Cushing’s disease in dogs can lead to serious symptoms and complications and even threaten your pup’s longevity. Today our Yucaipa vets explain the condition and its causes, along with complications and treatments.
Causes of Cushing’s Disease (Hyperadrenocorticism) in Dogs
A tumor in your dog’s pituitary gland can lead to an excessive concentration of cortisone in his or her body.
This can cause pituitary-dependent Cushing’s disease (also referred to as hyperadrenocorticism), a clinical condition that can leave your dog at risk for several serious illnesses and conditions, from diabetes to kidney damage.
Symptoms & Complications of Cushing’s Disease in Dogs
For dogs, the most common symptoms of Cushing’s disease include:
- Increased appetite
- Muscle weakness
- Excessive thirst or drinking
- Thick skin
- Hair loss
While at least one of these symptoms will appear with Cushing’s disease, it’s uncommon for dogs to display all of them. Because the signs are vague, it’s critical to visit your veterinarian right away if you notice any of them.
Dogs with Cushing’s disease have an increased risk of blood clots, diabetes, high blood pressure and kidney damage.
Diagnosing Cushing's Disease in Dogs
At Oak Glen Animal Hospital, our veterinarians are trained to diagnose and treat many internal diseases and conditions. We have access to diagnostic imaging tools and treatment methods to effectively identify and manage these issues. If we discover that your pet needs expertise or a procedure that we do not offer, we can refer you to an experienced internal medicine specialist.
To diagnose Cushing’s disease, your veterinarian will need to perform a physical exam and take blood tests. Tests may include but are not limited to a full chemistry panel, complete blood panel, urine culture, urinalysis and adrenal function tests (low-dose and high-dose dexamethasone suppression test, and potentially ACTH stimulation test). Note that adrenal function tests can result in false positives when another disease with similar clinical signs is present.
While ultrasound may help diagnose Cushing’s disease, it’s more useful in helping to identify other conditions that may be causing your dog’s symptoms. Other diseases that can cause similar symptoms include gastrointestinal disease, chronic inflammatory liver disease, bladder stones, gallbladder disease and tumors in the liver or spleen.
We may not be able to detect adrenal enlargement with an ultrasound since the results can be influenced by patient interference or movement due to gas in the overlying intestine. Most veterinarians prefer an MRI (magnetic resonance imaging) — an effective but expensive diagnostic imaging procedure — to assess your dog’s adrenal glands.
Treatments & Medication for Cushing’s Disease in Dogs
Currently, two main drugs can treat Cushing’s disease in dogs. A form of the insecticide DDT (drug names include Lysodren® and mitotane) can destroy the cells that produce cortisone in the adrenal glands.
Other medication 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 the medication, 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.
Adverse Reactions & Prognosis
With diligent observation and long-term management, the symptoms of Cushing’s disease can be minimized. When provided in the proper dosage, medication for Cushing’s disease can prove very effective in treating the condition. However, the wrong dose can cause mild or severe side effects.
With blood test monitoring, it’s unusual for adverse reactions to appear. But if they do, they may include:
- Lethargy, depression or weakness
- Gastrointestinal (stomach) upset - diarrhea or vomiting
- Picky eating, eating slowly (taking longer than normal to eat or leaving food), or decreased appetite
If you notice 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.
Pets 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.