Symptoms of Addison's Disease That Wax and Wane

Addison's Disease is caused by failure of the adrenal glands. In dogs, it may result from suddenly stopping steroid treatment for another disease, which is why vets advise owners to taper off their pet's steroid dosage. Many symptoms wax and wane, which is why Addison's Disease in dogs is referred to as "The Great Imitator." There are three different types of chronic Addison's Disease--primary, secondary and atypical. With the right diagnosis, dogs can receive medication that can potentially extend their lives for several years. Dogs can also have an Addisonian crisis, an acute stage of the disease involving vomiting, diarrhea and collapse. Such dogs must receive veterinary treatment immediately if they are to survive.

Lethargy and Depression

• Often an early sign of Addison's is the dog who is not quite right. There is nothing specific the owner can point to, but the dog isn't acting like himself--he's tired, lacks interest in things that used to excite him and seems depressed. The dog may perk up temporarily, but after a while the listlessness returns. The vet can determine if Addison's is the culprit by testing for electrolytes for primary Addison's Disease, while the secondary and atypical versions respond to the ACTH test. In this blood test, cortisol levels are measured. The dog is then injected with a hormone that produces cortisol. Another blood test is drawn one hour later. If the cortisol measurement is low and the hormone does little to stimulate it, Addison's Disease is the diagnosis.

Pain and Muscle Weakness

• Another sign of Addison's Disease is intermittent pain and muscle weakness. The dog may tremble or shake. In middle-aged dogs, this is often confused as the onset of arthritis. If a dog is suddenly reluctant to climb stairs, or into the car, or onto a chair, observe it carefully. If symptoms disappear then reappear a few weeks later, a visit to the vet may be in order.

Lack of Appetite/Increased Thirst

• Vomiting and diarrhea are signs of Addison's disease, but responsible dog owners take their animal to the vet if this activity continues for more than a short time. More subtle is a lack of appetite or increase in thirst, symptoms which come and go. If the dog normally has a robust appetite and doesn't want to eat, consult a vet. The finicky eater is more problematic, but take careful note of the dog's eating habits. Increased water consumption and the resultant increase in urine output is symptomatic of several diseases, including kidney failure, so any dog exhibiting this behavior should have a veterinary check-up.