How is Cushing’s disease treated in dogs?

Cushing’s disease, also known as hyperadrenocorticism, is a condition in dogs caused by excessive production of cortisol, a stress hormone, by the adrenal glands. This condition can significantly impact a dog’s quality of life, but with proper treatment, many dogs can live comfortably for years. Treatment for Cushing’s disease depends on the underlying cause, which can be either pituitary-dependent (most common) or adrenal-dependent. Below is a detailed explanation of how Cushing’s disease is treated in dogs, including the different approaches, potential risks, and long-term care considerations.

1. Diagnosis and Determining the Cause
Before treatment begins, it is crucial to confirm the diagnosis and identify the type of Cushing’s disease. This typically involves blood tests, urine tests, and imaging studies like ultrasounds or MRIs. Pituitary-dependent Cushing’s is caused by a tumor in the pituitary gland, while adrenal-dependent Cushing’s is caused by a tumor in one of the adrenal glands. The treatment approach varies depending on the type.

2. Medical Treatment for Pituitary-Dependent Cushing’s
For pituitary-dependent Cushing’s, the most common treatment is medication to control cortisol production. The two primary drugs used are trilostane and mitotane.

a. Trilostane: This drug inhibits an enzyme involved in cortisol production. It is administered orally, usually once or twice daily, and requires regular monitoring through blood tests to ensure the dosage is correct. Side effects may include lethargy, vomiting, or diarrhea, but these are usually manageable with dose adjustments.

b. Mitotane: This medication selectively destroys cortisol-producing cells in the adrenal glands. It is also given orally and requires careful monitoring. Mitotane can have more severe side effects, such as adrenal insufficiency, so close veterinary supervision is essential.

3. Surgical Treatment for Adrenal-Dependent Cushing’s
If the disease is caused by an adrenal tumor, surgery to remove the affected adrenal gland may be recommended. This is often the most effective treatment for adrenal-dependent Cushing’s, especially if the tumor is benign. However, surgery carries risks, such as complications from anesthesia or damage to surrounding tissues. Post-surgery, dogs may need temporary hormone replacement therapy until the remaining adrenal gland adjusts.

4. Radiation Therapy for Pituitary Tumors
In cases where the pituitary tumor is large and causing neurological symptoms, radiation therapy may be an option. This treatment aims to shrink the tumor and alleviate symptoms. It is typically used in conjunction with medication and requires specialized veterinary care.

5. Monitoring and Long-Term Care
Regardless of the treatment method, ongoing monitoring is essential. Regular blood tests, such as the ACTH stimulation test, are used to assess cortisol levels and ensure the treatment is effective. Dogs on medication may need periodic adjustments to their dosage. Additionally, owners should watch for signs of complications, such as excessive thirst, urination, or lethargy, and report these to their veterinarian promptly.

6. Potential Risks and Concerns
Treatment for Cushing’s disease is not without risks. Over-suppression of cortisol can lead to Addison’s disease, a condition where the body does not produce enough cortisol. This can be life-threatening if not addressed immediately. Dogs on long-term medication may also experience side effects, such as gastrointestinal issues or changes in appetite. Surgical and radiation treatments carry their own risks, including infection or incomplete tumor removal.

7. Prevention and Lifestyle Adjustments
While Cushing’s disease cannot be prevented, maintaining a healthy lifestyle can help manage symptoms and improve overall well-being. A balanced diet, regular exercise, and weight management are important. Dogs with Cushing’s are prone to skin infections and urinary tract issues, so good hygiene and regular veterinary check-ups are crucial.

8. When to Seek Professional Help
If your dog shows symptoms of Cushing’s disease, such as increased thirst, excessive panting, hair loss, or a pot-bellied appearance, consult your veterinarian immediately. Early diagnosis and treatment can significantly improve outcomes. Additionally, if your dog is undergoing treatment and experiences severe side effects or a sudden decline in health, seek veterinary care right away.

In conclusion, Cushing’s disease in dogs is a manageable condition with appropriate treatment and care. Whether through medication, surgery, or radiation therapy, the goal is to control cortisol levels and improve the dog’s quality of life. Regular monitoring, a healthy lifestyle, and close communication with your veterinarian are key to ensuring your dog remains happy and healthy.