[Standardization and clinical applications of the rapid and prolonged ACTH stimulation tests in patients with primary and secondary adrenal insufficiency].

Abstract

Some methodological aspects of the rapid ACTH stimulation test (RST) and the prolonged ACTH stimulation test (PST) remain heterogeneous, e.g. administration routes, time of the day, duration, interpretation criteria and clinical indications. To standardize both tests we studied the serum cortisol responses to ACTH in 16 normal subjects, 16 patients with Addison's disease (AD), 14 with hypopituitarism (HP) of different etiologies and 13 patients on chronic glucocorticoid (CG) treatment (doses equivalent to 5-20 mg/d of prednisone for at least 6 months). For the RST, 250mcg of Cortrosina Organon were injected as an IV bolus and blood collected before and 60 minutes later, whereas for the PST, 250mcg of Cortrosina-Depot Organon were injected IM, every 8 hours for 3 days, and blood drawn daily between 8 and 9 o'clock AM. The post-ACTH cortisol value was the single parameter chosen to interpret both tests (the absolute or percent increase was of no further value). The 95% lower confidence limits (mean minus 1.64 SD) for the RST and the 3rd day of PST were 19.1 and 49.0mcg/dL, respectively. AD patients did not increase cortisol in response to both the RST (1.1 +/- 1.2 to 1.2 +/- 1.1mcg/dL) or the PST (1.2 +/- 1.3 to 2.0 +/- 1.7mcg/dL). However, whereas 22 out of 27 patients with HP and CG showed a modest cortisol increase to the RST (1.6 +/- 2.3 to 5.6 +/- 4.7 mcg/dL), all had a gradual and nearly normal response on the 3rd day of the PST (1.6 +/- 2.1 to 29.6 +/- 16.6mcg/dL).(ABSTRACT TRUNCATED AT 250 WORDS)