Cushing's Syndrome
Hyperadrenocorticism (Cushing’s syndrome) refers to a clinical condition that results from having excess cortisone—a stress hormone—in the system. Approximately 15% of dogs with this disease have a tumor in one of the two adrenal glands that produce cortisone. Your dog, like 85% of dogs with the naturally acquired form of this disease, has a small benign tumor at the base of the brain in the pituitary gland. (This benign tumor will NOT harm the rest of the brain). The pituitary gland controls adrenal function. A tumor in the pituitary can cause excess demand for cortisone from the adrenal glands and results in symptoms recognized by you, the owner. The most common symptoms of Cushing’s syndrome in dogs include excess urination and water consumption, a voracious appetite, hair loss, muscle weakness, a “potbellied” appearance, panting, thin skin, and lethargy. Virtually all dogs with Cushing’s syndrome have at least one or two of these signs, but it would be uncommon for your dog to exhibit all of them. By running various laboratory tests, we have diagnosed your dog as having pituitary-dependent Cushing’s syndrome. Now, we are recommending treatment with Lysodren to cut down on this excessive hormone production which, without treatment, puts undue stress on your dog’s metabolism and causes noticeable discomfort.
During World War II, scientists did research on the insecticide, DDT in an attempt to create an extremely toxic form. One of the forms of DDT created was Lysodren, a chemical that destroys the cortisone-producing cells of adrenal glands in dogs. The drug has been used successfully in thousands of dogs with Cushing’s, but you must remember that it is a “poison” and that it must be used appropriately.
A day or two before starting treatment, begin feeding you dog one third of his or her normal food allotment twice daily (i.e., in 24 hours, feed a total of two thirds of the normal amount). This should make your dog even hungrier, but this is just for a brief time. After 1 or 2 days of reduced feeding, begin giving the prescribed “loading” dosage of Lysodren. The drug should be given immediately after your dog eats. So, begin to feed your dog, note how long it takes to finish the meal, and then give the medication (Lysodren is absorbed best from a stomach containing food).
The key to treating your dog is to watch him or her eat and to know when to stop giving the Lysodren. As long as their appetite is ravenous, give the medication. As soon as you see any reduction in appetite, STOP giving the drug and call our office to discuss this. Reduction in appetite may be noted as any of the following: your dog taking longer to finish the meal; eating half of the food, wandering away for a drink, and then finishing; or simply looking up at you once or twice before finishing. In other words, we do not want your dog to stop eating entirely, we wish to see a “reduction” in appetite as a signal to stop the medication. Other signals include reduced water intake, vomiting, diarrhea, and listlessness, but appetite reduction usually precedes these more worrisome symptoms.
You should not give the loading dose of
Lysodren for more than 8 days without testing to determine the effect of the
drug on the adrenal glands. The test is done in the hospital by appointment and
takes a total of two hours. When Lysodren has been demonstrated to have
sufficient effect in lowering the excess cortisol production, your pet can be
returned to a normal amount of food. Your dog will continue to receive Lysodren
for the rest of its life with a maintenance dosage so that cortisol will be
produced at an appropriate and safe level. The initial dose of Lysodren is
likely to be adjusted on the basis of testing performed. Tests will generally
be run one month after maintenance treatment has been started and then every two
to four months thereafter. Dogs that benefit the most from this treatment have
owners, like you, who are committed to helping their pet. Close observation and
frequent veterinary rechecks can only help in the long-term management of your
dog’s health.
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