Canine Cushings Disease: A Primer for Dog Owners

Canine Cushings disease is particularly insidious, as many owners mistake its symptoms for those of normal aging. Dogs with canine Cushings disease may gain weight, begin urinating in the house, and lose fur. However, canine Cushings disease is treatable, and treatment can greatly increase your dog's quality and length of life.

Roots of Canine Cushings Disease

Canine Cushings disease is essentially a hormonal imbalance related to the function of your dog's pituitary or adrenal gland. Canine Cushings disease could be the result of a tumor on or near the pituitary or adrenal gland. Malfunction of either of these glands means your dog will develop a high level of blood cortisol, which leads to the symptoms of canine Cushings disease.

Types of Canine Cushings Disease

There are three types of canine Cushings disease: pituitary dependant hyperadrenocorticism, adrenal-based hyperadrenocorticism, and iatrogenic hyperadrenocorticism.

In pituitary dependant hyperadrenocorticism, a tiny pituitary tumor causes your dog's pituitary gland to malfunction. Normally, your dog's pituitary and adrenal glands work together to produce an appropriate balance of hormones. In pituitary dependant hyperadrenocorticism, your dog's pituitary gland begins to produce too much adrenocorticotrophic hormone (ACTH), because it can no longer respond to the adrenal glands, which produce blood cortisol. Your dog's adrenal glands respond by excreting too much blood cortisol.

In adrenal-based hyperadrenocorticism, an adrenal tumor causes your dog's adrenal glands to overproduce blood cortisol. Adrenal-based hyperadrenocorticism is responsible for about fifteen percent of canine Cushings disease cases.

In iatrogenic hyperadrenocorticism, canine Cushings disease occurs as the result of corticosteroid overdose. Corticosteroid overdose is a risk when your are using steroids to treat chronic conditions, such as allergies. Fortunately, iatrogenic hyperadrenocorticism is reversible; you'll simply need to slowly wean your dog off of the corticosteroids.

Symptoms of Canine Cushings Disease

Symptoms of canine Cushings disease can be so vague and diverse that the disease can be difficult to spot.

  • Excessive thirst
  • Excessive urination
  • "Accidents" in housetrained dogs
  • Excessive appetite
  • Stealing food, begging, and becoming unusually overpossessive of food
  • A bloated, pot-bellied abdomen
  • Weight gain
  • Weight loss
  • Lethargy
  • Weakness in the hind legs
  • Reluctance to jump
  • Panting and overheating
  • Thinning hair or hair loss
  • Dull coat
  • Dry skin
  • Slow hair regrowth after grooming
  • Thin, wrinkled, fragile, or darkened skin
  • New susceptibility to infections, especially of the skin and urinary tract
  • Diabetes
  • Pancreatitis
  • Seizures

Diagnosis and Treatment of Canine Cushings Disease

Your vet will need to perform tests to determine if your dog is suffering from canine Cushings disease, especially since many of these symptoms could be indicative of other illnesses. Urine tests can tell your vet how much blood cortisol is in your dog's blood. Hormone tests, such as the ACTH stimulation test, low dose dexamethasone test, and high dose dexamethasone test, can help your vet isolate the cause of your dog's canine Cushings disease.

Treatment may be surgical or non-surgical in nature. Many dogs with canine Cushings disease are geriatric, and therefore may have other health problems that may make surgical treatment undesirable. Furthermore, many of the tumors responsible for canine Cushings disease are simply too small to be surgically removed. Non-surgical treatment involving medication can significantly improve your dog's quality of life.