Cushing's Disease In Dogs Overview
What Is Cushing's Disease?
Cushing's disease is also known as hyperadrenocorticism, or an increased level
of glucocorticoid hormones (cortisol, or hormones similar to cortisone) in your dog's body. This is
caused by an over-production of cortisol by the adrenal glands. This over-production, in turn, can be
caused by a hormone known as ACTH, which is secreted by the pituitary gland (in order
to instruct the adrenal glands to produce cortisol).
In addition to this, the high levels of cortisol may be caused by a defect in the adrenal glands themselves, though it is much more common for Cushing's disease to be related to problems with the pituitary gland (and its subsequent secretion of ACTH).
Dogs with Cushing's disease don't always show definitive symptoms right away. It's been suggested that a dog may show symptoms of this disease up to six years before a positive diagnosis for Cushing's disease is received. Also, many of the symptoms of Cushing's disease resemble the symptoms of aging in dogs (hair loss, muscle weakness, loss of bladder control), so might not provide an immediate cause for veterinary attention.
What Dogs Are Succeptible To Cushing's Disease?
Cushing's disease is most commonly seen in middle-age to older dogs, though a dog as young as two
years can possibly contract Cushing's disease. Some experts claim that female dogs are more likely
to develop Cushing's disease, though this is not confirmed by all sources.
There is also some evidence that suggests that dogs that have been spayed or neutered are slightly more likely to develop Cushing's disease. Though this disease can affect any breed of dog, the most commonly affected breeds include the Poodle, the Yorkshire Terrier, the Beagle, the Boston Terrier, the Boxer, the German Shepherd, the Golden Retriever and the Labrador Retriever.
Of the three types of Cushing's disease (which have three separate causes), pituitary-dependent Cushing's disease is most commonly seen in smaller dog breeds, usually dogs that are under 45 lbs in roughly 75% of cases. With adrenal-based Cushing's disease, in comparison, about 50% of cases are in dogs under 45 lbs, while the other 50% occur in dogs that weigh more than 45 lbs.
Is Cushing's Disease Serious?
Untreated Cushing's disease can possibly provide a significant amount of discomfort for your dog, and may eventually result in death. This is due to the importance of maintaining a proper balance of cortisol in your dog's system. It's necessary for the pituitary gland and the adrenal glands to both be functioning properly to maintain a proper level of secreted glucocorticoid hormones. With too much cortisol, your dog will essentially become “poisoned” by the excess cortisol being produced, as the balance is no longer in effect.
Is Cushing's Disease Treatment Dangerous?
Depending on your dog's health, and the treatment option you may choose, there may be many risks involved when treating Cushing's disease. Since many of the treatment options for Cushing's disease involve certain chemicals to reestablish a balanced level of cortisol, it is possible for your dog to develop a condition that occurs when cortisol levels are too low. This is called Addison's disease, and is the opposite of Cushing's disease.