Effect of Intravenous or Perivascular Injection of Synthetic Adrenocorticotropic Hormone on Stimulation Test Results in Dogs

Abstract

BackgroundStandard protocols for adrenocorticotropic hormone (ACTH) stimulation testing (ACTHst) often involve intravenous (IV) injection of corticotropin. ACTH might be unintentionally injected into the perivascular (PV) space.ObjectiveTo compare stimulation test results after IV and PV injections of ACTH.AnimalsTwenty privately owned dogs were studied: 10 healthy and 10 with trilostane‐treated naturally occurring hyperadrenocorticism (HAC).MethodsProspective study. Each of 20 dogs underwent 2 ACTHst not <4 nor more than 14 days apart. Five healthy and 5 HAC dogs had an IV ACTHst first and PV second; 5 healthy and 5 HAC dogs had a PV ACTHst first and IV second. Blood samples for measurement of serum cortisol concentration were collected before and 1 hour after ACTH administration.ResultsNo significant difference in results was demonstrated when comparing serum cortisol concentrations after IV and PV ACTH administration in all 20 dogs (median μg/dL; interval μg/dL: 8.2; 1.4–17.4 versus 7.8; 0.9–16.9; P = .23). No significant difference in results was demonstrated when comparing serum cortisol concentrations after IV and PV ACTH administration in the 10 healthy dogs (median μg/dL; interval μg/dL: 10.9; 7.3–17.4 versus 10.6; 7.1–16.9; P = .54) or in the 10 HAC dogs (median μg/dL; interval μg/dL: 6.3; 1.4–8.6 versus 5.2; 0.9–8.7; P = .061).Conclusions and Clinical ImportancePerivascular administration of ACTH does not significantly alter stimulation test results in healthy dogs or in dogs with HAC undergoing therapy with trilostane.

Diagnosis of canine spontaneous hypoadrenocorticism

“…Although doses of 5 ug/kg are typically used, doses as low as 1 ug/kg may be sufficient [ 71 ]. In healthy dogs, there is no difference between cortisol concentrations one-hour post-administration of intravenous, subcutaneous or intramuscular synthetic ACTH [ 72 , 73 ]. However, the absorption of ACTH administered subcutaneously or intramuscularly in severely dehydrated dogs might be delayed affecting the interpretation of the test.…”

“…However, the absorption of ACTH administered subcutaneously or intramuscularly in severely dehydrated dogs might be delayed affecting the interpretation of the test. As a consequence, intravenous administration is preferred [ 18 , 74 ].…”

Hypoadrenokortizismus beim Hund – ein Update zu Pathogenese, Diagnose und Therapie

“…einer Maximaldosis von 250 µg/Hund intravenös oder intramuskulär(9,30,47). Eine aktuelle Studie zeigte, dass auch eine fehlerhafte paravenöse Applikation die Aussagekraft dieses Tests nicht zu beeinträchtigen scheint(39). Der Großteil der Hunde mit einem HoAK hat sowohl vor als auch nach der Stimulation mit synthetischem ACTH eine Serum-Kortisolkonzentration von < 27 nmol/l (< 1 µg/dl)(72).…”