What is Cushing’s Disease in Dogs?
Cushing’s disease or Hyperadrenocorticism (or HAC) in dogs is a condition where the body’s adrenal glands produce too much cortisol. When there are elevated cortisol levels in the dog’s body, it can be prone to serious health conditions like diabetes and kidney damage.
The main cause of Cushing’s disease is a pituitary gland tumor that stimulates the adrenal glands to produce more cortisol. There are two types of Cushing’s disease, one is called pituitary-dependent and one is called adrenal-dependant Cushing.
Both types are treated with trilostane which targets the source of the problem rather than masking the symptoms as many other treatments do.
If your dog has symptoms of Cushing’s disease, then you should take them to your vet for urine and blood tests to confirm it. It can sometimes be hard to diagnose, and different breeds are more prone to it than others.
Once it has been diagnosed, your vet (DVM) may also do a tumor marker test or x-ray to confirm where it is. There are no treatments that can cure Cushing’s disease, but there are some medications you can use to reduce its symptoms like Vetoryl or Mitotane, which is solder under the brand name Lysodren.
What are the First Signs of Cushing’s Disease in Dogs?
While there are many signs indicating that a dog may have Cushing’s disease, the most common symptom is its pot-bellied appearance.
Some of the other common symptoms of Cushing’s disease in dogs are:
- Heavy panting due to a buildup of fluids in the lungs
- Increased thirst
- Frequent urination
- Increased appetite
- Lower activity levels
- Fragile and sensitive skin
- Hair loss
- Skin infections
- High blood pressure
- Kidney infections
- Bladder stones
- Urinary tract infections
- Blindness from damage to the eyes from too much cortisol over a long period
- Sexual dysfunction due to damage done by excessive hormone levels on the body’s reproductive system
- Diarrhea from internal bleeding from inflammation in the intestines caused by ulcers on the stomach lining as a result of prolonged steroid use
While this disease primarily affects older dogs, it can also affect younger dogs when a pituitary tumor or adrenal tumor is present.
What Triggers Cushing’s Disease in Dogs?
The most common trigger of Cushing’s disease in dogs is an increased production of cortisol which occurs as a result of pituitary tumor formation. The excess of cortisone can cause numerous side effects such as skin problems or diabetes.
The most common types of Cushing’s disease in dogs are pituitary-dependent or adrenal tumors.
Pituitary-dependent: Pituitary-dependent Cushing’s disease is triggered by a tumor on the pituitary gland at the base of the brain. This causes the brain to cause the adrenal gland to produce cortisol.
The majority of these tumors are quite small, but as the tumor begins to grow in size, neurological symptoms will reflect that. 80-85% of Cushing’s disease cases in dogs are caused by this type.
Adrenal-dependant: With the adrenal gland tumor type of Cushing’s disease, increased stress hormones are created, and up to 20% of Cushing’s disease cases are related to this.
Long-term steroid use: Cushing’s disease in dogs can also be triggered by long-term usage of certain steroids. This is known as iatrogenic Cushing’s disease.
Cancer: Other causes include tumors on other parts of the brain or cancer elsewhere in the body (especially lymphoma). Dogs with Cushing’s disease often have high levels of glucose (blood sugar) in their blood due to insulin resistance caused by excess cortisol production.
Dogs with Cushing’s disease develop very slowly over time, so it can be challenging for owners to notice symptoms early enough for treatment to be effective.
Toxins: Exposure to toxins can also lead to Cushing’s disease or make it worse if your dog already has the condition. These toxins include pesticides, herbicides, and insecticides; cleaning products; fertilizers; and metals such as lead or copper.
Medication: In addition, certain medications can cause an increased risk of Cushing’s syndrome, especially long-term steroid use.
What Dog Breeds are Prone to Cushing’s Disease?
Breeds that are prone to Cushing’s disease include the following:
- Boston Terrier
- Welsh Corgi
- Lhasa Apso
- German Shepherds
- Golden Retrievers
- Bernese Mountain Dogs
- Labrador Retrievers
How do You Treat Cushing’s Disease in Dogs?
The ACTH stimulation test is a specific diagnostic test used to diagnose this disease by measuring levels of cortisol after an injection. A low blood glucose level will confirm the diagnosis.
Other diagnostics your vet will do to diagnose your dog include:
- Bloodwork, including complete blood count
- Low-dose dexamethasone suppression test
- High-dose dexamethasone suppression test
- Magnetic resonance imaging (MRI) scans to detect tumors
- Abdominal ultrasound
- Urine cortisol: creatinine ratio test
For the dog to be effectively treated, the growth of the tumor needs to be stopped; this is done through surgical procedures that remove all traces of it. Some medical treatments exist but they’re not always successful in removing the tumors.
They include medications that reduce the production of adrenal corticoids and glucocorticoids, drugs that suppress adrenal gland function, and surgery on other organs affected by the illness.
Dogs with Cushing’s syndrome are usually given supplements such as vitamin C and B vitamins to help them maintain a healthy immune system.
Due to the severity of this illness, dogs diagnosed with Cushing’s syndrome may have problems functioning and may need assistance with everyday tasks such as walking or sitting up.
Treatments can vary depending on how much time has passed since the onset of symptoms, which cells are involved, and the size and location of any tumors.
Does Cushing’s Disease in Dogs Go Away?
No, Cushing’s disease in dogs won’t go away, but it can be managed.
Just like Addison’s disease in dogs, the onset of Cushing’s disease can be sudden, but it is often progressive with symptoms gradually worsening over time.
As mentioned, treatment for Cushing’s disease depends on the severity of the case and could involve medications or surgery. In some cases, treatment may not be needed at all.
Some dogs can live with this condition for years without treatment, while others will only live a few months before their quality of life declines significantly.
What’s the Life Expectancy of a Dog With Cushing’s Disease?
Dogs with untreated cases have an average life expectancy of one year or less without treatment because it leads to life-threatening secondary health conditions like:
The life expectancy depends on what type of Cushing’s disease your dog has.
Pituitary tumors: For dogs with smaller pituitary tumors, the right veterinary care and management of the condition can lead to a good prognosis and quality of life.
For dogs with pituitary-dependent Cushing’s disease, dogs will live between a range of two and two and a half years. If the tumor has expanded to certain areas of the brain, the life expectancy is less.
What are the End Stage Symptoms of Cushing’s Disease in Dogs?
End-stage symptoms of Cushing’s disease in dogs are related to the impact that the excess cortisol has on their bodies.
Some common clinical signs and symptoms of end-stage Cushing’s disease include
- Hair loss
- Weakened movement
- Kidney failure
- High blood sugar
- High cholesterol levels
- Congestive heart failure
- Weight loss
- Increased thirst
- Increased urination
- Muscle weakness or muscle wasting (atrophy)
- Skin problems such as redness and itching or flaking skin
- Blood clots
How Can I Prevent Cushing’s Disease in Dogs?
There is no definite way to prevent Cushing’s disease. However, there are some ways that you can reduce your dog’s risk of developing the disease.
Weight: Keep your dog at a healthy weight with the right diet. Make sure that you do not overfeed them or give them treats too often. Nutritionists say you should feed your dog plenty of fresh vegetables, chicken, and fish because these foods contain antioxidants that protect against free radicals generated by stress hormones that cause oxidative damage.
Avoid long-term steroid use: The side effects of long-term steroid use can increase the chances of your dog developing iatrogenic Cushing’s disease. Ensure your dog isn’t using steroids for a longer period.