Cushing’s Disease in Dogs

Types of Cushing's disease

There are three different types of Cushing’s disease in dogs, each characterized by their own causes.

The types of Cushing’s disease in dogs are:

• Pituitary-dependent Cushing’s disease, or PDC. This is caused by a tumor or growth on the pituitary gland. The tumor interferes with the pituitary gland, causing it to release hormones to the adrenal gland, which in turn forces the adrenal gland to produce more cortisol. It is the most common type of Cushing’s disease. This tumor might be benign or malignant (i.e. cancerous).
• Adrenal-dependent Cushing’s disease, or ADC. This type is caused by a tumor or growth on the adrenal gland, which causes the adrenal gland to release too much cortisol. As with PDC, this tumor could be benign or malignant.
• Latrogenic Cushing’s syndrome. This rare type of Cushing’s disease is caused by the excessive use of corticosteroid medications, which pushes the cortisol levels up. Corticosteroid medications include certain allergy medications and treatments for immune disorders.

In very rare cases, certain foods can cause your dog’s body to release an abnormal amount of cortisol, which could lead to Cushing’s disease. However, this is quite unlikely.

How is Cushing’s disease diagnosed in dogs

Cushing’s disease can be hard to diagnose. This is because the symptoms of Cushing’s disease can be caused by other diseases.

In order to diagnose Cushing’s disease, your veterinarian will first give your dog a full physical exam. They would probably need to take samples of your dog’s urine and blood to test. This will help them determine whether your dog has Cushing’s disease or not.

If your vet suspects that your dog has Cushing’s disease, they will try to pinpoint a potential cause. If your dog hasn’t been on corticosteroid medications, they might suggest an MRI and other tests to determine whether there are any tumors on your dog’s pituitary or adrenal glands.

If they find a tumor, they might check the rest of the body to see whether the tumors have spread. As mentioned, Cushing’s disease may be caused by cancerous tumors. Although it’s usually caused by benign tumors, it’s important to run all the necessary tests and screen your furbaby for cancer.

Cushing’s disease symptoms in dogs

The symptoms of Cushing’s disease can vary from dog to dog, and they can range from being severe to hardly noticeable.

The most common symptoms of Cushing’s disease include:

• Excessive thirst. Your dog might want to drink more water than usual. This could also lead to excessive urination. Your dog might get up multiple times at night to urinate, or they might have accidents despite being house trained.
• Hair loss and bald patches. Because your dog’s body is producing so much cortisol, it can disrupt the natural cycle of hair loss and growth. So, your dog might shed more hair than usual without the hair growing back.
• Changes in the skin. Often, Cushing’s disease causes the skin to become thinner and become more sensitive. Sometimes, the skin will develop scaly patches. Because it’s thinner, it might bruise more.
• Weight gain. High cortisol levels cause your dog’s body to hold onto fat and sugar, causing your dog to gain weight.
• Abdominal swelling. This can make the stomach look like it’s sagging.
• Fatigue and lethargy. Your dog might sleep more or seem uninterested in exercise and play. They might seem moody or tired.
• Low immunity. Your dog might get sick more often because cortisol prevents the immune system from functioning effectively.
• Changes in behavior. Due to the fatigue and physical changes, your dog might become grumpier and even aggressive.

If your dog has a few of the above symptoms and you suspect they might have Cushing’s disease, talk to your veterinarian. Explain which symptoms you’ve noticed, how long they’ve been noticeable, and whether you’ve seen any other changes in your dog’s behavior, mood, or health.

It’s possible for your dog to have a few of the above symptoms without having Cushing’s disease. For example, excessive thirst and urination could be caused by diabetes, and changes in the skin and coat could be caused by allergies.

The life expectancy of dogs with Cushing’s disease

While it’s a depressing thought to consider, we’re all likely to outlive our dogs – and it’s important that we have a realistic image of how Cushing’s disease can affect your dog. This includes speaking to your doctor about the prognosis.

On average, dogs with Cushing’s disease live until two years after their diagnosis. However, most dogs with Cushing’s disease are elderly, so they are likely to pass away from other causes, too.

If they have malignant tumors (that is, cancer), their life expectancy will be shorter as it’s more likely that they’ll pass away from cancer than from the Cushing’s disease itself.

However, some dogs with Cushing’s disease do live longer than two years. They are more likely to have a good prognosis if Cushing’s disease is caused by a benign tumor.

Your vet will be able to tell you about your dog’s specific prognosis based on their overall health, other medical conditions, and age. Although none of us like the thought of saying goodbye to our pups, preparing yourself mentally can help you through this difficult process.

The best diet for dogs with Cushing’s disease

If your dog has Cushing’s disease, it’s essential to talk to your vet about whether you should make any changes in their diet. Your vet might prescribe a specific type of dog food for your dog.

In general, you want to opt for high-quality food for your dog. Since muscle wasting is a symptom of Cushing’s disease, it’s a good idea to provide your dog with protein-rich foods. Cushing’s disease causes dogs to gain weight and hold onto fat and carbohydrates, so a protein-filled diet that is not too high in fat or carbohydrates is a good idea.

Avoid generic pet foods that contain carbohydrate-rich fillers. Whole grains are great, but low-quality fillers, white rice, and bread are off-limits.

Raw food diets

Your vet could also suggest you try a raw food diet. Preparing raw food diets for pets are more time- and effort-consuming than simply pouring kibble into your dog’s bowl, but it might be more healthful. By giving your dog wholesome, minimally processed food, you might support their immune system and overall health.

If you decide to try a raw food diet for your dog, do plenty of research beforehand. Chat to your vet, and ask whether your dog will require any supplements.

Foods to give dogs with Cushing’s disease

These foods are excellent additions to your dog’s diet.

• Beef and chicken (without skin or bones)
• Salmon
• Eggs
• Apples (without seeds), berries, and bananas
• Green leafy and cruciferous vegetables, such as spinach, broccoli, and bok choy
• Carrots, peas, and potatoes
• Root vegetables like pumpkin and butternut
• Sugar- and salt-free peanut butter (in moderation and as a treat)

Foods to avoid giving dogs with Cushing’s disease

If your dog has Cushing’s disease, you should avoid giving them the following foods, or only give them very very little.

• White rice
• Bread
• Liver
• Sugar-filled foods
• Cheap, non-vet-approved pet food

Supplements prescribed for dogs with Cushing’s disease

Your veterinarian might prescribe certain supplements to help with the symptoms of Cushing’s disease as well as the side effects of your dog’s treatments. These supplements might include one or more of the following:

• Gingko biloba
• Nettle
• Rosehip
• Kelp
• Garlic
• Wormwood
• Milk thistle
• Apple cider vinegar
• Fish oil

Bear in mind, though, that it might not be possible to treat your dog’s symptoms through diet and supplements alone. In more serious cases, your veterinarian will probably prescribe medication in order to treat your dog.

What treatment is there for dogs with Cushing’s disease

Cushing’s is a chronic disease, which means there’s no real cure for it. It doesn’t simply go away, although the symptoms may become more manageable over time. If the symptoms are mild, and depending on the type of Cushing’s disease your dog has, your veterinarian might advise against using medication.

Fortunately, there are a few different kinds of treatments that could help the disease become more manageable.

The treatment your vet gives your dog depends on the cause of Cushing’s disease. If the disease is caused by the long-term use of corticosteroid medications, your vet will probably wean the dog off the medication slowly. Abruptly stopping the use of corticosteroid medication can cause other health problems.

If your dog’s disease is caused by a tumor on their adrenal or pituitary glands, your vet may prescribe medication to shrink the tumor. Your vet will conduct tests to find out whether the tumors are benign (non-cancerous and non-growing) or malignant (cancerous and spreading). If your dog has cancer, the veterinarian might suggest surgery or radiation therapy.

Possible medications for Cushing’s disease in dogs

Your veterinarian may prescribe any of the following medications to treat Cushing’s disease:

• Vetoryl (trilostane). This FDA-approved drug can treat both pituitary-dependent Cushing’s disease as well as adrenal-dependent Cushing’s disease. It works by stopping the production of cortisol in the adrenal glands.
• Anipryl (selegiline). This FDA-approved treatment is used to treat pituitary-dependent Cushing’s disease. It prevents the pituitary gland from sending signals to the adrenal gland that cause it to produce cortisol.
• Lysodren (mitotane). This is a chemotherapy drug that was designed for humans, but can legally be used to treat dogs with Cushing’s. It essentially destroys the part of the adrenal gland that produces cortisol. While it’s meant for humans, it treats dogs effectively.

It’s likely that your dog will have to continue receiving treatment for Cushing’s disease for the rest of their life. However, it is possible for them to have a happy and fulfilling life, despite living with this disease.

Remember to follow your veterinarian’s instructions when it comes to giving your dog any prescription medication. If you have any questions or need advice, chat with your veterinarian immediately.