Cushing's Disease occurs when there is an over-active adrenal gland (known as Hyperadrenocorticism or HAC), which causes chronically increased cortisol to circulate in the blood.
Cortisol affects nearly every cell in the body and is a natural blood steroid, responsible for the presence of glucose in the bloodstream. More directly, cortisol creates a balance of glucose in the bloodstream by breaking down muscle (catabolism) and fat (lipoysis) tissue. Insulin’s job is to bring glucose into hungry cells and cortisol pulls glucose out.
Cushing’s disease and Hyperadrenocorticism have 3 types:
Pituitary-dependent, which results from a benign or malignant tumor in the brain and is responsible for 80- 90% of cases of Cushing's Disease in dogs.
Adrenal-dependent, caused by a cortisol-secreting tumor involving adrenal glands near kidney, responsible 15- 20% of Cushings Disease diagnoses.
Latrogenic hyperadrenocorticism is the result of long term veterinary steroid treatment for problems like skin allergies and causes adrenal gland atrophy.
The classic signsof Cushing's, known as the 5 P’s, are:
Polyuria (increased urination)
Polydipsia (increased drinking)
Polyphagia (increased appetite)
Other signs include bilateral weakness, symmetrical hair loss, thin skin and increased blood pressure.
Poor quality, highly processed commercial diets can also play a role in the onset of Canine Cushing’s disease. By metabolizing inferior, heat-processed ingredients, GI tract upsets and other inflammatory conditions such as colitis and skin problems, can occur. The treatment of these inflammatory conditions by conventional veterinarians often involves high-dose steroid treatments (cortisone injections, prednisone, and other derivatives of steroids) all of which are a contributing factor in one of the three types of Cushing’s disease.
For dogs with Cushing’s disease, symptoms vary extensively. Some dogs start with just one symptom and end up with to multiple clinical signs as the disease progresses. The symptoms include muscle weakness, or wasting (created by the over production of cortisol breaking down muscles), ravenous appetite, pot belly (large swollen belly), erratic blood glucose levels, depressed immune system (resulting in increase risk of infections), excessive urination and drinking (resulting in imbalances flushing of minerals), heat intolerance, skin sores and arthritis (from improper use of calcium), liver disease, mood changes, abnormal sleep patterns, hair thinning (balding), as you can see quite an array of disturbances to a dog’s whole body. Pets with Cushing's disease are more likely to form clots in their blood, which can lodge in the lungs, and be potentially fatal.
Diagnosis and Treatment
Diagnosis of Cushing's is made via a general health exam and profile, complete blood count, urinalysis and other specific tests if the signs point to Cushing's.
Conventional treatment for Cushings disease involves medication with drugs that suppress adrenal function.
A Holistic approach includes a healthy, natural diet, along with Traditional Chinese Medicine such as an herb called Si Miao San as well as the herb Ginkgo, which helps to lower cortisol secretion.
In general, the outlook for a pet with Cushing's disease is good, there are several conventional and complementary treatment approaches available and most pets who have the disease are able to lead normal lives while receiving treatment.
The book “Dogs, Diet, and Disease” by Caroline Levin has been a great guide for this information and we would recommend for anyone with a dog with Cushing’s or other metabolism disease.
Lucy Postins is founder and Chief Integrity Officer at The Honest Kitchen. She is a companion animal nutritionist who started The Honest Kitchen in her kitchen in 2002. She is passionate about advanced nutrition and holistic health including complementary modalities such as herbalism and homeopathy. Considered an expert in her field, Lucy frequently writes articles for local and national media, conducts radio interviews and educational spots, and occasionally holds educational seminars for pet owners on the importance of good nutrition. She also recently authored Dog Obsessed, a guide to a happier, healthier life for the pup you love.