Your pup's been seeming a bit off or listless lately, but the vet's had a difficult time pinning down a diagnosis. The symptoms for Addison's disease are similar to a host of other illnesses, so it's normal to go through a few tests. In the end, the ACTH will tell the tale.
If you've heard of the term "adrenal rush," you have an idea of the importance of the adrenal glands. Located on top of your pup's kidneys, these glands produce glucocorticoids and mineralocorticoids, two important types of hormones. The brain works with the adrenal glands, producing adrenocorticotropic hormone (ACTH), which stimulates the adrenal hormones. These hormones work together to help regulate sodium and potassium levels in poochie's body, as well as help in him respond to stress. If a dog has Addison's disease, his adrenal glands aren't producing enough corticosteroid hormones.
Symptoms of Addisons
Addison's disease develops slowly, gradually increasing in the severity of symptoms. Poochie may act a bit down or tired, something easily dismissed because she got an extra-heavy dose of exercise or maybe picked up a little bug while she was out. Other early signs are vomiting, shaking or shivering, weakness, loss of appetite and diarrhea. These mild symptoms can come and go, meaning the vet may treat them as they come. When your pup rebounds, there's no need for complicated diagnostic testing. These low points can occur after stressful events, such as kenneling your pup, or they may become more frequent. Often, the dog will become quite ill, sometimes in a form of shock known as an "Addisonian crisis," prompting more intense testing.
First Diagnostic Tests
If poochie experiences seizures, muscle tremors or an irregular heartbeat, she might be experiencing one of those crises. His blood sugar may drop to a dangerously low level, with the potassium level at an extreme high, with potentially fatal consequences. Along with X-rays, ultrasounds and urinalysis, a complete blood cell count and chemistry panel will provide valuable information. Addisonian dogs may show low sodium levels, high potassium levels, anemia and dehydration.
CBC and Chemistry Profile
The complete blood count can indicate anemia (low red blood cell count), high lymphocyte count and high eosinophils, all consistent with Addison's disease. The chemistry profile also may show high potassium and low sodium levels; high concentrations of urea nitrogen, creatinine, phosphorus and calcium; along with low glucose, which also are seen in Addisonian dogs.
ACTH Stimulation Test
The complete blood count and serum profile aren't definitive. They can show normal levels if poochie is between crises, and abnormal values also may be signs of other diseases. The only definitive test is the ACTH stimulation test, in which the cortisol level is measured from a blood sample. After the sample is drawn, he'll be given a dose of a drug similar to the hormone ACTH. After a bit of time, a second blood sample will be drawn to compare his cortisol levels. If his adrenal glands are functioning properly, his cortisol levels will be significantly higher. If not, his glands aren't able to produce additional cortisol and he's considered Addisonian.
Addison's disease can't be cured, but it can be treated, provided the pup isn't debilitated from an Addisonian crisis. If he's stable, treatment may be given by administration of adrenal gland hormones, typically prednisone or hydrocortisone pills, often with a mineralocorticoid supplement. This hormone replacement therapy will be lifelong. Fortunately, timely detection and proper treatment leads to a normal, good quality of life.