Hypothalamus-pituitary-adrenal axis evaluation in patients with hypothalamo-pituitary disorders: comparison of different provocative tests

Use of overnight metyrapone test in suspected secondary adrenal insufficiency: A retrospective single centre-study

OBJECTIVE

Overnight metyrapone test (OMT) is a dynamic test used to diagnose secondary adrenal insufficiency (SAI). Data on OMT use and its safety are scarce. We aimed to describe the indications and safety of outpatient OMT and compare OMT to the cosyntropin stimulation test (CST).

DESIGN

Single-centre retrospective study of adult patients undergoing OMT between 1 April 2018 and 27 January 2023.

MEASUREMENTS

OMT-related adverse events, post-OMT diagnosis of SAI, and OMT comparison to CST.

RESULTS

OMT was performed in 114 patients (81, 71% women) at a median age of 48 (interquartile range 37-58). The pretest probability for SAI was low in 52 (46%) patients, moderate in 48 (42%) patients and high in 14 (12%) patients. Adverse events were reported in 7 (6.1%) patients and were mild except for one hospitalization. No baseline or OMT-related factors were associated with the development of adverse events. Prevalence of the OMT-based SAI diagnosis was 26 (23%) and 47 (46%) using 11-deoxycortisol cutoff <7 and <10 mcg/dL, respectively. Higher pretest probability was associated with the OMT-based diagnosis of SAI. Post-OMT 11-deoxycortisol cutoff of 10 mcg/dL was used most to diagnose SAI. Compared to the OMT-based diagnosis of SAI (11-deoxycortisol cutoff of 10 mcg/dL), the specificity of CST was 100%, but the sensitivity was only 52%.

CONCLUSIONS

OMT was well tolerated and used in patients with low and moderate pretest probability for SAI. CST can erroneously exclude patients with SAI. Thus, OMT should be considered in selected patients with normal CST.

A Contemporary Approach to the Diagnosis and Management of Adrenal Insufficiency

Adrenal insufficiency (AI) can be classified into three distinct categories based on its underlying causes: primary adrenal disorders, secondary deficiencies in adrenocorticotropin, or hypothalamic suppression from external factors, most commonly glucocorticoid medications used for anti-inflammatory therapy. The hallmark clinical features of AI include fatigue, appetite loss, unintentional weight loss, low blood pressure, and hyponatremia. Individuals with primary AI additionally manifest skin hyperpigmentation, hyperkalemia, and salt craving. The diagnosis of AI is frequently delayed due to the non-specific symptoms and signs early in the disease course, which poses a significant challenge to its early detection prior to an adrenal crisis. Despite the widespread availability of lifesaving glucocorticoid medications for decades, notable challenges persist, particularly in the domains of timely diagnosis while simultaneously avoiding misdiagnosis, patient education for averting adrenal crises, and the determination of optimal replacement therapies. This article reviews recent advancements in the contemporary diagnostic strategy and approaches to optimal treatment for AI.

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.

Psychobiological risk factors for suicidal thoughts and behaviors in adolescence: a consideration of the role of puberty

Suicide is the second leading cause of death among adolescents. While clinicians and researchers have begun to recognize the importance of considering multidimensional factors in understanding risk for suicidal thoughts and behaviors (STBs) during this developmental period, the role of puberty has been largely ignored. In this review, we contend that the hormonal events that occur during puberty have significant effects on the organization and development of brain systems implicated in the regulation of social stressors, including amygdala, hippocampus, striatum, medial prefrontal cortex, orbitofrontal cortex, and anterior cingulate cortex. Guided by previous experimental work in adults, we also propose that the influence of pubertal hormones and social stressors on neural systems related to risk for STBs is especially critical to consider in adolescents with a neurobiological sensitivity to hormonal changes. Furthermore, facets of the pubertal transition, such as pubertal timing, warrant deeper investigation and may help us gain a more comprehensive understanding of sex differences in the neurobiological and psychosocial mechanisms underlying adolescent STBs. Ultimately, advancing our understanding of the pubertal processes that contribute to suicide risk will improve early detection and facilitate the development of more effective, sex-specific, psychiatric interventions for adolescents.

Low-dose short synacthen test with salivary cortisol in patients with suspected central adrenal insufficiency

CONTEXT

The low-dose short synacthen test (LDSST) is recommended for patients with suspected central adrenal insufficiency (AI) if their basal serum cortisol (F) levels are not indicative of an intact hypothalamic-pituitary-adrenal (HPA) axis.

OBJECTIVE

To evaluate diagnostic threshold for salivary F before and 30 min after administering 1 μg of synacthen, performed before 09:30 h.

DESIGN

A cross-sectional study from 2014 to 2020.

SETTING

A tertiary referral university hospital.

PATIENTS

In this study, 174 patients with suspected AI, 37 with central AI and 137 adrenal sufficient (AS), were included.

MAIN OUTCOME MEASURE

The diagnostic accuracy (sensitivity (SE), specificity (SP)) of serum and salivary F levels measured, respectively, by chemiluminescence immunoassay and liquid chromatography-tandem mass spectrometry.

RESULTS

Low basal serum or salivary F levels could predict AI. For the LDSST, the best ROC-calculated threshold for serum F to differentiate AI from AS was 427 nmol/L (SE 79%, SP 89%), serum F > 500 nmol/L reached SP 100%. A salivary F peak > 12.1 nmol/L after administering synacthen reached SE 95% and SP 84% for diagnosing central AI, indicating a conclusive reduction in the likelihood of AI. This ROC-calculated threshold for salivary F was similar to the 2.5th percentile of patients with a normal HPA axis, so it was considered sufficient to exclude AI. Considering AS those patients with salivary F > 12.1 nmol/L after LDSST, we could avoid unnecessary glucocorticoid treatment: 99/150 subjects (66%) had an inadequate serum F peak after synacthen, but salivary F was >12.1 nmol/L in 79 cases, who could, therefore, be considered AS.

CONCLUSIONS

Salivary F levels > 12.1 nmol/L after synacthen administration can indicate an intact HPA axis in patients with an incomplete serum F response, avoiding the need to start glucocorticoid replacement treatment.

Latent Adrenal Insufficiency: From Concept to Diagnosis

Primary adrenal insufficiency (PAI) is a rare disease and potentially fatal if unrecognized. It is characterized by destruction of the adrenal cortex, most frequently of autoimmune origin, resulting in glucocorticoid, mineralocorticoid, and adrenal androgen deficiencies. Initial signs and symptoms can be nonspecific, contributing to late diagnosis. Loss of zona glomerulosa function may precede zona fasciculata and reticularis deficiencies. Patients present with hallmark manifestations including fatigue, weight loss, abdominal pain, melanoderma, hypotension, salt craving, hyponatremia, hyperkalemia, or acute adrenal crisis. Diagnosis is established by unequivocally low morning serum cortisol/aldosterone and elevated ACTH and renin concentrations. A standard dose (250 µg) Cosyntropin stimulation test may be needed to confirm adrenal insufficiency (AI) in partial deficiencies. Glucocorticoid and mineralocorticoid substitution is the hallmark of treatment, alongside patient education regarding dose adjustments in periods of stress and prevention of acute adrenal crisis. Recent studies identified partial residual adrenocortical function in patients with AI and rare cases have recuperated normal hormonal function. Modulating therapies using rituximab or ACTH injections are in early stages of investigation hoping it could maintain glucocorticoid residual function and delay complete destruction of adrenal cortex.

Identifying Glucocorticoid Insufficiency in Silent Corticotroph Adenoma with Elevated Adrenocorticotropic Hormone

Silent corticotroph adenoma (SCA) is as an aggressive pituitary tumor. A 48 year old man developed hypogonadotrophic hypogonadism. The basal morning adrenocorticotropic hormone (ACTH) was elevated, but the basal morning and peak after ACTH (1-24) stimulation cortisol were normal. A 3.7 cm sellar mass with evidence of internal hemorrhage, encasement of the right internal carotid artery, and invasion of the right cavernous sinus were identified, resected, and stained positive for ACTH. Over the next 5 years, the basal morning ACTH and cortisol were normal, and imaging revealed the presence of a small residual tumor. One year later, the patient became fatigued and nauseated, with elevated ACTH. An overnight metyrapone stimulation test (OMST) revealed glucocorticoid insufficiency, without further increase in ACTH. Symptoms resolved with hydrocortisone treatment. This case study suggests that SCA can secrete an ACTH precursor that is detected by clinical assays but is not active biologically. Postoperative OMST reveals glucocorticoid insufficiency in this context.

Investigation of the Hypothalamo-pituitary-adrenal (HPA) axis: a contemporary synthesis

The hypothalamo-pituitary-adrenal (HPA) axis is one of the main components of the stress system. Maintenance of normal physiological events, which include stress responses to internal or external stimuli in the body, depends on appropriate HPA axis function. In the case of severe cortisol deficiency, especially when there is a triggering factor, the patient may develop a life-threatening adrenal crisis which may result in death unless early diagnosis and adequate treatment are carried out. The maintenance of normal physiology and survival depend upon a sufficient level of cortisol in the circulation. Life-long glucocorticoid replacement therapy, in most cases meeting but not exceeding the need of the patient, is essential for normal life expectancy and maintenance of the quality of life. To enable this, the initial step should be the correct diagnosis of adrenal insufficiency (AI) which requires careful evaluation of the HPA axis, a highly dynamic endocrine system. The diagnosis of AI in patients with frank manifestations is not challenging. These patients do not need dynamic tests, and basal cortisol is usually enough to give a correct diagnosis. However, most cases of secondary adrenal insufficiency (SAI) take place in a gray zone when clinical manifestations are mild. In this situation, more complicated methods that can simulate the response of the HPA axis to a major stress are required. Numerous studies in the assessment of HPA axis have been published in the world literature. In this review, the tests used in the diagnosis of secondary AI or in the investigation of suspected HPA axis insufficiency are discussed in detail, and in the light of this, various recommendations are made.

Adrenal insufficiency

Adrenal insufficiency (AI) is a condition characterized by an absolute or relative deficiency of adrenal cortisol production. Primary AI (PAI) is rare and is caused by direct adrenal failure. Secondary AI (SAI) is more frequent and is caused by diseases affecting the pituitary, whereas in tertiary AI (TAI), the hypothalamus is affected. The most prevalent form is TAI owing to exogenous glucocorticoid use. Symptoms of AI are non-specific, often overlooked or misdiagnosed, and are related to the lack of cortisol, adrenal androgen precursors and aldosterone (especially in PAI). Diagnosis is based on measurement of the adrenal corticosteroid hormones, their regulatory peptide hormones and stimulation tests. The goal of therapy is to establish a hormone replacement regimen that closely mimics the physiological diurnal cortisol secretion pattern, tailored to the patient's daily needs. This Primer provides insights into the epidemiology, mechanisms and management of AI during pregnancy as well as challenges of long-term management. In addition, the importance of identifying life-threatening adrenal emergencies (acute AI and adrenal crisis) is highlighted and strategies for prevention, which include patient education, glucocorticoid emergency cards and injection kits, are described.

Molecular characterization of the stress network in individuals at risk for schizophrenia

The biological mechanisms underlying inter-individual differences in human stress reactivity remain poorly understood. We aimed to identify the molecular underpinning of aberrant neural stress sensitivity in individuals at risk for schizophrenia. Linking mRNA expression data from the Allen Human Brain Atlas to task-based fMRI revealed 201 differentially expressed genes in cortex-specific brain regions differentially activated by stress in individuals with low (healthy siblings of schizophrenia patients) or high (healthy controls) stress sensitivity. These genes are associated with stress-related psychiatric disorders (e.g. schizophrenia and anxiety) and include markers for specific neuronal populations (e.g. ADCYAP1, GABRB1, SSTR1, and TNFRSF12A), neurotransmitter receptors (e.g. GRIN3A, SSTR1, GABRB1, and HTR1E), and signaling factors that interact with the corticosteroid receptor and hypothalamic-pituitary-adrenal axis (e.g. ADCYAP1, IGSF11, and PKIA). Overall, the identified genes potentially underlie altered stress reactivity in individuals at risk for schizophrenia and other psychiatric disorders and play a role in mounting an adaptive stress response in at-risk individuals, making them potentially druggable targets for stress-related diseases.

Second-Day Morning Cortisol Levels after Transsphenoidal Surgery Are Accurate Predictors of Secondary Adrenal Insufficiency with Diagnostic Cut-Offs Similar to Those in Non-Stressed Conditions

INTRODUCTION

Multiple studies tried to identify cortisol cut-offs after pituitary surgery that could accurately assess hypothalamic-pituitary-adrenal (HPA) axis function; however, there is no consensus nowadays. This study aimed to evaluate the accuracy of morning cortisol after transsphenoidal surgery in predicting long-term secondary adrenal insufficiency.

METHODS

In our tertiary center, we prospectively determined first- and second-day cortisol after transsphenoidal surgery in 92 patients without preoperative adrenal -insufficiency and not treated with glucocorticoids perioperatively. Definitive diagnosis of secondary adrenal insufficiency was obtained with re-evaluation 3 months after trans-sphenoidal surgery and clinical follow-up of at least 1 year.

RESULTS

Ten patients (10.8%) developed long-term postoperative secondary adrenal insufficiency. The ROC curves demonstrated that first-day cortisol had a moderate diagnostic accuracy, while a second-day cortisol ≤9.3 µg/dL (257 nmol/L) showed the best performance in predicting adrenal insufficiency (sensitivity [Se] 88.9%, specificity [Sp] 86.9%, AUC 0.921). Moreover, a second-day cortisol ≤3.2 µg/dL (89 nmol/L) was able to diagnose adrenal insufficiency in 100% of cases (Se 22.2%, Sp 100%) and >14 µg/dL (386 nmol/L) was able to exclude ACTH deficiency (Se 100%, Sp 57.4%).

CONCLUSIONS

Adrenal function can be carefully studied on the second day after pituitary surgery, using cut-off values that international guidelines suggested for non-stressed conditions. In fact, second-day cortisol levels ≤3.2 μg/dL (89 nmol/L) and >14 μg/dL (386 nmol/L) are diagnostic of secondary adrenal insufficiency and normal function, respectively. We also suggest performing a definitive re-evaluation with an HPA axis stimulation test when second-day cortisol values are between 3.3 and 14 μg/dL (90-386 nmol/L).

Central adrenal insufficiency: open issues regarding diagnosis and glucocorticoid treatment

Background

Central adrenal insufficiency (CAI) is characterized by impaired adrenocorticotropin (ACTH) secretion because of a disease or injury to the hypothalamus or the pituitary, leading to a reduced cortisol production. CAI suspicion arises more frequently in patients with pituitary tumors, cranial irradiation/surgery/injury/infections, as well as after exogenous glucocorticoid withdrawal. Nevertheless, a late diagnosis is not uncommon because CAI may present with nonspecific signs or symptoms, as fatigue or hyponatremia.

Content

The PubMed database was searched (years 1980–2018), using “central adrenal insufficiency” and “ACTH deficiency” as keywords. Subsequently, reference sections of the retrieved articles were searched.

Summary

Dynamic tests are needed when morning basal cortisol levels are not sufficient to exclude or to confirm CAI. Short Synacthen Test (SST) is the most used, and Endocrine Society’s guidelines recommend a cortisol peak >500 nmol/L to exclude CAI. Despite thresholds, understanding the pretest probability of ACTH deficiency (the clinical background of the patient) is essential because the diagnostic accuracy of SST in case of a negative result is suboptimal. Glucocorticoid replacement therapy, able to replicate cortisol circadian rhythm, is required in patients with CAI; fludrocortisone treatment is not necessary. Short-acting glucocorticoid drugs (hydrocortisone or cortisone acetate) are the most used; lower doses than previously used are nowadays recommended to reduce cortisol-related comorbidities. Promising results have been obtained with modified-release hydrocortisone, especially regarding glucose metabolism in patients with primary adrenal insufficiency.

Outlook

An accurate clinical diagnosis and a careful individualized therapy are mandatory in patients with CAI.

[Functional diagnostics in endocrinology]

When investigating many endocrinological diseases, basal laboratory parameters are not sufficient to distinguish between physiological and pathological hormone secretion. Functional diagnostics plays a decisive role in this context. Stimulation and suppression tests are used depending on whether under- or over-function needs to be diagnosed. This review article discusses selected functional tests, each of which plays an important role in current guidelines. Indications and test principles, including their performance, reliability, and limitations, are discussed. Topics covered include the ACTH stimulation test for the diagnosis of adrenal cortex insufficiency and the dexamethasone inhibition test for suspected Cushing's syndrome, as well as functional tests for the diagnosis of primary hyperaldosteronism, pheochromocytoma, acromegaly, growth hormone deficiency, thyroid nodules and suspicion of medullary thyroid carcinoma, insulinoma, and Zollinger-Ellison syndrome. Functional tests that are explicitly not recommended are also addressed.

Effects of Different Stressors Are Modulated by Different Neurobiological Systems: The Role of GABA-A Versus CB1 Receptor Gene Variants in Anxiety and Depression

Environmental stress and its interaction with genetic variation are key contributors in the development of depression and anxiety, yet there is a failure to identify replicable genetic variants and gene-interaction effects in the background of these psychiatric symptoms. Recently it has been reported that 5-HTTLPR and NOSI interact with financial but not other types of recent stressors in the development of depression. In the present study we investigated the interaction of GABRA6 rs3219151 and CNR1 rs7766029 in interaction with different types of recent life events on the presence of depression and anxiety in a large general population sample. 2191 participants completed the List of Threatening Experiences questionnaire which covers four categories of stressful life events (financial problems, illness/personal problems, intimate relationships, and social network) experienced over the previous year and the Brief Symptom Inventory for depression and anxiety symptoms. Participants were genotyped for rs3219151 and rs7766029. Data were analyzed with linear regression models with age and gender as covariates. Results indicated that CNR1 rs7766029 interacted significantly with financial but not other types of life events both in case of depression and anxiety symptoms. In contrast, GABRA6 rs3219151 showed a significant interaction with social network related life events in case of anxiety and with illness/personal problem-related life events in case of depression. Our results suggest that the psychological impact of different types of recent stress may be differentially modulated by distinct molecular genetic pathways. Furthermore, in case of certain genetic variants, the occurring psychiatric symptom may depend on the type of stress experienced.

A new stress sensor and risk factor for suicide: the T allele of the functional genetic variant in the GABRA6 gene

Low GABA transmission has been reported in suicide, and GABRA6 rs3219151 T allele has been associated with greater physiological and endocrine stress response in previous studies. Although environmental stress also plays a role in suicide, the possible role of this allele has not been investigated in this respect. In our present study effect of rs3219151 of GABRA6 gene in interaction with recent negative life events on lifetime and current depression, current anxiety, as well as lifetime suicide were investigated using regression models in a white European general sample of 2283 subjects. Post hoc measures for phenotypes related to suicide risk were also tested for association with rs3219151 in interaction with environmental stress. No main effect of the GABRA6 rs3219151 was detected, but in those exposed to recent negative life events GABRA6 T allele increased current anxiety and depression as well as specific elements of suicide risk including suicidal and death-related thoughts, hopelessness, restlessness and agitation, insomnia and impulsiveness as measured by the STOP task. Our data indicate that stress-associated suicide risk is elevated in carriers of the GABRA6 rs3219151 T allele with several independent markers and predictors of suicidal behaviours converging to this increased risk.

Recovery of steroid induced adrenal insufficiency

Secondary adrenal insufficiency can result from insufficient stimulation of the adrenal glands due to inadequate secretion or synthesis of adrenocorticotropic hormone (ACTH). This can be caused by hypopituitarism, central nervous system injury (tumors, radiation, and surgery) or long-term glucocorticoid therapy. Glucocorticoids were introduced in the 1950s, and have been used for their anti-inflammatory and other pharmacological effects, and also as replacement therapy for adrenal insufficiency. However, chronic glucocorticoid use may lead to suppression of the hypothalamic pituitary adrenal axis through negative feedback. This may lead to secondary adrenal insufficiency. Typically, the hypothalamic pituitary adrenal axis recovers after cessation of glucocorticoids, but the timing of recovery can be variable and can take anywhere from 6-12 months. Understanding the effect of exogenous glucocorticoids on the hypothalamic pituitary adrenal axis, recovery of the axis, and tests used to assess the recovery, are crucial to avoid prescribing unnecessary steroid replacement or missing a critical diagnosis with detrimental consequences.

Can the Gold Standard Be Beaten? How Reliable Are Various Modifications of the Synacthen Test Compared to the Insulin Tolerance Test

Criteria for the evaluation of the insulin tolerance test (ITT) and Synacthen test are still a matter of debate. The objective of the study was to make a comparison of serum and salivary cortisol during four stimulation tests. Sixty four healthy volunteers underwent the ITT, the Synacthen test with 1 (LDST), 10 (MDST) and 250 (HDST) μg dose of ACTH. Maximum serum cortisol response was observed at the 90 min of the ITT (49 %), HDST (89 %) and MDST (56 %) and at the 40 min of the LDST (44 %). Results expressed as 95 % confidence intervals: 408.0-843.6 and 289.5-868.1 nmol/l in the IIT at 60 and 90 min. In the HDST and the MDST serum cortisol reached the maximum at 90 min 542.6-1245.5 and 444.2-871.3 nmol/l. Levels of salivary cortisol followed the same pattern as serum cortisol. Salivary cortisol reached the maximum response in the HDST and the MDST at 90 min and at 40 min in the LDST. We confirmed good reliability of all tests with respect to timing of response and maximum response compared to the ITT. We proved that the MDST test can provide the similar response in serum cortisol to the HDST. Measuring either salivary cortisol or ACTH levels did not provide any additional benefit then measuring serum cortisol by itself.

Suboptimal rise in awakening-induced cortisol is an accurate marker of cortisol insufficiency in patients with normal renal function (eGFR >60 mL/min)

Background The insulin tolerance test is the gold standard for diagnosis of cortisol insufficiency. However, it is cumbersome, invasive, requires supervised hospital facilities and has unpleasant side-effects. A non-invasive outpatient-based test will be useful. We hypothesized that free cortisol concentrations in multiple spot urine samples can be used to diagnose cortisol insufficiency in patients with normal renal function (eGFR > 60 mL/min). Method Patients and controls provided urine samples at bedtime (S1), and first (S2) and second (S3) void the next day. Cortisol and creatinine were measured in all three samples, and cortisol:creatinine ratio (S1, S2 and S3) was used for further analysis. The sum of S1 + S2 + S3 was used to calculate total cortisol secretion (T). Variation (V) in cortisol secretion in response to circadian rhythm was calculated as the modulus of the difference between S1 and S2 and S2 and S3. Results Samples were collected from 96 controls and 11 patients. S1 was significantly lower vs . S2 and S3 in controls ( P < 0.0001) but not in patients. S2, S3, T and V were significantly lower in patients vs . controls ( P < 0.0001). ROC curve analysis using insulin tolerance test as gold standard showed that S2, S3, T and V were all equally accurate diagnostic markers for cortisol insufficiency (AUC: 0.87, NPV: 100%). The best balance of sensitivity and specificity was achieved using T (sensitivity: 100%, specificity: 58%). Conclusion Multiple spot urine samples test is an accurate, relatively inexpensive, non-invasive, convenient outpatient-based screening test for exclusion of cortisol insufficiency.

Prospective evaluation of a week one overnight metyrapone test with subsequent dynamic assessments of hypothalamic-pituitary-adrenal axis function after pituitary surgery

OBJECTIVE

To determine whether an overnight metyrapone test (OMT) within the first week postpituitary surgery can definitively assess the hypothalamic-pituitary-adrenal (HPA) axis, compared with subsequent dynamic tests and glucocorticoid requirement at 6 months.

DESIGN

Prospective study measuring morning cortisol levels on days 3 and 4 post-operatively, OMT day 5-7 and week 6, week 6 250 μg short Synacthen test (SST) and week 7 insulin tolerance test (ITT).

PATIENTS AND MEASUREMENTS

Forty participants who underwent pituitary surgery at a single centre (Cushing's disease excluded) were followed for at least 6 months. 46% had pre-operative adrenal insufficiency.

PRIMARY OUTCOME

week 1 OMT compared to glucocorticoid requirement at 6 months.

SECONDARY OUTCOMES

the performance of ITT as a "definitive" test and all tests compared to glucocorticoid requirement at 6 months.

RESULTS

Week 1 OMT showed concordance with ITT at week 7 of 78% and glucocorticoid requirement at 6 months of 81% respectively which was not significantly different from post-operative morning cortisol levels; 37% of participants with an abnormal OMT on day 6 had a normal OMT at week 6. All HPA axis tests showed similar concordance with glucocorticoid requirement at 6 months of 80%-85%.

CONCLUSIONS

Overnight metyrapone test within the first week after pituitary surgery was no better than an early morning cortisol level at predicting glucocorticoid requirement at 6 months. OMT at week 6 demonstrated recovery of HPA axis in a substantial proportion of participants who failed earlier assessments; thus, definitive testing should be delayed until 6 weeks post-operatively.

New diagnostic criteria for subclinical hypercortisolism using postsurgical hypocortisolism: the Co-work of Adrenal Research study

OBJECTIVE

There is no consensus on the biochemical diagnostic criteria for subclinical hypercortisolism (SH). Using parameters related to the hypothalamic-pituitary-adrenal axis, we aimed to develop a diagnostic model of SH for predicting postsurgical hypocortisolism and metabolic complications.

DESIGN

Prospective and cross-sectional, observational, multicentre study in Korea.

METHODS

After exclusion of overt Cushing's syndrome, adrenal incidentaloma (AI) patients who underwent unilateral adrenalectomy (n = 99) and AI patients (n = 843) were included. Primary outcome was defined as the presence of postsurgical hypocortisolism; secondary outcome was the presence of ≥4 complications (components of the metabolic syndrome and low bone mass). Postsurgical hypocortisolism was determined on the fifth postsurgery day using the ACTH stimulation test.

RESULTS

Thirty-three of the 99 patients developed postsurgical hypocortisolism. Analysis of the presurgery overnight 1-mg dexamethasone suppression test (1-mg DST) showed that all patients with cortisol levels of >138 nmol/l experienced postsurgical hypocortisolism, whereas those with levels of ≤61 nmol/l did not. The models of (i) 1-mg DST >138 nmol/l or (ii) >61 nmol/l with the presence of one among low levels of ACTH and dehydroepiandrosterone-sulphate had the highest accuracy (89·9%, P < 0·001) and odds ratio [OR 111·62, 95% confidence interval (CI) 21·98-566·74, P < 0·001] for predicting postsurgical hypocortisolism. Finally, patients with the same criteria in the 843 AI patients showed the highest risk for having ≥4 complications (OR 3·51, 95% CI 1·84-6·69, P < 0·001), regardless of gender, age, body mass index and bilaterality.

CONCLUSIONS

Our proposed model is able to accurately predict subtle cortisol excess and its chronic manifestations in AI patients.

Evaluation of the hypothalamic-pituitary-adrenal axis and its relationship with central respiratory dysfunction in children with Prader-Willi syndrome

BACKGROUND

Children with Prader-Willi Syndrome (PWS) have been considered at risk for central adrenal insufficiency (CAI). Hypothalamic dysregulation has been proposed as a common mechanism underlying both stress-induced CAI and central respiratory dysfunction during sleep.

OBJECTIVE

To evaluate CAI and sleep-related breathing disorders in PWS children.

PATIENTS AND METHODS

Retrospective study of cortisol response following either insulin tolerance test (ITT) or glucagon test (GT) in 20 PWS children, and comparison with 33 non- Growth Hormone deficient (GHD) controls. Correlation between sleep related breathing disorders and cortisol response in 11 PWS children who received both investigations.

RESULTS

In PWS children, the cortisol peak value showed a significant, inverse correlation with age (Kendall's τ = -0.411; p = 0.012). A similar though non-significant correlation was present between cortisol increase and age (τ = -0.232; p = 0.16). Similar correlations were found in controls. In only 1 of 20 PWS children (5 %), ITT was suggestive of CAI. Four patients had an elevated central apnea index but they all exhibited a normal cortisol response. No relationship was found between peak cortisol or cortisol increase and central apnea index (respectively p = 0.94 and p = 0.14) or the other studied polysomnography (PSG) parameters.

CONCLUSIONS

CAI assessed by ITT/GT is rare in PWS children. Our data do not support a link between CAI and central respiratory dysregulation.

Adrenal function and microbial DNA in noninfected cirrhotic patients with ascites: Relationship and effect on survival

BACKGROUND

There are few data on clinical relevance of adrenal dysfunction and its relationship with occult microbial DNA in noninfected haemodynamically stable cirrhotic patients with ascites.

AIMS

The aim of this study was to evaluate prognostic role of adrenal dysfunction, microbial DNA, and their relationship.

METHODS

Adrenal function was assessed in 93 consecutive patients following a corticotropin stimulation test. Adrenal dysfunction was defined as: basal cortisol <10 μg/dl, delta cortisol <9 μg/dl, or peak cortisol <18 μg/dl. Microbial DNA was assessed in blood and ascites of 54 consecutive patients. Patients were followed up until liver transplantation or death.

RESULTS

Adrenal dysfunction was not significantly associated with mortality, while the risk of death rose significantly with an increase in basal cortisol values (HR 1.13 per 1-μl/dl increase; 95% CI 1.01-1.26). Microbial DNA was independently associated with reduced survival (HR 8.05, 95% CI 1.57-41.2). In microbial DNA-positive patients a significant correlation was found between Model for End-Stage Liver Disease (MELD) score and basal cortisol values (Pearson's r=0.5107; p=0.018).

CONCLUSIONS

Microbial DNA and MELD score, but not adrenal function, were the best independent predictors of mortality in noninfected cirrhotic patients with ascites. High serum cortisol levels may be a systemic reaction to microbial translocation, increasing in parallel with deterioration of liver function.

Central adrenal insufficiency could not be confirmed by measurement of basal serum DHEAS levels in pubertal children

BACKGROUND

Central adrenal insufficiency (CAI) is due to a decrease of CRH and/or ACTH secretion. ACTH-dependent dehydroepiandrosterone sulphate (DHEAS) has been postulated as a possible marker of adrenal function in adult patients.

AIMS

To evaluate the usefulness of basal serum DHEAS determination to diagnose CAI in pubertal patients with a suspected diagnosis of CAI.

METHODS

Ninety-four pubertal patients suspected of having CAI were divided into two groups according to sufficient (group 1) or insufficient (group 2) low-dose ACTH test serum cortisol response. Concordance with low (<2.5th percentile) or normal (≥2.5th percentile) basal serum DHEAS levels for age and sex, respectively, was analysed.

RESULTS

Fifty patients (53.2%) in group 1 and 44 (46.8%) in group 2 were included. The median value of serum DHEAS levels in group 2 (0.7 µmol/l, interquartile range 0.44-1.49) was significantly lower than in group 1 (2.13 µmol/l, interquartile range 0.87-3.5; p < 0.03). Nevertheless, serum basal DHEAS levels as a diagnostic marker of CAI showed 39% sensitivity and 80% specificity.

CONCLUSION

In pubertal patients, basal serum DHEAS levels do not seem to be a useful tool to diagnose either sufficiency or insufficiency of secondary adrenal function.

Cushing's disease: predicting long-term remission after surgical treatment

Cushing's disease (CD) is a state of excess glucocorticoid production resulting from an adrenocorticotropic hormone (ACTH)–secreting pituitary adenoma. The gold-standard treatment for CD is transsphenoidal adenomectomy. In the hands of an experienced neurosurgeon, gross-total resection is possible in the majority of ACTH-secreting pituitary adenomas, with early postoperative remission rates ranging from 67% to 95%. In contrast to the strong data in support of resection, the clinical course of postsurgical persistent or recurrent disease remains unclear. There is significant variability in recurrence rates, with reports as high as 36% with a mean time to recurrence of 15–50 months. It is therefore important to develop biochemical criteria that define postsurgical remission and that may provide prognosis for long-term recurrence. Despite the use of a number of biochemical assessments, there is debate regarding the accuracy of these tests in predicting recurrence. Here, the authors review the various biochemical criteria and assess their utility in predicting CD recurrence after resection.

Systemic side-effects of topical corticosteroids

With the introduction of topical corticosteroids, a milestone has been achieved in dermatologic therapy; owing to its potent anti-inflammatory and ant proliferative effects, it became possible to treat some hitherto resistant dermatoses. But this magic drug can cause enough mischief if used inappropriately. Children are more susceptible to the systemic adverse effects because of enhanced percutaneous absorption through their tender skin. So, systemic side effects should be kept in mind while prescribing this therapeutically valuable topical medicament.

Systemic effects of intratympanic dexamethasone therapy

OBJECTIVE

The study aimed to assess the possible systemic effects of intratympanic dexamethasone (IT-Dex) on the hypothalamic-pituitary-adrenal (HPA) axis, inflammation, and bone metabolism.

DESIGN

A prospective cohort study including 30 adult patients of a tertiary referral ENT clinic treated with 9.6 mg IT-Dex over a period of 10 days was carried out.

METHODS

Effects on plasma and salivary cortisol concentrations (basal and after low-dose (1 μg) ACTH stimulation), peripheral white blood cell count, and biomarkers for bone turnover were measured before (day 0) and after IT-Dex (day 16). Additional measurements for bone turnover were performed 5 months after therapy. Clinical information and medication with possible dexamethasone interaction were recorded.

RESULTS

IT-Dex was well tolerated, and no effect was detected on the HPA axis (stimulated plasma and salivary cortisol concentration on day 0: 758±184 and 44.5±22.0 nmol/l; day 16: 718±154 and 39.8±12.4 nmol/l; P=0.58 and 0.24 respectively). Concentrations of osteocalcin (OC) and bone-specific alkaline phosphatase (BSAP) did not differ after dexamethasone (OC on days 0 and 16 respectively: 24.1±10.5 and 23.6±8.8 μg/l; BSAP on day 0, 16, and after 5 months respectively: 11.5±4.2, 10.3±3.4, and 12.6±5.06 μg/l); similarly, there was no difference in the peripheral white blood cell count (5.7×10(12)/l and 6.1×10(12)/l on days 0 and 16 respectively).

CONCLUSIONS

IT-Dex therapy did not interfere with endogenous cortisol secretion or bone metabolism.

Different cut-off values of the insulin tolerance test, the high-dose short Synacthen test (250 μg) and the low-dose short Synacthen test (1 μg) in assessing central adrenal insufficiency

OBJECTIVE

The short Synacthen test (SST) is widely used as alternative test to the insulin tolerance test (ITT) to investigate central adrenal insufficiency (CAI), but the methodology and cut-off values of the SST are controversial. Our aim was to evaluate the cut-off value of the ITT in normal subjects and to assess the different cut-off values of the high-dose SST (250 μg, HDT) and the low-dose SST (1 μg, LDT) in subjects with suspected CAI.

SUBJECTS AND METHODS

We conducted ITTs in 208 normal subjects to establish the cut-off value for the ITT, and 28 of those subjects underwent the HDT and LDT. From 1999 to 2007, 182 patients with suspected CAI were recruited and underwent ITTs, LDTs and HDTs to establish cut-off values and compare the diagnostic accuracy between the LDT and HDT.

RESULTS

The 95th percentile of the peak cortisol level during the ITT in the normal control subjects was 14·8 μg/dl. Receiver operator characteristics (ROC) analysis revealed that the optimal cut-off values of peak cortisol in the LDT and HDT in patients with suspected CAI were 15·8 and 17·4 μg/dl, respectively. However, the cut-off values from normative data (mean - 2 SD) were 18·3 μg/dl for the LDT and 20·5 μg/dl for the HDT in normal control.

CONCLUSIONS

The optimal cut-off values of SSTs needed to be individualized according to the type of SST and tested patient population.

Is routine endocrine evaluation necessary after paediatric traumatic brain injury?

BACKGROUND

Traumatic brain injury (TBI) is a common event in childhood. It is a recognised cause of hypopituitarism both in adult and paediatric patients. Routine endocrine evaluation has been proposed for adult TBI-survivors; nevertheless, incongruous data have been reported in children.

AIM

The goal of this study was to describe the prevalence of pituitary dysfunction after TBI in a cohort of children.

MATERIAL/SUBJECTS AND METHODS

This is a cross-sectional study comprising retrospective medical record review and prospective testing. Children with brain injury discharged from the Paediatric Intensive Care Unit from year 2004 to 2009 were recruited. Height and weight were recorded, systemic examination was performed and baseline pituitary function tests were undertaken. Provocative tests were performed only if abnormal basal levels were detected.

RESULTS

Thirty-six patients were collected; the mean age at assessment was 7.2 years and the mean interval since injury 3.3 years. All patients had skull fracture or intracranial haemorrhage; 36.6 % of them had moderate to severe TBI. No abnormalities were found on examination. Low serum IGF 1 levels were detected in four patients and two patients had low serum cortisol levels with inappropriately normal plasma ACTH concentrations. No evidence of pituitary dysfunction was observed in these patients after clinical follow-up, repeated baseline hormone levels or dynamic function tests.

CONCLUSIONS

No endocrine sequelae have been detected in this population. The routine endocrine evaluation in children with mild to moderate TBI might not be justified, according to our findings.

Comparison of the overnight metyrapone and glucagon stimulation tests in the assessment of secondary hypoadrenalism

OBJECTIVE

The insulin tolerance test (ITT) is contraindicated in a proportion of patients with suspected ACTH deficiency. The aim of this study was to investigate the diagnostic accuracy of the glucagon stress test (GST) compared with the overnight metyrapone test (OMT) in patients with contraindications to ITT.

DESIGN

This was a prospective comparison of the GST to the OMT in patients with suspected ACTH deficiency and contraindications to the ITT. The OMT was used as the standard for comparison. The study was conducted at two tertiary referral centres for pituitary disease.

PATIENTS

Seventy-eight patients underwent contemporaneous OMT and GST of whom 61 had sufficient suppression of cortisol during the OMT to be included in the comparison. Forty had suffered traumatic brain injury, 36 had organic pituitary disorders and two were classified as 'other'.

MEASUREMENTS

ACTH sufficiency was defined as 0800h 11-deoxycortisol ≥ 200 nmol/l on OMT and peak cortisol ≥ 440 nmol/l on GST, as per local reference ranges.

RESULTS

There was significant discrepancy between the proportion of patients diagnosed with ACTH deficiency using the OMT (39%) and GST (89%). From our data, a GST peak cortisol cut-off of ≥350 nm provides the combination of optimal sensitivity (71%) and specificity (57%), compared with a higher sensitivity (88%) but poor specificity (11%) using a cut-off of ≥440 nm.

CONCLUSIONS

The GST should be used with caution as a diagnostic test of ACTH reserve. The OMT should be used in preference to the GST to assess the hypothalamic pituitary adrenal axis where ITT is contraindicated.

[Secondary adrenal insufficiency due to exogenous glucocorticoid therapy]

Prolonged glucocorticoid therapy is considered to be the most common cause of secondary adrenal insufficiency. Despite this, its true incidence remains unknown and the risk of acute adrenal insufficiency seems to be overestimated. The cosyntropin stimulation test is a very valuable test to assess the adrenal reserve but not to predict the risk of acute adrenal insufficiency. Otherwise, this test is well correlated with the adrenal response to a stress but not with clinical events. The corticosteroid withdrawal modalities are very heterogeneous, non-consensual, and have never been strictly evaluated. Several studies have demonstrated that the need for glucocorticoids coverage during a stress has been overestimated and that hydrocortisone doses should not necessarily be markedly increased. A prospective study of patients after withdrawal would be the only mean to assess the true incidence of this complication and to propose a rational strategy to prevent it. Meanwhile, the education of patients and physicians should be a mandatory step in the management of the patients with a potential risk of adrenal insufficiency.

Role of the pituitary–adrenal axis in granulocyte-colony stimulating factor-induced neuroprotection against hypoxia–ischemia in neonatal rats

Several reports indicate that the activity of the hypothalamic–pituitary–adrenal axis (HPA) is increased after a brain insult and that its down-regulation can improve detrimental outcomes associated with ischemic brain injuries.Granulocyte-colony stimulating factor (G-CSF) is a neuroprotective drug shown in the naïve rat to regulate hormones of the HPA axis. In this study we investigate whether G-CSF confers its neuroprotective properties by influencing the HPA response after neonatal hypoxia–ischemia (HI). Following the Rice–Vannucci model, seven day old rats (P7)were subjected to unilateral carotid ligation followed by 2.5 h of hypoxia. To test our hypothesis,metyrapone was administered to inhibit the release of rodent specific glucocorticoid, corticosterone, at the adrenal level. Dexamethasone, a synthetic glucocorticoid, was administered to agonize the effects of corticosterone.Our results show that both G-CSF and metyrapone significantly reduced infarct volume while dexamethasone treatment did not reduce infarct size even when combined with G-CSF. The protective effects of G-CSF do not include blood brain barrier preservation as suggested by the brain edema results. G-CSF did not affect the pituitary released adrenocorticotropic hormone (ACTH) levels in the blood plasma at 4 h, but suppressed the increase of corticosterone in the blood. The administration of G-CSF and metyrapone increased weight gain, and significantly reduced the Bax/Bcl-2 ratio in the brain while dexamethasone reversed the effects of G-CSF. The combination of G-CSF and metyrapone significantly decreased caspase-3 protein levels in the brain, and the effect was antagonized by dexamethasone.We report that G-CSF is neuroprotective in neonatal HI by reducing infarct volume, by suppressing the HI-induced increase of the Bax/Bcl-2 ratio, and by decreasing corticosterone in the blood. Metyrapone was able to confer similar neuroprotection as G-CSF while dexamethasone reversed the effects of G-CSF. In conclusion, we show that decreasing HPA axis activity is neuroprotective after neonatal HI, which can be conferred by administering G-CSF.

Impact of head trauma on pituitary function

There have been in the past decade a growing number of studies relating head trauma to hypopituitarism. This condition may affect the rehabilitation process, and identification of such patients is therefore required. However, the widely different methods used so far for this purpose have provided inconsistent results. The incidence rate of hypopituitarism has probably been overestimated. This review focuses on the impact of head trauma on pituitary function, the diagnostic method, risk factors, and treatment options.

The comparison of low and standard dose ACTH and glucagon stimulation tests in the evaluation of hypothalamo-pituitary-adrenal axis in healthy adults

Evaluation of the HPA axis is still a challenge; due to different sensitivities and stimulation efficiencies of dynamic tests, lack of standard assays for cortisol measurement and lack of data regarding the effects of age and gender on the results of the HPA axis evaluation with different dynamic tests. This study was performed to compare 1 μg ACTH, 250 μg ACTH and glucagon tests in the evaluation of HPA axis. The study was carried out on 55 healthy individuals (28 men, 27 women). 10-12 volunteers were included from every decades between 20 and 70 years. Low dose short synacthen test (1 μg ACTH), standard dose short synacthen test (250 μg ACTH) and glucagon tests were performed consecutively. The mean peak cortisol response to standard dose ACTH stimulation test was found to be significantly higher than the low dose ACTH and glucagon stimulation tests. The mean peak cortisol responses to low dose ACTH and the glucagon stimulation tests were not significantly different. The mean peak cortisol responses did not differ significantly between different age or sex groups. The lowest peak cortisol responses obtained after low dose ACTH and glucagon stimulation tests were 12.5 and 9.1 μg/dl respectively in the volunteers who all had cortisol responses higher than 20 μg/dl after standard dose ACTH stimulation test. The lowest cortisol responses obtained during 250 μg ACTH, 1 μg ACTH and glucagon stimulation tests were found to be 20.1, 12.5 and 9.1 μg/dl in a known group of healthy people. So the consideration of appropriate hormonal cut-off levels for each test seems reasonable. The age, sex and body mass indeces were not shown to affect the cortisol response to dynamic stimulation tests.

Adrenocortical insufficiency in horses and foals

The adrenal cortices produce various steroid hormones that play vital roles in several physiologic processes. Although permanent adrenocortical insufficiency is rare in all species, emerging evidence in both human and equine medicine suggests that transient reversible adrenocortical dysfunction resulting in cortisol insufficiency frequently develops during critical illness. This syndrome is termed relative adrenal insufficiency (RAI) or critical illness-related corticosteroid insufficiency (CIRCI) and can contribute substantially to morbidity and mortality associated with the primary disease. This review discusses the mechanisms, diagnosis, and clinical consequences of adrenocortical insufficiency, with particular focus on the current understanding of RAI/CIRCI in horses and foals.

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.

Impaired hypothalamic regulation of endocrine function and delayed counterregulatory response to hypoglycemia in Magel2-null mice

Hypothalamic dysfunction may underlie endocrine abnormalities in Prader-Willi syndrome (PWS), a genetic disorder that features GH deficiency, obesity, and infertility. One of the genes typically inactivated in PWS, MAGEL2, is highly expressed in the hypothalamus. Mice deficient for Magel2 are obese with increased fat mass and decreased lean mass and have blunted circadian rhythm. Here, we demonstrate that Magel2-null mice have abnormalities of hypothalamic endocrine axes that recapitulate phenotypes in PWS. Magel2-null mice had elevated basal corticosterone levels, and although male Magel2-null mice had an intact corticosterone response to restraint and to insulin-induced hypoglycemia, female Magel2-null mice failed to respond to hypoglycemia with increased corticosterone. After insulin-induced hypoglycemia, Magel2-null mice of both sexes became more profoundly hypoglycemic, and female mice were slower to recover euglycemia, suggesting an impaired hypothalamic counterregulatory response. GH insufficiency can produce abnormal body composition, such as that seen in PWS and in Magel2-null mice. Male Magel2-null mice had Igf-I levels similar to control littermates. Female Magel2-null mice had low Igf-I levels and reduced GH release in response to stimulation with ghrelin. Female Magel2-null mice did respond to GHRH, suggesting that their GH deficiency has a hypothalamic rather than pituitary origin. Female Magel2-null mice also had higher serum adiponectin than expected, considering their increased fat mass, and thyroid (T(4)) levels were low. Together, these findings strongly suggest that loss of MAGEL2 contributes to endocrine dysfunction of hypothalamic origin in individuals with PWS.

The low-dose ACTH test does not identify mild insufficiency of the hypothalamnic-pituitary-adrenal axis in children with inadequate stress response

OBJECTIVE

To investigate retrospectively the sensitivity of published cortisol cut-off points of the low-dose ACTH test (LDAT) in children with proven mild hypothalamic-pituitary-adrenal (HPA) axis insufficiency.

PATIENTS AND METHODS

The HPA axis of 11 pediatric patients (age range: 5.5-14.5 yr) with established mild HPA axis insufficiency was reinvestigated with the LDAT. The sensitivity of the LDAT was calculated on the basis of published stimulated cortisol cut-off points.

RESULTS

The LDAT showed both a significantly higher cortisol peak and a greater cortisol rise compared with the ITT (both P < 0.01). The LDAT yielded a low sensitivity of 9-55% using published cortisol cut-off points as references.

CONCLUSION

Using published cortisol cut-off points, the LDAT showed a poor sensitivity to detect mild HPA axis insufficiency. We cannot recommend the use of the LDAT as a screening test of HPA axis impairment in such children.

Comparison of pituitary-adrenal responsiveness between insulin tolerance test and growth hormone-releasing peptide-2 test: a pilot study

Insulin tolerance test (ITT) is the gold standard for assessing the hypothalamic-pituitary-adrenal (HPA) function. GH-releasing peptide (GHRP)-2, which has a strong GH-stimulating activity, is useful for diagnosing GH deficiency as well as ITT. Additionally, GHRP-2 is also known to activate HPA axis. There have been no comparative studies of pituitary-adrenal responsiveness between GHRP-2 test and ITT in patients with hypothalamic/pituitary disease. To assess whether GHRP-2 test could be an alternative to ITT for diagnosing HPA axis failure, both ITT and GHRP-2 test were performed in 15 patients suspected of hypopituitarism. A 100mug dose of GHRP-2 was administered intravenously and plasma ACTH and serum cortisol concentrations were measured. In ITT, a peak cortisol value over 18mug/dl is considered normal. Nine patients were diagnosed as HPA axis failure by ITT. Their median peak cortisol in GHRP-2 test was 11.4mug/ml. In 6 patients diagnosed as normal HPA axis status by ITT, their median peak cortisol in response to GHRP-2 test was 21.4mug/dl, significantly higher (p=0.0032) than seen in patients diagnosed as HPA axis failure. There was a strong correlation between the peak cortisol in GHRP-2 test and ITT (r=0.817; p<0.0001). When the cut-off value for the peak cortisol in GHRP-2 test was set to 13-14mug/dl for diagnosing HPA axis failure, the specificity and sensitivity were 100% and 88.9%, respectively. Although further studies that include normal subjects are needed, these preliminary results suggest the possibility that GHRP-2 test may be an alternative to ITT for assessing HPA axis function.

Hypopituitarism following traumatic brain injury: prevalence is affected by the use of different dynamic tests and different normal values

OBJECTIVE

Traumatic brain injury (TBI) has emerged as an important cause of hypopituitarism. However, considerable variations in the prevalence of hypopituitarism are reported. These can partly be explained by severity of trauma and timing of hormonal evaluation, but may also be dependent on endocrine tests and criteria used for diagnosis of hypopituitarism.

METHODS

Systematic review of studies reporting prevalence of hypopituitarism in adults >or=1 year after TBI focusing on used (dynamic) tests and biochemical criteria.

RESULTS

We included data from 14 studies with a total of 931 patients. There was considerable variation in definition of hypopituitarism. Overall, reported prevalences of severe GH deficiency varied between 2 and 39%. Prevalences were 8-20% using the GHRH-arginine test (cutoff <9 microg/l), 11-39% using the glucagon test (cutoff 1-5 microg/l), 2% using the GHRH test (no cutoff), and 15-18% using the insulin tolerance test (ITT; cutoff <3 microg/l). Overall, the reported prevalence of secondary adrenal insufficiency had a broad range from 0 to 60%. This prevalence was 0-60% with basal cortisol (cutoff <220 or <440 nmol/l), 7-19% using the ACTH test, and 5% with the ITT as first test (cutoff <500 or <550 nmol/l). Secondary hypothyroidism was present in 0-19% (free thyroxine) or 5-15% (thyroid-releasing hormone stimulation). Secondary hypogonadism was present in 0-29%.

CONCLUSION

The reported variations in the prevalence rates of hypopituitarism after TBI are in part caused by differences in definitions, endocrine assessments of hypopituitarism, and confounding factors. These methodological issues prohibit simple generalizations of results of original studies on TBI-associated hypopituitarism in the perspective of meta-analyses or reviews.

Adrenal function testing in pediatric cancer survivors

BACKGROUND

Central adrenal insufficiency is observed after cranial radiation therapy for cancer. Screening at risk patients is recommended, but the best screening strategy is unknown.

METHODS

A retrospective review of pediatric cancer survivors who underwent hypothalamic/pituitary/adrenal axis testing was conducted. Data included: cancer diagnosis, radiotherapy dose, other endocrinopathies, and adrenal function testing. Adrenal testing included sequential low-dose corticotropin test (LDCT) and standard-dose corticotropin test (SDCT). 8 a.m. serum cortisol levels were compared to LDCT results. LDCT results were compared by radiotheroapy dose and according to the presence of endocrine comorbidities.

RESULTS

Seventy-eight subjects (56% male, mean age at diagnosis 6.5 years) underwent testing. 67.9% had been treated with radiotherapy to the hypothalamus/pituitary. Mean time to diagnosis of adrenal insufficiency was 6.8 years after cancer diagnosis. Adequate adrenal function was found in 65% of patients by LDCT and 89% by SDCT. Only 21% of patients had basal serum cortisols collected at 8 a.m. Agreement between 8 a.m. baseline cortisol and LDCT was fair. Agreement between random baseline cortisol and LDCT was poor. Prevalence of central adrenal insufficiency diagnosed by LDCT increased with radiotherapy dose (8% for 10-19.9 Gy; 83% for >or=40 Gy) and the number of endocrine comorbidities.

CONCLUSIONS

In pediatric cancer survivors, central adrenal insufficiency was common even in patients receiving <40 Gy to the hypothalamus/pituitary. We recommend use of LDCT, not 8 a.m. serum cortisol to screen patients who received >30 Gy of radiotherapy and those with other central endocrinopathies.

The diagnosis and investigation of adrenal insufficiency in adults

There is considerable variation in the methods used to diagnose and investigate adrenal insufficiency in clinical practice. These include a range of adrenocorticotropin (ACTH) stimulation and other dynamic testing protocols, serum cortisol cut-off values for diagnosis and tests used for differential diagnosis. With the introduction of modern cortisol and ACTH assays, the interpretation of tests used for diagnosis and differential diagnosis has become more complex and requires local validation. This review examines the basis of normal hypothalamic-pituitary-adrenal axis function and adrenal insufficiency states based upon an evidence base accumulated over the past four decades. The role of the laboratory in the differential diagnosis and interpretation based upon assay methodology is discussed. The accurate identification of patients who may benefit from corticosteroid replacement in special settings such as critical illness is challenging and will be explored.

Perioperative cortisol can predict hypothalamus-pituitary-adrenal status in clinically non-functioning pituitary adenomas

BACKGROUND

Peri-operative steroids are administered routinely to patients with pituitary adenoma undergoing transsphenoidal adenomectomy (TSA).

AIM

To evaluate hypothalamic-pituitary-adrenal (HPA) axis before and after programmed endoscopic TSA (E-TSA) in patients with clinically non-functioning pituitary macroadenoma (NFPA).

DESIGN

Open prospective.

SETTING

Tertiary referral hospitals.

PATIENTS

Seventy-two consecutive patients (20-87 yr, 37 males).

INTERVENTIONS

Adrenal steroid replacement therapy (ASRT) was given only in patients with hypocortisolism [08:00 h cortisol (F) <8 microg/dl].

MAIN OUTCOME MEASUREMENTS

After ETSA, achieving wide (>90%) selective resection of the adenoma in all, F and clinical picture were checked at day 2. The low-dose (1 microg) ACTH test (LDACTH) was performed at 6 weeks and repeated at 12 months.

RESULTS

Hypocortisolism was present pre-operatively in 14 patients (19.4%), persisted post-operatively in all but one, and was detected de novo at the post-operative day 2 control in 6 (10.3%). In all but one the post-operative day 2 basal F and peak F during LDACTH test were concordant. No patient whose F was > 8 microg/dl was treated with ASRT or developed symptoms of adrenal failure during the follow-up (1-11 yr, median 5).

CONCLUSIONS

HPA function is usually preserved in NFPA and is infrequently impaired after complete tumor removal by E-TSA. The 08:00 h. plasma cortisol evaluation before and 2 days after surgery, using as cut-off the value of 8 microg/dl, allows full evaluation of HPA status. Peri-operative steroid treatment should be given only in patients with hypocortisolism.