| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
Original Studies |
Institute for Endocrinology and Diabetes, Schneider Children’s Medical Center of Israel, Petah Tiqva 49292 Israel; and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
Address all correspondence and requests for reprints to: Naomi Weintrob, Institute of Pediatric and Adolescent Endocrinology, Schneider Children’s Medical Center of Israel, 14 Kaplan Street, Petah Tiqva 49292, Israel.
 |
Abstract |
|---|
 Top Abstract IntroductionSubject and MethodsResultsDiscussionReferences |
|---|
IIH and the 250 µg and 1 µg/1.73 m2 ACTH tests were performed in groups 2 and 3; group 1 underwent only the ACTH tests. Pass peak cortisol level was defined as 520 nmol/L. No significant difference was noted between the standard and low-dose tests in the 30-min cortisol response to ACTH. Basal and peak cortisol levels attained on both ACTH tests were similar in groups 1 and 2 and significantly lower in group 3 (P < 0.0001). Both the 250 and 1 µg ACTH tests were highly correlated with IIH (r = 0.71, P < 0.0001 for the 250 µg, r = 0.7, P < 0.0001 for the 1 µg, n = 30), and both demonstrated high sensitivity (90% each) and specificity (100% and 90%, respectively) compared with IIH. We conclude that in idiopathic MPHD patients, both the standard and low-dose ACTH tests are equivalent to IIH in detecting HPA insufficiency. We suggest that they can replace IIH as a screening test for the integrity of the HPA axis in children with suspected MPHD.
|
Introduction |
|---|
|
TopAbstractIntroductionSubject and MethodsResultsDiscussionReferences |
|---|
This test, however, has some major drawbacks. A physician must be present throughout the procedure, it is contraindicated in infants and in patients with cardiovascular disease or history of seizures, and it involves some elements of risk; death following the use of IIH has been reported from either hypoglycemia or overly vigorous replacement of glucose (6). As a consequence, clinicians have been using other GH stimulation tests (7, 8), and the simple, innocuous short ACTH test has been used as an alternative to investigate the HPA axis. The results of the ACTH test, however, have not always correlated with those of IIH (9, 10), and its use for the detection of partial or recent secondary adrenal insufficiency is controversial (4, 11, 12). Recently, a low-dose (1 µg/1.73 m2) ACTH test has been introduced and found to be more sensitive than the standard 250-µg test to assess the integrity of the entire HPA axis (13, 14, 15, 16, 17).
The purpose of our study was to compare the results of both the 250-µg and 1-µg ACTH tests with those of IIH in patients with idiopathic IGHD or MPHD to determine whether the 1-µg ACTH test can replace IIH as a screening procedure for secondary adrenal insufficiency in this group of patients.
|
Subject and Methods |
|---|
|
TopAbstractIntroductionSubject and MethodsResultsDiscussionReferences |
|---|
Three groups of subjects were studied (clinical data and
endocrine status are summarized in Table 1
): group 1 (control) consisted of 13
patients (age 7.5–15 yr, 3 males) referred to our Pediatric
Endocrinology Clinic for evaluation of early or accelerated puberty,
hirsutism, or short stature, with no other evidence of pituitary or
adrenal pathology; group 2 consisted of 20 patients (age 4.0–19 yr, 13
males) with either IGHD (n = 13) or MPHD (n = 7) and a
preserved HPA axis as demonstrated by normal cortisol response on IIH;
and group 3 consisted of 10 patients (age 9.5–27 yr, 9 males) with
MPHD and impaired HPA reserve as demonstrated by subnormal cortisol
response on IIH. GH deficiency was diagnosed by a subnormal GH response
(<7 ng/mL) on at least two stimulation tests and was treated with
biosynthetic GH in a dose of 0.06 u/kg per day, 6 days a week. Patients
with secondary hypothyroidism were treated by the appropriate dose of
L-thyroxin (thyroxin sodium), whereas patients with
secondary hypogonadism received sex hormone replacement therapy. In
group 3, four subjects were under continuous treatment with
hydrocortisone (5–10 mg/day), which was stopped 48 h before each
test; the remainder were given hydrocortisone only during stress.
|
Testing protocol
All tests were carried out at 0800–0900 h following an overnight fast on separate days. Groups 2 and 3 underwent IIH and the 250-µg and 1-µg ACTH tests; group 1 underwent only the ACTH tests.
For IIH (patients >4 yr of age) an indwelling IV cannula was inserted into the forearm and heparinized, and 0.1 u/kg body weight short-acting human insulin was administered. Sampling for glucose level was carried out every 15 min and for GH and cortisol every 30 min, for 120 min. The test was considered adequate for GH and HPA reserve assessment if hypoglycemia of 2.2 mmol/L (40 mg/dL) or less was documented.
The standard and low-dose ACTH tests were carried out by iv injection of 250 µg or 1 µg/1.73 m2, respectively, of ACTH (1–24) (Synacthen, Ciba-Geigy, Basel, Switzerland). Blood samples for cortisol determination were drawn at 1, 30, and 60 min after injection. For the 1-µg procedure, a stock solution of 50 µg/mL was kept at 4 C in a plastic tube for 2 weeks and used to prepare a fresh concentration of 1 µg/mL for each test. For IIH and the ACTH tests, the pass level was defined as a peak serum cortisol concentration equal to or greater than 520 nmol/L (19.4 µg/dL) (12).
Hormone assays
Blood samples were immediately separated and kept frozen at -C until assayed. The serum cortisol and GH concentrations were determined with a commercially available solid-phase chemiluminescent enzyme immunoassay in the Immulite automated analyzer (DPC, Los Angeles, CA). The detection limit was 28 nmol/L for cortisol and 0.05 ng/mL for GH. The intra- and interassay coefficients of variation were, respectively, 9% and 10.3% with a cortisol level of 110 nmol/L; 6.8% and 9.9% with a cortisol level of 640 nmol/L; 3.7% and 3.8% with a GH level of 2.7 ng/mL; and 4% and 3.3% with a GH level of 12 ng/mL. Serum glucose was measured by the GOD-PAP enzymatic colorimetric test on a Hitachi 717/911 device (Hitachi, Osaka, Japan) with typical interassay coefficients of variation of 0.7–3%.
Statistical analysis
Within-group differences between the tests and differences between the groups were analyzed by ANOVA with repeated measures and by preplanned comparisons within ANOVA. Correlations between the different test procedures were also determined, both overall and within each group tested. Sensitivity and specificity were calculated with standard formulas. Statistical analyses were performed with JMP software (SAS Institute, Cary, NC) and Excel (Microsoft, Redmond, WA).
|
Results |
|---|
|
TopAbstractIntroductionSubject and MethodsResultsDiscussionReferences |
|---|
Mean basal cortisol level was 408 ± 61 nmol/L. All control
patients showed HPA sufficiency on the 250-µg test, with a peak
cortisol value of 597 nmol/L or more. On the 1-µg ACTH test, however,
two patients had low (borderline) levels of 509 and 513 nmol/L (those
results might be considered normal had a pass value of 500 nmol/L been
chosen). The mean peak serum cortisol level was slightly lower on the
1-µg ACTH test than on the 250-µg test [F(1, 42) = 3.82,
P = 0.057] (Fig. 1),
although the mean 30-min cortisol levels were similar to each other
(Fig. 2A). Peak cortisol levels on the
1-µg ACTH test were obtained after 30 min in 10/13 subjects and after
60 min in 3 (though these passed the cut-off point at 30 min). All
subjects reached peak levels at 60 min on the 250-µg test (all passed
the cut-off point at 30 min, 
542 nmol/L).
|
|
By definition, all patients of this group had satisfactory results
on IIH with peak cortisol levels equal to or greater than 520 nmol/L in
response to a blood glucose level lower than 2.2 mmol/L. Mean basal
cortisol level was 383 ± 38 nmol/L. The results of this group
were not significantly different from those of the control group (Fig. 1
). The kinetics of the 1-µg test (Fig. 2B) were also similar to
those of the control group with 11/20 patients showing a peak cortisol
response at 30 min. Two patients failed the low-dose test, achieving a
peak cortisol level of 356 and 435 nmol/L; on a repeated 1-µg test,
peak cortisol levels were 681 and 516 nmol/L, respectively. All
patients achieved a peak cortisol level of 579 nmol/L or more on the
250-µg test, though at 30 min, two patients had levels of only 451
and 355 nmol/L; 60-min levels for the latter were 579 and 769 nmol/L,
respectively. These patients attained levels of 689 and 856 nmol/L on
the 30-min 1-µg test. None of the patients in group 2 showed
secondary adrenal insufficiency during follow-up periods ranging from 3
months to 15.4 yr (median, 7.9 yr).
Patients with impaired HPA axis (group 3)
Mean basal cortisol level of group 3 (80 ± 24 nmol/L) was
much lower than that of both groups 1 and 2 [F(1, 85) = 37.5,
P < 0.0001]. Peak cortisol levels on IIH were lower
than 520 nmol/L in all (blood glucose <2.2 mmol/L, range 0.8–2.0
mmol/L). There were no significant differences between the peak
cortisol responses on IIH and either the 250-µg ACTH test or the
1-µg test (Fig. 1). The peak response of group 3 on IIH was
significantly lower than that of group 2 [F(1, 28) = 64.9,
P < 0.0001].
Because the peak cortisol responses on the ACTH tests were not
significantly different between groups 1 and 2, we combined them for
subsequent comparisons. Peak cortisol responses of group 3 to both ACTH
tests were significantly lower than the peak responses of groups 1 and
2 [F(1, 41) = 89.8, P < 0.0001, F(1, 41) = 44.2,
P < 0.0001, respectively]. All 10 patients (Fig. 2C)
peaked at 60 min on the 250-µg ACTH test; in 8/10 patients, the
60-min cortisol response on the 1-µg test was greater (5 patients) or
equal to the 30-min level. There was only 1 patient who failed the IIH
and passed both ACTH tests. In this patient, peak cortisol levels were
206 (IIH), 633 (1 µg), and 601 nmol/L (250 µg), and the lowest
plasma glucose level was 1.6 mmol/L (at 30 min on IIH). However, the
30-min cortisol level on the 250-µg test was only 487 nmol/L,
compared with 633 nmol/L at 30 min on the 1-µg test.
ACTH tests vs. IIH in groups 2 and 3
There were highly significant correlations between peak serum cortisol levels on IIH and on both the 1-µg (r = 0.70, P < 0.0001, n = 30) and the 250-µg ACTH tests (r = 0.71, P < 0.0001, n = 30). Mean peak cortisol levels attained on the 1-µg and 250-µg tests were similar to those attained on IIH (P = 0.63, P = 0.22, respectively). Both the 250- and 1-µg ACTH tests demonstrated high sensitivity (90%) and specificity (100% and 90%, respectively) compared with IIH. If we choose the 30-min 250-µg test as more indicative of HPA axis function (11, 12), then its sensitivity against IIH increases to 100%, and its specificity decreases to 90%.
|
Discussion |
|---|
|
TopAbstractIntroductionSubject and MethodsResultsDiscussionReferences |
|---|
The availability of a simple, reliable, bedside test for assessing HPA axis reactivity would greatly facilitate diagnosis of adrenal insufficiency. In this study, we evaluated the sensitivity of the short ACTH test compared to IIH, the gold standard for assessing the integrity of the HPA axis in MPHD patients. Discrepancies between these tests have been attributed to the original cut-off value for the peak cortisol response at 30 min after stimulation with 250 µg of ACTH and to the specific population under study (11, 12). False-positive results are more frequent when the pass values are lower (<550 nmol/L), and when the patients have recent or partial ACTH deprivation (9, 10, 13).
Early studies by Landon et al. (19) made it clear that the infusion of 4 µg/h of ACTH (ß 1–24 corticotropin) is sufficient for maximal stimulation of the adrenal cortex. Recently, Dickstein et al. (13) and Crowley et al. (14) reported that in healthy subjects, the standard 250-µg dose well exceeds the adrenal cortex dose-response curve, and that a dose as low as 0.5–1.0 µg can elicit the same maximal response at 20–30 min. Indeed, the low-dose 1-µg ACTH test proved even more efficient in detecting secondary adrenal insufficiency than the standard 250-µg test in patients receiving long-term systemic corticosteroid therapy (13), asthmatic patients receiving inhaled corticosteroids (16), and subjects with pituitary tumors evaluated some months following surgery (15).
Our results for the 1-µg and 250-µg ACTH tests are in accordance with those of Dickstein et al. (13): an identical cortisol response was noted at 30 min within each of the study groups. The rise in serum cortisol in response to the low dose was of shorter duration, as shown previously (13, 14, 15, 16), because of the more rapid clearance of the smaller dose of corticotropin. Cortisol levels of all the control subjects at 30 min were >540 nmol/L on the standard-dose test and >500 nmol/L on the 1-µg test, indicating that we might need to define a different pass level for each test.
The age at testing and the male/female ratio in the three subject
groups were different (Table 1), but because serum cortisol levels (20)
do not correlate with either age or gender and the low dose was
given/m2, we assume that those differences are irrelevant
to the results.
Previous studies evaluating the two short ACTH tests against IIH in adult patients with pituitary tumors (15, 17) or who were receiving long-term glucocorticoid therapy (17) showed better agreement between IIH and the 1-µg test than between IIH and the 250-µg test. In our group of patients with idiopathic MPHD, both the 1-µg and the 250-µg tests demonstrated a similar high sensitivity and specificity against the IIH in detecting secondary adrenal insufficiency. The similar sensitivities might be explained by the severity of the adrenal insufficiency, reflected in the very low basal and peak cortisol levels. By contrast, the basal cortisol levels of the patients with pituitary diseases and impaired HPA axis investigated by Tordjman et al. (15), were not different from those of controls, indicating only a partial ACTH deficiency. Our results are in line with the notion of Lindholm and Kehlet (11) and Clayton (12), that the standard 250-µg, 30-min ACTH test is reliable for assessing the integrated HPA axis function, except in cases of acute ACTH deprivation or partial mild secondary adrenal insufficiency. Two patients with an intact HPA axis on IIH had negative results on the 1 µg/1.73 m2 test, attaining 30-min cortisol levels of only 356 and 435 nmol/L, but positive results on repeated tests, with levels of 681 and 516 nmol/L, respectively. Dilution errors might explain these discrepant results, reminding us that no biochemical test is 100% reliable.
Because IIH simultaneously stimulates GH, ACTH, and cortisol secretion, the combination of another reliable but safe test for assessing GH reserve with the innocuous short ACTH test can replace IIH as the first screening tests for the integrity of both axes. For this purpose, the use of clonidine (8) with the short ACTH test is now under study.
In summary, we showed that the 30-min short ACTH test with either the low (1 µg/1.73 m2) or the standard dose (250 µg) is equivalent to IIH in detecting secondary adrenal insufficiency in MPHD patients. We suggest that the ACTH test replace IIH as the first screening test for the integrity of the HPA axis in infants or children with suspected idiopathic MPHD.
|
Acknowledgments |
|---|
Received June 9, 1997.
Revised August 11, 1997.
Accepted September 12, 1997.
|
References |
|---|
|
TopAbstractIntroductionSubject and MethodsResultsDiscussionReferences |
|---|
This article has been cited by other articles:
 |
|
 |
|
  T. Deutschbein, N. Unger, K. Mann, and S. Petersenn Diagnosis of secondary adrenal insufficiency in patients with hypothalamic-pituitary disease: comparison between serum and salivary cortisol during the high-dose short synacthen test Eur. J. Endocrinol., January 1, 2009; 160(1): 9 - 16. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. Kazlauskaite, A. T. Evans, C. V. Villabona, T. A. M. Abdu, B. Ambrosi, A. B. Atkinson, C. H. Choi, R. N. Clayton, C. H. Courtney, E. N. Gonc, et al. Corticotropin Tests for Hypothalamic-Pituitary- Adrenal Insufficiency: A Metaanalysis J. Clin. Endocrinol. Metab., November 1, 2008; 93(11): 4245 - 4253. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. S Abeyagunawardena, P. Hindmarsh, and R. S Trompeter Adrenocortical suppression increases the risk of relapse in nephrotic syndrome Arch. Dis. Child., July 1, 2007; 92(7): 585 - 588. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. A.R. Doi, I. Lasheen, K. Al-Humood, and K. A.S. Al-Shoumer Relationship between Cortisol Increment and Basal Cortisol: Implications for the Low-Dose Short Adrenocorticotropic Hormone Stimulation Test Clin. Chem., April 1, 2006; 52(4): 746 - 749. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. Abraham, J. Gottschalk, and F. R. Ungemach Evidence for Ototopical Glucocorticoid-Induced Decrease in Hypothalamic-Pituitary-Adrenal Axis Response and Liver Function Endocrinology, July 1, 2005; 146(7): 3163 - 3171. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M Maghnie, E Uga, F Temporini, N Di Iorgi, A Secco, C Tinelli, A Papalia, M. Casini, and S Loche Evaluation of adrenal function in patients with growth hormone deficiency and hypothalamic-pituitary disorders: comparison between insulin-induced hypoglycemia, low-dose ACTH, standard ACTH and CRH stimulation tests Eur. J. Endocrinol., May 1, 2005; 152(5): 735 - 741. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 E. F Kozyra, R. S Wax, and L. D Burry Can 1 {micro}g of Cosyntropin Be Used to Evaluate Adrenal Insufficiency in Critically Ill Patients? Ann. Pharmacother., April 1, 2005; 39(4): 691 - 698. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. C. Walvoord, M. B. Rosenman, and E. A. Eugster Prevalence of Adrenocorticotropin Deficiency in Children with Idiopathic Growth Hormone Deficiency J. Clin. Endocrinol. Metab., October 1, 2004; 89(10): 5030 - 5034. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. I. Dorin, C. R. Qualls, and L. M. Crapo Diagnosis of Adrenal Insufficiency Ann Intern Med, August 5, 2003; 139(3): 194 - 204. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Schmiegelow, U. Feldt-Rasmussen, A. K. Rasmussen, M. Lange, H. S. Poulsen, and J. Muller Assessment of the Hypothalamo-Pituitary-Adrenal Axis in Patients Treated with Radiotherapy and Chemotherapy for Childhood Brain Tumor J. Clin. Endocrinol. Metab., July 1, 2003; 88(7): 3149 - 3154. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. S. Dökmetas, R. Çolak, F. Kelestimur, A. Selçuklu, K. Ünlühizarci, and F. Bayram A Comparison between the 1-{micro}g Adrenocorticotropin (ACTH) Test, the Short ACTH (250 {micro}g) Test, and the Insulin Tolerance Test in the Assessment of Hypothalamo-Pituitary-Adrenal Axis Immediately after Pituitary Surgery J. Clin. Endocrinol. Metab., October 1, 2000; 85(10): 3713 - 3719. [Abstract] [Full Text]
|
|
|
|
|
|
E. Arvat, L. Di Vito, F. Lanfranco, M. Maccario, C. Baffoni, R. Rossetto, G. Aimaretti, F. Camanni, and E. Ghigo Stimulatory Effect of Adrenocorticotropin on Cortisol, Aldosterone, and Dehydroepiandrosterone Secretion in Normal Humans: Dose-Response Study J. Clin. Endocrinol. Metab., September 1, 2000; 85(9): 3141 - 3146. [Abstract] [Full Text]
|
|
|
|
|
|
E. J. Nye, J. E. Grice, G. I. Hockings, C. R. Strakosch, G. V. Crosbie, M. M. Walters, and R. V. Jackson Comparison of Adrenocorticotropin (ACTH) Stimulation Tests and Insulin Hypoglycemia in Normal Humans: Low Dose, Standard High Dose, and 8-Hour ACTH-(1-24) Infusion Tests J. Clin. Endocrinol. Metab., October 1, 1999; 84(10): 3648 - 3655. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. S. Krasner Glucocorticoid-Induced Adrenal Insufficiency JAMA, August 18, 1999; 282(7): 671 - 676. [Full Text] [PDF]
|
|
|
|
|
|
D. H. P. Streeten Editorial: Shortcomings in the Low-Dose (1 {micro}g) ACTH Test for the Diagnosis of ACTH Deficiency States J. Clin. Endocrinol. Metab., March 1, 1999; 84(3): 835 - 837. [Full Text]
|
|
|
|
|
|
T. A. M. Abdu, T. A. Elhadd, R. Neary, and R. N. Clayton Comparison of the Low Dose Short Synacthen Test (1 {micro}g), the Conventional Dose Short Synacthen Test (250 {micro}g), and the Insulin Tolerance Test for Assessment of the Hypothalamo-Pituitary-Adrenal Axis in Patients with Pituitary Disease J. Clin. Endocrinol. Metab., March 1, 1999; 84(3): 838 - 843. [Abstract] [Full Text]
|
|
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Endocrinology | Endocrine Reviews | J. Clin. End. & Metab. |
| Molecular Endocrinology | Recent Prog. Horm. Res. | All Endocrine Journals |
