Cushing’s Disease is a common endocrine disease in dogs and is unfortunately very tricky to diagnose. It is often discovered through a mix of symptom assessments and blood tests. The key is to let your vet know about anything that’s different with your pet.
What Is Cushing’s Disease?
Cushing’s disease, also known as hyperadrenocorticism, occurs when the body produces too much cortisol. Cortisol is a hormone produced and stored by the adrenals, which are two small glands that are above the kidneys. Cortisol helps the body during times of stress, as well as regulating appropriate body weight, skin condition, and tissue structure. Decreased or excessive production of these substances, especially cortisol, may be life-threatening.
Symptoms of Cushing's Disease in Dogs
Cushing’s disease usually develops slowly. Symptoms can mimic other diseases and often are mistaken for normal signs of aging. If you see the signs of Cushing’s disease in your dog, get to a veterinarian for a proper diagnosis so they can prescribe treatment.
Here are some common symptoms associated with Cushing’s disease in dogs:
Signs and Symptoms
- Increased thirst and urination
- Increased appetite
- Hair loss or poor hair coat
- Thinning, discolored, scaly, or unhealthy skin
- A potbellied or distended abdomen
- Weight gain
- Weakness and lethargy
- Chronic skin and urinary infections
- Excessive panting
Cushing's disease is most commonly seen in dogs six years or older. Breeds that are more likely to be affected by this disease are the Dachshund, Terrier, Poodle, German Shepherd, Boxer, Labrador Retriever, Australian Shepherd, Cocker Spaniel, and Maltese.
Causes of Cushing's Disease
The most common cause of Cushing’s disease in dogs is benign growths on the pituitary gland. Malignant pituitary tumors may also cause the disease on rare occasions. Benign growths make up about 80 to 85 percent of naturally occurring Cushing’s disease cases in dogs. Tumors on the adrenal glands may also be present and have an equal chance of being benign or malignant.
Cushing’s disease may also occur as a side effect from overuse of corticosteroid medications, which are commonly prescribed for allergies, immune disorders, cancers, and inflammation.
Diagnosing Cushing’s disease can be difficult, especially in the early stage of the disease, and there is no single test to diagnose Cushing's disease. However, the testing process is crucial to determine the best treatment options and prognosis for your pet.
The first steps in diagnosing Cushing’s disease is that your veterinarian should obtain a good history, performing a thorough head to tail exam, and obtaining basic lab work, including a complete blood count, blood chemistry profile, and a urinalysis.
If those findings provide a strong suspicion for the presence of Cushing's disease, the veterinarian will recommend a blood test called an ACTH stimulation test, or LDDS (Low Dose Dexamethasone Suppression) test. These two tests are hormone tests that challenge the adrenal gland. An over-productive adrenal gland responds quite differently than a normal adrenal gland in the face of ACTH or dexamethasone injections.
Veterinarians may need to also run a urine cortisol:creatinine ratio.
Veterinarians generally perform several blood and urine tests over a period of time, and then compare the results to normal levels.
Lastly, an abdominal ultrasound examination may be recommended and can be a valuable part of the diagnostic process for Cushing’s disease. Ultrasound lets your veterinarian see the adrenal glands and determine their size and the presence of a tumor. If a tumor is present, radiographs will be recommended to see if the tumors have spread
Treatment options include medical management and surgery. Surgery may be an option only in cases where an adrenal gland tumor has been found. Medical management is the most common treatment for the majority of canine Cushing’s disease. The two drugs most commonly used are called Milotane and Trilostane. These help to suppress the production of cortisol and manage the symptoms associated with the disease. Most dogs can be successfully treated with few side effects from the medications. However, your pet must be carefully monitored using blood tests and clinical signs
Although there is no cure to this disease, medical treatment and management can help your dog live comfortably for several years. Your dog will require lifelong treatment once it is diagnosed and it's important to obtain frequent recheck examinations to assess your pet’s response to therapy. Your veterinarian will help provide recheck examination guidelines to best accommodate you and your pet.