Performance of glucagon stimulation test in diagnosing central adrenal insufficiency in children when utilising the Roche Elecsys® cortisol II assay: a pilot study

OBJECTIVES

The glucagon stimulation test (GST) is used for the simultaneous assessment of central adrenal insufficiency (CAI) and growth hormone deficiency. The new Roche cortisol II (C II) assay was recently introduced, confounding interpretation of the GST. The performance of the GST in diagnosing central adrenal insufficiency (CAI), utilising the C II assay, was therefore compared with that of the overnight metyrapone test (ONMTPT).

METHODS

A diagnostic accuracy study was performed by retrospectively analysing folders and laboratory records of 25 children and adolescents investigated for hypopituitarism with the GST and the ONMTPT between September 2016 and December 2019. The peak serum cortisol (C) of the GST, the post-metyrapone serum 11-deoxycortisol and adrenocorticotropin levels of the ONMTPT were recorded. Diagnostic performance of the GST at a previously suggested cut-off of 374 nmol/L was evaluated.

RESULTS

Seventeen boys and 8 girls, aged 1.7-16.3 years (median 7.3 years) were identified. The sensitivity of the post-GST C-level at 374 nmol/L was 0.40 (95% confidence interval [CI] 0.17-0.69), specificity 0.64 (95% CI 0.39-0.84), positive predictive value 0.44 (95% CI 0.19-0.73), negative predictive value 0.60 (95% CI 0.36-0.80), accuracy 0.54 (95% CI 0.35-0.72), positive likelihood ratio (+LR) 0.93 (95% CI 0.49-1.77) and negative LR 1.12 (95% CI 0.40-3.15). The area under the receiver of operating characteristics (ROC) curve was 0.379 (95% CI 0.142-0.615).

CONCLUSIONS

This study suggests that the GST at any C II cut-off cannot replace the ONMTPT as a diagnostic test for CAI in children. Findings should be confirmed in a larger study.

Hypothalamic-pituitary-adrenal axis suppression in asthma: A glucocorticoid receptor polymorphism may protect

BACKGROUND

Asthmatic children on corticosteroids can develop hypothalamic-pituitary-adrenal axis suppression (HPAS). Single nucleotide polymorphisms (SNPs) rs242941 and rs1876828 of the corticotrophin-releasing hormone receptor 1 (CRHR1) gene were associated with lower stimulated cortisol (F) levels, whereas rs41423247 of the glucocorticoid receptor (NR3C1) gene was associated with higher basal F levels. The objective of the current study was to confirm whether these three SNPs are associated with HPAS in asthmatic children.

METHODS

DNA was extracted from saliva obtained from 95 asthmatic children, who had previously undergone basal F and metyrapone testing. Thirty-six children were classified as suppressed. Non-suppressed children were subclassified according to their post-metyrapone adrenocorticotropin (PMTP ACTH) level into a middle (106-319 pg/mL) and a high (>319 pg/mL) ACTH response group. TaqMan^® polymerase chain reaction assays were utilized.

RESULTS

Only rs41423247 was inversely associated with HPAS (OR = 0.27 [95% CI 0.06-0.90]). Its GC genotype was inversely associated with HPAS (log odds = -1.28, P = .021). √PMTP ACTH was associated with CC (effect size = 10.85, P = .005) and GC genotypes (effect size = 4.06, P = .023). The C allele is inherited as a dominant trait (effect size = -1.31 (95% CI -2.39--0.33; P = .012). In the high ACTH response group, both genotypes affected the PMTP ACTH (effect sizes 1.41 and 15.46; P-values .023 and <2 × 10^-26 for GC and CC, respectively).

CONCLUSIONS

The C allele of rs41423247 was found to be protective against HPAS. CC genotype is associated with the highest PMTP ACTH response.

[Clinical features and diagnosis of secondary adrenal insufficiency followed complex treatment nonpituitary brain tumors]

BACKGROUND

The most of the current studies include patients who are different by the etiology of secondary adrenal insufficiency (SAI), or investigate SAI among other late effects of the radiation therapy.

AIMS

To describe the features of SAI and to select the best method of screening SAI in adult patients followed complex treatment of nonpituitary brain tumors in childhood.

MATERIALS AND METHODS

It was the retrospective cross-sectional study. 31 patients after the complex treatment of nonpituitary brain tumors in childhood and 20 healthy volunteers were examined. Age and sex ratio were comparable between the groups. Biochemical and clinical blood tests, levels of cortisol, ACTH, DHEA-C were evaluated. The insulin tolerance test (ITT) was performed for all patients and 11 volunteers.

RESULTS

The prevalence of SAI by ITT was 45.2%. The levels of basal cortisol (BC) were significantly higher in patients without SAI in comparison with the SAI group and volunteers (505 [340; 650] vs 323 [233; 382] and 372 [263; 489] nmol / l; pSAI- without_SAI=0.001; pwihtout_SAI-healthy = 0.04). The SAI group had DHEA-C significantly lower than in other groups one (3.1 [1.8; 3.4] vs 5.1 [2.5; 6.4] and 6.8 [4.1; 8.9]; рSAI- without_SAI = 0.036; pSAI-healthy = 0.001). ROC analysis showed that BC and DHEA-S can be used as high-quality screening tests for SAI (AUC = 89.3% and 88.3%). The maximum level of cortisol (656 [608-686] vs 634 [548-677]; p = 1) and the time of its increase (45 and 60 min) did not differ during ITT in patients without SAI and volunteers. Side effects: delayed hypoglycemia occurred in 4/14 patients of the SAI group 4090 minutes late of injection 60-80 ml of 40% glucose solution for stopping hypoglycemia in the test.

CONCLUSIONS

45.2% of patients followed craniospinal irradiation had SAI that is characterized by a decrease in DHEA-C levels. A highly normal level of basal cortisol was observed in 45% of patients without SAI. DHEA-C and blood cortisol can be used for SAI screening.

International survey on high- and low-dose synacthen test and assessment of accuracy in preparing low-dose synacthen

OBJECTIVE

The short synacthen test (SST) is widely used to assess patients for adrenal insufficiency, but the frequency and protocols used across different centres for the low-dose test (LDT) are unknown. This study aimed to survey centres and test the accuracy of ten different synacthen preparation strategies used for the LDT.

METHODS

Members of 6 international endocrine societies were surveyed regarding diagnostic tests used for adrenal insufficiency, and in particular the SST. Synacthen was diluted for the LDT and concentrations measured using a synacthen ELISA.

RESULTS

Survey responses were received from 766 individuals across 60 countries (52% adult, 45% paediatric endocrinologists). The SST is used by 98% of centres: 92% using high-dose (250 μg), 43% low-dose and 37% both. Ten low-dose dilution methods were assessed and variation in synacthen concentration was demonstrated with intramethod coefficients of variation (CV) ranging from 2.1% to 109%. The method using 5% dextrose as a diluent was the least variable (CV of 2.1%). The variation in dilution methods means that the dose of synacthen administered in a LDT may vary between 0.16 and 0.81 μg.

CONCLUSIONS

The high-dose SST is the most popular diagnostic test of adrenal insufficiency, but up to 72% of paediatric endocrinologists use a LDT. There is considerable variation observed both within and between low-dose synacthen dilution methods creating considerable risk of inaccurate dosing and thereby invalid results.