Cushing’s disease in dogs (hyperadrenocorticism): causes, symptoms and treatment

Cushing’s disease in dogs is a disease with various symptoms, which should not be underestimated.
Canine hyperadrenocorticism, better known as Cushing’s disease, named after its discoverer, is a more common disease in older dogs, whose incidence increases with age.

This can affect all breeds, although some, like Poodle, Beagle and Dachshund seem to be more prone. This pathology is characterized by an excessive production of cortisol by the adrenal glands, placed immediately above the kidneys,

which can have three different causes:

Pituitary tumor: This is a neoplasm that affects the pituitary gland located in the brain; this leads to the increase of a hormone called ACTH, which will over-stimulate the adrenal glands, causing abnormal production of cortisol. It is the most common cause of Cushing in dogs, quantifiable in about 85% of cases;
Adrenal tumors: In this case, the neoplasm affects one or both adrenal glands, which begin to produce an excess of cortisol;
Administration of corticosteroids: In dogs, chewing may also be caused by excessive consumption of corticosteroids, in excessive or prolonged doses, or by abrupt discontinuation of the drug, without the necessary reduction of scaling. In this case, we are talking about iatrogenic hyperadrenocorticism of the dog.

Cushing’s disease in dogs: symptoms

The symptoms of Cushing’s disease are very varied and can sometimes be initially underestimated by the owner, as they are neither specific nor attributable to the age of the dog. Instead, it is important to identify the disease as early as possible, as this can contribute to a better quality of life for the animal and prolong the course of the disease.

The first signs of hyperadrenocorticism in dogs are:

-Production of abundant amounts of urine (polyuria);
– Hitting in inappropriate places: the dog, even if he had never done it before, sometimes urinates at home;
– increased thirst (polydipsia);
– increased hunger (polyphagia);
– barrel-shaped belly

To these initial symptoms, which may be noticed by the owner and which need to be paid attention, others may follow as the disease progresses:

– Hyperpigmentation of the skin, which takes on a dark color;
– Loss of hair (alopecia);
– urinary infections;
– enlargement of the liver;
– muscular weakness;
– pulmonary thromboembolism

Cushing’s disease in dogs: diagnosis

To diagnose hyperadrenocorticism in dogs, the veterinarian, in addition to observing the clinical signs and relying on the description of the symptoms given by the owner, will have to perform specific tests to confirm the diagnosis.

The first step usually consists of blood tests, which will reveal an increase in red blood cells, hemoglobin, hematocrit and transaminases, as well as stress leukograms, increased cholesterol levels and blood sugar. A urine test will also very often indicate a low density.

We will do an abdominal ultrasound to look at the condition of the adrenal glands, which may present a tumor mass, if the Cushing is caused in the dog by a neoplasm of the adrenal glands, or that, anyway, its size can increase . when subjected to excessive stimulation; also the liver will generally appear enlarged.

The definitive confirmation of the diagnosis of hyperadrenocorticism can however only be obtained by a specific test: stimulation with ACTH.

The fasting dog is first taken to check the level of basal cortisol, after which ACTH is administered intravenously or intramuscularly, then after one hour, the blood sample is repeated to measure the variation of the concentration of cortisol in the blood after stimulation. If the value is greater than 20, the suspicion of Cushing in the dog is high.

Cushing’s disease in dogs: care

If the cause of Cushing is a tumor of the adrenal glands, surgery is usually performed with removal, whereas when the disease is iatrogenic, corticosteroid-based treatments are suspended.

If it is more a pituitary hyperadrenocorticism, the treatment aims to control the production of cortisol by means of specific drugs: trilostane, the most commonly used, acts by reducing the activity of the adrenal glands. This is a therapy in which most dogs respond positively and usually within 10 days of treatment, symptoms such as excessive thirst and hunger decrease, but they can have side effects.