Q J Med 2000; 93: 603-609
© 2000 Association of Physicians
Primary hypoadrenalism assessed by the 1 µg ACTH test in hospitalized patients with active pulmonary tuberculosis
From the Endocrine-Diabetes Unit, Groote Schuur Hospital and University of Cape Town, Cape Town, South Africa
Primary hypoadrenalism, assessed by 250 µg ACTH stimulation, is uncommon in patients with active pulmonary tuberculosis (PTB). Since 1 µg ACTH produces an equivalent +30 min cortisol response to 250 µg in control subjects, the 250 µg 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 µg ACTH in 21 controls, 18 HIV-positive (BMI 19.5±0.9 kg/m2, albumin 24±1.4 g/l, CD4 count 192±47/mm3) and 22 HIV-negative (BMI 19.3±0.8 kg/m2, albumin 29±1 g/l, CD4 count 652±76/mm3) 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 µg 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 µg ACTH test, is uncommon in a cohort of ill, hospitalized patients with active PTB, irrespective of HIV status.
Address correspondence to Dr S.G. Soule, Department of Medicine, UCT Medical School, Observatory 7925, Western Cape, South Africa. e-mail: ssoule{at}uctgsh1.uct.ac.za