Treating Cushing's Disease in Dogs

Cause of Cushing's Disease in Dogs

If your dog has a tumor in or on their pituitary gland, this can lead to an excessive concentration of cortisone in their body resulting in Dependent Cushing’s disease or Hyperadrenocorticism. This serious condition can put your dog at risk of several other conditions and illnesses, ranging from kidney damage to diabetes.

Symptoms & Complications of Cushing’s Disease

Symptoms of Cushing's tend to be somewhat vague making it imperative to see your vet right away if you notice any of them. Dogs with Cushing’s disease face an increased risk of kidney damage, high blood pressure, blood clots and diabetes. If your dog is suffering from Cushing's they may display any of the following symptoms: 

Diagnosing Cushing's Disease in Dogs

Blood tests will be done to diagnose Cushing’s disease, however, other tests will be necessary to diagnose the cause of your dog's symptoms which may be related to other conditions caused by Cushing's disease. Depending on your dog's symptoms tests may include urinalysis, urine culture, adrenal function tests (low dose and high dose dexamethasone suppression test, and potentially ACTH stimulation test), full chemistry panel, and complete blood panel.

At Veterinary Medical And Surgical Group–OC (VMSG-OC) in Orange County, our vets are experienced in the diagnosis and treatment of a wide range of internal medicine conditions. We have access to state-of-the-art diagnostic imaging tools and treatment methods to identify and manage these issues.

In combination with a physical exam to look for signs of the disease, these tests can help your vet arrive at a diagnosis. Keep in mind that adrenal function tests can result in false positives when another disease with similar clinical signs is present.

Though an ultrasound may help diagnose Cushing’s disease, it’s more valuable in helping to rule out other conditions that could be causing your dog’s symptoms. Other diseases that may cause similar symptoms include tumors in the spleen or liver, bladder stones, gallbladder disease, gastrointestinal disease, and chronic inflammatory liver disease.

An ultrasound may not be able to detect adrenal enlargement, since patient movement or interference due to gas in the overlying intestine can influence test results. Most vets prefer magnetic resonance imaging (MRI) - an effective but expensive diagnostic imaging procedure that allows your vet to assess your dog’s adrenal glands.

Cushing’s Disease in Dogs Treatment

There are two main drugs that can be used to treat your pup's Cushing’s disease. A form of the insecticide DDT (drug names include Lysodren^® and mitotane) can destroy the cells that produce cortisone in the adrenal glands. Also, medications such as trilostane help decrease the amount of cortisone that the adrenal glands produce. This accomplishes this goal by inhibiting specific steps in the cortisone production process. Both trilostane and mitotane can effectively treat and control the signs of Cushing’s disease.

Discuss which may be the most effective treatment for your dog, and follow your vet's instructions diligently.

After the induction phase with mitotane, you will need to bring your dog to our clinic for an ACTH stimulation test, which “stimulates” the adrenal gland. This test can be done on an outpatient basis to help your vet determine the starting point for a mitotane maintenance dose. If the mitotane is working, the adrenal gland will not overreact to the stimulation.

Though you won’t need an induction phase for trilostane, dogs often require small adjustments to trilostane doses early in treatment. Over their lifetime, routine monitoring of blood tests may indicate that other adjustments need to be made. How well clinical symptoms of Cushing’s disease can be controlled can also mean changes are required.

No matter which medication your vet feels is best for your pooch, your dog will likely be on it for the long term and may require periodic adjustments in doses. He or she will need to come in for ACTH stimulation tests as often as monthly until we can control the excessive production of cortisone. Regular testing will be needed.

Possible Adverse Reactions & Prognosis for Dogs With Cushing's Disease

In many cases, symptoms related to Cushing’s disease can be minimized with diligent observation and long-term management. When provided in the proper dosage, medication for Cushing’s disease can prove very effective in treating the condition. That said, the wrong dose can cause mild or even severe side effects.

With regular blood test monitoring, it’s unusual for adverse reactions to appear. But if they do, they may include:

• Lethargy or depression
• General weakness
• Stomach upset (Gastrointestinal symptoms - diarrhea or vomiting)
• Picky eating or decreased appetite

If you spot any of these symptoms, discontinue the medication and call your veterinarian right away.

While medication costs and the need for frequent blood monitoring can make Cushing’s disease expensive to manage, diligent follow-up care and monitoring for adrenal function can make for a good prognosis.

Dogs with Cushing's disease who do not receive adequate monitoring and follow-up often experience relapses and severe illness or death, as a result of complications.

Note: The advice provided in this post is intended for informational purposes and does not constitute medical advice regarding pets. For an accurate diagnosis of your pet's condition, please make an appointment with your vet.