Diagnosing Cushings Disease in Dogs

Cushings disease in dogs is caused by the production of glucocorticoids in excess. The glucocorticoids are hormones produced by the adrenal gland. The adrenal gland is located in the abdomen, in the vicinity of the kidneys.

Cushings disease, also known as hyperadrenocorticism, is more frequent in senior dogs that are older than 8. Certain breeds are more prone to developing this disease.

Symptoms of Cushings Disease

Cushings disease occurs when the glucocorticoids are in excess. This excess may be caused by a disease of the adrenal gland or a tumor located in the area.

The glucocorticoids have the role of stabilizing the cell membranes, the blood sugar levels and help in urine production.

A dog with Cushings disease will display symptoms such as:

  • Increased thirst
  • More frequent urination
  • Weakness
  • Lethargy
  • Hair loss
  • Thinner and poor quality skin
  • Decreased muscle mass

Cushings disease may affect the dog’s immune system, making him more exposed to various infections, so there may be secondary diseases accompanying Cushing’s.

The symptoms occur long time after the onset of the disease, so when you notice these symptoms in your dog, you need to visit the vet immediately.

Diagnosing Cushings

The disease may be diagnosed with an ACTH stimulation test. Two blood samples are needed: one before the injection of ACTH and one sample 45 to 60 minutes after the injection. If the levels of cortisol are elevated, this is a clear sign of Cushings disease.

A low dose dexamethasone suppression test (LDDS) is also an efficient test to diagnose Cushing’s. This test also needs two blood samples, one prior and one after the shot of dexamethasone.

Treatment Options

Cushings disease treatment options depend on the cause of the excess cortisol levels. If the disease is caused by a tumor, this may be removed surgically, provided it is not too large.

Medication may also be administered to treat Cushings disease. Mitotane is a drug that may destroy parts of the adrenal gland, resulting in lower levels of glucocorticoids. This drug is cytotoxic, so must be used with caution. The dog must be monitored while under medication. If this drug is administered in excess, the dog may develop Addison’s disease, which is a deficit in glucocorticoids production.

Ketokonazole or adrenal inhibitor medication may also be used to reduce the production of cortisol.

Unfortunately, if the disease is caused by a tumor, the medication will be permanent.

If the disease is caused by the hyperactivity of the adrenal gland, the medication may be discontinued, but the dog must be kept under medical supervision.

Talk to your vet about the best treatment options for you dog. Given that Cushings occurs mostly in senior dogs, it is important to coordinate the treatment for Cushings with other medication your dog may require for other medical conditions.

Typically, dogs with Cushings live for 2 years after the onset of the symptoms. However, a lot of dogs with Cushings may die of old age or due to other secondary infections.