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What pet parents need to know about Cushing’s disease in dogs

Sick dog with cushing's disease

Cushing’s disease is a serious yet underdiagnosed health condition in dogs that occurs when the adrenal glands overproduce cortisol in your pet’s body. Excess cortisol can put a dog at risk of several serious conditions and illnesses, from kidney damage to diabetes, and can be life-threatening. 

The symptoms of Cushing’s disease can be difficult to detect, so what should pet parents watch out for? What are your dog’s treatment options if they are diagnosed with Cushing’s disease? 

Table of contents 

What is Cushing’s disease? 

Cushing’s disease, also referred to as hyperadrenocorticism, is an endocrine (hormonal) disorder that is most common in middle- to older-aged dogs. The condition causes a dog’s adrenal glands to overproduce the stress hormone cortisol. As cortisol helps the body perform a variety of essential functions, Cushing’s disease can be very harmful and even fatal in dogs. 

Causes of Cushing’s disease 

A naturally occurring syndrome, hyperadrenocorticism has three possible causes. Identifying the cause is important because each type of Cushing’s disease is treated differently, and each has a different prognosis. Causes of Cushing’s disease include: 

  1. Pituitary gland tumor – The most common cause of Cushing’s disease (85% – 90% of all cases) is the development of a tumor on a dog’s pituitary gland, which is located at the base of the brain. The tumor may be either benign or malignant.  
  1. Adrenal gland tumor – Less common than a pituitary gland tumor, a benign or malignant tumor on one of a dog’s two adrenal glands can also cause Cushing’s disease. Adrenal tumors are at higher risk of being cancerous, often making this form of Cushing’s disease more serious than other types. 
  1. Prolonged steroid use – Cushing’s disease can also be caused by excessive administration of an oral or injectable steroid, such as Prednisone or Dexamethasone. Referred to as iatrogenic Cushing’s disease, overuse of steroids causes excessive cortisol production that can do more harm than good for your dog’s body.  

Predisposed breeds 

In dogs, certain breeds are at a higher risk of developing Cushing’s disease than others. Some of the breeds predisposed to hyperadrenocorticism include: 

  • Dachshunds  
  • Poodles (especially miniature poodles)  
  • Cocker Spaniels 
  • Beagles 
  • Boston Terriers 
  • Boxers 

For unknown reasons, females of these breeds are at a particularly high risk of developing Cushing’s disease compared to their male counterparts. If you have one of these breeds at home, it is important to consult your veterinarian about monitoring for Cushing’s disease, especially as your dog ages. 

Cushing’s disease symptoms 

Unfortunately, many dogs have advanced cases of Cushing’s disease before their owner even recognizes any issues. Symptoms can take at least one year to develop and are often mistaken for common signs of aging, as almost all patients are older than eight years of age when Cushing’s disease develops. 

The first clue that something may be wrong is a potty-trained dog wanting to go outside far more than usual, including at night, to urinate. In addition to excessive urination, other possible symptoms include: 

  • Extreme thirst 
  • Increased appetite 
  • Lethargy 
  • Obesity 
  • Panting 
  • Persistent urinary tract infections 
  • Skin issues – Thinning, lesions and chronic infections, dark spots, mineralization, and hair loss 
  • Weakness and loss of muscle 

Many dogs with Cushing’s disease also develop a bloated or “pot-bellied” appearance to their abdomen. This swelling takes place as a result of an increase and redistribution of fat within the abdominal organs, including the liver, and a stretching and atrophy of the muscles of the abdominal wall as the organs get heavier. 

Treatment options 

Treating Cushing’s disease is expensive and ongoing, requiring consistent, close monitoring by your veterinarian. When it comes to determining an appropriate treatment strategy, the cause or location of the tumor dictates a dog’s options. 

  • Pituitary tumor – This form of Cushing’s disease, although the most common, tends to be the most complicated to treat. According to VCA Animal Hospitals, surgical techniques for removing pituitary tumors in dogs are still new and rarely utilized. Instead, common medications such as trilostane and mitotane selectively destroy part of the adrenal cortex to help lower cortisol levels and reduce the symptoms of Cushing’s disease. Careful monitoring is required to ensure that the drugs don’t destroy all of the cortex and that the cortisol stays at a defined level. If the activity of the adrenal gland can be controlled with medication, many dogs with this form of Cushing’s disease can live normal lives for many years. These medications can, however, have serious side effects, so close supervision by a veterinarian is essential. 
  • Adrenal tumor – This form of Cushing’s disease requires major abdominal surgery, which is typically possible because these tumors are more easily targeted due to their location in the abdomen. However, experts from the Veterinary Specialty Center note that about 50% of adrenal tumors are malignant, growing aggressively, metastasizing quickly, and difficult to entirely remove. If the surgery is successful and the entire tumor is removed, there is a good chance that the dog will regain normal health. If surgery is not an option, some of these patients can be managed with medication. 
  • Iatrogenic Cushing’s disease – For cases of Cushing’s disease brought on by overuse of steroids, the steroid being given should be discontinued. Any changes in your dog’s medication regimen should be done in a controlled, gradual manner so that other complications do not occur. Unfortunately, this usually results in a recurrence of the disease that was being treated by steroids. Consult your veterinarian about your dog’s options. 

The average survival time for a dog with Cushing’s disease is about two years, with only 10 percent of patients living beyond four years. Because the illness is most often diagnosed in senior dogs, Small Door Vets notes that many of these patients die of unrelated causes brought on by aging. 

Can you prevent Cushing’s disease in your dog? 

For many pet parents who have received a Cushing’s disease diagnosis for their dog, they may be wondering if there was anything they could have done to prevent the illness. 

Unfortunately, Cushing’s disease cannot be entirely prevented. Generally, pet owners should avoid administering steroids to their dog for prolonged periods of time. This may help reduce the risk of developing iatrogenic Cushing’s disease.  

Bottom line on Cushing’s disease in dogs 

Cushing’s disease is an insidious illness and can cause serious health issues for your dog. Understanding the causes, symptoms, treatment options, and necessary management steps can prepare you for the road ahead. Be sure to consult your veterinarian as soon as possible if your dog exhibits any possible symptoms.