Cushing's & Diabetes in Dogs

Cushing's and diabetes are difficult to diagnose separately, let alone together, due to the similarity of the illnesses' signs and symptoms. Each illness affects the other, so treatment of a dog with both conditions needs patience and keen observation.

  1. Definitions and Explanations

    • Cushing's disease is also known as hyperadrenocorticism. It occurs when a dog's adrenal glands produce excess cortisol (cortisone). Adrenal gland cortisol production is controlled by the pituitary gland. Most Cushing's is caused by pituitary gland tumor. It also results from adrenal gland tumors or corticosteroid medical treatments. Diabetes mellitus, also known as diabetes, is caused by decreased production or functioning of insulin. Genetics plays a role although some diabetes is immune-mediated, according to PetEducation.com. The dog's immune system works against the pancreas as it attempts to produce insulin.

    Similar Symptoms and Risks

    • Cushing's and diabetes share signs and symptoms including increased appetite, increased thirst and urination, obesity, lethargy and elevated blood glucose. Cushing's dogs often exhibit poor or thinning coats, skin infections, bruising and excessive panting. Diabetic dogs may exhibit loss of appetite as diabetes progresses, consequential weight loss and rapid cataract development that may lead to blindness. Cushing's and diabetes can occur at any age but are most common in middle-aged and older dogs. Females are more affected by both diseases.

    Diagnosis and Differentiation

    • Cushing's is diagnosed via complete blood count, biochemistry, urine tests, urinalysis, abdominal X-rays and ultrasound as well as reactions to hormone administration and drug administration tests. Diabetes is diagnosed using urine tests, urine culture, urinalysis, complete blood count and chemistry panel. According to the Pets With Diabetes website, diabetic dogs pose special problems when testing for Cushing's. Untreated diabetes can lead to complications that increase cortisol levels, which are signs identical to Cushing's. Stressed diabetic dogs have similar blood panels and blood chemistry abnormalities to Cushing's dogs.

    Treatment

    • Cushing's is treated with various medications including Lysodren (mitotane), Anipryl (L-deprenyl) and Ketoconazole. The first destroys cortisol-producing cells in the adrenal cortex. The second's effectiveness is controversial while the third drug potentially harms the liver. Surgery is an option only with Cushing's caused by adrenal gland tumor. Slowly discontinuing cortisone medications solves medically-induced Cushing's. Diabetes is managed by insulin with a combination of controlled diet and exercise. Several types of insulin are used. Characteristics differ as to source, duration of action, concentration and frequency of administration, according to PetEducation.com.

    Expert Insight

    • Pets With Diabetes states, "As the Cushing's is brought under control your [diabetic] animal's insulin needs will be greatly reduced. Therefore it's very important to monitor your animal's blood glucose until the correct maintenance dose is determined so an overdose of insulin doesn't happen." Veterinarians and specialists must consider the whole picture of a dog's physical condition and test results when treating coexisting Cushing's and diabetes.