Cushing’s Disease in Dogs – Causes, Symptoms & Treatment

Every dog owner’s fear is the one day they take their dog to the veterinarian to find something potentially life threatening with their dog, such as Cushing’s Disease. But what exactly is Cushing’s Disease in dogs and how do you spot it?

Cushing’s disease is a medical condition where there is too much cortisol hormone being produced by the dog’s endocrine system. Although cortisol is naturally produced and essential for healthy living, having too much or too little can lead to health problems.

A rise in the level of cortisol would hamper the metabolic process and lead to gastrointestinal disorders, hypertension and other complications.

Causes of Cushing’s Disease in Dogs

To truly understand Cushing’s Disease we must discuss this normal biological process in both humans and dogs. The pituitary gland is responsible for producing the ACTH (adrenocorticotrophic hormone) through the brain’s hypothalamus.

This ACTH hormone will signal the adrenal glands to release glucocorticoid hormones into the bloodstream. Glucocorticoid is a cortisone-like or cortisol hormone that impacts many functions in the body and is necessary for life.

This hormone regulates weight, responds to stress, balances the blood sugar levels and even fights infections.

When the cortisol level is sufficient, then the pituitary gland will cease secretion of the ACTH hormone. When the levels drop, it will start producing more hormones.

, Cushing’s disease specifically refers to a development of a benign tumor in the dog’s pituitary gland, which then causes the increase in cortisol levels despite sufficient levels.

Dog Age

Tumors in the pituitary gland are the cause of Cushing’s disease and there is certainly a positive correlation between old age and tumors. From this logic, it is easy to see why this medical condition is most common in middle-aged and older dogs. In fact, the average age of a dog with Cushing’s is roughly 10 years old.

Dog Breeds

It doesn’t matter what breed of dog you own, all dogs despite the breed are at risk for this disease. However, that doesn’t mean all dog breeds have the same chance of developing Cushing’s.

Medical statistics have showed that dog breeds such as: german shepherds, boxers, dachshunds, beagles, poodles, labrador retrievers, golden retrievers and all types of terriers have an increased chance at developing Cushing’s disease.

Size of Dog

Pituitary-dependent Cushing’s is more common in small dogs or medium-sized dogs. The medical records show that roughly 75% of the patient dogs are under 44 pounds. However, for adrenal-based cushing’s, just slightly over 50% of the cases were dogs under 44 pounds.

Glucocorticoid Treatments

There are cases where dogs need excessive glucocorticoid treatments for common issues like inflammation or allergies. Glucocorticoid can also be used as a form of therapy for a dog with low cortisone levels.

However, the injections of this specific hormone can directly cause Cushing’s disease. Like we mentioned, Cushing’s develops when the level of this hormone is too high.

Symptoms: Cushing’s Disease in Dogs

The reason why this medical condition is so dangerous is because it is extremely difficult to properly diagnose. Cushing’s disease is more common in older dogs, but the symptoms are similar to that of a normal aging dog.

This is why I encourage all dog owners to try to observe their dogs as closely as possible. Being able to communicate with your vet about the details in behavior and habit can help significantly with the diagnosis and potentially save your canine’s life.

Symptoms of Cushing’s include (but are not limited to):

• An increase in thirst or hunger
• Heavy breathing/panting
• Sudden gain of weight or obesity
• Shedding more hair than usual (at a quicker rate)
• A development of Coprophagia
• Development of extra fat on neck and shoulder
• A decrease in energy levels
• Insomnia
• Darkening of the skin
• “Blackheads” appearing on skin
• Stretching of the skin (thin skin)
• Bruising from weakened thinner skin
• Hard white patches on skin

If one or more of these symptoms arise, consult with your veterinarian, especially if you have a middle-aged or elder dog. The tumor that causes this condition does not grow overnight, meaning Cushing’s is a disease that develops gradually along with its symptoms. Both the dog owner and the veterinarian may not be able to spot this condition in the early stages.

Common First Sign Symptoms in Dogs

Two of the most common symptoms is the increase for thirst and urination. Most owners report that the thirst increase is noticeable, as they would constantly have to fill up the dog’s water bowl. If a middle-aged or older dog is suddenly having accidents or crying to be let out to urinate at odd hours, it may be time to pay the vet a visit.

For dogs with Cushing’s, a significant gain in weight from an increased appetite is also considered a popular first symptom. The increase in cortisol is responsible for the increase in appetite, leading to the weight gain. Muscles begin to shrink, but certain organs such as the liver begin to grow larger. The belly may seem bloated compared to the other parts of their body. They will develop a shortness of breath and will become more easily tired from routine activities.

Don’t focus too much on these symptoms listed above. The most important thing to do is to spot any behavioral changes with your dog. If your dog isn’t acting normal and your gut feeling says something is wrong, bring them to a veterinarian to check them out as soon as possible.

Cushing’s Disease Treatments for Dogs

Fortunately, there are many ways to treat this disease. However, the method of treatment will depend on various factors, including how early the dog gets diagnosed with Cushing’s disease. Consult with a veterinarian to see which treatment method would be ideal for your dog.

Drug Therapies For Cushing’s

There are several drug therapies available for this condition. Drug therapy is a good option for those dogs that are still in the early stages of Cushing’s or those that have gone through the surgery procedure with little success. Each has its own side effects to watch out for.

Lysodren

This drug is effective because it kills the outside layer of the adrenal gland, which is the manufacturer of the cortisol hormones. In order to safely take this drug, the dog needs to be monitored by taking frequent blood tests to ensure a normal level of cortisol in their system.

Potential side effects include the development of Addison’s disease. However, it is a very convenient drug because it is taken with the dog’s food.

Ketoconazole

This drug was first used as a way to fight fungal infections in humans, but is now a common drug used to fight Cushing’s disease in dogs. Ketoconazole works by suppressing the secretion of cortisol in the adrenal glands.

The good news is that the dog can’t develop Addison’s disease from this. The bad news is that it requires constant dosing and can be very costly. Also, roughly 20 to 25 percent of all dogs can’t even absorb this drug. To determine if it is possible, consult with your vet.

Anipryl

This drug was first used to treat Parkinson’s disease in humans. However, in 1997, Anipryl became approved to treat Cushing’s disease in dogs.

This drug is effective because it balances the chemicals in the brain,  relieves symptoms and reduces cortisol secretion. This drug is quite pricey and may take a while to show results, but aside from that, there are very little side effects or negatives.

Trilostane

Approved in 2009, Trilostane is a drug that inhibits an enzyme responsible for the secretion of cortisol. Because there is a chance of developing Addison’s disease, dogs taking this drug needs to be monitored with frequent blood tests. Some notable side effects include a lack of energy and a reduction in appetite.

Tumor Removal Through Surgery

There comes a point when the pituitary tumor becomes too large in late stages of Cushing’s and requires surgery to remove the tumor. The hope is for the pituitary gland to gradually return to normal, but that will certainly not be the case in the beginning.

During the dog’s recovery process, cortisol treatments will be needed because the pituitary needs some time to go back to normal to start producing ACTH again. Sometimes the tumor will not be completely removed and will require radiation treatment afterwards.

Adrenal Gland Removal

This option is the very last resort to save your dog. If you have gone through the surgery to remove the tumor and various medications and still have no success, the last thing to try is to remove the adrenal glands to stop the high level of cortisol production.

There is a chance that the dog develops Nelson syndrome, where the removal of the adrenal glands backfires and the pituitary tumor starts to get bigger.

Cushing’s Disease Untreated in Dogs

The most important thing to do if your dog has Cushing’s disease is to take action. If this condition is left untreated, the disease will develop into something very serious and become life-threatening.

Other serious disorders will begin to develop, such as kidney failure, diabetes, liver failure, congestive heart failure and inflections on the skin, eras, gums, eyes and bladder.

Always be aware of any odd behavioral changes in your dog, especially towards the latter part of their lives. If you start to see any symptoms and your dog is at least six years, it may be a good idea to visit your veterinarian as soon as possible.

Cushing’s disease is not a condition that can be 100% cured, but that doesn’t mean these treatments will be ineffective. At the very least, you will be able to prolong their life while keeping their quality of life much more pleasant.

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The Smart Canine is an online resource dedicated to providing dog owners with the most accurate information on dog care and training. Although our staff has done extensive research on the topic of Cushing’s Disease in dogs, we still recommend professional advice. Every dog is unique with a different medical case. It is impossible for us to diagnose or treat your dog through the web without ever seeing the dog.