Adrenocorticotropin stimulation tests in patients with hypothalamic-pituitary disease: low dose, standard high dose and 8-h infusion tests

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.

Dynamic Tests in Pituitary Endocrinology: Pitfalls in Interpretation during Aging

Aging and age-related diseases represent hot topics of current research. Progressive damage in morphology and function of cells and tissue characterizes the normal process of aging that is influenced by both genetic and environmental factors. The ability of each individual to adapt to these stressors defines the type of aging and the onset of age-related diseases (i.e., metabolic syndrome, inflammatory disorders, cancer, and neurodegenerative diseases). The endocrine system plays a critical role in this process because of its complex relationships with brain, immune system, and skeletal muscle; thus, alterations in hormonal networks occur during aging to maintain homeostasis, with consequent under- or overactivity of specific hypothalamic-pituitary-peripheral hormone axes. On the other hand, the increase in life expectancy has led to increasing incidence of age-related diseases, including endocrine disorders, which may prompt assessment of endocrine function in aging individuals. In this context, there is growing awareness that natural changes of endocrine physiology and physiopathology occurring with increasing age may necessitate age-driven diagnostic cutoffs requiring validation in the elderly. This review aims to analyze the available literature on the hormone response to the most important dynamic tests currently used in the clinical practice for the screening of anterior pituitary-related diseases to underline pitfalls in interpretation during aging.

Diagnosis and Management of Adrenal Insufficiency in Hospitalized Patients

BACKGROUND

Plasma cortisol is commonly obtained in hospitalized hypotensive patients, and adrenocorticotropic hormone (ACTH) challenge is typically conducted to further workup hypocortisolemia. It is important to recognize that relative adrenal insufficiency (AI) is the most common cause of low cortisol levels and failed ACTH challenge in ill patients. Both cortisol and synthetic ACTH challenge assays are unreliable in critically ill patients. In clinical practice, corticosteroid therapy in septic shock patients results in immediate hemodynamic benefits with less vasopressor and ventilator dependence.

AREAS OF UNCERTAINTY

There is no consensus about the diagnostic criteria of relative AI, appropriate cortisol level, and the dose used for synthetic ACTH challenge in patients with septic shock. There is controversy about the mortality benefits of supplemental steroid therapy and about the use of adjunctive fludrocortisone.

DATA SOURCES

PubMed search of randomized control trials and meta-analyses.

THERAPEUTIC OPINION

Despite all the controversies, hospital physicians frequently use steroids in patients with septic shock with hypocortisolemia. Hydrocortisone should be the choice of steroid for most relative AI patients, and fludrocortisone can be added on a case-by-case basis in refractory shock. Most of the adverse effects induced by a short course of steroids are easily managed in the inpatient setting.

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.

A systematic review and meta-analysis of Synacthen tests for assessing hypothalamic-pituitary-adrenal insufficiency in children

BACKGROUND

The diagnostic value of tests used in assessing hypothalamic-pituitary-adrenal axis (HPA) in children remains controversial.

DESIGN

A systematic review and meta-analysis with receiver-operated-characteristic curve was undertaken to assess the diagnostic values of conventional standard dose 250 μg tetracosactrin (ACTH), short Synacthen test (SSST) and/or low-dose Synacthen test (LDSST) in the assessment of HPA insufficiency in children. Studies eligible for inclusion were any study that compared the use of the LDSST and/or SSST in the assessment of central adrenal insufficiency in children compared with reference standard test.

RESULTS

There were no randomised trials found. SSST resulted in higher specificity and positive likelihood ratio than LDSST. The LDSST had a higher sensitivity (86% vs 61%) but a lower specificity (88% vs 99%) than the SSST, but there was high heterogeneity from the LDSST studies with various doses of Synacthen used.

CONCLUSIONS

Lack of standardisation of assays and protocols with regard to timing, frequency and dose has resulted in diagnostic inaccuracies. There is no clear evidence to indicate that LDSST is superior to SSST in the assessment of HPA axis in children. The choice of either SSST or LDSST should be individualised based on clinical judgement for each patient. This systematic review has identified the need for a well-designed, adequately powered, randomised controlled trial on the use of diagnostic tests used in assessing HPA axis in children.

Clinical and diagnostic approach to patients with hypopituitarism due to traumatic brain injury (TBI), subarachnoid hemorrhage (SAH), and ischemic stroke (IS)

The hypothalamic-pituitary dysfunction attributable to traumatic brain injury (TBI), aneurysmal subarachnoid hemorrhage (SAH), and ischemic stroke (IS) has been lately highlighted. The diagnosis of TBI-induced-hypopituitarism, defined as a deficient secretion of one or more pituitary hormones, is made similarly to the diagnosis of classical hypopituitarism because of hypothalamic/pituitary diseases. Hypopituitarism is believed to contribute to TBI-associated morbidity and to functional and cognitive final outcome, and quality-of-life impairment. Each pituitary hormone must be tested separately, since there is a variable pattern of hormone deficiency among patients with TBI-induced-hypopituitarism. Similarly, the SAH and IS may lead to pituitary dysfunction although the literature in this field is limited. The drive to diagnose hypopituitarism is the suspect that the secretion of one/more pituitary hormone may be subnormal. This suspicion can be based upon the knowledge that the patient has an appropriate clinical context in which hypopituitarism can be present, or a symptom known as caused by hypopituitarism. Hypopituitarism should be diagnosed as a combination of low peripheral and inappropriately normal/low pituitary hormones although their basal evaluation may be not distinctive due to pulsatile, circadian, or situational secretion of some hormones. Evaluation of the somatotroph and corticotroph axes require dynamic stimulation test (ITT for both axes, GHRH + arginine test for somatotroph axis) in order to clearly separate normal from deficient responses.

Pituitary dysfunction after traumatic brain injury: a clinical and pathophysiological approach

Traumatic brain injury (TBI) is a growing public health problem worldwide and is a leading cause of death and disability. The causes of TBI include motor vehicle accidents, which are the most common cause, falls, acts of violence, sports-related head traumas, and war accidents including blast-related brain injuries. Recently, pituitary dysfunction has also been described in boxers and kickboxers. Neuroendocrine dysfunction due to TBI was described for the first time in 1918. Only case reports and small case series were reported until 2000, but since then pituitary function in TBI victims has been investigated in more detail. The frequency of hypopituitarism after TBI varies widely among different studies (15-50% of the patients with TBI in most studies). The estimates of persistent hypopituitarism decrease to 12% if repeated testing is applied. GH is the most common hormone lost after TBI, followed by ACTH, gonadotropins (FSH and LH), and TSH. The underlying mechanisms responsible for pituitary dysfunction after TBI are not entirely clear; however, recent studies have shown that genetic predisposition and autoimmunity may have a role. Hypopituitarism after TBI may have a negative impact on the pace or degree of functional recovery and cognition. What is not clear is whether treatment of hypopituitarism has a beneficial effect on specific function. In this review, the current data related to anterior pituitary dysfunction after TBI in adult patients are updated, and guidelines for the diagnosis, follow-up strategies, and therapeutic approaches are reported.

Hypopituitarism after subarachnoid haemorrhage, do we know enough?

Background

Fatigue, slowness, apathy and decrease in level of activity are common long-term complaints after a subarachnoid haemorrhage (SAH). They resemble the symptoms frequently found in patients with endocrine dysfunction. Pituitary dysfunction may be the result of SAH or its complications. We therefore hypothesized that it may explain some of the long-term complaints after SAH.

We reviewed the literature to clarify the occurrence, pattern and severity of endocrine abnormalities and we attempted to identify risk factors for hypopituitarism after SAH. We also assessed the effect of hypopituitarism on long-term functional recovery after SAH.

Methods

In a MEDLINE search for studies published between 1995 and 2014, we used the term subarachnoid haemorrhage in combination with pituitary, hypopituitarism, growth hormone, gonadotropin, testosterone, cortisol function, thyroid function and diabetes insipidus. We selected all case-series and cohort studies reporting endocrine function at least 3 months after SAH and studied their reported prevalence, pathogenesis, risk factors, clinical course and outcome.

Results

We identified 16 studies describing pituitary function in the long term after SAH. The reported prevalence of endocrine dysfunction varied from 0 to 55% and the affected pituitary axes differed between studies. Due to methodological issues no inferences on risk factors, course and outcome could be made.

Conclusions

Neuroendocrine dysfunction may be an important and modifiable determinant of poor functional outcome after SAH. There is an urgent need for well-designed prospective studies to more precisely assess its incidence, clinical course and effect on mood, behaviour and quality of life.

Electronic supplementary material

The online version of this article (doi:10.1186/s12883-014-0205-0) contains supplementary material, which is available to authorized users.

Hypopituitarism in the elderly

Pituitary dysfunction in elderly can represent a true diagnostic and therapeutic challenge to clinicians caring for these patients. Symptoms associated with partial or total hypopituitarism, such as fatigue, lower muscle strength and decreased libido, are nonspecific and can be often attributed to normal aging. Gold standard pituitary diagnostic testing carries higher risks in elderly and is classically replaced by alternative testing. Furthermore, the benefits and safety of selective pituitary hormonal replacement, specifically sexual and growth hormone replacement, remain subject of controversy in this group of patients. Recognizing and appropriately treating hypopituitarism in elderly is crucial for the survival and well being of the older patients with this disease.

Comparison of low-dose and high-dose cosyntropin stimulation testing in children

BACKGROUND

  There is no consensus among pediatric endocrinologists in using low-dose (LD) versus high-dose (HD) cosyntropin to test for secondary/tertiary adrenal insufficiency. This paper compares LD and HD cosyntropin stimulation testing in children for evaluation of hypothalamic-pituitary-adrenal axis (HPAA) and suggests a new peak cortisol cut-off value for LD stimulation testing to avoid false positivity.

METHODS

  Data of 36 children receiving LD (1 µg) and HD (249 µg) cosyntropin consecutively during growth hormone (GH) stimulation testing were analyzed in two groups. Group A were patients who passed GH stimulation testing and were not on oral, inhaled or intranasal steroids (intact hypothalamic-pituitary axis, n= 19). Group B were patients who failed GH stimulation testing and/or were on oral, inhaled or intranasal steroids (impaired hypothalamic-pituitary axis, n= 17).

RESULTS

  In group A, the mean peak cortisol response in LD cosyntropin was 18.5 ± 2.4 µg/dL and that for the HD cosyntropin was 24.8 ± 3.1 µg/dL (r: 0.76, P≤ 0.05). In group B, the mean peak cortisol response in LD cosyntropin was 15.7 ± 6.1 µg/dL and that for HD cosyntropin was 21.7 ± 7.9 µg/dL (r: 0.98, P≤ 0.05). When a standard cut-off of 18 µg/dL was used, 37% of the patients with intact HPAA failed LD cosyntropin testing, but a cut-off of 14 µg/dL eliminated false positive results.

CONCLUSIONS

  LD cosyntropin stimulation testing results should be interpreted cautiously when used alone to prevent unnecessary long-term treatment. Using a lower cut-off for LD (≥14 µg/dL) seems to avoid false positive results and still detects most cases of impaired HPAA.

The rational use of pituitary stimulation tests

BACKGROUND

Diseases of the pituitary gland can lead to the dysfunction of individual hormonal axes and to the corresponding clinical manifestations. The diagnostic assessment of pituitary function has not yet been standardized.

METHODS

The members of the Neuroendocrinology Section and the Pituitary Study Group of the German Society for Endocrinology (Deutsche Gesellschaft für Endokrinologie) prepared outlines of diagnostic methods for the evaluation of each of the pituitary hormonal axes. These outlines were discussed in open session in recent annual meetings of the Section and the Study Group.

RESULTS

For the evaluation of the thyrotropic axis, basal TSH and free T4 usually suffice. For the evaluation of the gonadotropic axis in men, the testosterone level should be measured; if the overall testosterone level is near normal, then calculating the free testosterone level may be additionally useful. In women, an intact menstrual cycle is sufficient proof of normal function. In the absence of regular menstruation, measurement of the basal estradiol and gonadotropin levels aids in the diagnosis of the disturbance. For the evaluation of the adrenocorticotropic axis, the basal cortisol level may be helpful; provocative testing is in many cases necessary for precise characterization. The evaluation of the somato-tropic axis requires provocative testing. Aside from the insulin tolerance test, the GHRH-arginine test has become well established. Reference ranges normed to the body mass index (BMI) are available.

CONCLUSION

The diagnostic evaluation of pituitary insufficiency should proceed in stepwise fashion, depending on the patient's clinical manifestations and underlying disease. For some pituitary axes, measurement of basal hormone levels suffices; for others, stimulation tests are required. In general, the performance of combined pituitary tests should be viewed with caution.

The pituitary-adrenal axis in adult thalassaemic patients

OBJECTIVE

We previously described in young thalassaemic patients an altered cortisol and ACTH responsiveness suggesting an impaired adrenocortical reserve. Owing to iron overload, a worsening of adrenal function should be expected in adult patients.

DESIGN

In 124 adults with beta-thalassaemia, urinary free cortisol (UFC) and plasma ACTH levels were determined and compared with those measured in 150 controls. In 45 patients, cortisol was measured in response to: i) tetracosactide 1 microg as an i.v. bolus (low-dose test, LDT) and ii) tetracosactide 250 microg infused i.v. over 8 h (high-dose test, HDT).

RESULTS

UFC and serum cortisol were within the reference range in all patients. Conversely, basal plasma ACTH values were above the upper limit of the normal range in 19 patients. There were no statistically significant differences in the mean values of UFC, basal serum cortisol and plasma ACTH between patients and controls. A subnormal cortisol response to the LDT was registered in 18 out of 56 patients. Three of these patients also displayed a subnormal response to the HDT, together with elevated baseline plasma ACTH levels. In the LDT, a positive correlation was found between basal and peak cortisol values (P<0.0001). The latter were negatively correlated with basal ACTH values in both LDT (P<0.0001) and HDT (P<0.0001).

CONCLUSIONS

Adult thalassaemic patients often present a subtle impairment of adrenocortical function. This may become clinically relevant in case of major stressful events. Thus, we recommend an assessment of adrenocortical function in all adult thalassaemic patients.

Low-dose and high-dose synacthen tests and the hemodynamic response to hydrocortisone in acute traumatic brain injury

INTRODUCTION

In order to identify whether low-dose (1 microg) tetracosactide (Synacthen) testing may be preferable to high-dose (250 microg) testing in the diagnosis of adrenal insufficiency in traumatic brain injury (TBI), as suggested by studies in other forms of critical illness.

METHODS

We retrospectively reviewed the results of modified tetracosactide tests (involving administration of both low-dose and high-dose tetracosactide) conducted for clinical indications in patients in a neurocritical care unit within 10 days of TBI. Sixty-three modified tests were included and cortisol concentrations before and after administration of tetracosactide were extracted from the hospital records. Data were also extracted regarding hemodynamic response to empirical corticosteroid therapy, based on rapid weaning from vasoactive drugs.

RESULTS

Cortisol increments at 30 and 60 min following tetracosactide correlated well in the low-dose test (r(2) = 0.875, P < 0.0001). The mean cortisol concentration was 581 nmol/l at 30 min and 556 nmol/l at 60 min in the low-dose test. Cortisol increments following low-dose and high-dose testing correlated well overall (r(2) = 0.839, P < 0.0001), but results were discordant in 27 of 63 cases (43%) when the same diagnostic threshold was used. ROC curve analysis showed that both tests performed poorly in identifying hemodynamic steroid responsiveness (AUC 0.553 and 0.502, respectively).

CONCLUSIONS

In the low-dose tetracosactide test, it is sufficient to determine cortisol concentrations at baseline and at 30 min. Low-dose and high-dose tests give discordant results in a significant proportion of cases when using the same diagnostic threshold. Neither test can be used to guide the initiation of corticosteroid therapy in acute TBI.

Adrenal insufficiency in pediatric critical illness: controversies regarding its prevalence, pathogenesis, definition and management

Proper functioning of the hypothalamic–pituitary–adrenal axis is necessary for normal homeostasis in children and especially under conditions of stress, such as critical illness. Disturbances of this axis have been classified collectively under the heading of adrenal insufficiency. Although the majority of literature has focused on children with septic shock, more recent evidence suggests that adrenal insufficiency occurs in a much broader group of critically ill children. Its etiology in pediatric critical illness remains unclear but is most likely multifactorial. Several studies have suggested possible diagnostic criteria for adrenal insufficiency in pediatric critical illness; however, to date none of these biochemical definitions have been validated. Similarly, current management of this condition in children remains based primarily on an empiric, best-practice approach. Future large-scale studies are needed to elucidate the prevalence, pathogenesis, definition, diagnosis and management of this condition.

Secondary hypoadrenalism

Secondary adrenal insufficiency (SAI) is a clinical disorder that results from hypothalamic or hypophyseal damage or from prolonged administration of supraphysiological doses of glucocorticoids. Since glucocorticoids are widely used for a variety of diseases, the prevalence of SAI is by far exceeding that of primary adrenal insufficiency. Although the presentation of adrenal insufficiency may be insidious and difficult to recognize, an appropriate adrenocortical hormone replacement could lead to a normal quality of life and longevity can be achieved. The spectrum of adrenal insufficiency ranges from overt adrenal crises to subtle dysfunctions in asymptomatic patients who may be at risk of developing acute adrenal insufficiency since their hypothalamic-pituitary-adrenal (HPA) axis cannot appropriately react to stress. Thus, identification of patients with subtle abnormalities of the HPA is mandatory for avoiding this life-threatening event in stressful conditions. The optimal tests and the optimal testing sequence for adrenal insufficiency are still matter of debate. Insulin tolerance test (ITT) could be the gold standard, as it tests the whole HPA axis, but there are some patients who pass the ITT failing the ACTH test. Various alternatives to the ITT, including the standard cosyntropin stimulation test (SST) and low-dose SST, have been proposed since the adrenal gland in SAI loses the capacity for a prompt response to ACTH stimulation. The standard ACTH dose, but not the 1 microg dose, increases adrenal blood flow and this may contribute to produce an early cortisol response of greater magnitude. Moreover, the loss of the early cortisol response to ACTH stimulation could be a specific property of adrenal insufficiency, thus being a sensitive and early marker of failing adrenal function. While the results of the SSTs are often positive in patients with long-standing and severe disease, in patients with mild or recent-onset SAI these tests, using either 250 microg or 1 microg ACTH, tend to give normal results; thus, a negative cosyntropin test result does not rule out the possibility of SAI. Further studies with a systematic comparison of the different tests in large series of patients submitted to a prolonged follow-up are needed to solve the controversy of the optimal diagnostic strategy of SAI.

Endocrine aspects of critical illness

Metabolic disorders and endocrine changes are common and relevant in critically ill patients. Thereby, endocrinopathies, electrolyte or metabolic derangements may either pre-exist or develop, and left unattended, may lead to significant morbidity and mortality. The homeostatic corrections which have emerged in the course of human evolution to cope with the catastrophic events during critical illness involve a complex multisystem endeavour, of which the endocrine contribution is an integral component. Although the repertoire of endocrine changes has been probed in some detail, discerning the vulnerabilities and failures of this system is far more challenging. The ensuing endocrine topics illustrate some of the current issues reflecting attempts to gain an improved insight and clinical outcome for critical illness. Disturbances in glucose and cortisol homeostasis during critical illness are two controversially debated topics in the current literature. The term "hormokine" encompasses the cytokine like behaviour of hormones during inflammation and infections. The concept is based on an ubiquitous expression of calcitonin peptides during sepsis. Adrenomedullin, another member of the calcitonin peptide superfamily, was shown to complement and improve the current prognostic assessment in lower respiratory tract infections. Procalcitonin is the protopye of "hormokine" mediators circulating procalcitonin levels increase several 10,000-fold during sepsis improve the clinical assessment especially of respiratory tract infections and sepsis safely and markedly reduces antibiotic usage in non-bacterial respiratory tract infections and meningitis. Adrenomedullin, another member of the calcitonin peptide superfamily, was shown to complement and improve the current prognostic assessment in lower respiratory tract infections. Hormokines are not only biomarkers of infection. Hormokines are also pivotal inflammatory mediators. Like all mediators, their role during systemic infections is basically beneficial, possibly to combat invading microbes. Yet, with increasing levels they can become harmful for their host. Multiple mechanisms of action were proposed. In several animal models the modulation and neutralization of hormokines during infection was shown to improve survival and thus might open new treatment options for severe infections, especially of the respiratory tract.

The hypothalamic-pituitary-adrenal axis in critical illness

The hypothalamic-pituitary-adrenal response to stress is a dynamic process. The homeostatic corrections that have emerged in the course of human evolution to cope with the catastrophic events during critical illness involve a complex multisystem endeavor. Although the repertoire of endocrine changes has been probed in some detail, discerning the vulnerabilities and failures of this system is far more challenging. One of the most controversially debated topics in the current literature is the characterization and optimal treatment of allegedly inadequate adaptations of the hypothalamic-pituitary-adrenal axis during critical illness. This outline attempts to touch briefly some of the debated issues, stir the discussion, and thereby contribute to resolving the dispute.

Adrenal function in 23 children with paracoccidioidomycosis

Adrenal involvement by Paracoccidioides brasiliensis was described at necropsies and in many clinical studies, but only in adults. Therefore, the aim of this study was to evaluate adrenal function in children with paracoccidioidomycosis. Twenty-three children with the systemic form of paracoccidioidomycosis were evaluated and divided in two Groups: Group A (n = 8) included children before treatment and Group B (n = 15) children after the end of treatment. Plasma cortisol (basal and after ACTH test), ACTH, renin activity, aldosterone, sodium and potassium were measured. They were within normal range in all cases, except for renin activity and aldosterone, which were elevated in some cases. Group A patients showed basal and post-ACTH cortisol levels significantly greater than Group B patients. The results showed that adrenal function was not compromised in these children with paracoccidioidomycosis.

Assessment of adrenal suppression in children with asthma treated with inhaled corticosteroids: use of dehydroepiandrosterone sulfate as a screening test

BACKGROUND

Inhaled corticosteroids (ICs) are considered first-line therapy for persistent asthma. At medium to high doses, ICs can suppress the hypothalamic-pituitary-adrenal (HPA) axis. Various provocative stimuli have been used to evaluate HPA axis function, but they are labor intensive and time-consuming. Dehydroepiandrosterone sulfate (DHEA-S) is a corticotropin-dependent adrenal androgen precursor that is suppressible in patients treated with ICs.

OBJECTIVES

To evaluate DHEA-S as a possible marker for HPA axis dysfunction in children treated with ICs.

METHODS

Children with moderate-to-severe persistent asthma and a history of medium- to high-dose IC exposure for at least 6 months were evaluated using low-dose and standard high-dose cosyntropin stimulation testing to assess adrenal function, and DHEA-S levels were compared with the results.

RESULTS

Thirteen (59%) of 22 patients exhibited an abnormal cortisol response to cosyntropin. Age- and sex-specific mean DHEA-S z scores were significantly lower in cosyntropin abnormal responders (-1.2822) compared with normal responders (0.2964) (P = .008). The receiver operating characteristic curve for DHEA-S z scores had an area of 0.786 (95% confidence interval, 0.584-0.989), reaching 100% sensitivity with a DHEA-S z score of -1.5966 or less and 100% specificity with a DHEA-S z score greater than 0.0225.

CONCLUSIONS

Most children develop biochemical evidence of adrenal suppression after treatment with medium to high doses of ICs. The presence of low DHEA-S levels can be used as a screening test to identify the child who needs more formal testing of the HPA axis.

Isolated corticotrophin deficiency

Isolated ACTH deficiency (IAD) is a rare disorder, characterized by secondary adrenal insufficiency (AI) with low or absent cortisol production, normal secretion of pituitary hormones other than ACTH and the absence of structural pituitary defects. In adults, IAD may appear after a traumatic injury or a lymphocytic hypophysitis, the latter possibly due to autoimmune etiology. Conversely, a genetic origin may come into play in neonatal or childhood IAD. Patients with IAD usually fare relatively well during unstressed periods until intervening events spark off an acute adrenal crisis presenting with non specific symptoms, such as asthenia, anorexia, unintentional weight loss and tendency towards hypoglycemia. Blood chemistry may reveal mild hypoglycemia, hyponatremia and normal-high potassium levels, mild anemia, lymphocytosis and eosinophilia. Morning serum cortisol below 3 microg/dl are virtually diagnostic for adrenal insufficiency. whereas cortisol values comprised between 5-18 microg/dl require additional investigations: insulin tolerance test (ITT) is considered the gold standard but-when contraindicated-high or low dose-ACTH stimulation test with serum cortisol determination provides a viable alternative. Plasma ACTH concentration and prolonged ACTH infusion test are useful in differential diagnosis between primary and secondary adrenal insufficiency. For some patients with mild, near-to-asymptomatic disease, glucocorticoid replacement therapy may not be required except during stressful events; for symptomatic patients, replacement doses i.e., mean daily dose 20 mg (0.30 mg/kg) hydrocortisone or 25 mg (0.35 mg/kg) cortisone acetate, are usually sufficient. Administration of mineralocorticoids is generally not necessary as their production is maintained.

Stimulation of the hypothalamic-pituitary-adrenal axis with the opioid antagonist nalmefene

Nalmefene Stimulation of the HPA Axis.

BACKGROUND

The Hypothalamic-pituitary-adrenal (HPA) axis plays a vital role in the body's response to stress. The traditional gold standard for evaluating the HPA axis, the insulin hypoglycemia test (IHT), has several known limitations, and a second test, the standard ACTH stimulation test, can detect severe deficiencies of cortisol, but often misses mild or early cases. Therefore, a better test for the evaluation of the HPA axis is needed. This study evaluated the opiate antagonist nalmefene as a stimulation test of the HPA axis.

METHODS

25 healthy subjects were studied, 9 women and 16 men, mean age 30.4 yr. (range 21-55), and mean BMI 24.1 kg/m2 (range 18.6-34.2). Subjects received one of 3 doses of intravenously administered nalmefene: 2 mg (n = 6), 6 mg (n = 12), or 10 mg (n = 7). Serum cortisol and plasma ACTH were measured before and serially over two hours after the administration of nalmefene.

RESULTS

ACTH and cortisol levels rose significantly and similarly after the 10 mg dose and the 6 mg dose. After the 10 mg dose, mean peak ACTH was 82.4 +/- 22.6 pg/ml and mean peak cortisol was 25.2 +/- 1.8 microg/dl. After the 6 mg dose, mean peak ACTH was 70.3 +/- 7.7 pg/ml and mean peak cortisol was 24.7 +/- 1.7 microg/dl. Cortisol levels rose above 18 microg/dl in all subjects receiving 10 mg of nalmefene, and in all but two of the subjects receiving 6 mg of nalmefene. Side effects to nalmefene were of greater duration and intensity in the subjects receiving 10 mg of nalmefene vs. those receiving 6 or 2 mg. These included most notably fatigue, lightheadedness, nausea and vomiting.

CONCLUSIONS

Of the nalmefene doses we studied, 6 mg achieved the best combination of stimulation of ACTH and cortisol and fewest side effects. If further studies show a concordance between nalmefene and IHT, nalmefene testing could be used to assess the HPA axis in patients at risk for dysfunction of this axis.

A new less-invasive and more informative low-dose ACTH test: salivary steroids in response to intramuscular corticotrophin

OBJECTIVE

The intravenous low-dose ACTH test has been proposed as a sensitive tool to assess adrenal function through circulating steroids. The aims of this study were to: (a) find the minimal intramuscular ACTH dose that induced serum and salivary cortisol and aldosterone responses equivalent to those obtained after a pharmacological dose of ACTH; and (b) define the minimum normal salivary cortisol and aldosterone responses in healthy subjects to that dose of ACTH. We also compared the performances of the standard- and low-dose ACTH intramuscular tests to screen patients with known hypothalamo-pituitary-adrenal impairments.

DESIGN

Rapid ACTH tests were performed in individuals using various intramuscular doses (12.5, 25 and 250 microg) at 2-week intervals.

SUBJECTS

Twenty-one healthy volunteers and 19 patients with primary (nine cases) and secondary (10 cases) adrenal insufficiency.

MEASUREMENT

Serum and salivary cortisol and aldosterone concentrations were measured at baseline and after ACTH. Serum cortisol > or = 552.0 nmol/l and aldosterone > or = 555.0 pmol/l concentrations at 30 min after 250 microg of ACTH were defined as normal responses.

RESULTS

In healthy volunteers cortisol and aldosterone responded to ACTH in a dose-dependent manner. The time to peak in saliva for each steroid was delayed as the dose of ACTH increased. The minimum ACTH dose that produced equivalent steroid responses at 30 min to 250 microg of ACTH (standard-dose test; SDT) was 25 microg (low-dose test; LDT). Saliva collection 30 min after LDT and SDT showed cortisol and aldosterone concentrations of at least 20.0 nmol/l and 100.0 pmol/l, respectively. These values were defined as normal steroid responses. Blunted salivary steroid responses to LDT and SDT were found in all patients with primary adrenal insufficiency. Subnormal salivary cortisol levels in response to LDT and SDT were found in all patients with secondary adrenal insufficiency. In five patients full recovery of adrenal function was demonstrated by both tests after steroid withdrawal. In the follow-up of four patients studied during the recovery period, subnormal SAF response after LDT and normal after SDT was demonstrated. Preservation of the adrenal glomerulosa was found in all the patients with secondary adrenal insufficiency through the normal rise in salivary aldosterone after both LDT and SDT.

CONCLUSIONS

Adrenal function can be accurately investigated with simultaneous measurements of salivary cortisol and aldosterone in response to 25 microg of corticotrophin injected into the deltoid muscle. Our data suggest that this may become a useful and relatively noninvasive clinical tool to detect subclinical hypoadrenal states.

Low- and standard-dose corticotropin and insulin hypoglycemia testing in the assessment of hypothalamic-pituitary-adrenal function after pituitary surgery

The optimal means of assessing the integrity of the hypothalamic-pituitary-adrenal (HPA) axis after pituitary surgery remains controversial. We compared low-dose (1 micro g iv) and standard-dose (250 micro g im) corticotropin tests performed 1 and 4-6 wk after pituitary surgery with an insulin hypoglycemia test performed at 4-6 wk. Forty-one patients (21 male and 20 female; median age, 52 yr; range, 23-73 yr) who had undergone pituitary surgery were studied (Cushing's disease excluded). Twenty-two of the 41 patients had normal cortisol responses to all tests both at 1 and 4-6 wk after surgery. Eight patients had subnormal cortisol responses to all tests. Of the 11 patients with discrepant results, seven had subnormal responses only after the low-dose corticotropin test; the remaining four patients had borderline responses to one or more tests. At 4-6 wk after surgery, subjects with a 30-min serum cortisol after standard-dose corticotropin of less than 350 nmol/liter (12.7 micro g/dl) consistently had a subnormal response to hypoglycemia, and those with a serum cortisol greater than 650 nmol/liter (23.6 micro g/dl) had a normal response to hypoglycemia. Definitive testing of the HPA axis using the standard-dose corticotropin test can be carried out provided it is performed at least 4 wk after pituitary surgery. A 30-min cortisol level greater than 650 nmol/liter (23.6 micro g/dl) indicates adequacy of the HPA axis, and a level of less than 350 nmol/liter (12.7 micro g/dl) indicates ACTH deficiency. No further testing is then required. An intermediate level of 350-650 nmol/liter (12.7-23.6 micro g/dl) warrants further assessment using the insulin hypoglycemia test.