualified veterinarian regarding all medical conditions for your assistance dog.