The short Synacthen test: is less best?

The Association of the Hypothalamic-Pituitary-Adrenal Axis with Appetite Regulation in Children with Fetal Alcohol Spectrum Disorders (FASDs)

Prenatal alcohol exposure causes growth impairment and a wide range of developmental, physical, and cognitive disorders in children, collectively referred to as fetal alcohol spectrum disorders (FASDs). In the course of FASDs, abnormalities can also affect eating behavior and nutritional status, but these problems have received little attention. Therefore, the aim of our study was to determine the levels of hormones involved in the action of the hypothalamic–pituitary–adrenal axis: proopiomelanocortin (POMC), cortisol, and adrenocorticotropic hormone (ACTH), in the serum of patients with FASDs. To our knowledge, none of these hormones studied have yet been evaluated in FASDs to date. We investigated 62 FASD patients and 23 healthy controls by applying an enzyme-linked immunosorbent method (ELISA). Fasting POMC levels were significantly lower in patients with FASDs (10.97 vs. 18,57 ng/mL, p = 0.039) compared to controls. However, there were no differences in cortisol concentrations. Additionally, the sex and subgroup status (fetal alcohol syndrome (FAS), neurobehavioral disorder associated with prenatal alcohol exposure (ND-PAE), and FASD risk) did not affect hormone levels. POMC was positively correlated with some clinical parameters such as age, BMI percentile, carbohydrate biomarkers, and ACTH. A positive correlation was observed between ACTH and cortisol levels, as well as ACTH and cholesterol levels. Data analysis showed no HPA axis abnormalities in the form of elevated serum cortisol and ACTH levels. Differences in POMC concentration may indicate the involvement and/or impairment of central nervous system structures in hormonal alterations in FASD individuals, caused by prenatal alcohol exposure. Hormonal dysregulation in FASDs can contribute to reduced growth and development, as well as many other disturbed processes, including neurological/neurodevelopmental dysfunctions. Further insightful studies involving a larger group of patients are needed to determine the potential impact of the measured hormones.

Baseline morning cortisol level as a predictor of pituitary-adrenal reserve: a comparison across three assays

CONTEXT

The short ACTH stimulation test (250 μg) is the dynamic test most frequently used to assess adrenal function. It is possible that a single basal cortisol could be used to predict the dynamic response, but research has been hampered by the use of different assays and thresholds.

OBJECTIVE

To propose a morning baseline cortisol criterion of three of the most commonly used modern cortisol immunoassays - Advia Centaur (Siemens), Architect (Abbott) and the Roche Modular System (Roche) - that could predict adrenal sufficiency.

DESIGN

Observational, retrospective cross-sectional study at two centres.

PATIENTS AND MEASUREMENTS

Retrospective analysis of the results of 1019 Short Synacthen tests (SSTs) with the Advia Centaur, 449 SSTs with the Architect and 2050 SSTs with the Roche Modular System assay. Serum cortisol levels were measured prior to injection of 250 μg Synacthen and after 30 min. Overall, we were able to collate data from a total of 3518 SSTs in 3571 patients.

RESULTS

Using receiver-operator curve analysis, baseline cortisol levels for predicting passing the SST with 100% specificity were 358 nmol/l for Siemens, 336 nmol/l for Abbott and 506 nmol/l for Roche. Utilizing these criteria, 589, 158 and 578 SSTs, respectively, for Siemens, Abbott and Roche immunoassays could have been avoided.

CONCLUSIONS

We have defined assay-specific morning cortisol levels that are able to predict the integrity of the hypothalamo-pituitary-adrenal axis. We propose that this represents a valid tool for the initial assessment of adrenal function and has the potential to obviate the need for dynamic testing in a significant number of patients.

Adrenal suppression in patients taking inhaled glucocorticoids is highly prevalent and management can be guided by morning cortisol

CONTEXT

Up to 3% of US and UK populations are prescribed glucocorticoids (GC). Suppression of the hypothalamo-pituitary-adrenal axis with the potential risk of adrenal crisis is a recognized complication of therapy. The 250 μg short Synacthen stimulation test (SST) is the most commonly used dynamic assessment to diagnose adrenal insufficiency. There are challenges to the use of the SST in routine clinical practice, including both the staff and time constraints and a significant recent increase in Synacthen cost.

METHODS

We performed a retrospective analysis to determine the prevalence of adrenal suppression due to prescribed GCs and the utility of a morning serum cortisol for rapid assessment of adrenal reserve in the routine clinical setting.

RESULTS

In total, 2773 patients underwent 3603 SSTs in a large secondary/tertiary centre between 2008 and 2013 and 17.9% (n=496) failed the SST. Of 404 patients taking oral, topical, intranasal or inhaled GC therapy for non-endocrine conditions, 33.2% (n=134) had a subnormal SST response. In patients taking inhaled GCs without additional GC therapy, 20.5% (34/166) failed an SST and suppression of adrenal function increased in a dose-dependent fashion. Using receiver operating characteristic curve analysis in patients currently taking inhaled GCs, a basal cortisol ≥348 nmol/l provided 100% specificity for passing the SST; a cortisol value <34 nmol/l had 100% sensitivity for SST failure. Using these cut-offs, 50% (n=83) of SSTs performed on patients prescribed inhaled GCs were unnecessary.

CONCLUSION

Adrenal suppression due to GC treatment, particularly inhaled GCs, is common. A basal serum cortisol concentration has utility in helping determine which patients should undergo dynamic assessment of adrenal function.

Prospective evaluation of a protocol for reduced glucocorticoid replacement in transsphenoidal pituitary adenomectomy: prophylactic glucocorticoid replacement is seldom necessary

BACKGROUND

Most pituitary surgery centres prescribe perioperative glucocorticoids to subjects undergoing transsphenoidal pituitary adenomectomy (TSA), despite reports suggesting this may be unnecessary. Evidence-based guidelines for glucocorticoid use in TSA have recently been published but there are no prospective studies of their utility.

OBJECTIVE

To implement and assess a protocol for reduced glucocorticoid replacement for subjects undergoing TSA.

DESIGN

Prospective and retrospective cohort study in an Australian pituitary surgery centre.

PATIENTS AND MEASUREMENTS

Clinical and biochemical data for 56 TSAs performed for non-ACTH-secreting tumours between March 2004 and April 2006 were prospectively collected and compared with data for 47 TSAs performed between October 2001 and November 2003, before implementation of the protocol. In the prospective cohort, a postoperative days 1-3 morning serum cortisol threshold of 250 nmol/l (91 microg/dl) was used to guide long-term glucocorticoid requirement.

RESULTS

Implementation of the protocol was associated with significant reductions in dose and duration of glucocorticoid treatment post TSA in 44 'low-risk' cases (no preoperative glucocorticoid use or evidence of pituitary apoplexy). In two low-risk cases, long-term glucocorticoid replacement was required despite postoperative cortisol greater than 250 nmol/l. Following the remaining 42 low-risk operations, glucocorticoid was not prescribed on hospital discharge on the basis of morning serum cortisol > 250 nmol/l and no clinical evidence of hypocortisolism. None of these 42 cases required glucocorticoid treatment for hypocortisolism following surgery. Short synacthen tests were performed in 35 of these subjects a minimum of 6 months after surgery and were normal. Use of the protocol was not associated with differences in postoperative complications.

CONCLUSIONS

Reduced glucocorticoid replacement in TSA is safe and reduces patient exposure to glucocorticoids and their potential adverse events. The occurrence of hypocortisolism in two low-risk subjects with serum cortisol > 250 nmol/l highlights the importance of daily clinical assessment when using this protocol.

Effects of glucocorticoids on the hypothalamic-pituitary-adrenal axis in children and adults

Inhaled and intranasal corticosteroids are widely used as effective, first-line treatments for asthma and allergic rhinitis. Despite a good safety profile of these formulations, there is increasing concern about their propensity to produce systemic adverse effects. Suppression of the hypothalamic-pituitary-adrenal axis is one of the most important potential complications. This article reviews the effects of inhaled and intranasal corticosteroids on the hypothalamic-pituitary-adrenal axis function in adults and children.

Assessing the HPA axis in patients with pituitary disease: a UK survey

OBJECTIVE

Assessing the integrity of the hypothalamic-pituitary-adrenal (HPA) axis following pituitary surgery is necessary to determine the requirement for glucocorticoid replacement therapy, but there remains controversy about the optimum way to measure this.

DESIGN AND MEASUREMENTS

Postal questionnaire survey among UK endocrinologists to evaluate the current methods used.

RESULTS

The response rate was low (81 out of 598 questionnaires mailed), although 85% were consultants. Fifty-five percent measured 9:00 h plasma cortisol in the immediate postoperative phase. Most carried out definitive testing between 4 and 12 weeks: 36% routinely used the insulin tolerance test (ITT), 59% used the short synacthen test (SST). The 30-min cortisol value was used by 67% as a 'pass' when interpreting the results. Others included cortisol measurement at 60 min (17%) or incremental value (7%). For long-term follow-up of patients not rendered ACTH-deficient by surgery, 64% used the SST for patients who had received radiotherapy. If patients had not had radiotherapy, 42% used the SST, whereas 33% did no routine testing unless the patient was symptomatic or there was evidence of tumour recurrence on imaging. If patients were symptomless but 'failed' the chosen test, 28% still treated the patient with glucocorticoid replacement, 38% retested before treatment and 24% recommended glucocorticoid cover for when unwell or 'stressed'. Fifty-six percent used hydrocortisone at doses of 20 mg/day as replacement therapy.

CONCLUSION

Thus, assessment of the HPA axis remains controversial. Although the SST is becoming more popular, there is still considerable variation in the interpretation of results and, in particular, the decision of whether or not to treat with lifelong glucocorticoid replacement therapy.

The low-dose ACTH test does not provide a useful assessment of the hypothalamic-pituitary-adrenal axis in secondary adrenal insufficiency

OBJECTIVE

The 1 microg ACTH stimulation test has been introduced to improve the sensitivity of ACTH as a test of the integrity of hypothalamic-pituitary-adrenal axis (HPAA). This study aims to compare the sensitivity, specificity and diagnostic accuracy of the "low-dose" 1 microg ACTH (LDACTH) test and the "standard dose" 250 microg ACTH (SDACTH) test, with the overnight metyrapone test (OMT) which assesses the entire HPAA.

DESIGN

A prospective evaluation of the performance of SDACTH and LDACTH screening tests in a diverse cohort of patients with possible adrenal insufficiency as routinely encountered in clinical practice using the OMT as the reference method.

PATIENTS

A total of 51 patients (26 with asthma on inhaled glucocorticoid, nine with hypopituitarism, three with hypothyroidism, one with hyponatraemia, one with Crohn's disease, one with encephalitis and 10 with non-specific symptoms) each underwent SDACTH, LDACTH and OMT tests in random sequence at least 1 week apart.

MEASUREMENTS

Blood was sampled for plasma cortisol levels at 0 and 30 min after intravenous administration of 1 microg and 250 microg of ACTH. Metyrapone 30 mg/kg body weight was taken orally at midnight, and plasma samples were taken for measurement of 11-deoxycortisol and cortisol next morning between 08.00 and 09.00 h. The OMT was deemed to be abnormal when both 11-deoxycortisol and cortisol levels were less than 200 nmol/l.

RESULTS

The sensitivity and specificity at an empirical "normal" plasma cortisol threshold value of 500 nmol/l were 67% and 100% for the SDACTH test, and 73% and 81% for the LDACTH test, respectively. As the plasma cortisol cut-off value was increased to 550 nmol/l and 600 nmol/l, the sensitivity of the SDACTH test was 67% and 80% and specificity was 97% and 92%, respectively. The sensitivity of the LDACTH test increased from 93% at plasma cortisol cut-off value of 550 nmol/l to 100% at plasma cortisol cut-off value of 600 nmol/l. However, the specificity of the LDACTH test fell from 72% to 56% as the plasma cortisol cut-off value was increased from 550 nmol/l to 600 nmol/l. A receiver operating characteristic curve demonstrated that the specificity of the SDACTH test was higher than the specificity of the LDACTH test at any given level of sensitivity.

CONCLUSIONS

Both the LDACTH and SDACTH tests fail to achieve acceptable levels of sensitivity and specificity to be useful as screening tests for secondary adrenal insufficiency. In this context the OMT can be safely used to assess the integrity of the entire HPAA.