Fast resolution of hypercortisolism in dogs with portosystemic encephalopathy after surgical shunt closure

Abstract

The aim of this study was to investigate whether hypercortisolism in dogs with congenital portosystemic shunts disappeared after surgical closure of the shunts concomitantly with recovery from hepatic encephalopathy. We examined 22 dogs before and four weeks after partial surgical closure of a single, large congenital portosystemic shunt (PSS). Parameters measured to characterise the basal activity of the pituitary–adrenal axis were the cortisol:creatinine (C/C) ratio in home-sampled urine and total and free cortisol in plasma. The binding characteristics of cortisol binding globulin (CBG) in pooled pre- and postoperative plasma were also determined. Ammonia and bile acid concentrations were measured in plasma to characterise the liver perfusion and function. Clinical symptoms relevant to liver function, cortisol excess, and hepatic encephalopathy were recorded semiquantitatively using a standardized questionnaire.The dogs had hypercortisolism before surgery, which had normalized four weeks later. The pre- and postoperative concentrations (means ±SEM) were, respectively, 238 ± 45 nMand 126 ± 19 nMfor total cortisol, 15.5 ± 2.6 nMand 8.4 ± 1.3 nMfor free cortisol in plasma, 13.4 ± 4.3 × 10–6and 3.9 ± 0.4 × 10–6forC/Cin urine. The pre- and postoperative Bmax values ofCBGwere 41 and 79, and Kd values were 3.8 and 5.5. The concentrations of ammonia were 217 ± 23 μMand 32 ± 3.1 μM, and of bile acids 110 ± 33 and 11.1 ± 2.0 μM, respectively. We conclude that there is a close relation between portosystemic encephalopathy and hypercortisolism in dogs withPSSand that both deviations resolve completely within four weeks of closure of the shunt.