ona is a 23 month old German Shorthair Pointer, who presented to us last month with a history of vomiting, diarrhea and in appetence for about a week. The owners had recently changed the diet and thought that might be the cause of the problem. On presentation, Mona was depressed, lethargic and dehydrated. She had no gross physical abnormalities except watery diarrhea on rectal palpation. Mona was tested for intestinal parasites, and Parvovirus. Both tests were negative. Radiographs of the belly were taken and no obvious foreign bodies were found. Blood tests revealed mild dehydration and some electrolyte abnormalities and evidence of pancreatitis. Mona was started on intravenous fluids, anti- nausea drugs and antibiotics. She improved greatly over the next 2 days and was discharged feeling fine and eating well.

Three days later, Mona returned to the clinic with the same original symptoms of vomiting and weakness. Blood tests were repeated and were found to be normal except for abnormal sodium and potassium values. Based on these findings, a relatively uncommon disease known as Addison’s disease hypoadrenocorticism) was considered as a possible cause. In this disease, the body does not make enough or any of the hormone Aldosterone in the adrenal glands. Aldosterone is responsible for keeping the amount of sodium and potassium in the blood regulated though its effects on the kidneys. When the sodium gets too low, the symptoms of vomiting and diarrhea, weakness and weight loss can occur. Addison’s disease is often called “the great pretender” because it presents like many other disease states.

We performed a test called the ACTH stimulation test on Mona which confirmed the diagnosis of Addison’s. She was started on a synthetic version of Aldosterone by injection and responded beautifully within 24 hours. This drug has to be administered once monthly to keep her healthy, but as long as she gets it, her prognosis is quite good. She is at home with her owners just waiting for hunting season to open!