Results from the study were presented by Dr Karen Tobias at the Society of Veterinary Soft Tissue Surgeons Conference.
Adrenal Response to Adrenocorticotropic Hormone in Dogs before and after Surgical Attenuation of a Single Congenital Portosystemic Shunt
Article first published online: 4 JUL 2008
Copyright © 2008 by the American College of Veterinary Internal Medicine
Journal of Veterinary Internal Medicine
Volume 22, Issue 4, pages 832–838, July–August 2008
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How to Cite
Holford, A.L., Tobias, K.M., Bartges, J.W. and Johnson, B.M. (2008), Adrenal Response to Adrenocorticotropic Hormone in Dogs before and after Surgical Attenuation of a Single Congenital Portosystemic Shunt. Journal of Veterinary Internal Medicine, 22: 832–838. doi: 10.1111/j.1939-1676.2008.0142.x
- Issue published online: 4 JUL 2008
- Article first published online: 4 JUL 2008
- Submitted June 30, 2007; Revised September 26, 2007; Accepted May 12, 2008.
- ACTH stimulation test;
- Adrenal insufficiency;
Background: Dogs with single congenital portosystemic shunts (CPSS) often develop postoperative hypoglycemia and prolonged anesthetic recovery. These abnormalities could be attributable to inadequate adrenal response. However, adequacy of adrenal response after CPSS surgery is unexplored.
Hypothesis: Dogs with CPSS have inadequate postoperative adrenal response.
Animals: Eight nonoperated, 8 ovariohysterectomy (OHE), and 16 CPSS dogs.
Methods: Consecutive day ACTH stimulation tests were performed on nonoperated healthy dogs, healthy dogs before and after OHE, and CPSS dogs before and after surgery. Adequate response was defined as >50% or >30 ng/mL increase in cortisol after ACTH administration. Blood glucose (BG) was monitored before and after surgery. Prolonged anesthetic recovery and refractory hypoglycemia episodes were recorded.
Results: Results of consecutive day ACTH stimulation tests did not vary in normal dogs. Results of preoperative ACTH stimulation tests of CPSS and OHE dogs were not significantly different. Dogs with CPSS had higher postoperative baseline cortisol concentrations (median, 329 ng/mL) than OHE dogs (median, 153 ng/mL). Postoperative cortisol increase after ACTH in CPSS was ≤50% in 10/16 and ≤30 ng/mL in 6/16. After surgery, BG was ≤60 mg/dL in 7/16 CPSS dogs. Cortisol concentrations were not correlated with BG. Two CPSS dogs had refractory hypoglycemia and 4 had delayed recovery; all improved with dexamethasone administration (0.1–0.2 mg/kg/IV).
Conclusions and Clinical Importance: Contrary to previous reports, baseline cortisol concentrations in CPSS and healthy dogs are similar. Many CPSS dogs have postoperative hypercortisolemia. Response to ACTH does not correlate with postoperative hypoglycemia or prolonged anesthetic recovery.