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

Abstract

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.

Adrenocortical function in hospitalised patients with active pulmonary tuberculosis receiving a rifampicin-based regimen—a pilot study

“…10 Finally, the occurrence of SIADH was the commonest metabolic abnormality encountered in our patients, having been diagnosed in about one-third of cases on admission to hospital. This figure is higher than the 10% prevalence rate reported in the recent study by Kaplan et al 9 and may be ascribed to most of our patients being HIV seropositive and having had more advanced disease, despite similar diagnostic criteria being employed. The mechanisms involved relate to increased total body water with decreased total body sodium as a consequence of enhanced or an abnormal pattern of ADH release.…”

“…In this regard, our finding is in keeping with the low incidence of primary hypoadrenalism reported in other recent African studies involving similar patient cohorts. 9,17 It is difficult to interpret the lower than expected mean levels of serum ACTH in both study groups on admission to hospital. Since pre-existing basal levels of ACTH were unknown, we cannot say whether the recorded values represented some increase from healthy baseline status.…”

Endocrine and Metabolic Aspects of Tuberculosis

“…Differences in the methods of assessment of adrenal insufficiency have led to a wide range in the reported incidence of pretreatment adrenal insufficiency. When adrenal function is measured appropriately in patients with tuberculosis prior to treatment, primary adrenal insufficiency is uncommonly found (11)(12)(13)(14). An impaired ACTH response has sometimes been observed in the setting of an elevated basal cortisol level, but the clinical significance of this finding is uncertain (15,16).…”

Endocrine dysfunction among adult patients with tuberculosis: An African experience

“…[13141516171819] The reason for this disparity is the varying criteria for defining adrenal insufficiency and diagnostic methods used.…”

“…In another case-control study by Kaplan et al .,[14] to assess the magnitude of adrenal insufficiency and the effect of HIV coinfection on adrenal function in 21 healthy controls and 18 HIV positive and 22 HIV negative hospitalized TB patients, a very low frequency of hypoadrenalism of 1.6% (documented in 1 HIV negative TB patient) was reported. Adrenal insufficiency in this study was defined as a 30-min cortisol level ≤414 nmol/L after a 1 μg ACTH stimulation test.…”