Canine Addison’s Disease
VETERINARIAN SPECIALTY CASE STUDY
“The Case of the Stomach-Churning Chihuahua”
Atypical Addison’s Disease in an Atypical Dog
‘Lexi’ is a 7-year old female spayed Chihuahua. She was seen by her primary care veterinarian for vomiting and innapetance. She was given an injection of Cerenia and sent home on famotidine. Within a few days, Lexi again became inappetant and developed vomiting and bloody diarrhea. In-house blood work revealed hypoalbuminemia of 1.9 g/dL (2.3 -4.0) and a mild hypoglycemia of 71 (74 – 143). Lexi was then referred to ASG.
On initial presentation to the emergency service, Lexi was tachycardic (HR 150) with normal respiratory rate and effort. She was approximately 5-7% dehydrated and her blood pressure was 100mmHg. A PCV/TS was 55%/5.0, and her electrolytes and blood glucose were normal.
Lexi was transferred to the Internal Medicine specialty department. Overnight, Lexi became more hypoglycemic and hypotensive. She was started on 5% dextrose in her crystalloids and her blood pressure responded to the addition of a hetastarch CRI. Bloodwork to Antech revealed hypoalbuminemia 1.9 g/dL (2.7 – 4.4), hypoglycemia 65 mg/dL (70 – 138), and hypocholesterolemia 80 mg/dL (92 – 324). The CBC was within normal limits and an abdominal ultrasound was unremarkable.
4. Problem List:
- Vomiting, hematochezia, inappetance
The main differentials for this included primary GI disease (e.g. inflammatory bowel disease), atypical Addison’s disease, and liver disease. An ACTH stimulation test, bile acids, and a fecal O & P were submitted. The bile acids and fecal came back normal. The ACTH stim revealed a pre of <0.7 and a post of <0.7, which is diagnostic for Addisons disease.
Addisons disease is classically defined as immune-mediated destruction of the adrenal gland leading to deficiencies in glucocorticoids and mineralocorticoids. Atypical Addisons is defined as a deficiency in glucocorticoids only. Lexi displayed many of the characteristic signs of glucocorticoid deficiency including gastrointestinal signs (vomiting, hematochezia, inappetance), hypoglycemia, hypoalbuminemia, hypocholesterolemia, and a lack of a stress leukogram. Because there is no deficiency of mineralocorticoids in Atypical Addisons disease, you will not see the electrolyte changes associated with typical Addison’s. Atypical Addison’s disease is an important differential for dogs presenting with this constellation of signs.
Lexi was started on dexamthasone 0.1 mg/kg q 12 hours and continued with supportive care. Her blood glucose stabilized and her gastrointestinal signs resolved, and she was discharged on prednisone 0.5 mg/kg q12 hours. Lexi continues to do well and has been weaned down to 0.25 mg/kg po every other day.
by Emilie Chaplow, VMD
Diplomate American College of Veterinary Internal Medicine
*Photo of Chihuahua is not “Lexi.”