Elevated Cortisol Levels in Dogs

Elevated cortisol levels in dogs cause a condition that is also referred to as canine Cushing’s disease. This is a disorder of the adrenal glands causing a high level of cortisol in blood. Cushing’s disease is a common condition in older dogs and it is often mistaken for the aging process itself. Left untreated, it can cause severe problems in the pet.

Causes of Elevated Cortisol Level (Hyperadrenocorticism)

The pituitary gland produces the adrenocorticotrophic hormone (ACTH) as directed by the hypothalamus. This hormone stimulates the adrenal glands to secrete glucocorticoid, which is a cortisol-like hormone. The glucocorticoids are responsible not only for the reaction of the body to stress but also for some metabolic functions such as regulating the blood sugar level, the fat metabolism.and the immune system. The causes of canine hyperadrenocorticism may include some factors such as:

  • Pituitary tumors, which are typically benign tumors called also microadenomas
  • Adrenal tumors that secret too much cortisol. 50% of these tumors are benign adenomas and 50% are malignant. 15% of canine Cushing’s cases are adrenal-based
  • Certain drugs (corticosteroids) given for allergies can induce the so called iatrogenic hyperadrenocorticism. If your vet discontinues the drug, this condition is fully reversible

Some breeds are at greater risk to develop Cushing’s disease including German shepherds, Golden and Labrador retrievers, terriers and poodles. Pituitary dependent Cushing’s is more common in small dogs, under 20 kg (44 pounds).

Symptoms of Elevated Cortisol

The symptoms of high cortisol levels can vary and they tend to appear gradually and progressively. Some of the most frequent symptoms of the disease are:

  • Excessive water consumption(polydipsia)
  • Excessive urination (polyuria)
  • Excessive appetite((polyphagia)
  • Weight gain
  • Loss of muscle mass
  • Exercise intolerance
  • Excessive panting
  • Hair thinning and hair loss
  • Easily bruised skin
  • Skin and coat changes
  • Susceptibility to infections
  • Pot bellied appearance

Diagnosing Dogs with Elevated Cortisol Level

A blood test and a urinalysis may reveal the elevated cortisol level in your pet. If an x-ray and ultrasounds are performed, the vet may detect the enlarged liver and enlarged or atrophied adrenals. A CT scanning of the adrenal gland and a MRI of the pituitary gland can detect the presence of adenomas. A general examination to determine any other symptoms should be done.

Some specific lab-tests are also recommended such as a urine cortisol/ creatinine ratio test, an ACTH stimulation test and a Dexamethasone suppression test.

Treatment Options for Elevated Cortisol Levels

The treatment will depend on the type of Cushing’s disease the dog is diagnosed with.. If the Cushing’s disease is caused by steroid medication, the condition will subside once the medication is discontinued. If there are tumors, chemotherapy or the surgery can be the solution. After chemotherapy your pet’s body won’t produce cortisol at all. In this situation the replacement of cortisol with hydrocortisone or prednisolone is necessary. When your dog can’t undergo a surgery, some cortisol-inhibiting drugs (e.g. metyrapone, ketoconazole) can be administered.

Left untreated Cushing’s disease may lead to death. Most dogs with this disease can’t be cured but the quality of their life can be improved.