Cushings disease in dogs or hyperadrenocorticism is a condition that occurs due to excessive production of glucocorticoid hormones by the adrenal gland. This disease is quite complex with a wide range of causes and symptoms.
There are two types of Cushings disease, the pituitary based and the adrenal based. The pituitary based disease (PDH) results due to excessive secretion of ACTH by the pituitary gland (usually due to the presence of tumors), which in turn stimulates the adrenal gland to produce excessive glucocorticoid. About 80% of the canine Cushings disease cases are of this type.
The adrenal based disease results due to excessive secretion of glucocorticoid, mostly due to tumors in the adrenal gland and about 20% of the Cushings disease cases are of this type. A third type of this disease known as the ‘iatrogenic’ Cushings disease results due to ingestion of high doses of steroids and the symptoms disappear once the doses are reduced or discontinued.
Symptoms
The symptoms of this disease starts and progresses so gradually that most often owners mistake them as symptoms of ‘old age’. One of the most common Cushings disease dog symptoms is hair loss and thinning of skin.
Another common symptom is increase in water intake and urination. Water intake can increase up to ten times their normal intake resulting in excessive urination. Increase in appetite is also common and dogs might start to beg persistently for food or try to steal food. Abdominal enlargement is also found in about 80% of the affected dogs. Other symptoms include recurring infections of the urinary tract, excessive panting and loss of ability to reproduce.
Diagnosis
Dogs that are suspected of being affected by Cushings disease are recommended to have a complete blood count check, urinalysis and a chemistry profile. Since the symptoms are varied there are several different types of tests that can be conducted to confirm the presence of Cushings disease in dogs. The most common tests include an ultrasound, low dose dexamethasone suppression test and the urine cortisol to creatinine ratio test.
Other tests that might be recommended include the ACTH stimulation test, the abdominal ultrasound and the high dose dexamethasone suppression test which is done to find whether the disease is pituitary based or adrenal based.
Treatment
Treatment for Cushings disease in dogs depends on the type of disease and can be surgical in case of tumors in adrenal or pituitary glands or nonsurgical treatments which are more common. The only oral medication used until recently to treat this disease was Lysodren. It is very convenient to use and also quite inexpensive which is why this medication is still used widely. However, Lysodren has some serious side effects and the patient must be closely monitored during the initial phase of therapy.
Newer medications include Trilostane to treat dogs with adrenal tumors and Ketoconazole, which is an oral antifungal agent that hinders the secretion of steroid hormones. Vetoryl and Anipryl are other drugs that are used to treat Cushings disease in dogs.
Cushings disease dog’s life expectancy
Most cases occur in older dogs and with proper treatment some dogs can lead a productive life for up to three years. If the disease is detected and treated early Cushings disease dog’s life span can be near normal.
