Primary hypoadrenalism assessed by the 1 microg ACTH test in hospitalized patients with active pulmonary tuberculosis

Primary hypoadrenalism, assessed by 250 microg ACTH stimulation, is uncommon in patients with active pulmonary tuberculosis (PTB). Since 1 microg ACTH produces an equivalent +30 min cortisol response to 250 microg in control subjects, the 250 microg dose is supraphysiological and may lack sensitivity for the diagnosis of hypoadrenalism. Furthermore, the impact of coexistent HIV infection on the prevalence of primary hypoadrenalism in PTB is uncertain. We thus determined the cortisol response to an intravenous bolus of 1 microg ACTH in 21 controls, 18 HIV-positive (BMI 19.5+/-0.9 kg/m(2), albumin 24+/-1.4 g/l, CD4 count 192+/-47/mm(3)) and 22 HIV-negative (BMI 19.3+/-0.8 kg/m(2), albumin 29+/-1 g/l, CD4 count 652+/-76/mm(3)) patients with active PTB. The mean basal cortisol was greater in patients than in controls (559 vs. 373 nmol/l, p=0. 0009). The mean cortisol after 1 microg ACTH stimulation did not, however, differ significantly when comparing either patients and controls or patients who were HIV-positive and -negative (p>0.05). Using the minimum +30 min cortisol derived from the 21 controls as a marker of normal adrenal function (414 nmol/l), a single patient was classified as hypoadrenal. In conclusion, primary hypoadrenalism, as assessed by the 1 microg ACTH test, is uncommon in a cohort of ill, hospitalized patients with active PTB, irrespective of HIV status.