Snow Leopard

Snow Leopard
Snow Leopard cub (7 mos old) - Cape May County Zoo

Friday, January 28, 2011

When Stress Can Be Deadly

Those adrenal glands we discussed yesterday can FAIL to produce some of the necessary things that the body needs to function and survive.  

There are two main parts of the gland: the cortex (outer layer) and medulla (inner section). They each produce different things. The cortex produces steroids that work on carbohydrate metabolism (corticosteroids)  and electrolyte regulation (mineralocorticoids).  The medulla produces epinephrine and norepinephrine. This is the "adrenaline" we associate with the "fight or flight" response in animals, including us! 

There are two types of deficiencies seen:
1. Both a lack of the corticosteroid and mineralocorticoid production - so no cortisol and the loss of the ability to regulate sodium and potassium (this can REALLY cause some serious problems)
2. A lack of ONLY the corticosteroid portion, so the electrolyte situation is NOT affected.

Some breeds that are more susceptible to this are: Standard Poodles, Portuguese Water Dogs, Great Danes, Rotties, and some terriers but again, any breed can develop this. I have seen it in a number of Labrador Retrievers.

The signs are often vague and can come and go. Then can include vomiting, not eating well, diarrhea, and lethargy.  Sometimes they seem to do better after they get some fluids and a shot of a steroid (which can be a general treatment for a LOT of things). They can also have an acute crisis and arrive in a state of collapse. Stresses can cause this to happen - including boarding, grooming, travel, vet visits, etc. 

Bloodwork can show some changes that point to this but again, more specific testing is needed to confirm this diagnosis. In this case, we use the ACTH stimulation test. Giving ACTH SHOULD stimulate the adrenal glands to produce cortisol (see yesterday's feedback loop diagram). We also want to measure the ACTH level in some cases to see which of the 2 problems is going on. 

The bloodwork can show what first appears to be "kidney failure" and some have misdiagnosed dogs with this when, in fact, they had Addison's. We also want to see what the sodium and potassium levels are. This will be also be checked periodically throughout the animal's life as this requires LIFELONG treatment. 

Treatment is a monthly (typically) injection given in the muscle. Owners can be taught to do this at home but I've had clients who were not comfortable with it and would bring their dog in for us to do it. This is a very costly drug - especially since many of the dogs are larger and require a larger dose.   Also, they are put on oral prednisone and this may be increased during times of "stress." The dogs that simply have a cortisol deficiency do not need the injection. 

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