TY - JOUR
T1 - Use of low- and high-dose dexamethasone tests for distinguishing pituitary-dependent from adrenal tumor hyperadrenocorticism in dogs
AU - Feldman, Edward C
AU - Nelson, Richard W
AU - Feldman, Marsha S.
PY - 1996/8/15
Y1 - 1996/8/15
N2 - Objective: To evaluate low- and high-dose dexamethasone suppression tests for differentiating pituitary dependent hyperadrenocorticism (PDH) from adrenal tumor hyperadrenocorticism (ATH) in dogs Design: Prospective study. Animals: 181 dogs with PDH and 35 dogs with ATH. Procedure: Plasma cortisol concentrations from dogs with naturally developing hyperadrenocorticism were evaluated before, and 4 and 8 hours after administration of standard low- and high-doses of dexamethasone (0.01 mg/kg of body weight, IV, and 0.1 mg/kg, IV; respectively). Results: In response to the low-dose test, all but 3 dogs had an 8-hour post-dexamethasone plasma cortisol concentration that was consistent with a diagnosis of hyperadrenocorticism, that is, ≤ 1.4 μg/dl. Criteria used to distinguish PDH from ATH in response to low-dose dexamethasone included a 4-hour post-dexamethasone plasma cortisol concentration < 50% of the basal value or < 1.4 μg/dl, or an 8-hour post-dexamethasone plasma cortisol concentration < 50% of the basal concentration. Criteria used to distinguish PDH from ATH in response to high-dose dexamethasone included 4- or 8-hour post-dexamethasone plasma cortisol concentrations < 50% of the basal concentration or < 1.4 μg/dl. In response to the low-dose test, 111 dogs met criteria for suppression (each had PDH). In response to the high-dose test, 137 dogs met criteria for suppression (2 had ATH, 135 had PDH). Twenty-six dogs with PDH (12%) had indications of adrenal suppression in response to high-dose but not low-dose testing. Clinical Implications: Low-dose dexamethasone test has value as a discrimination test to distinguish dogs with PDH from those with ATH. The high-dose test need only be considered in dogs with hyperadrenocorticism that do not have adrenal suppression in response to the low-dose test.
AB - Objective: To evaluate low- and high-dose dexamethasone suppression tests for differentiating pituitary dependent hyperadrenocorticism (PDH) from adrenal tumor hyperadrenocorticism (ATH) in dogs Design: Prospective study. Animals: 181 dogs with PDH and 35 dogs with ATH. Procedure: Plasma cortisol concentrations from dogs with naturally developing hyperadrenocorticism were evaluated before, and 4 and 8 hours after administration of standard low- and high-doses of dexamethasone (0.01 mg/kg of body weight, IV, and 0.1 mg/kg, IV; respectively). Results: In response to the low-dose test, all but 3 dogs had an 8-hour post-dexamethasone plasma cortisol concentration that was consistent with a diagnosis of hyperadrenocorticism, that is, ≤ 1.4 μg/dl. Criteria used to distinguish PDH from ATH in response to low-dose dexamethasone included a 4-hour post-dexamethasone plasma cortisol concentration < 50% of the basal value or < 1.4 μg/dl, or an 8-hour post-dexamethasone plasma cortisol concentration < 50% of the basal concentration. Criteria used to distinguish PDH from ATH in response to high-dose dexamethasone included 4- or 8-hour post-dexamethasone plasma cortisol concentrations < 50% of the basal concentration or < 1.4 μg/dl. In response to the low-dose test, 111 dogs met criteria for suppression (each had PDH). In response to the high-dose test, 137 dogs met criteria for suppression (2 had ATH, 135 had PDH). Twenty-six dogs with PDH (12%) had indications of adrenal suppression in response to high-dose but not low-dose testing. Clinical Implications: Low-dose dexamethasone test has value as a discrimination test to distinguish dogs with PDH from those with ATH. The high-dose test need only be considered in dogs with hyperadrenocorticism that do not have adrenal suppression in response to the low-dose test.
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M3 - Article
C2 - 8756877
AN - SCOPUS:0029778939
VL - 209
SP - 772
EP - 775
JO - Journal of the American Veterinary Medical Association
JF - Journal of the American Veterinary Medical Association
SN - 0003-1488
IS - 4
ER -