Cushing’s disease is one of the most prevalent endocrine disorders contributing to canine geriatric decline. The most common cause is overstimulation of the adrenal glands by the pituitary gland (PDH) causing increased cortisol production. A less common cause is an adrenal tumor. Cushing’s can predispose the patient to urinary tract infection, skin infection, muscle wasting, hair loss, respiratory problems, bruising, testicular atrophy, liver disease, diabetes and many other problems. Without treatment, hyperadrenocorticism is a progressive disorder with an unfavorable prognosis. Death can result from tumor metastasis, hypertension, cardiovascular disease, insulin resistant diabetes, and increased susceptibility to infection. Fortunately, the disease progresses slowly.

The symptoms seen by the pet owner are often attributed to aging. Classic symptoms are obesity, lethargy, pendulous abdomen, hair loss, excessive thirst, increased urine output, and mental changes. Unfortunately, the symptoms are sometimes subtle and some patients show no outward signs. Diagnosis can sometimes be difficult.

Most patients with PDH respond to treatment with the drug Lysodren. Treatment is continued for the remainder of the patient’s life. Adrenal tumors often require surgery.