Cushing’s disease in dogs can be fatal. Our vets in Rock Hill 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 result in pituitary-dependent Cushing's disease (also known as hyperadrenocorticism), a clinical condition that puts your dog at risk for a variety of serious illnesses and conditions, including diabetes and kidney damage.
Symptoms & Complications of Cushing’s Disease in Dogs
For dogs, the most common symptoms of Cushing’s disease include:
- Panting
- Increased appetite
- Lethargy
- Muscle weakness
- Excessive thirst or drinking
- Thick skin
- Hair loss
- Potbelly
While at least one of these symptoms is common in dogs with Cushing's disease, it is unusual for them to appear all at once. Because the symptoms are hazy, it's critical to see your veterinarian as soon as possible 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
Your veterinarian will need to perform a physical exam and blood tests to diagnose Cushing's disease. A full chemistry panel, complete blood panel, urine culture, urinalysis, and adrenal function tests are examples of tests (low-dose and high-dose dexamethasone suppression test, and potentially ACTH stimulation test). It should be noted that adrenal function tests can produce false positive results 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 medications like 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.
Following the mitotane induction phase, you will need to bring your dog to our clinic for an ACTH stimulation test, which "stimulates" the adrenal gland. This test can be performed as an outpatient procedure to assist your veterinarian in determining the starting point for a mitotane maintenance dose. If the mitotane is functioning properly, the adrenal gland will not overreact to 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
Cushing's disease symptoms can be reduced with careful monitoring and long-term management. Medication for Cushing's disease can be very effective in treating the condition when given in the correct dosage. However, the incorrect dose can result in mild to 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.