Adrenal Response to Adrenocorticotropic Hormone in Dogs before and after Surgical Attenuation of a Single Congenital Portosystemic Shunt

Abstract

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 450% or 430 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.

Delayed emergence from anaesthesia in a patient with agenesis of the ductus venosus

“…The hepatic portal vein carries venous blood drained from the spleen, gastrointestinal tract, and associated organs and supplies approximately 75% of the blood supply to the liver. A congenital portosystemic shunt has been reported to prolong anaesthetic recovery in dogs [6]. The portosystemic shunt in our patient may have reduced the blood supply to the liver and therefore contributed to delayed metabolism of fentanyl.…”

Postattenuation neurologic signs after surgical attenuation of congenital portosystemic shunts in dogs: A review

“…Perioperative hypoglycemia is a recognized complication of cEHPSS attenuation in small dogs. 57 Hypoglycemia is sporadically reported in dogs with PAS 1,2,4,46,47 but there are many reported cases of PANS and PAS that occurred with normoglycemia. 1,4,[10][11][12][13]16,17,32,38,39,44,46 In a retrospective study involving 75 dogs with PAS, 46 glucose concentrations at the time of seizure occurrence were ≥3.3 mmol/L in 91.9% dogs for which values were available.…”

“…Perioperative hypoglycemia is a recognized complication of cEHPSS attenuation in small dogs 57 . Hypoglycemia is sporadically reported in dogs with PAS 1,2,4,46,47 but there are many reported cases of PANS and PAS that occurred with normoglycemia 1,4,10–13,16,17,32,38,39,44,46 .…”

Adrenal function evaluation in critically ill dogs with low doses of synthetic ACTH

“…However, it was observed that dogs with Δ-cortisol levels < 3 ug/dL had higher risk of developing hypotension and were four times more likely to die. Holford et al (2008) evaluated 16 dogs with portosystemic shunt in the pre-and postoperative periods of ameroid ring constrictor placement, finding no significant differences in basal cortisol and post-ACTH levels in the control group, but just an increase in basal cortisol values in the post-surgical group.…”