Cushing or hyperadrenocorticism is a hormonal disease caused by a continuous increase in the hormone cortisol. Dogs, cats, and horses, like humans, can suffer from it, but it is more common in dogs than in cats and horses. If your dog has been diagnosed with Cushing, and you want to know more about the disease, in My Animals, we offer you information about its detection and management.
Why does Cushing occur?
The adrenal glands are located above the kidney and have a coma. They are responsible for producing and secreting different hormones, including cortisol. Its secretion is regulated by another hormone called corticotropin (ACTH) and produced in the pituitary gland, and this, in turn, is produced by the corticotropin-releasing hormone (CRH) that is synthesized in the hypothalamus.
Cortisol adapts the body to stress situations, prepares us for ‘fight or flight’ situations. It has many effects, including glucose, protein, and fat metabolism, to provide energy. It also increases blood pressure and regulates the body’s water balance. The problem appears when the effects of cortisol are constantly maintained in the body.
Cushing appears as a result of persistently elevated cortisol levels. There are several main causes of this increase in blood cortisol:
- Pituitary hyperadrenocorticism, caused by a tumor in the pituitary gland that secretes an increase in ACTH and, as a consequence, cortisol. It is the most frequent cause, between 80 and 90% of cases.
- Adrenal hyperadrenocorticism, caused by a tumor in the adrenal gland, which produces an excess of cortisol. It is less frequent, around 10 to 20% of clinical cases.
- Iatrogenic hyperadrenocorticism, in dogs, long treated with corticosteroids. It is quite frequent in older dogs.
What are the symptoms of Cushing in dogs?
There are many symptoms associated with this disease. We can find:
- Polyuria – polydipsia: the dog drinks and urinates much more frequently than normal.
- Polyphagia: great appetite increase.
- Hair loss.
- Bloating of the abdomen
- Generalized hyperpigmentation.
- Atrophy of the dermis and subcutaneous tissue decrease.
- Calcium deposits in the dermis (head, back, or belly).
How is Cushing detected?
In addition to the clinical signs, Cushing in dogs is diagnosed by a series of tests in the veterinarian. Blood tests can guide the diagnosis, but this is only confirmed by the stimulation test or cortisol suppression.
In the simulation test, blood is drawn, and cortisol is measured. ACTH is injected and, one hour later, blood is drawn again to measure cortisol. The suppression test is similar, but in this case, a synthetic hormone is injected that mimics cortisol. This last type allows verifying if the hyperadrenocorticism is pituitary or adrenal.
Other tests that help the diagnosis are an ultrasound of the adrenal glands to see if they are enlarged or the measurement of the cortisol/creatinine ratio in urine. If the ratio is high, the animal may suffer Cushing.
Cushing treatment in dogs
The removal of the adrenal or pituitary tumor would be a cure for Cushing, but given the complexity and risks of the surgery, due to the proximity to the aorta and cava vessels, if it is an adrenal tumor, most cases are treated with medication.
Normally, a medicine called trilostane is used orally and for life. Trilostane blocks the synthesis of adrenal steroid hormones. Between 70% and 90% of dogs respond favorably to this treatment with one or two daily doses.
There are other medications, and it will be the professional who determines which one to use for each case. It is very important to keep a rigorous control in the veterinarian. Early detection also influences the success of the treatment.
Now you know what Cushing is, it is detection and handling. Remember the importance of making annual checks at the veterinarian to check the health status of your pet, especially if you notice any symptoms.