Cushing’s disease or hyperadrenocorticism is an endocrine or hormonal related disease, mainly affecting dogs of ages 7-9 years. It is characterized by the overproduction of the hormone cortisol from the adrenal glands located above the kidneys.
In 85% of cases, it is due to damage in the pituitary gland, which is the small gland located below the brain. For the remaining 15%, it can be a tumor, either malignant or benign, of the adrenal glands.
Causes of Cushing’s disease in dogs
Two types of tumor can cause the Cushing’s disease in dogs: a tumor of the pituitary gland causes 85% of cases of Cushing’s disease in dogs or an adrenal gland tumor. Cortisol has a significant role in the balance of the protein, lipids and carbohydrates metabolism.
Usually, dogs secrete this hormone under stress to help prepare the body to fight against this emotional state. However, the overproduction of cortisol can have consequences which can damage the organs and muscles of the animal.
Excessive use of corticosteroids in medical treatment can also cause too much cortisol in the body. In the latter case, the dog can return to a healthy state upon stopping the medication.
Symptoms of Cushing’s disease in dogs
Dogs suffering from Cushing’s disease can have premature ageing symptoms, and if not treated quickly, his health deteriorates. Other conditions that can result from Cushing’ syndrome are diabetes, pulmonary embolism, kidney infection, and inflammation of the pancreas.
Dogs with Cushing’s syndrome show many signs and symptoms; the slightest change in the appearance or behaviour of your dog should alert you.
- Polyurea-polydipsia: your sog drinks a lot and therefore urinates more often.
- Polyphagia: his appetite increases
- Abdominal distension: a “hanging” belly
- Panting: breathing with an open mouth, even when at rest
- Fatigue, lethargy
- Weakness and muscles wasting
- Skin signs: symmetrical alopecia (loss of hair) on the flanks, skin thinning and increase in elasticity, skin pigmentation.
How to diagnose
A blood test, Ultrasounds and an ACTH stimulation test (the hormone responsible for the excessive production of cortisol), or a dexamethasone test are required to detect Cushing’s disease. These tests will also help the veterinarian better determine the origin of the disease.
Treatments for Cushing’s disease in dogs
The treatment given depends on the causes of the disease. In case of an adrenal tumor, surgery may be necessary. If surgery is not possible fr the tumor, the veterinarian will recommend the use of “mitotane”, a potent molecule, but unfortunately, it has a lot of undesirable effects. In the case of a pituitary gland tumor, the vet can either consider surgery or the use of “trilostane”, a molecule which blocks the synthesis of cortisol.
While each case can be completely different, drug treatment is generally sufficient to control the effects of a pituitary gland tumor. In the case of an adrenal tumor, the dog’s prognosis for survival will be better with surgery. Note that the post-treatment survival rate is 1.7 years on average; however, many dogs have lived much longer after surgery.
Which breeds are more prone to Cushing’s disease?
Cushing’s disease of dogs is quite common in certain breeds of dogs especially poodles, dachshunds and small terriers like the Jack Russel terrier and Staffordshire bull terrier.
In all cases, the treatment must be carried out for life, and the dog must be checked regularly, to see if his Cushing is reduced and stabilized.