Cushing's is caused by a tumor in the pituitary or the adrenal gland, causing an over production of ACTH hormones which in turn triggers an overproduction of cortisol. A life threatening condition affecting inner organs like kidneys and liver. Some of the most common signs are hair-loss, a pot-belly, lethargic behavior, incontinence, and being overly interested in food and water. Cushing's is many times mistaken with normal aging signs of dogs, making it a silent killer.
This is what we learned along the way:
Back in 2011, Viva was diagnosed with Cushing's based on a urine test and a ACTH stimulation test. During her life, she continued to have ACTH tests quarterly to measure her cortisol levels for possible adjustment of her medicin dosage. Although the test is reliable to measure levels for treatment adjustments, it proved unreliable for the diagnosis itself, when the results are negative. Negative test results should always be followed up by at least an LDDS test, and even better, by an ultrasound, to indicate the type of Cushing's which is significant for what treatment options are available.
The recommended dosage of Trilostane (Vetoryl), the medication for Cushing's disease, was set too high for larger dogs. Something Viva found out the hard way. But thankfully our vet read the signs correct and adjusted her doses far below the recommended dosage for a dog of her size. Later, in 2012, research was done that confirmed that at least dogs weighing more than 30 kg. need a significant lower dosage of Trilostane, maybe even dogs weighing more than 15 kg.
Once or twice a day administering of medication
The last has not been said on this subject. Basically Trilostane works up to 8-10 hours, and that might require a twice-a-day administration, instead of an only once daily which is standard. Research is still being done, and some vets are already recommending twice daily administration of Vetoryl. At least some research here and here has shown, there is hardly risk in trying. We never got that far with Viva, it was something I was discussing with our vet, as I could see she consistently was showing more lethargic signs during the end of the day.
A dog with Cushing's requires continuous research, together with your vet, and to be vigorous about measuring the clinical signs of your dog. We always kept a Cushing's diary, and it was a great help in supporting Viva in her battle against Cushing's. Whatever research was available at the time, or not, the diary was always right.