Prolonged hypocortisolemia in hydrocortisone replacement regimens in adrenocorticotrophic hormone deficiency

Interpretation of Steroid Biomarkers in 21-Hydroxylase Deficiency and Their Use in Disease Management

The most common form of congenital adrenal hyperplasia is 21-hydroxylase deficiency (21OHD), which in the classic (severe) form occurs in roughly 1:16 000 newborns worldwide. Lifelong treatment consists of replacing cortisol and aldosterone deficiencies, and supraphysiological dosing schedules are typically employed to simultaneously attenuate production of adrenal-derived androgens. Glucocorticoid titration in 21OHD is challenging as it must balance the consequences of androgen excess vs those from chronic high glucocorticoid exposure, which are further complicated by interindividual variability in cortisol kinetics and glucocorticoid sensitivity. Clinical assessment and biochemical parameters are both used to guide therapy, but the specific purpose and goals of each biomarker vary with age and clinical context. Here we review the approach to medication titration for children and adults with classic 21OHD, with an emphasis on how to interpret adrenal biomarker values in guiding this process. In parallel, we illustrate how an understanding of the pathophysiologic and pharmacologic principles can be used to avoid and to correct complications of this disease and consequences of its management using existing treatment options.

A Prospective Study of Children Aged 0-8 Years with CAH and Adrenal Insufficiency Treated with Hydrocortisone Granules

CONTEXT

Children with congenital adrenal hyperplasia (CAH) and adrenal insufficiency (AI) require daily hydrocortisone replacement with accurate dosing.

OBJECTIVE

Prospective study of efficacy and safety of hydrocortisone granules in children with AI and CAH monitored by 17-OHP (17-hydroxyprogesterone) saliva profiles.

METHODS

Seventeen children with CAH (9 male) and 1 with hypopituitarism (male), aged from birth to 6 years, had their hydrocortisone medication changed from pharmacy compounded capsules to hydrocortisone granules. Patients were followed prospectively for 2 years. In children with CAH, the therapy was adjusted by 17-OHP salivary profiles every 3 months. The following parameters were recorded: hydrocortisone dose, height, weight, pubertal status, adverse events, and incidence of adrenal crisis.

RESULTS

The study medication was given thrice daily, and the median duration of treatment (range) was 795 (1-872) days, with 150 follow-up visits. Hydrocortisone doses were changed on 40/150 visits, with 32 based on salivary measurements and 8 on serum 17-OHP levels. The median daily mg/m2 hydrocortisone dose (range) at study entry for the different age groups 2-8 years, 1 month to 2 years, <28 days was 11.9 (7.2-15.5), 9.9 (8.6-12.2), and 12.0 (11.1-29.5), respectively, and at end of the study was 10.2 (7.0-14.4), 9.8 (8.9-13.1), and 8.6 (8.2-13.7), respectively. There were no trends for accelerated or reduced growth. No adrenal crises were observed despite 193 treatment-emergent adverse events, which were mainly common childhood illnesses.

INTERPRETATION

This first prospective study of glucocorticoid treatment in children with AI and CAH demonstrates that accurate dosing and monitoring from birth results in hydrocortisone doses at the lower end of the recommended dose range and normal growth, without occurrence of adrenal crises.

An integrated PK-PD model for cortisol and the 17-hydroxyprogesterone and androstenedione biomarkers in children with congenital adrenal hyperplasia

Aims

The aim of this study was to characterize the pharmacokinetic/pharmacodynamic relationships of cortisol and the adrenal biomarkers 17‐hydroxyprogesterone and androstenedione in children with congenital adrenal hyperplasia (CAH).

Methods

A nonlinear mixed‐effect modelling approach was used to analyse cortisol, 17‐hydroxyprogesterone and androstenedione concentrations obtained over 6 hours from children with CAH (n = 50). A circadian rhythm was evident and the model leveraged literature information on circadian rhythm in untreated children with CAH. Indirect response models were applied in which cortisol inhibited the production rate of all three compounds using an I_max model.

Results

Cortisol was characterized by a one‐compartment model with apparent clearance and volume of distribution estimated at 22.9 L/h/70 kg and 41.1 L/70 kg, respectively. The IC₅₀ values of cortisol concentrations for cortisol, 17‐hydroxyprogesterone and androstenedione were estimated to be 1.36, 0.45 and 0.75 μg/dL, respectively. The inhibitory effect was found to be more potent on 17OHP than D4A, and the IC₅₀ values were higher in salt‐wasting subjects than simple virilizers. Production rates of cortisol, 17‐hydroxyprogesterone and androstenedione were higher in simple‐virilizer subjects. Half‐lives of cortisol, 17‐hydroxyprogesterone and androstenedione were 60, 47 and 77 minutes, respectively.

Conclusion

Rapidly changing biomarker responses to cortisol concentrations highlight that single measurements provide volatile information about a child's disease control. Our model closely captured observed cortisol, 17‐hydroxyprogesterone and androstenedione concentrations. It can be used to predict concentrations over 24 hours and allows many novel exposure metrics to be calculated, e.g., AUC, AUC‐above‐threshold, time‐within‐range, etc. Our long‐range goal is to uncover dose–exposure–outcome relationships that clinicians can use in adjusting hydrocortisone dose and timing.

Pharmacokinetic/Pharmacodynamic Evaluation of Hydrocortisone Therapy in Pediatric Patients with Congenital Adrenal Hyperplasia

OBJECTIVES

Patients with congenital adrenal hyperplasia (CAH) require lifelong replacement therapy with glucocorticoids. Optimizing hydrocortisone therapy is challenging, since there are no established cortisol concentration targets other than the cortisol circadian rhythm profile. 17-hydroxyprogesterone (17-OHP) concentrations are elevated in these patients and commonly used to monitor therapy. This study aimed to characterize the pharmacokinetics/pharmacodynamics (PK/PD) of cortisol using 17-OHP as a biomarker in pediatric patients with CAH and to assess different hydrocortisone dosing regimens.

METHODS

Cortisol and 17-OHP concentrations from 30 CAH patients (7-17 years of age) receiving standard hydrocortisone replacement therapy (5-20 mg) twice (n = 17) or 3 times (n = 13) daily were used to develop a PK/PD model. Sequentially, simulated cortisol concentrations for clinically relevant 3- and 4-times daily dosing regimens were compared with cortisol and 17-OHP target ranges and to concentrations in healthy children.

RESULTS

Cortisol concentration-time profiles were accurately described by a 2-compartment model with first-order absorption and expected high bioavailability (82.6%). A time-delayed model with cortisol-mediated inhibition of 17-OHP synthesis accurately described 17-OHP concentrations. The cortisol concentration inhibiting 50% of 17-OHP synthesis was 48.6 nmol/L. A 4-times-daily dosing better attained the target ranges and mimicked the cortisol concentrations throughout the 24-hour period than 3-times-daily.

CONCLUSIONS

A PK/PD model following hydrocortisone administration has been established. An improved dosing regimen of 38% at 06:00, 22% at 12:00, 17% at 18:00, and 22% at 24:00 of the daily hydrocortisone dose was suggested. The 4-times-daily dosing regimen was superior, avoiding subtherapeutic cortisol concentrations and better resembling the circadian rhythm of cortisol.

The Challenges of Cortisol Replacement Therapy in Childhood: Observations from a Case Series of Children Treated with Modified-Release Hydrocortisone

BACKGROUND

Hydrocortisone is the preferred treatment for adrenal insufficiency in childhood. A small minority of children experience low cortisol concentrations and symptoms of cortisol insufficiency, poorly responsive to modifications in dosing. We speculated that treatment with modified-release hydrocortisone Plenadren^® may be beneficial in these selected patients.

OBJECTIVE

The aim of this article was to report cortisol profiles during treatment with standard formulation hydrocortisone and Plenadren, and growth and weight gain during treatment with Plenadren in selected children with adrenal insufficiency.

PATIENTS AND METHODS

Data are reported as median (range). Eight patients (5 male) age 11.0 years (8.8-13.3), with adrenal insufficiency for 4.3 years (2.2-10.0) were treated with Plenadren in doses derived from cortisol concentrations measured during treatment with standard formulation hydrocortisone.

RESULTS

Plasma cortisol was 262 nmol/L (114-654) 2 h after the morning dose (hydrocortisone dose 6.1 mg/m² [4.3-7.1]) of standard formulation hydrocortisone. After 4 h, cortisol concentration was 81 nmol/L (56-104) and was < 100 nmol/L in six patients. Two hours after Plenadren administration (hydrocortisone dose 12.1 mg/m² [8.3-17.6]), plasma cortisol concentration was 349 nmol/L (150-466), and after 4 h it was 239 nmol/L (99-375) and < 100 nmol/L in one patient. Six hours after the Plenadren dose, cortisol concentration was < 100 nmol/L in four patients and after 8 h cortisol concentration was < 100 nmol/L in seven patients (sample not obtained in one patient). Six patients elected to continue treatment with Plenadren. After 4.2 years (2.7-6.0), change in height standard deviation score (SDS) was 0.1 SD (- 0.2 to 0.2) and body mass index SDS was 0.3 SD (0-1.1).

CONCLUSION

Smoother cortisol profiles and more sustained cortisol exposure were achieved during treatment with Plenadren, which was the preferred treatment in most patients. Robust clinical trials are required to determine the place of this medication in paediatric practice.

Primary adrenal insufficiency in children: Diagnosis and management

Primary adrenal insufficiency (PAI) is a life-threatening disorder of adrenal cortex which is characterized by deficient biosynthesis of glucocorticoids, with or without deficiency in mineralocorticoids and adrenal androgens. Typical manifestations of primary adrenal insufficiency include hyperpigmentation, hypotension, hypoglycaemia, hyponatremia with or without hyperkalemia that are generally preceded by nonspecific symptoms at the onset. Recessively inherited monogenic disorders constitute the largest group of primary adrenal insufficiency in children. The diagnostic process of primary adrenal insufficiency includes demonstration of low cortisol concentrations along with high plasma ACTH and identifying the cause of the disorder. Specific molecular diagnosis is achieved in more than 80% of children with PAI by detailed clinical and biochemical characterization integrated with advanced molecular tools. Hormone replacement therapy determined on the type and the severity of deficient adrenocortical hormones is the mainstay of treatment. Optimized methods of steroid hormone delivery, improved monitoring of hormone replacement along with intensive education of patients and families on the rules during intercurrent illness and stress will significantly reduce the morbidity and mortality associated with primary adrenal insufficiency.

Immediate-release granule formulation of hydrocortisone, Alkindi®, for treatment of paediatric adrenal insufficiency (Infacort development programme)

Treatment of paediatric patients with adrenal insufficiency is challenging due to the lack of appropriate glucocorticoid preparations for children, and the use of either pharmacy- or parent-compounded hydrocortisone tablets. Alkindi (hydrocortisone granules in capsules for opening) is a new therapeutic option for paediatric adrenal insufficiency. Areas Covered: Drawbacks of current therapy and formulation and clinical trial programme for Alkindi. Expert Commentary: Compounding hydrocortisone has multiple issues including inconsistent dosing with under and over treatment and practical problems for parents who compound the drug themselves or travel long distances to a compounding pharmacy and the cost of compounding by the pharmacy. Alkindi® is a novel paediatric formulation of immediate release hydrocortisone licensed for use in paediatric adrenal insufficiency. Alkindi® is formulated to address the needs of neonates, infants and young children, being available at appropriate paediatric doses of 0.5, 1.0, 2.0 and 5.0 mg, is multiparticulate, allowing either direct oral dosing or dosing mixed with food, is taste masked to obscure the bitter taste of hydrocortisone and is bioequivalent to current hydrocortisone preparations. Clinical trials in young children with adrenal insufficiency demonstrated cortisol levels after dosing similar to those seen in healthy children and the drug was well tolerated and favoured over current therapy by parents. Alkindi® will provide a licenced treatment option for accurate dosing in children with adrenal insufficiency where compounded adult tablets of hydrocortisone are unsuitable.

Absorption and tolerability of taste-masked hydrocortisone granules in neonates, infants and children under 6 years of age with adrenal insufficiency

OBJECTIVES

There is no licensed, dose-appropriate formulation of hydrocortisone for children with adrenal insufficiency (AI) and patients rely on compounded adult medication. The aim of this study was to evaluate the absorption, palatability and safety of Infacort^® , an immediate-release, granule formulation of hydrocortisone with taste masking.

STUDY DESIGN

Single site with satellites attended by a "flying" doctor from investigator site. Open-label, single-dose study in three consecutive child cohorts (n = 24) with AI; Cohort 1, children aged 2 to <6 years (n = 12); Cohort 2, infants aged 28 days to <2 years (n = 6); Cohort 3, neonates aged 1 to <28 days (n = 6).

METHODS

Fasted children were given a single dose of Infacort^® as dry granules administered directly from a capsule or spoon followed by a drink. The primary end-point was the maximum serum cortisol concentration up to 240 minutes after Infacort^® administration. Secondary end-points were palatability and adverse events (AEs).

RESULTS

All children showed an increase in cortisol above baseline after Infacort^® (P < .0001), with geometric mean ± SD cortisol concentration at 60 minutes of 575.8 ± 299.5 nmol L^-1 . There was no failure in administration of Infacort^® , and 95.5% of parents/carers preferred Infacort^® to their child's current medication. In 7 children who completed the palatability questionnaire, 80% of responses were very good or neutral, and 20% were adverse. No serious or severe treatment-emergent AEs were reported.

CONCLUSIONS

Infacort^® is well tolerated, easy to administer to neonates, infants and children and shows good absorption, with cortisol levels at 60 minutes after administration similar to physiological cortisol levels in healthy children.

Content uniformity of quartered hydrocortisone tablets in comparison with mini-tablets for paediatric dosing

OBJECTIVES

Children requiring cortisol replacement therapy are often prescribed hydrocortisone doses of 2.5 mg, but as this is commercially unavailable 10 mg tablets, with functional break lines, are split commonly in an attempt to deliver the correct dose. This study aimed to determine the dose variation obtained from quartered hydrocortisone tablets when different operators performed the splitting procedure and to ascertain whether better uniformity could be attained from mini-tablets as an alternative formulation.

METHODS

Hydrocortisone 10 mg tablets were quartered by four different operators using a standard pill splitter. Hydrocortisone 2.5 mg mini-tablets (3 mm diameter) were formulated using a wet granulation method and manufactured using a high-speed rotary press simulator. The weight and content uniformity of the quartered tablets and mini-tablets were assessed according to pharmacopoeial standards. The physical strength and dissolution profiles of the mini-tablets were also determined.

RESULTS

More than half of all quartered 10 mg tablets were outside of the ±10% of the stated US Pharmacopoeia hydrocortisone content (mean 2.34 mg, SD 0.36, coefficient of variation (CV) 15.18%) and more than 40% of the quartered tablets were outside the European Pharmacopoeia weight variation. Robust mini-tablets (tensile strengths of >4 MPa) were produced successfully. The mini-tablets passed the pharmacopoeial weight and content uniformity requirements (mean 2.54 mg, SD 0.04, CV 1.72%) and drug release criteria during in vitro dissolution testing.

CONCLUSION

This study confirmed that quartering 10 mg hydrocortisone tablets produces unacceptable dose variations and that it is feasible to produce 3 mm mini-tablets containing more accurate doses for paediatric patients.

Is physiological glucocorticoid replacement important in children?

Cortisol has a distinct circadian rhythm with low concentrations at night, rising in the early hours of the morning, peaking on waking and declining over the day to low concentrations in the evening. Loss of this circadian rhythm, as seen in jetlag and shift work, is associated with fatigue in the short term and diabetes and obesity in the medium to long term. Patients with adrenal insufficiency on current glucocorticoid replacement with hydrocortisone have unphysiological cortisol concentrations being low on waking and high after each dose of hydrocortisone. Patients with adrenal insufficiency complain of fatigue, a poor quality of life and there is evidence of poor health outcomes including obesity potentially related to glucocorticoid replacement. New technologies are being developed that deliver more physiological glucocorticoid replacement including hydrocortisone by subcutaneous pump, Plenadren, a once-daily modified-release hydrocortisone and Chronocort, a delayed and sustained absorption hydrocortisone formulation that replicates the overnight profile of cortisol. In this review, we summarise the evidence regarding physiological glucocorticoid replacement with a focus on relevance to paediatrics.

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.

Improving outcomes in patients with adrenal insufficiency: a review of current and future treatments

INTRODUCTION

Adrenal insufficiency is a rare but life-threatening disease. Conventional therapy consists of glucocorticoid replacement using hydrocortisone administered two or three times daily. Although such therapy extends life expectancy, mortality is not normalized, and quality of life remains poor. This failure to restore normal health is thought to be due to the inability of conventional glucocorticoid replacement therapy to normalize total cortisol exposure and to respond to the increased need for glucocorticoids during illness and stress. Also, current management regimens do not restore or replicate the intrinsic circadian rhythm of cortisol secretion.

AREAS COVERED

This narrative review was based on a PubMed and Medline search of all English-language articles on the safety and efficacy of glucocorticoid replacement therapy in patients with adrenal insufficiency. Based on this search we discuss current treatment strategies in terms of the failure to maintain or normalize metabolism and quality of life in patients with adrenal insufficiency. The rationale for, and technology behind, the development of modified-release preparations of hydrocortisone are described, together with the evidence suggesting that hydrocortisone preparations that mimic the physiological circadian pattern of cortisol release are more effective than conventional glucocorticoid replacement therapies.

CONCLUSIONS

Modified-release hydrocortisone treatments for patients with adrenal insufficiency more closely mimic the physiological circadian pattern of cortisol secretion than conventional twice or thrice daily treatment. The available evidence suggests that these modified-release preparations should improve metabolic outcomes and quality of life.

Nocturnal hypoglycaemia in ACTH and GH deficient children: role of continuous glucose monitoring

OBJECTIVES

To evaluate the usefulness of continuous glucose monitoring (CGM) to identify nocturnal hypoglycaemia in children affected by combined ACTH and GH deficiency and to optimize the hydrocortisone replacement therapy in these patients.

STUDY DESIGN

Eleven patients with ACTH and GH deficiency (five boys and six girls, age 1·6-16·8 years) underwent CGM for 36 h, including two nights. At least two consecutive glucose levels <2·78 mm were considered hypoglycaemic episodes. The differences in age and doses of hydrocortisone and recombinant human growth hormone (rhGH) between children with and without hypoglycaemia were analysed. The percentage of the glucose values <3·33 mm and the mean glucose levels were also evaluated.

RESULTS

Continuous glucose monitoring demonstrated nocturnal hypoglycaemia lasting from 30 to 155 min (1·5% of the total monitoring time) in three cases (27%). No statistically significant differences in age and rhGH dose were observed between children with or without hypoglycaemia. Conversely, the difference in the hydrocortisone doses between the patients with and without hypoglycaemia resulted statistically significant (5·9 vs 8·5 mg/m²/day; P = 0·04). Eight patients presented glucose values less than 3·33 mm during 5% of the total monitoring time. Hydrocortisone dose showed significant positive linear relation with mean glucose level (r = 0·79, P = 0·0035) and inverse relation with time lags of glucose levels under 3·33 mm (r = -0·65, P = 0·03).

CONCLUSIONS

Our study shows that CGM may represent a valuable tool to detect nocturnal asymptomatic hypoglycaemic episodes and optimize the hydrocortisone therapeutic regimen in children with ACTH and GH deficiency.

Therapy of adrenal insufficiency: an update

Adrenal insufficiency may be caused by the destruction or altered function of the adrenal gland with a primary deficit in cortisol secretion (primary adrenal insufficiency) or by hypothalamic-pituitary pathologies determining a deficit of ACTH (secondary adrenal insufficiency). The clinical picture is determined by the glucocorticoid deficit, which may in some conditions be accompanied by a deficit of mineralcorticoids and adrenal androgens. The substitutive treatment is aimed at reducing the signs and symptoms of the disease as well as at preventing the development of an addisonian crisis, a clinical emergency characterized by hypovolemic shock. The oral substitutive treatment should attempt at mimicking the normal circadian profile of cortisol secretion, by using the lower possible doses able to guarantee an adequate quality of life to patients. The currently available hydrocortisone or cortisone acetate preparations do not allow an accurate reproduction of the physiological secretion pattern of cortisol. A novel dual-release formulation of hydrocortisone, recently approved by EMEA, represents an advancement in the optimization of the clinical management of patients with adrenal insufficiency. Future clinical trials of immunomodulation or immunoprevention will test the possibility to delay (or prevent) the autoimmune destruction of the adrenal gland in autoimmune Addison's disease.

Salivary cortisol determination in patients from the Basque Country with recurrent aphthous stomatitis. A pilot study

OBJECTIVES

Stress and anxiety are controversial factors involved in the complex pathogenesis of Recurrent Aphthous Stomatitis (RAS). The determination of salivary cortisol is a useful, simple and safe test to detect states of high stress or anxiety. The aim of this study is to check for changes in salivary cortisol levels in patients with RAS during periods of active disease.

STUDY DESIGN

A measurement of cortisol employing Enzyme-Linked Immuno Sorbent Assay (ELISA) was carried out in samples of unstimulated saliva from 20 patients with active lesions of RAS and 10 healthy individuals used as controls.

RESULTS

Increased levels of salivary cortisol were detected in 3 cases, all of them within the group of patients with RAS. In none of the control group patients the level of salivary cortisol was increased. The mean level of salivary cortisol was 0.64 mg / dl (range 0.2 to 1.62) for patients with RAS and 0.57 mg / dl (range 0.25 to 1.09) for controls.

CONCLUSION

Salivary cortisol levels are not statistically higher in patients with active lesions of RAS.

Lower cortisol levels in children with asthma exposed to recurrent maternal distress from birth

BACKGROUND

Existing evidence supports associations between exposure to maternal distress and the development of childhood asthma, between exposure to maternal distress and an increased cortisol response in children, and between childhood asthma and an attenuated cortisol response.

OBJECTIVE

To investigate the association between children's cortisol levels and the combined predictors of exposure to maternal distress and childhood asthma.

METHODS

Serum cortisol levels were examined at age 7 to 10 years in relation to asthma status and exposure to maternal distress in a representative sample of children (n = 503) born in 1995. Data from health care and prescription databases were linked with additional data collected in this longitudinal study. Maternal distress was defined as a physician diagnosis of a depressive or anxiety disorder or a prescription history of related medications as reported in the mothers' health care records. Children's asthma status was determined via examination by 2 pediatric allergists.

RESULTS

A multiple linear regression analysis revealed that exposure to maternal distress restricted to the first year of life predicted elevated cortisol levels in children, regardless of asthma status (>40% increase). A significant interaction was discovered in the group of children exposed to maternal distress extending beyond the postnatal period such that no asthma predicted a 25.9% increase in cortisol and a diagnosis of asthma predicted a 5.2% decrease in cortisol. Cortisol levels were further lowered in atopic and bronchial hyperresponsive asthma.

CONCLUSION

Among children exposed to recurrent maternal distress, an elevation in cortisol levels occurs in response to an acute stressor when there is no accompanying diagnosis of asthma, whereas, in comparison, children with asthma tend to exhibit lower cortisol levels.

Corticosteroid physiology and principles of therapy

The adrenal cortex secretes glucocorticoids (GC), mineralocorticoids (MC) and androgens. GC maintain homeostasis, MC regulate fluid and electrolyte balance and adrenal androgens contribute to development of secondary sexual characteristics. Pharmacologic GC therapy is frequently indicated in the pediatric age group. Besides having many important side effects, prolonged high dose systemic GC therapy has a suppressive effect on endogenous steroid production. Therefore, GC therapy should be withdrawn gradually and stopped based on assessment of hypothalamo-pituitary-adrenal (HPA) axis recovery. Patients with HPA axis suppression require physiological replacement of GC along with enhancement of doses during periods of stress. Due to its immunosuppressive effects, issues about safety and efficacy of live virus vaccines in patients receiving systemic high dose GC therapy must be borne in mind.

Evaluation of adrenal function using the human corticotrophin-releasing hormone test, low dose Synacthen test and 9am cortisol level in children and adolescents with central adrenal insufficiency

BACKGROUND

The insulin tolerance test (ITT) has become less popular in paediatrics because of the risks associated with hypoglycaemia. Human corticotrophin-releasing hormone (hCRH) test results correlate with the ITT and may be an acceptable method to test for central adrenal insufficiency (CAI). Simpler tests, such as the low dose Synacthen test (LDST) and 9am cortisol, have also been proposed.

OBJECTIVE

To compare the ability of the hCRH test, LDST, 9am cortisol level and 24-h cortisol profiles to diagnose CAI in a paediatric population.

DESIGN AND SETTING

A cross-sectional study in a tertiary paediatric endocrine clinic.

PARTICIPANTS

Thirty-one children and adolescents (aged 2.3-18.3 years) with CAI risk factors had an hCRH test, LDST, 9am cortisol and 24-h cortisol profile performed.

RESULTS

Of 23 patients with confirmed CAI (hCRH peak cortisol < 400 nmol/), 19 failed the LDST (peak cortisol < 267 nmol/l, i.e. 10th percentile for controls). Nineteen would have failed based on the 10th percentile cut point for 9am cortisol (< 140 nmol/l). Using receiver operating characteristic (ROC) curve coordinates, a 9am cortisol < 108 nmol/l was sensitive (83%) and specific (99%) for CAI. The 9am cortisol levels measured on two occasions were repeatable (94%) and correlated (r = 0.83, P = 0.01). All eight adrenally sufficient patients (hCRH peak cortisol > or = 400 nmol/l) passed the LDST. Seven had normal 9am cortisol (> or = 140 nmol/l). The 24-h cortisol area under the curve (AUC) for these patients was within the 10th-90th percentiles for control subjects' AUC. The peak cortisol to hCRH and LDST were correlated (r = 0.88, P = 0.01), with no difference between the peaks (mean difference -5.3 nmol/l, P = 0.69).

CONCLUSIONS

In children with CAI risk factors, the diagnosis can be made if unstressed 9am cortisol is < 108 nmol/l. As cortisol levels > 381 nmol/l are highly suggestive of normal hypothalamic-pituitary-adrenal (HPA) function, stimulation testing need only be performed if 9am cortisol is 108-381 nmol/l. The LDST should be interpreted cautiously because mild CAI may be missed. When stimulation results are marginal, 24-h cortisol profiles can provide reassurance of normal cortisol status.