The intramuscular glucagon stimulation test does not provide good discrimination between normal and inadequate ACTH reserve when used in the investigation of short healthy children

Reliability of Agreement between Insulin, Clonidine, and Glucagon Stimulation Tests for the Diagnosis of Growth Hormone Deficiency in Children: A Retrospective Cohort Study

Growth hormone (GH) deficiency (GHD) is a rare disorder. The diagnosis of GHD requires a combination of two provocative GH tests. This study aimed to find agreement between commonly used medications to determine which combined tests have high reliability of agreement. This retrospective cohort included 201 children who underwent GH provocation testing from January 2012 to December 2022. The insulin tolerance test (ITT) with the clonidine stimulation test (CST) or glucagon stimulation test (GST) with the CST were performed. We calculated Cohen's kappa to determine the agreement between the test medications by considering the post-stimulation peak GH level with a cut-off value of 10 ng/mL as the primary outcome. A total of 151 patients underwent the two provocative tests and were included in the analysis. Of these patients, 119 underwent the ITT and CST and 54 (45.3%) were diagnosed with GHD. However, 32 patients underwent the GST and CST and 18 (56.2%) were diagnosed with GHD. The kappa value for ITT and CST was 0.258 (25.8%), indicating fair agreement between clonidine and insulin (p = 0.005). However, the kappa value for CST and GST was 0.178 (17.8%), representing slight agreement. The correlation coefficient revealed a very strong relationship between ITT and CST. Clonidine has fair agreement and a very strong correlation coefficient with ITT when used to diagnose GHD in children. Among the commonly used pharmacological tests for GH provocation in our unit, the CST was considered the best pharmacological test in terms of safety and reduced parental anxiety.

Current Screening Strategies for the Diagnosis of Adrenal Insufficiency in Children

Adrenal insufficiency can arise from a primary adrenal disorder, secondary to adrenocorticotropic hormone deficiency, or by suppression of hypothalamic-pituitary-adrenal axis due to exogenous glucocorticoids. Diagnosis of adrenal insufficiency is usually delayed because the initial presentation is often subtle and nonspecific. Clinician awareness and recognition is crucial for timely diagnosis to avoid adrenal crisis. Current screening strategies for the diagnosis of adrenal insufficiency in children in various clinical situations are discussed in this review.

Is the fear from insulin tolerance test in the evaluation of short stature justified?

Among growth hormone (GH) provocative tests, insulin tolerance test (ITT) is considered a valuable test in children with short stature to diagnose GH deficiency. However, many pediatric endocrinologists are reluctant to perform it. We conducted a nationwide survey among all the pediatric endocrine clinics' heads in Israel regarding their position on this issue. We found that the number of endocrine units performing ITT is almost nil. Sense of fear from severe hypoglycemia was a dominating cause for not performing ITT. We review the pros and cons of performing ITT versus other tests, especially glucagon test. Glucagon tolerance test is not considered the test of choice by some endocrinologists but recommended by others including in Israel. We also note the influence of a widely cited report published in 1992 (many times inaccurately) on endocrinologists' views.

CONCLUSION

A nationwide survey in Israel revealed a high rate of reluctance to perform ITT. The rationale behind this attitude was a sense of fear of performing the test by many endocrinologists. We discuss the preferences for choosing GH stimulation tests and the pros and cons of alternatives to ITT. The fear of not performing ITT was not always justified.

WHAT IS KNOWN

• ITT test is considered a gold standard in the evaluation of short stature to diagnose GH deficiency by many endocrinologists.

WHAT IS NEW

• High reluctance rate found in Israel to perform ITT, prompted us to evaluate the attitudes of pediatric endocrinologists around the world showing conflicting ideas. • The role of a single paper sometimes misquoted also contributed to these conflicting results.

Approach to the Patient: Management of Pituitary Hormone Replacement Through Transition

Hypopituitarism in childhood is a rare, complex disorder that can present with highly variable phenotypes, which may continue into adult life. Pituitary deficits can evolve over time, with unpredictable patterns resulting in significant morbidity and mortality. Hypopituitarism and hypothalamic dysfunction may be associated with challenging comorbidities such as obesity, learning difficulties, behavioral issues, sleep disturbance, and visual impairment. Transition is the purposeful planned movement of adolescents and young adults with chronic conditions from child-centered to adult-oriented health care systems with a shift from parent- to patient-focused care. To achieve effective transition within a health care setting, the inherent challenges involved in the evolution from a dependent child to an independent adult must be recognized. Transition is a critical time medically for patients with hypopituitarism. Complex issues with respect to puberty, attainment of optimal stature, adherence to treatment, and acceptance of the need for life-sustaining medications need to be addressed. For health care professionals, transition is an opportunity for reassessment of the pituitary deficits and the need for lifelong replacement therapies, often against a background of complex psychological issues. We present 4 illustrative cases of hypopituitarism of differing etiologies with diverse clinical presentations. Diagnostic and management processes from clinical presentation to young adulthood are discussed, with a particular focus on needs and outcomes through transition.

Baseline and peak cortisol response to the low dose short Synacthen test relates to indication for testing, age and sex

Objective

To review the outcomes of a simplified low dose Synacthen test (LDSST) performed in a tertiary endocrine service over seven years, and to examine for relationships between cortisol measurements and indication for testing, age and sex.

Design

Retrospective, observational study of LDSST performed in 2008 – 2014 (N=335) and 2016-2020 (N=160).

Methods

LDSST were performed by endocrine nurses. Synacthen 500ng/1.73m 2 administered as IV bolus, sampling at 0, 15, 25 and 35 minutes.

Results

Mean (± 1SD) baseline cortisol was 221 ± 120 nmol/L, peak 510 ± 166nmol/L and increment 210 ± 116 nmol/L. 336 (70%) of patients had a normal response (baseline cortisol >100nmol/L, peak >450nmol/L), 78 (16%) a suboptimal response (peak cortisol 350-450nmol/L) and were prescribed hydrocortisone to during periods of stress only, 67 (14%) an abnormal response (baseline <100nmol/L or peak <350nmol/L) and were prescribed daily hydrocortisone. Basal, peak and incremental increases in cortisol were higher in females (p=0.03, p<0.001, p=0.03 respectively). Abnormal results occurred most frequently in patients treated previously with pharmacological doses of glucocorticoids or structural brain abnormalities (p<0.0001).

Discussion

There are concerns that the specificity of the LDSST is poor. The low prevalence and strong association of abnormal results with indication for testing, suggests that over diagnosis occurred infrequently in this clinical setting.

Safety assessment and potential risks of the glucagon stimulation test in the diagnosis of secondary adrenal insufficiency

BACKGROUND

Although it takes more time, the glucagon stimulation test (GST) is a reliable measure for assessing growth hormone (GH) and adrenocorticotropic hormone (ACTH) secretion. The GST is considered to be a safe test, however, it still has mild side effects and potential risks.

OBJECTIVE

The objective of this study was to analyze the side effects of the GST while testing adrenal insufficient patients.

METHODS

This was a prospective study in which GST was performed in eighty-one patients (44 men, 37 women, mean age: 35.83±19.62 years) with pituitary disorder. The GST consisted in an intramuscular injection of 1 mg of glucagon. Blood samples were collected at baseline, and 30, 60, 90, 120, 150, 180 and 210 min after glucagon injection for cortisol measurements. All patients were asked to report side-effects associated with this test.

RESULTS

The mean peak blood glucose level under GST was 9.01±2.03 mmol/L and the mean glycemic nadir was 4.34±1.75 mmol/L was found most frequently during the 30th minute (p <10-3). During the test, 35 subjects (43.2%) had side effects with a mean age of 42.89 ± 19.75 years. Frequent side effects included: nausea (29.62%), vomiting (27.16%), abdominal cramps (18.51%) and hunger (13.58%). All patients tolerated the test until the end. Adverse effects were significantly more prevalent in patients older than 50 years (p=0.012).

CONCLUSIONS

The GST is a reliable alternative to assess hypothalamic pituitary adrenal axis but should be cautiously used especially in the elderly although its minor side effects.

[The glucagon test in diagnosis of secondary adrenal insufficiency after craniospinal irradiation: the feasibility of application, the features of performing the test, and its diagnostic informativity]

BACKGROUND

The glucagon test (GT) is a promising alternative to the insulin hypoglycemia test (IHT) in diagnosis of secondary adrenal insufficiency (SAI).

AIM

To study the feasibility of using the GT in patients after craniospinal irradiation and to determine the cut-off value to rule out SAI.

METHODS

A total of 28 patients (14 males and 14 females) with the median age of 19 years (17; 23) who had undergone combination treatment (surgery, craniospinal irradiation (35 Gy) with boost to the tumor bed, and polychemotherapy) of extrapituitary brain tumors no later than 2 years before study initiation and 10 healthy volunteers of matching sex and age were examined. All the subjects underwent the GT and IHT with an interval of at least 57 days. The cortisol, ACTH, and glucose levels were measured.

RESULTS

Twelve out of 28 patients were diagnosed with SAI according to the IHT results. ROC analysis revealed that cortisol release during the GT 499 nmol/L ruled out SAI [100% sensitivity (Se); 62% specificity (Sp)], while the absence of a rise 340 nmol/l verified SAI (Sp 100%; 55% Se). For GT, the area under a curve (AUC) was 93.6%, which corresponds to a very good diagnostic informativity. In 19 patients, the IHT and GT results were concordant (in ten patients, the release of cortisol occurred above the cut-off value in both tests; no release was detected in nine patients). In nine cases, the results were discordant: the maximum cortisol level detected in the GT was 500 nmol/l, but the IHT results ruled out SAI (the GT yielded a false positive outcome). Contrariwise, in three (10.7%) patients the release of cortisol detected in the GT was adequate, while being insufficient in the IHT test. Adverse events (nausea) were reported during the GT test in 9 (25%) subjects; one patient had hypoglycemia (1.8 mmol/l).

CONCLUSION

GT is highly informative and can be used as a first-level stimulation test for ruling out SAI in patients exposed to craniospinal irradiation performed to manage brain tumors. The cortisol level of 500 nmol/L is the best cut-off value for ruling out SAI according to the GT results. The insulin hypoglycemia test is used as the second-level supporting test in patients with positive GT results.

Cortisol Levels in Glucagon Stimulation Test in Children Assessed for Short Stature: Clinical and Laboratorial Correlations

To assess total cortisol levels in children being evaluating for short stature with normal cortisol reserve and to correlate this response to clinical and laboratory data. Children assessed with glucagon test in our department were recruited in this study retrospectively. Inclusion criteria were: i) age>1 year, ii) absence of chronic illness or medication interfering with ACTH-cortisol axis, iii) GH stimulation levels>3ng/mL at least in one provocation test (glucagon or clonidine), iv) absence of multiple pituitary growth hormone deficiencies, v) normal short Synacthen test in cases of low cortisol response in glucagon test.Two hundred and thirty-seven subjects (160 males, 67.5%) with a mean age of 9.02±3.19 years, were finally included in the analysis. Cortisol peak levels but not cortisol AUC were significantly increased in females compared to males (26.83±7.31 μg/dl vs. 24.04±7.20 μg/dl). When linear correlations were studied, both cortisol peak levels and cortisol AUC were linearly but inversely correlated to age (r=-0.234, p<0.001 and r=-0.315, p<0.001, respectively). Finally, cortisol AUC was inversely correlated to weight Z-scores (r=-0.160, p=0.014). When our analysis was limited only to subjects with intact GH response (GH peak> 7 ng/mL), age was still inversely correlated to cortisol AUC (r=-0.312, p<0.001), and cortisol AUC was linearly correlated to GH AUC assessed with clonidine test (r=0.223, p=0.013). Girls, younger and thinner children exhibit higher cortisol response to glucagon test.

Pediatric Adrenal Insufficiency: Diagnosis, Management, and New Therapies

Adrenal insufficiency may result from a wide variety of congenital or acquired disorders of hypothalamus, pituitary, or adrenal cortex. Destruction or dysfunction of the adrenal cortex is the cause of primary adrenal insufficiency, while secondary adrenal insufficiency is a result of pituitary or hypothalamic disease. Timely diagnosis and clinical management of adrenal insufficiency are critical to prevent morbidity and mortality. This review summarizes the etiologies, presentation, and diagnosis of adrenal insufficiency utilizing different dynamic hormone testing and describes current treatment recommendations and new therapies.

SERUM FREE CORTISOL DURING GLUCAGON STIMULATION TEST IN HEALTHY SHORT-STATURED CHILDREN AND ADOLESCENTS

OBJECTIVE

The total cortisol (TC) response may be measured during the glucagon stimulation test (GST) for growth hormone (GH) reserve in order to assess the integrity of the hypothalamic-pituitary-adrenal (HPA) axis. Measurements of TC are unreliable in conditions of albumin and cortisol-binding globulin (CBG) alterations (e.g., hypoproteinemia or CBG deficiency). We aimed to measure the serum free cortisol (sFC) response to the GST in children and adolescents and determine whether it could predict the GH response to glucagon stimulation.

METHODS

Infants and children with either short stature or growth attenuation who were referred for evaluation of GH reserve underwent the GST.

RESULTS

The study population consisted of 103 subjects (62 females), median age 3.9 years (range, 0.5-14). The mean basal and peak TC levels were 13.3 ± 6.7 μg/dL and 29.6 ± 8.8 μg/dL, respectively. The mean basal and peak sFC levels were 0.7 ± 0.8 μg/dL and 1.7 ± 1.1 μg/dL, respectively. There was a negative correlation between peak TC and age ( r = -0.3, P = .007) but not between peak sFC and age ( r = -0.09, P = .36). Ninety-five percent of the patients had peak TC levels >15.8 μg/dL and peak sFC levels >0.6 μg/dL.

CONCLUSION

Our results on a cohort of healthy short-statured children can serve as reference values for the sFC response during GST. Based on these results, we propose peak TC levels >15.8 μg/dL and peak sFC levels >0.6 μg/dL for defining normalcy of the HPA axis during the GST in children and adolescents.

ABBREVIATIONS

ACTH = adrenocorticotrophic hormone BMI = body mass index CBG = cortisol-binding globulin GH = growth hormone GST = glucagon stimulation test HPA = hypothalamic-pituitary-adrenal SDS = standard deviation score sFC = serum free cortisol TC = total cortisol.

The diagnosis and treatment of adrenal insufficiency during childhood and adolescence

The diagnosis and treatment of adrenal insufficiency in childhood and adolescence poses a number of challenges. Clinical features of chronic adrenal insufficiency are vague and non-specific, and mimic many other causes of chronic ill health. A range of diagnostic tests are available for the assessment of adrenal function, all of which have advantages and disadvantages. Cortisol responses to these tests may vary with age and between genders. Knowledge of normal cortisol levels during health and ill health in childhood is also limited, and the cortisol replacement therapies available in clinical practice enable only crude mimicry of physiological patterns of cortisol secretion. An awareness of the limitations of diagnostic tests and treatments is important, and critical clinical assessment, integrating clinical and biochemical data, is essential for the diagnosis and treatment of children with suspected adrenal insufficiency. The aim of this review is to draw on data from clinical studies to inform a pragmatic approach to the child presenting with symptoms of chronic adrenal insufficiency. Clinical features of primary and secondary adrenal insufficiency, and syndromes associated with these diagnoses are described. Factors to consider when selecting a diagnostic test of adrenal function and interpretation of test results are considered. Finally, the limitations of cortisol replacement therapy are also discussed.