Cushing’s Disease

What is it?

Cushing’s Disease is more appropriately known as hyperadrenocoticism is usually caused by a tumour on the ptuitary gland. The tumour itself may be benign or malignant, significant or microscopic. This tumour results in the overproduction of cortisone, this is the cause of Cushing’s disease in around 85% of cases. A tumour on the adrenal gland itself results in the overproduction of cortisol, around 15% of is the result of Adrenal tumours. Cushing’s Disease can also result from the overprescription of steroidal medications for the treatment of other conditions such as repeated ear infections or injury. The increasing use of Non-Steroidal Anti-Inflammatory Drugs (NSAIDs), has seen a significant reduction in this cause of Cushing’s.

https://www.dogsnaturallymagazine.com/understanding-cushings-disease-in-dogs/

https://www.akc.org/expert-advice/health/cushings-disease-in-dogs/

http://www.canismajor.com/dog/cushings.html

Signs and Symptoms to look for.

Early signs of Cushing’s are often increased eating, drinking and urination. There may also be loss of muscle mass and tone accompanied by the development of a “pot” belly. The skin and coat may also thin and lose condition. There may also be a lowered tolerance for exercise and increased panting. As many of these symptoms are associated with aging the early stages of the disease are frequently missed by the owner.

How is it diagnosed?

There are a number of tests which can be used to diagnose Cushing’s Disease in dogs. Some of the diagnostic tests will give “false” positives as significant changes in the dogs environment (including Vet visits) can trigger changes in the production of hormones causing a false reading or result. Other conditions may also trigger changes which may result in an incorrect diagnosis. Most of the testing methods for diagnosing Cushing’s are expensive and in some cases require repeat testing. The initial test is to establish some “base-line” data and a follow up test at a later time is required for confirmation purposes.

A reliable urine test (approx 90% accurate), the Cortisol-Creatinine Ratio Test is useful in ruling out Cushing’s Disease. A urine specific gravity of less than 1.025 is consistent with Cushing’s Disease while a urine specific gravity of more than 1.025 is usually not associated with Cushing’s Disease.

Prognosis.

Cushing’s is generally considered to be a life long condition which is most often treated with various medications. the most commonly used drug being Vetoryl.

Common side effects resulting from the use of this drug include poor or reduced appetite, vomiting, lack of energy, diarrhoea, and general weakness. More serious side-effects are uncommon but not unknown. For this reason it is vital that the dog has regular physical check-ups and blood work.

Most of the information I have been able to find in regards to the long term prospects of dogs with Cushing’s Disease suggests that most of those that are diagnosed with the disease where the primary cause is a ptuitary tumour generally die within 36 months of diagnosis. Where the disease is caused by a tumour on the adrenal gland generally survive for only around 30 months. Having said that, some owners report that their dog continues to do well for five years or more.

Treatment.

The most commonly used drug to treat Cushing’s disease is Vetoryl. This drug works by stopping the production of cortisol in the adrenal glands. This drug is contraindicated in dogs with liver or kidney disease, dogs that are pregnant and dogs that are on certain types of heart medications. 

In those dogs where the disease is caused by a tumour on the adrenal gland surgery to remove the tumour may be an option. I do know one owner that has opted for laproscopic adrenalectomy as a treatment and the dog is doing well post surgery.

I am not aware of any currently available options for removal of a tumour from the ptuitary gland.

https://www.fda.gov/ForConsumers/ConsumerUpdates/ucm151209.htm

Sorcha and Cushings.

Sorcha (Ch Caeruleus Octavia Lucila) joined us in 2001 and was with us for nearly 15 years. She was a very loving dog and presented us with three beautiful litters including a number of bi-colour pups.

Sorcha was identified as a “Cushingoid” dog by our vet at approximately 11.5 years of age due to signs and symptoms she was presenting with, ie, drinking and urinating excessively, development of a “pot” belly, thinning of the coat and skin as well as becoming lethargic.

To rule out other possible causes the Vet recommended the use of a number of “herbal” remedies for fluid retention, heart function and other possible causes.

After seeing no improvement we had specific Cushing’s Disease tests done which confirmed that she did in fact have Cushing’s Disease.

Initial treatment was commenced using Vetoryl and initial response to this treatment was very good. Sorcha accepted the Vetoryl in a chunk of treat (chicken, cheese, etc) readily. Skin and coat health returned and her energy levels were up. There was a significant reduction in drinking and urination and her “pot” belly disappeared.

Over the following months, Sorcha regained her health and returned to being an “older” but “normal” Bedlington Terrier of that age. Regular physical check-ups became part of the “routine” and allowed us to keep on top of her progress.

At around 20 - 24 months after medication with Vetoryl it became increasingly difficult to administer the drug and Sorcha often refused the treats concealing the medication. We got to a point where it became so difficult to administer the drug we made the difficult decision to stop treatment using Vetoryl. 

As a consequence of coming off the treatment the usual symptoms of Cushing’s returned and Sorcha’s health went downhill rapidly. Heart, lung and kidney functions were compromised due to increased fluid retention which is one of the symptoms associated with this disease. Loss of coat and skin condition was again obvious as was the “pot” belly. 

We did all we could to ease the symptoms including the use of herbal remedies to help with fluid retention and improve the strength of her heart contractions. 

Over the final month or so her health and general condition fluctuated between the occasional good day with many poor days in between.

Sadly, on her final day, she was  struggling for breath, her gum colour was very poor and she was very lethargic. We took her to the Vet to help her over the bridge. 

We were thankful for the extra couple of years these treatments allowed us to have with Sorcha and we certainly enjoyed that time with her. 

If we were to have another of our dogs develop Cushing’s would we go through the same process? I think it is highly likely. The only difference might be that if the dog started to refuse the medication again we would stop earlier and assist them “beyond” before the bad days came to outnumber the good. I think we held on to Sorcha for too long and she was ready to go earlier than we released her.