diabetic and hypothyroid (both common in Cush dogs). We suspected Cushings' in 2002 but Criss kept getting negative results on ACTH-stim tests and LDDS tests. We then sent her frozen blood samples to the University of Tennessee (only lab in USA) for a complete adrenal panel workup. She has something commonly referred to as 'atypical Cushings'.
Cushings' is normally the overproduction of cortisol by the adrenals. It can be caused by either a tumor on the adrenal gland (operable) or a tiny micro-tumor on the pituitary (80% of Cush cases). There are at least three tests to get a positive for Cushings'. One is the ACTH-stim which measures both a pre and post stimulation amount of cortisol in the blood. One is a Low-dose dexamethasone suppression test and one is a high-dose dexamethasone suppression test. Some vets start with a Urine Cortisol:Creatinine Ratio urine test. Some may recommend an ultrasound of the adrenal glands.
Under no circumstances should a dog be treated with either of the two Cushings' drugs without complete confidence that the dog has Cushings'.
The two drugs used today are either Lysodren, a chemo drug that destroys the adrenal cortex and Trilostane which is taken daily. Criss has been on Lysodren for 4 1/2 years. Somebody mentioned Anipryl, but it no longer recommended. Anipryl is used for Canine Cognitive Dysfunction.
Here is a link to a free forum for owners of Cushings' pets.
http://www.caninecushings.net/forums/Be sure to check out 'Important Information and Resources'. Lots of info on the testing and treatment protocols.
Edited: Forgot to add that I buy Lysodren from Canada at about $3.80 per 500mg tablet. Criss takes 1500mg. across 8 days, taking a pill on every 4th. day.