DAISY: A HAPPY DOG WITH A BIG THIRST

Daisy is a Schnauzer and enjoys the good life in the country and has always enjoyed having good health. This year however she sprang a surprise on her Mum and Dad by developing the clinical signs of Cushing’s disease.

Cushing’s disease is where there is too much cortisol being released into the blood supply. The most common cause is due to a tumour growing in the pituitary gland and releasing too much adrenocorticotropic hormone (ACTH) which causes to adrenal gland to release too much cortisol. The other name for this condition is hyperadrenocorticism.
Cortisol is a metabolic regulator and thus can influence a number of organs or systems in the body. Depending on what system is affected the most will be reflected in the presenting signs.

Hyperadrenocorticism is a condition that usually appears in mid to late age and can affect some breeds more than others, especially the poodle dachshund, boxer and beagles. In cats this is a relatively rare condition. Severity varies greatly and depends on duration and severity of cortisol excess. In some cases signs are related to the growing neoplasm which is in the base of the brain thus causing neurological changes.

• Some of the clinical signs are:
• Increased urination and drinking
• pendulous abdomen,
• hair loss,
• lethargy,
• increased panting
• skin changes with pigmentation and formation of comedones
• facial nerve palsy

Daisy was presented because of an increased water intake. This is due to the effect of cortisol on the kidneys causing reduced concentrating ability and thus increased loss of body fluids. She was also more lethargic and tended to have a pendulous abdomen.

Her condition was confirmed by a blood test which involves injection a synthetic cortisol releasing hormone and measuring the body’s response. Unfortunately Daisy failed and thus the cause and severity of the condition was known. Daisy has a fairly severe form of the condition and treatment was commenced with an anti-cancer drug called Lysodren. The aim of the treatment is to kill enough of the tumour cells in the pituitary gland to bring the condition under control then maintain this level. This procedure requires careful monitoring. In humans this condition is now treated with laser therapy. A surgeon burns away the tumour using a laser directed through the roof of your mouth.

During Daisy’s treatment she developed a complication, unfortunately too many cells were destroyed and this functional area of the gland was obliterated. This left her with no cortisol releasing hormone and created a condition known as Idiopathic hypoadrenocorticism. This condition is characterised by the loss of potassium which causes collapse, heart arrhythmias and death. Daisy fortunately responded well to treatment and with supplementary hormone therapy has quite a normal healthy lifestyle. Although the development of hypoadrenocorticism is a possible complication of the treatment of Cushing’s Disease, it is to some extent easier to treat and less harmful to the animal once steady blood levels of the supplementary drugs are obtained.