Approach to the patient with possible Cushing's syndrome

Polycystic Ovary Syndrome in the Context of Pituitary Adenomas: Prevalence, Pathophysiology and Clinical Management

OBJECTIVE

Many review articles have explored data regarding the coexistence of specific types of pituitary adenomas (PAs) and polycystic ovary syndrome (PCOS), particularly focusing on the potential pathogenesis of this intersection and overlapping features. However, a comprehensive evaluation encompassing the full spectrum of PAs and their association with PCOS remains lacking. This review aims to provide a broad assessment of the interactions between these entities, emphasizing pathophysiological mechanisms, clinical presentations, diagnostic challenges and therapeutic implications.

METHODS

A comprehensive literature search was conducted in the PubMed/MEDLINE database, focusing primarily on publications from the years 2000 to 2024, while also including seminal papers from the 1950s. The reference lists of selected articles were also manually searched. Inclusion criteria encompassed review articles, retrospective studies, clinical trials, case reports and meta-analyses providing data on the pathogenesis, clinical features, diagnostic challenges and therapeutic approaches related to PCOS and different PAs.

RESULTS

PCOS and functioning PAs often exhibit overlapping clinical features, complicating diagnosis and management. PCOS may precede and delay the diagnosis of growth hormone (GH)-secreting adenomas. The prevalence of PCOS or its features in acromegaly is influenced by disease activity, while approximating 13% in cases with controlled disease. Excess GH and insulin-like growth factor 1 (IGF-1) adversely affect ovarian function through direct pathways and by inducing insulin resistance, contributing to acromegaly-associated PCOS. In Cushing's syndrome (CS), findings consistent with PCOS may be present in 46% of patients, with cortisol excess contributing to menstrual dysfunction, hyperandrogenism and insulin resistance. While the prevalence of PCOS in patients with prolactinomas remains under-researched, recent studies indicate a 2.8%-10% prevalence of prolactinomas in PCOS. Elevated prolactin (PRL) levels in these patients may promote insulin resistance, further contributing to PCOS pathogenesis. Moreover, increased androgen bioavailability may be observed in all three aforementioned adenomas. To date, no studies have provided prevalence data for PCOS in other types of PAs.

CONCLUSIONS

Distinct clinical features, along with biochemical evaluations and imaging, can help differentiate the presence of both PAs and PCOS. Moreover, excluding other mimicking disorders is essential for an accurate diagnosis of PCOS. The persistence or recurrence of menstrual dysfunction, hyperandrogenism and metabolic disturbances in patients with controlled functioning adenomas may indicate a coexisting PCOS diagnosis. Timely diagnosis may optimize management and improve long-term outcomes for both conditions. Future studies should focus on investigating the clinical differences between patients with co-occurring PCOS and PAs compared to those with PCOS alone, ideally in larger cohorts, to better understand unique diagnostic and therapeutic considerations.

"Who and how to screen for endogenous hypercortisolism among young women presenting with clinical hyperandrogenism and/or menstrual abnormalities "

Endogenous Cushing's syndrome (CS) is rare, with an incidence of 0.7-2.4 per million population per year according to population-based studies. However, evaluation of patients presenting disorders potentially related to cortisol excess, and therefore with a 'high risk of clinical suspicion' profile, could bring out several unrecognized cases. CS represents one of the most challenging endocrine diseases, with clinical features overlapping with those of common conditions affecting general population, invariably resulting in potential mis- or delayed diagnosis with negative consequences in terms of morbidity and mortality. CS is remarkably prevalent among young females, variably presenting with menstrual irregularities and/or signs and symptoms of hyperandrogenism. Herein we briefly reviewed literature on prevalence and clinical impact of menses abnormalities, acne and hirsutism -also coexisting in the context of a polycystic ovary syndrome- in CS, aiming at clarifying if, when and how to screen for hypercortisolism young women with these disorders.

Relationship Among Fragility Fractures and the Overall Cardiovascular Burden in Endogenous Cushing Syndrome

Context

Patients with endogenous Cushing syndrome (CS), in addition to significant cardiovascular morbidity, are burdened by a high prevalence of fragility fractures. Bone mineral density (BMD) alone poorly predicts the risk of fracture, and the implementation of trabecular bone score (TBS) is supported only by scant evidence. Indeed, reliable predictors of fractures in endogenous CS are still lacking.

Objective

This work aimed to analyze the prevalence and the potential predictors of fragility fractures in our patients with CS.

Methods

A monocentric, retrospective, cross-sectional study. A total of 51 patients with overt CS were enrolled. Main outcome measures included biochemical evaluation, BMD measurement, TBS evaluation, fracture presence, body composition evaluation, and arterial intima-media thickness (IMT) assessment.

Results

Fragility fractures were found in 62.7% of patients at diagnosis. Fractured patients exhibited lower spine T-score (P = .03), longer disease duration (P = .025), higher waist circumference (P = .006), and predominantly male sex (P = .008). Increased serum uric acid levels (P = .001), greater IMT (P = .017), and higher prevalence of venous thromboembolism events (31.3% vs 5.3%, P = .037) and atherosclerotic plaques (47% vs 5.3%, P = .002) were described in the fracture group.Multivariable logistic regression identified the presence of atherosclerosis (OR 13.35; 95% CI 1.154-154.34, P = .038) and osteoporosis (OR 11.30; 95% CI 1.55-82.56, P = .017) as independent predictors. TBS values were inversely correlated with body mass index, fat and lean mass, and serum uric acid, and positively correlated with high-density lipoprotein cholesterol.

Conclusion

CS patients with higher overall burden of cardiovascular morbidity are more prone to experience fragility fractures.

Clinical and Biochemical Data for the Diagnosis of Endogenous Hypercortisolism: The "Cushingomic" Approach

CONTEXT

The clinical presentation of Cushing syndrome (CS) overlaps with common conditions. Recommended screening tests are serum cortisol after 1-mg overnight dexamethasone suppression test (DST), urinary free cortisol (UFC), and late-night salivary cortisol (LNSC).

OBJECTIVE

We analyzed the diagnostic accuracy of screening tests in 615 patients without CS (263 suspected CS, 319 adrenal and 33 pituitary incidentaloma) and 40 with CS.

METHODS

Principal component analysis, K-means clustering, and neural network were used to compute an integrated analysis among tests, comorbidities, and signs/symptoms of hypercortisolism.

RESULTS

The diagnostic accuracy of screening tests for CS was high; DST and UFC were slightly superior to LNSC. The threshold of DST should be adapted to the population considered, especially in adrenal incidentaloma (AI) with mild autonomous cortisol secretion: The cutoff to differentiate CS should be increased to 196 nmol/L. Diabetes, hypertension, and obesity were more common in patients without CS: The direction of their vectors was not aligned and their correlation with screening tests was poor. Clustering allowed us to differentiate those patients without CS into cluster 1 (aged osteoporotic patients with impaired screening tests), cluster 2 (hypertensive and metabolic phenotype), and cluster 3 (young individuals with a low likelihood of overt CS). A neural network model that combined screening tests and clinical presentation was able to predict the CS diagnosis in the validation cohort with 99% precision and 86% accuracy.

CONCLUSION

Despite the high diagnostic accuracy of screening tests to detect CS, cortisol-related comorbidities or AI should be considered when interpreting a positive test.

Subtyping of Cushing's Syndrome: A Step Ahead

Cushing's Syndrome (CS) is a rare disease due to chronic endogenous cortisol secretion. In recent years, new developments have broadened the spectrum of differential diagnosis, traditionally categorized as adrenocorticotropic hormone (ACTH)-dependent and ACTH-independent forms. Moreover, increased awareness of the detrimental effects of cortisol on cardiometabolic health and the risk of cardiovascular events lead to increased diagnosis of mild forms, especially in the context of adrenal incidentalomas.This review provides an up-to-date narrative of the most recent literature regarding the challenges of CS diagnosis. After the description of the diagnostic tools available, the functional non-neoplastic hypercortisolism (formerly known as pseudo-Cushing state) is characterized, followed by the subtyping of the different conditions of hypercortisolism, including the differential diagnosis of ACTH-dependent forms and the management of adrenal hypercortisolism, with peculiar attention to the new genetic classification of adrenal CS, mild autonomous cortisol secretion, and bilateral adrenal adenomas.

Effervescent-assisted Liquid-phase Microextraction Employing Switchable Hydrophilicity Solvent for the Determination of Cortisol and Testosterone in Oral Fluid by High-Performance Liquid Chromatography-Diode Array Detection

Cortisol and testosterone are important biomarkers for diagnosing complex disorders, including polycystic ovary syndrome and Cushing's syndrome, where symptomatology usually overlaps with other prevalent disorders. This work proposes, for the first time, an analytical method based on a switchable hydrophilicity solvent as an extraction phase for the determination of cortisol and testosterone in oral fluid (OF) by high-performance liquid chromatography with diode-array detection. The optimized extraction conditions consisted of 1000 µL of OF, 100 µL of decanoic acid solution (65 mg/mL), 170 µL of Na2CO3, 900 µL of H2SO4 and 150 µL of acetonitrile for dilution. The method was validated, and coefficients of determination higher than 0.9926, the limit of detection of 4.55 ng/mL and the limit of quantification of 15.00 ng/mL were obtained. Intra-day precision varied from 5.6% to 11.9%, inter-day precision ranged from 6.1% to 13.5%, and relative recoveries ranged from 98.9% to 104.6% for cortisol, and 89.1% to 103.9% for testosterone. This methodology was successfully applied to five OF samples from volunteers. Moreover, the greenness of this methodology was evaluated based on the sample preparation metric of sustainability achieving a global score of 7.37 which can be considered sustainable.

Management of functional neuroendocrine tumors

Functional neuroendocrine neoplasms (NENs) are those associated with specific symptoms related to the hormonal secretion of the NENs. Although less than 25 % of NENs are functional at diagnosis,1 the associated syndromes significantly increase the patient burden of disease. Management of hormonal NEN symptoms may involve tumor resection or other reduction strategies (e.g., chemotherapy, embolotherapy, etc), but also specific therapies directed at decreasing hormonal synthesis, secretion, or end-organ effects. In this review, we focus on specific symptomatic management of many of the NEN syndromes, which may be pursued in addition to management primarily directed at tumor bulk and growth. A continued focus on symptom management related to the hormonal secretions of NENs, in the context of other efforts to reduce tumor bulk and growth, could significantly improve patient wellbeing.

Endogenous Cushing's Syndrome Due to Right Adrenal Adenoma Presenting With Bilateral Leg Oedema and Skin Ulceration

Cushing's syndrome (CS) is a rare disorder characterized by an excess of glucocorticoids, leading to distinctive clinical manifestations. However, its presentation can be atypical, complicating diagnosis. We describe a 53-year-old woman's case of endogenous, adrenocorticotropic hormone (ACTH)-independent CS, presenting with bilateral leg edema and shin ulceration, without the classic signs of moon face or truncal obesity initially. Despite being treated for hypertension and dyslipidemia for a decade, and having a history of left capsular hemorrhage, the diagnosis of CS was not considered until extensive testing was conducted. Investigations revealed a low ACTH level, elevated urinary free cortisol, and a right adrenal mass, leading to the diagnosis of CS caused by an adrenal adenoma. Following laparoscopic adrenalectomy, the patient's symptoms rapidly improved. This case underscores the importance of considering CS in the differential diagnosis of edema and skin ulceration, especially when clinical presentations deviate from the norm. It highlights the complexity of CS pathogenesis and the need for thorough evaluation to prevent misdiagnosis, emphasizing that not all patients will present with or recognize the classic.

Three-Dimensional Fast Spin Echo Pituitary MRI in Treatment-Naïve Cushing's Disease: Reduced Impact of Reader Experience and Increased Diagnostic Accuracy

BACKGROUND

In patients with Cushing's disease, the preoperative identification of pituitary adenomas is crucial to treatment. However, increasing diagnostic accuracy remains an unresolved issue.

PURPOSE

To evaluate the diagnostic accuracy and the impact of readers' experience regarding high-resolution contrast-enhanced magnetic resonance imaging (hrMRI) for identifying pituitary adenomas in comparison with conventional contrast-enhanced MRI (cMRI) and dynamic contrast-enhanced MRI (dMRI).

STUDY TYPE

Retrospective.

POPULATION

Sixty-five patients (median age, 39 years; interquartile range [IQR], 28-53 years; 60% females) with treatment-naïve Cushing's disease.

FIELD STRENGTH/SEQUENCE

3-T, seven fast spin echo sequences.

ASSESSMENT

The diagnostic accuracies of identifying pituitary adenomas on cMRI, dMRI, combined cMRI and dMRI (cdMRI), and hrMRI were independently evaluated by six readers with three experience levels (high: >20 years, modest: 10-20 years, low: <10 years; two readers for each experience level). Readers were asked to localize the lesion, and measure its diameter on the sequence where identified. The reference standard was postoperative histopathology. The impact of readers' experience and interobserver agreement were assessed. Image quality was assessed using a 5-point Likert scale, including overall image quality, sharpness, and structural conspicuity.

STATISTICAL TESTS

McNemar's test, Cochran's test, Wilcoxon signed-rank test, Mann-Whitney U test, and κ statistics for interobserver agreement. A P-value <0.05 was considered statistically significant.

RESULTS

For identifying pituitary adenomas (median diameter, 5 mm; IQR, 4-5 mm), hrMRI had significantly higher sensitivity (87.7%-93.8%) than cMRI, dMRI, and cdMRI (52.3%-75.4%) for readers with different experience levels. The interobserver agreement was moderate (κ = 0.461-0.523). The sensitivity for hrMRI was comparable between readers with different experience levels (P = 0.371). All image quality scores on hrMRI were significantly higher than cMRI and dMRI (5.0 vs. 4.0).

DATA CONCLUSION

For identifying pituitary adenomas in patients with treatment-naïve Cushing's disease, hrMRI may show high diagnostic accuracy and seems not to be affected by readers' experience.

LEVEL OF EVIDENCE

3 TECHNICAL EFFICACY: Stage 2.

Adipose tissue in cortisol excess: What Cushing's syndrome can teach us?

Endogenous Cushing's syndrome (CS) is a rare condition due to prolonged exposure to elevated circulating cortisol levels that features its typical phenotype characterised by moon face, proximal myopathy, easy bruising, hirsutism in females and a centripetal distribution of body fat. Given the direct and indirect effects of hypercortisolism, CS is a severe disease burdened by increased cardio-metabolic morbidity and mortality in which visceral adiposity plays a leading role. Although not commonly found in clinical setting, endogenous CS is definitely underestimated leading to delayed diagnosis with consequent increased rate of complications and reduced likelihood of their reversal after disease control. Most of all, CS is a unique model for systemic impairment induced by exogenous glucocorticoid therapy that is commonly prescribed for a number of chronic conditions in a relevant proportion of the worldwide population. In this review we aim to summarise on one side, the mechanisms behind visceral adiposity and lipid metabolism impairment in CS during active disease and after remission and on the other explore the potential role of cortisol in promoting adipose tissue accumulation.

Corticotropin-releasing hormone test predicts the outcome of unilateral adrenalectomy in primary bilateral macronodular adrenal hyperplasia

PURPOSE

Primary bilateral adrenal hyperplasia (PBMAH) is associated with hypercortisolism and a heterogeneous clinical expression in terms of cortisol secretion and related comorbidities. Historically, treatment of choice was bilateral adrenalectomy (B-Adx); however, recent data suggest that unilateral adrenalectomy (U-Adx) may be an effective alternative. For the latter, factors predicting the postsurgical outcome (e.g., biochemical control) have not been identified yet.

METHODS

PBMAH patients undergoing U-Adx for overt Cushing's syndrome (CS) in two tertiary care centers were retrospectively analysed. Remission was defined as a normalization of urinary free cortisol (UFC) without the need for medical treatment. The potential of hCRH test as a predictor of U-Adx outcome was evaluated in a subgroup.

RESULTS

23 patients were evaluated (69% females, mean age 55 years). Remission rate after U-Adx was 74% at last follow up (median 115 months from UAdx). Before U-Adx, a positive ACTH response to hCRH (Δ%ACTH increase > 50% from baseline) was associated with higher remission rates.

CONCLUSIONS

Three of four patients with PBMAH are surgically cured with U-Adx. Pre-operative hCRH testing can be useful to predict long-term remission rates.

Genetically predicted plasma cortisol and common chronic diseases: A Mendelian randomization study

OBJECTIVE

Cushing's syndrome is characterized by hypercortisolaemia and is frequently accompanied by comorbidities such as type 2 diabetes, hypertension, osteoporosis, depression and schizophrenia. It is unclear whether moderate but lifelong hypercortisolaemia is causally associated with these diseases in the general population. We aimed to address this research gap using a Mendelian randomization approach.

METHODS

We used three cortisol-associated genetic variants in the SERPINA6/SERPINA1 region as genetic instruments in a two-sample, inverse-variance-weighted Mendelian randomization analysis. We obtained summary-level statistics for cortisol and disease outcomes from publicly available genetic consortia, and meta-analysed them as appropriate. We conducted a multivariable Mendelian randomization analysis to assess potential mediating effects.

RESULTS

A 1 standard deviation higher genetically predicted plasma cortisol was associated with greater odds of hypertension (odds ratio: 1.12; 95% confidence interval [CI]: 1.05-1.18) as well as higher systolic blood pressure (mean difference [MD]: 0.03 SD change; 95% CI: 0.01-0.05) and diastolic blood pressure (MD: 0.03 SD change; 95% CI: 0.01-0.04). There was no evidence of association with type 2 diabetes, osteoporosis, depression and schizophrenia. The association with hypertension was attenuated upon adjustment for waist circumference, suggesting potential mediation through central obesity.

CONCLUSION

There is strong evidence for a causal association between plasma cortisol and greater risk for hypertension, potentially mediated by obesity.

Bilateral inferior petrosal sinus sampling: Procedural data from a German single-center study

PURPOSE

To assess radiation exposure and diagnostic performance of bilateral inferior petrosal sinus sampling for the distinction of pituitary and ectopic adrenocorticotropin-dependent Cushing's syndrome.

MATERIALS AND METHODS

Procedural data of bilateral inferior petrosal sinus procedures were retrospectively evaluated. The analysis included the patients' clinical and demographic data, procedural radiation exposure, and complication rates, sampling results, clinical course of the patients, and calculation of diagnostic performance data.

RESULTS

The cases of 46 patients diagnosed with adrenocorticotropin-dependent Cushing's syndrome were evaluated. Bilateral inferior petrosal sinus sampling was successfully performed in 97.8 % of the cases. The overall median procedure-related fluoroscopy time was 7.8 min. (range 3.2-36.2 min.), and the median procedural dose area product was 11.9 Gy*cm2 (range 2.1-73.7 Gy*cm2). Radiation doses due to digital subtraction angiography series for visualization of the inferior petrosal sinus were 3.6 Gy*cm2 (range 1.0-18.1 Gy*cm2). Radiation doses due to fluoroscopy had a higher impact on the overall radiation exposure and were significantly influenced by the patients' habitus. The sensitivity, specificity, and positive and negative predictive values were 84 %, 100 %, 100 %, and 72 % before stimulation with corticotropin-releasing hormone, and 97 %, 100 %, 100 %, and 93 % after stimulation. Concordance between magnetic resonance imaging studies and bilateral inferior petrosal sinus sampling results was only found in 35.6 % of the cases. The periprocedural complication rate was 2.2 %, with one patient experiencing vasovagal syncope during catheterization.

CONCLUSION

Bilateral inferior petrosal sinus sampling is a safe procedure with high technical success rates und excellent diagnostic performance. The procedure-related radiation exposure shows large variations and depends on the complexity of cannulation as well as the patients' habitus. Fluoroscopy accounted for the largest proportion of radiation exposure. Acquisition of digital subtraction angiography series for the verification of correct catheter placement appears justified.

KEY POINTS

· Bilateral inferior petrosal sinus sampling with CRH stimulation provides high diagnostic performance in the distinction of pituitary and ectopic Cushing's syndrome.. · The associated radiation exposure is not negligible and is significantly influenced by the use of fluoroscopy and the patients' habitus.. · Digital subtraction angiography contributes less to the overall radiation dose and appears justified for the verification of correct catheter placement..

CITATION FORMAT

· Augustin A, Detomas M, Hartung V et al. Bilateral inferior petrosal sinus sampling: Procedural data from a German single-center study. Fortschr Röntgenstr 2023; 195: 1009 - 1017.

High-resolution contrast-enhanced MRI with three-dimensional fast spin echo improved the diagnostic performance for identifying pituitary microadenomas in Cushing's syndrome

OBJECTIVES

To assess the diagnostic performance of high-resolution contrast-enhanced MRI (hrMRI) with three-dimensional (3D) fast spin echo (FSE) sequence by comparison with conventional contrast-enhanced MRI (cMRI) and dynamic contrast-enhanced MRI (dMRI) with 2D FSE sequence for identifying pituitary microadenomas.

METHODS

This single-institutional retrospective study included 69 consecutive patients with Cushing's syndrome who underwent preoperative pituitary MRI, including cMRI, dMRI, and hrMRI, between January 2016 to December 2020. Reference standards were established by using all available imaging, clinical, surgical, and pathological resources. The diagnostic performance of cMRI, dMRI, and hrMRI for identifying pituitary microadenomas was independently evaluated by two experienced neuroradiologists. The area under the receiver operating characteristics curves (AUCs) were compared between protocols for each reader by using the DeLong test to assess the diagnostic performance for identifying pituitary microadenomas. The inter-observer agreement was assessed by using the κ analysis.

RESULTS

The diagnostic performance of hrMRI (AUC, 0.95-0.97) was higher than cMRI (AUC, 0.74-0.75; p ≤ .002) and dMRI (AUC, 0.59-0.68; p ≤ .001) for identifying pituitary microadenomas. The sensitivity and specificity of hrMRI were 90-93% and 100%, respectively. There were 78% (18/23) to 82% (14/17) of the patients, who were misdiagnosed on cMRI and dMRI and correctly diagnosed on hrMRI. The inter-observer agreement for identifying pituitary microadenomas was moderate on cMRI (κ = 0.50), moderate on dMRI (κ = 0.57), and almost perfect on hrMRI (κ = 0.91), respectively.

CONCLUSIONS

The hrMRI showed higher diagnostic performance than cMRI and dMRI for identifying pituitary microadenomas in patients with Cushing's syndrome.

KEY POINTS

• The diagnostic performance of hrMRI was higher than cMRI and dMRI for identifying pituitary microadenomas in Cushing's syndrome. • About 80% of patients, who were misdiagnosed on cMRI and dMRI, were correctly diagnosed on hrMRI. • The inter-observer agreement for identifying pituitary microadenomas was almost perfect on hrMRI.

Ketoconazole as second-line treatment for Cushing's disease after transsphenoidal surgery: systematic review and meta-analysis

Introduction

The first-line treatment for Cushing's disease is transsphenoidal surgery for pituitary tumor resection. Ketoconazole has been used as a second-line drug despite limited data on its safety and efficacy for this purpose. The objective of this meta-analysis was to analyze hypercortisolism control in patients who used ketoconazole as a second-line treatment after transsphenoidal surgery, in addition to other clinical and laboratory criteria that could be related to therapeutic response.

Methods

We searched for articles that evaluated ketoconazole use in Cushing's disease after transsphenoidal surgery. The search strategies were applied to MEDLINE, EMBASE, and SciELO. Independent reviewers assessed study eligibility and quality and extracted data on hypercortisolism control and related variables such as therapeutic dose, time, and urinary cortisol levels.

Results

After applying the exclusion criteria, 10 articles (one prospective and nine retrospective studies, totaling 270 patients) were included for complete data analysis. We found no publication bias regarding reported biochemical control or no biochemical control (p = 0.06 and p = 0.42 respectively). Of 270 patients, biochemical control of hypercortisolism occurred in 151 (63%, 95% CI 50-74%) and no biochemical control occurred in 61 (20%, 95% CI 10-35%). According to the meta-regression, neither the final dose, treatment duration, nor initial serum cortisol levels were associated with biochemical control of hypercortisolism.

Conclusion

Ketoconazole can be considered a safe and efficacious option for Cushing's disease treatment after pituitary surgery.

Systematic review registration

https://www.crd.york.ac.uk/prospero/#searchadvanced, (CRD42022308041).

An evaluation of pharmacological options for Cushing's disease: what are the state-of-the-art options?

INTRODUCTION

Untreated Cushing's syndrome (CS) is associated with significant morbidity and mortality. Cortisol normalization is a key goal to treatment. Pituitary surgery remains the first-line approach for Cushing's disease, but sometimes it is impracticable, unsuccessful, or complicated by recurrence. Medical therapy has been historically considered a palliative. However, in the latest years, interest on this topic has grown due to both the availability of new drugs and the reevaluation of the old, commonly used drugs in clinical practice.

AREAS COVERED

In this article, we will discuss the current options and future directions of medical therapy for CS, aiming at fitting best patients' features. An extensive literature search regarding already approved and investigational principles was conducted (PubMed, ClinicalTrials.gov. Available drugs include inhibitors of ACTH secretion, steroidogenesis inhibitors, and glucocorticoid receptor antagonists; drugs acting at different levels can be also combined in uncontrolled patients.

EXPERT OPINION

Since there is still no standardized pharmacological approach and the superiority of one drug over another has not been established yet in the absence of comparative studies, each time clinicians' choices should be patient-tailored. Age, gender, tumor features, severity of hypercortisolism, comorbidities/complications, rapidity of action, side effects, drug-drug interactions, contraindications, availability, patients' preferences, and costs should be all considered.

Dynamic testing for differential diagnosis of ACTH-dependent Cushing Syndrome: a systematic review and meta-analysis

OBJECTIVE

Diagnostic accuracy of testing currently used for the differential diagnosis of Cushing's disease (CD) vs ectopic -ACTH secretion (EAS) is difficult to interpret. The present study aimed to identify and evaluate the diagnostic accuracy of corticotropin-releasing hormone (CRH) test, desmopressin test, and high-dose dexamethasone suppression test (HDDST) when used to establish a CD or EAS diagnosis.

DESIGN

This study is a systematic review of the literature and meta-analysis.

METHODS

MEDLINE, OVID, and Web of Science databases were searched for articles published between the years 1990-2021. Articles included described at least one test(s) (CRH, desmopressin, or HDDST) and the diagnostic reference standard(s) (histopathology, petrosal sinus sampling, surgical remission, imaging, and long-term follow-up) used to establish a CD or EAS diagnosis.

RESULTS

Sixty-two studies were included: 43 reported the use of HDDST, 32 CRH test, and 21 desmopressin test. CRH test was found to have the highest sensitivity in detecting CD (ACTH 86.9%, 95% confidence interval [CI] 82.1-90.6, cortisol 86.2%, 95%CI 78.3-91.5) and the highest specificity in detecting EAS (ACTH 93.9%, 95%CI 87-98.3, cortisol 89.4%, 95%CI 82.8-93.7). This resulted in a high diagnostic odds ratio (58, 95%CI 43.25-77.47), large area under the curve, and a receiver-operating characteristic (ROC) of 0.934. The diagnostic accuracy of HDDST and desmopressin test(s) was lower than that of the CRH test.

CONCLUSION

The meta-analysis indicates that a patient with a positive ACTH response after a CRH test is highly likely to have CD. Further studies analysing role of dynamic testing in addition to imaging are needed.

Diagnostic accuracy of bilateral inferior petrosal sinus sampling using desmopressin or corticotropic- releasing hormone in ACTH-dependent Cushing's syndrome: A systematic review and meta-analysis

The current gold standard diagnostic method for Cushing disease (CD) is bilateral inferior petrosal sinus sampling (BIPSS) after corticotropin-releasing hormone (CRH) stimulation. Due to shortages of CRH, BIPSS has been performed with desmopressin (DDAVP) instead. The objective of this systematic review and meta-analysis was to estimate the diagnostic accuracy of BIPSS using DDAVP or CRH for the differential diagnosis of Cushing's syndrome (CS). A literature review was done in PubMed, Scopus, EMBASE, and google scholar databases to derive summary estimates of the overall diagnostic sensitivity and accuracy of BIPSS using DDAVP or CRH in Cushing's syndrome. Pooled sensitivity, specificity, diagnostic odds ratio and summary receiver operating characteristic curves (SROC) for differential diagnosis of Cushing's syndrome in the random-effects models, were computed. Overall, 11 different studies with a total of 612 participants, were eligible for the analysis. Five articles with data on BIPSS using DDAVP, 5 papers on BIPSS using CRH, and another one evaluated the results of stimulation using DDAVP, with or without CRH, for differential diagnosis of Cushing's syndrome. The pooled (95% CI) sensitivity and specificity of BIPSS using DDAVP, were 96% (91-98%) and 1.00 (0.00-1.00), respectively. The area under the SROC curve was 0.95. The pooled (95% CI) sensitivity and specificity of BIPSS using CRH, were 98% (92-99%) and 1.00 (0.00-1.00), respectively, and the area under the SROC curve was 0.98. The I² index (95% CI) was 0% (0-100%) for both BIPSS using DDAVP and using CRH. As a result, DDAVP stimulation is a safe, effective, less expensive, valuable and available alternative to CRH in the setting of BIPSS for all age groups of patients with CS. Registration code in PROSPERO: CRD42021292531.

β-cell function and insulin sensitivity contributions on incident diabetes in patients with endogenous Cushing's syndrome

OBJECTIVE

To evaluate the relative contributions of β-cell function and insulin sensitivity on the deterioration of glucose tolerance from OGTT in patients with endogenous CS.

METHODS

We retrospectively analyzed the data of 60 patients with CS and determined the glucose metabolism and β-cell function through OGTT. Their general characteristics were retrieved. A series of parameters for assessing insulin sensitivity and β-cell function was calculated. The logistic regression model was used to investigate insulin sensitivity and β-cell function contributions on incident diabetes.

RESULTS

Of the 60 patients with CS, 10 (16.7%), 21 (35%), and 29 (48.3%) were classified as CS/ normal glucose tolerance (NGT), CS/prediabetes, and CS/diabetes mellitus (DM). Compared with the HCs, the CS/NGT patients had higher HOMA-IR and lower ISI-Matsuda but with a compensatory increase in HOMA-β. Significant decreasing trends were observed in HOMA-β, AUC_I/G and ΔI₃₀/ΔG₃₀ among CS/NGT, CS/prediabetes and CD/DM groups. The OR of incident diabetes compared with the high AUC_I/G/high ISI group was significant in the low AUC_I/G/high ISI group.

CONCLUSION

Impairment of the β-cell function had a more profound effect on incident diabetes than decreased insulin sensitivity. An approach based on an OGTT has utility for diagnosing dysglycaemia and β-cell dysfunction in patients with CS.

The Effect of Endogenous Cushing Syndrome on All-cause and Cause-specific Mortality

OBJECTIVE

We aimed to perform a systematic review and meta-analysis of all-cause and cause-specific mortality of patients with benign endogenous Cushing syndrome (CS).

METHODS

The protocol was registered in PROSPERO (CRD42017067530). PubMed, EMBASE, CINHAL, Web of Science, and Cochrane Central searches were undertaken from inception to January 2021. Outcomes were the standardized mortality ratio (SMR), proportion, and cause of deaths. The I2 test, subgroup analysis, and meta-regression were used to assess heterogeneity across studies.

RESULTS

SMR was reported in 14 articles including 3691 patients (13 Cushing disease [CD] and 7 adrenal CS [ACS] cohorts). Overall SMR was 3.0 (95% CI, 2.3-3.9; I2 = 80.5%) for all CS, 2.8 (95% CI, 2.1-3.7; I2 = 81.2%) for CD and 3.3 (95% CI, 0.5-6.6; I2 = 77.9%) for ACS. Proportion of deaths, reported in 87 articles including 19 181 CS patients (53 CD, 24 ACS, and 20 combined CS cohorts), was 0.05 (95% CI, 0.03-0.06) for all CS subtypes with meta-regression analysis revealing no differences between CS subtypes (P = .052). The proportion of deaths was 0.1 (10%) in articles published before 2000 and 0.03 (3%) in 2000 until the last search for CS (P < .001), CD (P < .001), and ACS (P = .01). The causes of death were atherosclerotic diseases and thromboembolism (43.4%), infection (12.7%), malignancy (10.6%), active disease (3.5%), adrenal insufficiency (3.0%), and suicide (2.2%). Despite improved outcomes in recent years, increased mortality from CS persists. The causes of death highlight the need to prevent and manage comorbidities in addition to treating hypercortisolism.

Indication to dynamic and invasive testing in Cushing's disease according to different neuroradiological findings

PURPOSE

Dynamic testing represents the mainstay in the differential diagnosis of ACTH-dependent Cushing's syndrome. However, in case of undetectable or detectable lesion < 6 mm on MRI, bilateral inferior petrosal sinus sampling (BIPSS) is suggested by current guidelines. Aim of this study was to analyze the performance of CRH, desmopressin and high-dose dexamethasone suppression test (HDDST) in the differential diagnosis of ACTH-dependent Cushing's syndrome as well as the impact of invasive and noninvasive tests on surgical outcome in patients affected by Cushing's disease (CD).

METHODS

Retrospective analysis on 148 patients with CD and 26 patients with ectopic ACTH syndrome.

RESULTS

Among CD patients, negative MRI/lesion < 6 mm was detected in 97 patients (Group A); 29 had a 6-10 mm lesion (Group B) and 22 a macroadenoma (Group C). A positive response to CRH test, HDSST and desmopressin test was recorded in 89.4%, 91·4% and 70.1% of cases, respectively. Concordant positive response to both CRH/HDDST and CRH/desmopressin tests showed a positive predictive value of 100% for the diagnosis of CD. Among Group A patients with concordant CRH test and HDDST, no difference in surgical outcome was found between patients who performed BIPSS and those who did not (66.6% vs 70.4%, p = 0.78).

CONCLUSIONS

CRH, desmopressin test and HDDST have high accuracy in the differential diagnosis of ACTH-dependent CS. In patients with microadenoma < 6 mm or non-visible lesion, a concordant positive response to noninvasive tests seems sufficient to diagnose CD, irrespective of MRI finding. In these patients, BIPSS should be reserved to discordant tests.

Osilodrostat oral tablets for adults with Cushing's disease

INTRODUCTION

Endogenous Cushing's syndrome (CS) is a rare, multi-systemic condition resulting from chronic glucocorticoid excess sustained by a pituitary adenoma (Cushing's disease, CD), an adrenal adenoma or, less frequently, a neuroendocrine tumor. The optimal first-line option is surgery, but when it is contraindicated/refused, or in case of severe, life-threatening disease, medical treatment is a first-line choice. Osilodrostat (LCI699, Isturisa®) is a new, orally active adrenal steroidogenesis inhibitor currently approved by the FDA and EMA for the treatment of endogenous CS.

AREAS COVERED

We illustrate the pharmacologic profile of osilodrostat and summarize the efficacy and safety of osilodrostat from the first phase I studies to the most recent evidence.

EXPERT OPINION

Osilodrostat acts as a potent, reversible inhibitor of 11β-hydroxylase (CYP11B1) and 18-hydroxylase (or aldosterone synthase, CYP11B2), counteracting both gluco- and mineralocorticoid production. According to the results of the LINC1, LINC2, and LINC3 studies and the preliminary findings of LINC4, osilodrostat offers an excellent efficacy in controlling hypercortisolism with a good tolerability. The non-negligible risk of adrenal insufficiency/steroid withdrawal symptoms, hypokalemia, and hyperandrogenism disorders, and the possibility, albeit rare, of pituitary tumor enlargement, require further confirmation and careful monitoring.

High-dose dexamethasone suppression test is inferior to pituitary dynamic enhanced MRI in the differential diagnosis of ACTH-dependent Cushing's syndrome

PURPOSE

The differential diagnosis of adrenocorticotropic hormone (ACTH)-dependent Cushing's syndrome remains a challenge in clinical practice. The present study was aimed at assessing the diagnostic performance of pituitary dynamic contrast-enhanced magnetic resonance imaging (dMRI), high-dose dexamethasone suppression test (HDDST), and a combination of both tests for patients with ACTH-dependent Cushing's syndrome.

METHODS

A total of 119 consecutive patients with ACTH-dependent Cushing's syndrome confirmed surgically were enrolled: 101 with proven Cushing's disease and 18 with proven ectopic ACTH syndrome. All patients underwent pituitary dMRI and HDDST. The sensitivity and specificity of pituitary dMRI, HDDST, and a combination of both tests were determined.

RESULTS

The sensitivity and specificity of pituitary dMRI for diagnosing Cushing's disease were 80.2 and 83.3%, respectively, with a positive predictive value of 96.4%. The sensitivity and specificity of HDDST were 70.3 and 77.8%, respectively, with positive predictive value of 94.7%. A combination of both tests showed that the combined criteria of more than 50% suppression of serum cortisol on HDDST and a positive pituitary dMRI finding yielded a high specificity of 94.4 and sensitivity of 59.4%. The combined criteria of more than 68% suppression on HDDST and/or a positive pituitary dMRI finding yielded a sensitivity of 86.1% and specificity of 83.3%.

CONCLUSIONS

Pituitary dMRI was superior to HDDST in the differential diagnosis of ACTH-dependent Cushing's syndrome. HDDST is recommended in combination with pituitary dMRI to establish a diagnosis process because of the significantly increased specificity with the combination.

The promising role of risk scoring system for Cushing syndrome: Time to reconsider current screening recommendations

Despite the current screening approach for Cushing syndrome (CS), delayed diagnosis is common due to broad spectrum of presentation, poor discriminant symptoms featured in diabetes and obesity, and low clinical index of suspicion. Even if initial tests are recommended to screen CS, divergent results are not infrequent. As global prevalence of type 2 diabetes and obesity increases, CS may not be frequent enough to back routine screening to avoid false-positive results. This represents a greater challenge in countries with limited health resources. The development of indexes incorporates clinical features and biochemical data that are largely used to provide a tool to predict the presence of disease. In clinical endocrinology, indexes have been used in Graves' ophthalmology, hirsutism, and hypothyroidism. The use of clinical risk scoring system may assist clinicians in discriminating CS in the context of at-risk populations and, thus, may provide a potential intervention to decrease time to diagnosis. Development and validation of clinical model to estimate pre-test probability of CS in different geographic source population may help to establish regional prediction model for CS. Here, we review on the latest progress in clinical risk scoring system for CS and attempt to raise awareness for the use, validation, and/or development of clinical risk scores in CS.

Selective resection of cushing microadenoma guided by preoperative hybrid 18-fluoroethyl-L-tyrosine and 11-C-methionine PET/MRI

PURPOSE

11-C-methionine (MET)-positron emission tomography (PET) as an adjunct to magnetic resonance imaging (MRI) has been proposed as a suitable molecular imaging modality for localizing pituitary adenomas in Cushing's disease. 18-F-Fluoroethyl-L-tyrosine (FET)-PET, which is more widely available has not yet been reported in this context.

METHODS

Retrospective double-center cohort study on 15 patients who underwent transsphenoidal surgery for biochemically proven Cushing's disease between 2011 and 2019. Preoperative MET-PET/MRI and/or FET-PET/MRI were compared with intraoperative and histopathological examinations using the Mann Whitney U test and the Fisher's Exact test, along with positive predictive value calculations.

RESULTS

Fifteen patients were included, with a mean age of 47.2 (18-69) years. Six patients received either a MET-PET/MRI or a FET-PET/MRI and 3 patients both exams, respectively. 67% of the tumors were detected by MRI (MET-PET-group [56%]; FET-PET-group [78%]). All tumors were microadenomas with a mean adenoma volume of 0.19 cm3 (0.02-0.78), all of which displayed a circumscribed pathological FET- and/or MET-uptake. FET-PET/MRI results positively correlated with the localization of the tumor confirmed intraoperatively and histopathologically in all cases, resulting in a sensitivity and specificity of FET-PET/MRI for tumor localization of 100% (95% CI 66.37-100%). One MET-PET/MRI suggested a localization contralateral to the expected spot. The sensitivity and specificity of MET-PET for tumor localization hence was 89% (95% CI 51.75-99.72%).

CONCLUSIONS

Preoperative hybrid FET-PET/MRI and MET-PET/MRI have a high predictive value in localizing corticotroph adenoma for selective adenomectomy in Cushing's disease.

Frequently asked questions and answers (if any) in patients with adrenal incidentaloma

PURPOSE

Adrenal incidentalomas (AIs) are incidentally discovered adrenal masses, during an imaging study undertaken for other reasons than the suspicion of adrenal disease. Their management is not a minor concern for patients and health-care related costs, since their increasing prevalence in the aging population. The exclusion of malignancy is the first question to attempt, then a careful evaluation of adrenal hormones is suggested. Surgery should be considered in case of overt secretion (primary aldosteronism, adrenal Cushing's Syndrome or pheochromocytoma), however the management of subclinical secretion is still a matter of debate.

METHODS

The aim of the present narrative review is to offer a practical guidance regarding the management of AI, by providing evidence-based answers to frequently asked questions.

CONCLUSION

The clinical experience is of utmost importance: a personalized diagnostic-therapeutic approach, based upon multidisciplinary discussion, is suggested.

Second-Line Tests in the Diagnosis of Adrenocorticotropic Hormone-Dependent Hypercortisolism

Cushing’s syndrome (CS) is a rare disease caused by chronic and excessive cortisol secretion. When adrenocorticotropin hormone (ACTH) is measurable, autonomous adrenal cortisol secretion could be reasonably ruled out in a differential diagnosis of CS. ACTH-dependent CS accounts for 80%–85% of cases and involves cortisol production stimulated by uncontrolled pituitary or ectopic ACTH secretion. Pituitary adenoma is not detected in up to one-third of cases with pituitary ACTH secretion, whereas cases of CS due to ectopic ACTH secretion may be associated with either malignant neoplasia (such as small cell lung carcinoma) or less aggressive neuroendocrine tumors, exhibiting only the typical symptoms and signs of CS. Since the differential diagnosis of ACTH-dependent CS may be a challenge, many strategies have been proposed. Since none of the available tests show 100% diagnostic accuracy, a step-by-step approach combining several diagnostic tools and a multidisciplinary evaluation in a referral center is suggested. In this review, we present a clinical case to demonstrate the diagnostic work-up of ACTH-dependent CS. We describe the most commonly used dynamic tests, as well as the applications of conventional or nuclear imaging and invasive procedures.

Effectiveness of Medical Treatment of Cushing's Disease: A Systematic Review and Meta-Analysis

Objective

The objective of this systematic review was to evaluate the effectiveness and safety of pasireotide, cabergoline, ketoconazole, levoketoconazole, metyrapone, osilodrostat, and temozolomide for the treatment of Cushing's disease (CD).

Methods

The primary outcomes were the proportion of CD control, adverse events (AE), and reduction of urinary free cortisol. Search strategies were applied to Embase, Medline, and CENTRAL. Independent reviewers assessed the study eligibility, extracted data, and evaluated risk of bias. Standardized mean difference was calculated with 95% confidence interval (CI) for continuous data (i.e., pre- and post-intervention). Random meta-analyses for the proportion of CD control and AE were conducted.

Results

Twenty-nine controlled and non-controlled studies were included. No study with temozolomide and levoketoconazole and one study with osilodrostat fulfilled the inclusion criteria. The meta-analyses of proportion of CD control was 35% for cabergoline (95% CI: 27-43%, six studies, 141 participants), 44% for pasireotide (95% CI: 25-35%, eight studies, 522 participants), 41% for ketoconazole (95% CI: 36-46%, six studies, 450 participants), 66% for metyrapone (95% CI: 46-87%, four studies, 66 participants), and of 66.4% for osilodrostat (95% CI: 57.9, 74.3, 97 participants, one study). One study compared two different treatments (cabergoline vs. ketoconazole), and no statistical difference was observed in CD control (RR: 0.53, 95% CI: 0.15 to 1.87, 14 participants, very low certainty of evidence). The most frequent AE associated with pasireotide was hyperglycemia, dizziness and nausea with cabergoline and metyrapone, and elevated transaminases with ketoconazole.

Conclusion

The superiority of one drug over another could not be determined due to lack of controlled studies, but the proportion of disease control identified in our meta-analysis may support clinical decision. New therapeutic options should be investigated due to the limited efficacy and tolerability of the currently available medical treatment for patients with Cushing's disease.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42020205567, identifier CRD42020205567.

Refractory hypokalaemia and hypertension with metabolic alkalosis: an acute presentation of Cushing's disease secondary to a pituitary macroadenoma

A 68-year-old woman presented with right arm cellulitis, not responsive to oral antibiotics. Intravenous antibiotics were commenced, and an ultrasound scan confirmed a collection that was surgically drained. She developed refractory hypokalaemia with normal magnesium, no gastrointestinal losses and no iatrogenic cause. She was hypertensive, hyperglycaemic, alkalotic, clinically obese with proximal myopathy and skin bruising. These clinical findings and refractory hypokalaemic hypertension with metabolic alkalosis raised a suspicion of Cushing's syndrome (CS). 24-hour urinary free cortisol (24 hours) was grossly raised on two occasions. The adrenocorticotropic hormone (ACTH) was significantly raised at 154 ng/L, confirming ACTH-dependant CS. A CT scan of the thorax, abdomen and pelvis excluded an ectopic source of hypercortisolaemia. MRI pituitary revealed an invasive macroadenoma. Treatment with endoscopic debulking resulted in the resolution of hypokalaemia and metabolic alkalosis with significant improvement in hyperglycaemia and hypertension.

The usefulness of the combined high-dose dexamethasone suppression test and desmopressin stimulation test in establishing the source of ACTH secretion in ACTH-dependent Cushing's syndrome

Bilateral inferior petrosal sinus sampling (BIPSS) is the current gold standard test for differentially diagnosing ACTH-dependent Cushing's syndrome (CS). However, BIPSS is an invasive procedure, and its availability is limited. We retrospectively analysed the 24-hour urinary free cortisol (UFC) level during the high-dose dexamethasone suppression test (HDDST) and plasma ACTH/cortisol levels after the desmopressin stimulation test (DDAVP test) in subjects with confirmed Cushing's disease (CD) (n = 92) and ectopic ACTH-dependent CS (EAS) (n = 16), and evaluated the positive predictive value (PPV) of the two combined-tests in the aetiological diagnosis of ACTH-dependent CS. The percent changes in UFC levels after the HDDST and in ACTH/cortisol levels after DDAVP administration relative to the corresponding basal levels and the area under the receiver operating characteristic (ROC) curve (AUC) were analysed. UFC suppression below 62.7% suggested a pituitary origin with a sensitivity (SE) of 80% (95% CI: 70-88) and a specificity (SP) of 80% (95% CI: 52-96). A threshold increase in the ACTH level after DDAVP stimulation of 44.6% identified CD with an SE of 91% (95% CI: 83-97) and an SP of 75% (95% CI: 48-93). The combination of both tests yielded an SE of 95.5% and PPV of 98.4% for CD, and significantly improved the efficiency of the differential diagnosis between CD and EAS. These dual non-invasive endocrine tests may substantially reduce the need for BIPSS in the etiological investigation of ACTH-dependent CS.

A multidisciplinary approach to the management of adrenal incidentaloma

An adrenal incidentaloma (AI) is an adrenal neoplasm incidentally discovered during an imaging unrelated to suspected adrenal disease. The aim of the present review is to offer practical guidance on the multidisciplinary approach of AIs.Areas covered:The prevalence of AI is high in the aging population (up to 5-8%); however, hormonally active or malignant conditions are rare. After the discovery of an AI, it is suggested to assess in parallel if the mass is potentially malignant and functionally active. The answer to the former question is mainly based on medical history (extra-adrenal malignancies, new-onset of signs or symptoms) and imaging (conventional radiology and/or nuclear medicine). The answer to the latter question is a complete endocrine evaluation of both cortical (glucocorticoids, mineralocorticoids) and medullary (catecholamines) secretion.Expert opinion:A multidisciplinary discussion is suggested for patients with adrenal disease, after the exclusion of nonfunctioning benign cortical adenoma, in order to plan a close and tailored follow-up for the suspected malignant or functioning forms. Surgery is advised for patients with malignant disease (adrenocortical cancer) or with clinically relevant secreting neoplasm (primary aldosteronism, Cushing's syndrome, and pheochromocytoma).

Cushing Syndrome Associated Myopathy: It Is Time for a Change

Cushing syndrome is the result of excessive levels of glucocorticoids. Endogenous Cushing syndrome is rare with an incidence of two to three cases per million per year. Clinically, the presentation consists of a characteristic phenotype including skin symptoms and metabolic manifestations. A frequent co-morbidity with high impact on quality of life is Cushing syndrome associated myopathy. It characteristically affects the proximal myopathy, impairing stair climbing and straightening up. The pathophysiology is complex and involves protein degradation via the forkhead box O3 (FOXO3) pathway, intramuscular fat accumulation, and inactivity-associated muscle atrophy. Surgical remission of Cushing syndrome is the most important step for recovery of muscle function. Restoration depends on age, co-morbidities and postoperative insulin-like growth factor concentrations. At average, functionality remains impaired during the long-term compared to age and sex matched control persons. Growth hormone therapy in individuals with impaired growth hormone secretion could be an option but has not been proved in a randomized trial.

A case series of bilateral inferior petrosal sinus sampling with desmopressin in evaluation of ACTH-dependent Cushing's syndrome in Iran

BACKGROUND

Differentiating the etiology of ACTH-dependent Cushing's syndrome (CS) has remained challenging due to the limited accuracy of noninvasive assays. Nowadays, bilateral inferior petrosal sinus sampling (BIPSS) with corticotropin-releasing hormone (CRH) is the gold standard method in the diagnostic work-up of complex CS. However, this method is as yet far from being widespread. The limited utility of this method could be due to many factors such as limited availability of an experienced interventionist, limited availability of CRH, and cost of the procedure. So far, very few studies have been conducted using desmopressin instead of CRH. In this study, we report the use of BIPSS with desmopressin as a diagnostic tool in a series of patients with suspected Cushing's disease (CD) and equivocal imaging in a tertiary referral center in Iran.

METHODS

A total of 13 patients with ACTH-dependent CS and no significant lesions in their pituitary MRI participated in this retrospective case series. All patients underwent BIPSS with desmopressin, and, following centralization of CS, transsphenoidal surgery (TSS) was carried out and diagnosis of CD was confirmed using standard methods.

RESULTS

Of the 13 patients with confirmed CD (by pathology or biochemical response after surgery), eight (61.5%) were female, with a median age of 32 years (IQR: 26-41). The median duration of disease was 24 months (IQR: 11-48). During BIPSS, all patients had a central-to-peripheral gradient greater than 2 under basal conditions. This central-to-peripheral gradient did not increase to > 3 after desmopressin administration in two of these patients. Based on the gradient after BIPSS, the sensitivity of this modality in the diagnosis of CD was 100%. Eight of the 13 patients had right lateralization in both BIPSS and TSS; therefore, the accuracy rate of lateralization by BIPSS was 61.5%. No complications occurred after BIPSS, the exception being the development of groin hematoma in one patient.

CONCLUSION

No significant benefits of adding desmopressin to BIPSS were observed. The sensitivity of BIPSS in the diagnosis of CD was high, whereas it has moderate accuracy in tumor lateralization.

Neuroendocrine control of appetite and metabolism

Body homeostasis is predominantly controlled by hormones secreted by endocrine organs. The central nervous system contains several important endocrine structures, including the hypothalamic-pituitary axis. Conventionally, neurohormones released by the hypothalamus and the pituitary gland (hypophysis) have received much attention owing to the unique functions of the end hormones released by their target peripheral organs (e.g., glucocorticoids released by the adrenal glands). Recent advances in mouse genetics have revealed several important metabolic functions of hypothalamic neurohormone-expressing cells, many of which are not readily explained by the action of the corresponding classical downstream hormones. Notably, the newly identified functions are better explained by the action of conventional neurotransmitters (e.g., glutamate and GABA) that constitute a neuronal circuit. In this review, we discuss the regulation of appetite and metabolism by hypothalamic neurohormone-expressing cells, with a focus on the distinct contributions of neurohormones and neurotransmitters released by these neurons.

Diabetes, Active Disease, and Afternoon Serum Cortisol Levels Predict Cushing's Disease Mortality: A Cohort Study

CONTEXT

Cushing's disease (CD) is a life-threating disease, with increased mortality in comparison with the general population.

OBJECTIVE

This study aimed to evaluate standardized mortality ratios (SMRs) in CD patients. We also analyzed independent risk factors related to increased mortality.

DESIGN

We conducted a longitudinal cohort study in a 3rd level specialty center, from 1979 to 2018, in patients with CD.

RESULTS

From 1375 cases with a pathology diagnosis of pituitary adenoma, 191 cases had the confirmed diagnosis of CD (14%). A total of 172 patients completed follow-up, with a mean age at diagnosis of 33 ± 11 years, female predominance (n = 154, 89.5%), majority of them with microadenoma (n = 136, 79%), and a median follow-up of 7.5 years (2.4-15). Eighteen patients (10.5%) died, 8 of them (44%) were with active CD, 8 (44%) were under remission, and 2 (11%) were under disease control. Estimated all-cause SMR = 3.1, 95% confidence interval (CI) 1.9-4.8, P < 0.001. Cardiovascular disease was the main cause of death (SMR = 4.2, 1.5-9.3, P = 0.01). Multivariate Cox regression models adjusted for potential cofounders showed that diabetes (HR = 5.2, IC 95% 1.8-15.4, P = 0.002), high cortisol levels after 1600 hours at diagnosis (3.4, 2.3-7.0, P = 0.02), and active CD (7.5, 3.8-17.3, P = 0.003) significantly increased the risk of mortality.

CONCLUSIONS

Main cause of CD mortality was cardiovascular disease. Main risk factors for mortality were uncontrolled diabetes, persistently high cortisol levels after 1600 hours at diagnosis, and active disease at last follow-up.

New types of localization methods for adrenocorticotropic hormone-dependent Cushing's syndrome

The management of endogenous Cushing's syndrome (CS) typically involves two key steps: (i) confirmation of autonomous hypercortisolism and (ii) localization of the cause to guide treatment. Adrenocorticotropic hormone (ACTH)-dependent CS is most commonly due to a pituitary corticotrope tumor which may be so small as to evade detection on conventional magnetic resonance imaging (MRI). Although biochemical testing (e.g., corticotropin stimulation; dexamethasone suppression) can provide an indication of the likely origin of ACTH excess, bilateral inferior petrosal sinus catheterization offers greater accuracy to distinguish pituitary-driven CS [Cushing's Disease (CD)] from the ectopic ACTH syndrome [EAS, e.g., due to a bronchial or pancreatic neuroendocrine tumor (NET)]. In patients with CD, 40-50% may not have a pituitary adenoma (PA) readily visualized on standard clinical MRI. In these subjects, alternative MR sequences (e.g., dynamic, volumetric, fluid attenuation inversion recovery) and higher magnetic field strength (7T > 3T > 1.5T) may aid tumor localization but carry a risk of identifying coincidental (non-causative) pituitary lesions. Molecular imaging is therefore increasingly being deployed to detect small ACTH-secreting PA, with hybrid imaging [e.g., positron emission tomography (PET) combined with MRI] allowing precise anatomical localization of sites of radiotracer (e.g., ¹¹C-methionine) uptake. Similarly, small ACTH-secreting NETs, missed on initial cross-sectional imaging, may be detected using PET tracers targeting abnormal glucose metabolism (e.g., ¹⁸F-fluorodeoxyglucose), somatostatin receptor (SSTR) expression (e.g., ⁶⁸Ga-DOTATATE), amine precursor (e.g., ¹⁸F-DOPA) or amino acid (e.g., ¹¹C-methionine) uptake. Therefore, modern management of ACTH-dependent CS should ideally be undertaken in specialist centers which have an array of cross-sectional and functional imaging techniques at their disposal.

Low Diagnostic Utility of Overnight High-Dose Dexamethasone Suppression Test in ACTH-Dependent Cushing's Syndrome

OBJECTIVE

Overnight high-dose dexamethasone suppression test (ON-HDDST) is a simple test to localize the source of ACTH in patients with ACTH-dependent Cushing's syndrome (CS). However, previous studies have reported its varying accuracy. We studied the utility of ON-HDDST in diagnosing Cushing's disease (CD) in a series of patients with CD and ectopic ACTH syndrome (EAS).

METHODS

We conducted a retrospective study of 88 patients with ACTH-dependent CS (plasma ACTH > 20.0 pg/mL), who underwent an ON-HDDST. CD and EAS were diagnosed in 68 and 20 patients, respectively. Patients were investigated using MRI of the sellar region, CT of the thorax/abdomen, Gallium-68-DOTANOC PET scan, and bilateral inferior petrosal sinus sampling as required.

RESULTS

Patients with EAS had a significantly higher serum cortisol after ON-HDDST than patients with CD (median [IQR], 19.9 [12.4-31.1] μg/dL vs 9.9 [5.1-25.0] μg/dL, P <.01). A suppressed ON-HDDST (≥50% fall from baseline) was noted in 44 (65%) patients with CD and 3 (15%) patients with EAS (P <.0001). Among patients with CD, cortisol suppression >50% was noted in 35 (76%) of patients with microadenoma and 7 (44%) with macroadenoma. Among patients with EAS, ON-HDDST was suppressed in 1 of 6 patients (17%) with an occult tumor and 2 of 14 patients (14%) with a localized tumor. The ROC curve plotted for the percentage suppression of cortisol had an area under the curve (AUC) of 0.72 (P =.01). The best test parameters, with 65% sensitivity, 85% specificity, 94% positive predictive value, 42% negative predictive value, and 69% accuracy, were at 50% cutoff level.

CONCLUSION

The ON-HDDST had a poor diagnostic value in differentiating CD and EAS.

Adrenal Incidentaloma

An adrenal incidentaloma is now established as a common endocrine diagnosis that requires a multidisciplinary approach for effective management. The majority of patients can be reassured and discharged, but a personalized approach based upon image analysis, endocrine workup, and clinical symptoms and signs are required in every case. Adrenocortical carcinoma remains a real concern but is restricted to <2% of all cases. Functional adrenal incidentaloma lesions are commoner (but still probably <10% of total) and the greatest challenge remains the diagnosis and optimum management of autonomous cortisol secretion. Modern-day surgery has improved outcomes and novel radiological and urinary biomarkers will improve early detection and patient stratification in future years to come.

Human Corticotropin-Releasing Hormone Tests: 10 Years of Real-Life Experience in Pituitary and Adrenal Disease

CONTEXT

The human corticotropin-releasing hormone (CRH) test (hCRHtest) is used to differentiate Cushing disease (CD) from ectopic adrenocorticotropin (ACTH) secretion (EAS), to assess autonomous cortisol secretion by the adrenal glands, and to characterize pseudo-Cushing syndrome (CS) or adrenal insufficiency (AI).

MAIN OUTCOME MEASURE

The main outcome measure of this study was to assess the diagnostic accuracy of the hCRHtest.

METHODS

We measured ACTH and cortisol levels; collected the peak values (peakACTH and peakcortisol), and calculated the percentage increases (∆%ACTH and ∆%cortisol) after an intravenous bolus of 100 μg hCRH.

DESIGN AND SETTING

This cross-sectional study of hCRH tests from 2010 to 2019 took place in a referral university hospital center.

PATIENTS

We enrolled 200 patients: 86 CD, 15 EAS, 18 adrenal CS, 25 mild adrenal autonomous cortisol secretion, 31 pseudo-CS, and 25 suspected AI.

RESULTS

The hCRHtest was performed mainly for the differential diagnosis of ACTH-dependent CS or adrenal lesions (P = .048). PeakACTH and peakcortisol were higher in CD, and ∆%ACTH and ∆%cortisol were able to differentiate CD from EAS with a sensitivity and specificity greater than 80%. In patients with low (< 10 pg/mL) or indeterminate (10-20 pg/mL) basalACTH levels, an absent or reduced peakACTH response was able to differentiate adrenal from ACTH-dependent forms. PeakACTH and peakcortisol after hCRHtest were lower in pseudo-CS than in CD, but ∆%ACTH and ∆%cortisol were similar. The role of hCRHtest in patients with AI was limited.

CONCLUSIONS

The hCRHtest test is the mainstay of the differential diagnosis of ACTH-dependent CS. It is also useful for pointing to a diagnosis of CD in the event of bilateral adrenal masses, and in patients with low basalACTH.

High positive predictive value of the combined pituitary dynamic enhanced MRI and high-dose dexamethasone suppression tests in the diagnosis of Cushing's disease bypassing bilateral inferior petrosal sinus sampling

The purpose of the study is to evaluate the positive predictive value of the combined pituitary dynamic enhanced MRI (dMRI) and high-dose dexamethasone suppression tests (HDDST) in the diagnosis of Cushing's disease (CD) bypassing bilateral inferior petrosal sinus sampling (BIPSS). A total of 118 patients with Cushing's syndrome (CS), who underwent pituitary dMRI, HDDST and BIPSS were included. Positive predictive value of pituitary dMRI, HDDST, BIPSS and the combined test were calculated and tumor lateralization accuracy was further analyzed. The positive predictive value of the combined pituitary dMRI and HDDST was 98.6%, higher than that of BIPSS. There were 96.8% of patients, who had either negative findings in pituitary dMRI or HDDST, showing centralizing BIPSS results. For tumor lateralization, the accuracy by pituitary dMRI was 88.6%, whereas BIPSS was 57.5%. Therefore, CS patients with both positive findings in pituitary dMRI and HDDST need no further invasive evaluation to establish the definite diagnosis of CD. BIPSS will improve the diagnostic accuracy when negative findings were found in either pituitary dMRI or HDDST.

Dexamethasone measurement during low-dose suppression test for suspected hypercortisolism: threshold development with and validation

BACKGROUND AND AIM

Dexamethasone Suppression Test (DST), recommended for Cushing's Syndrome (CS) diagnosis, explores the pituitary feedback to glucocorticoids. Its diagnostic accuracy could be affected by dexamethasone bioavailability, and therefore, we have developed and validated a dexamethasone threshold after 1-mg DST.

MATERIALS AND METHODS

We studied 200 subjects: 125 patients were considered retrospectively and 75 were enrolled prospectively as the validation cohort. Serum dexamethasone, Late Night Salivary Cortisol (LNSC), and Urinary Free Cortisol (UFC) were measured with LC-MS/MS. Normal LNSC and UFC levels were used to exclude CS. The lower 2.5th percentile of dexamethasone distribution in non-CS patients with cortisol ≤ 50 nmol/L after 1-mg DST was used as threshold.

RESULTS

16 patients were CS and 184 non-CS (108 adrenal incidentaloma and 76 excluded CS); 4.5 nmol/L resulted the calculated threshold. Cortisol after 1-mg DST confirmed high sensitivity (100% at 50 nmol/L cut-off) and moderate-low specificity (63%, increased to 91% at 138 nmol/L) to diagnose CS in the whole cohort of patients. We could reduce the number of false-positive results (from 10 to 6 and from 7 to 4 in AI and excluded CS) considering adequate dexamethasone levels. Dexamethasone levels were not affected by hypercortisolism, age, gender, smoke, weight, and creatinine. 6% of non-CS patients did not achieve adequate dexamethasone levels (40% of tests with serum cortisol > 138 nmol/L after 1-mg DST).

CONCLUSIONS

We developed and validated the routine dexamethasone measurement during 1-mg DST: it is independent from patient's clinical presentation, and it should be used to increase the specificity of serum cortisol levels.

Pituitary-adrenal axis and peripheral cortisol metabolism in obese patients

BACKGROUND AND AIM

A close relationship between adiposity and increased cortisol levels is well established in patients with endogenous hypercortisolism. Nevertheless, hypothalamic-pituitary-adrenal (HPA) axis regulation in overweight subjects is still a matter of concern. We studied free cortisol (urinary free cortisol, UFC and late night salivary cortisol, LNSC), pituitary feedback (serum cortisol after 1 mg dexamethasone suppression test, 1 mg DST) and peripheral cortisol metabolism (urinary cortisol to cortisone ratio, F/E^ratio) in a large series of overweight subjects without Cushing's Syndrome.

MATERIALS AND METHODS

We considered 234 patients divided in 5 BMI classes, matched for age and gender (BMI ≤ 25 kg/m²n = 38; 25-30 n = 58; 30-35 n = 52; 35-40 n = 52; >40 n = 34). UFC, LNSC and urinary F/E^ratio were assessed with LC-MS.

RESULTS

We collected 183 LNSC, 176 UFC, 152 1 mg DST and 64 F/E^ratio tests. UFC levels were higher in lean subjects, and they decreased according to the BMI classes (p = 0.022). Non-suppressed cortisol levels (>50 nmol/L) after 1 mg DST were observed especially in patients with normal weight or mild obesity. Patients with BMI ≥ 35 kg/m² revealed a reduced F/E^ratio (0.39 vs. 0.61, p = 0.006). The specificity of tests (false positive results) was higher considering 1 mg DST or UFC in obese patients, on the contrary impaired cortisol rhythm (LNSC above normality) was observed in 47 subjects, irrespective of weight.

CONCLUSIONS

Overweight and obese subjects are characterised by an original regulation of HPA axis (reduced UFC levels, increased suppression after 1 mg DST) and peripheral cortisol metabolism (reduced F/E^ratio), suggesting an effort to counteract hypercortisolism.

Determinants of outcome of transsphenoidal surgery for Cushing disease in a single-centre series

BACKGROUND

First-line therapy of Cushing disease (CD) is transsphenoidal surgery (TSS) aimed to obtain a complete removal of the pituitary adenoma and remission of disease.

PURPOSE

To analyse the surgical outcome of patients with CD who underwent TSS in our Centre.

METHODS

Retrospective analysis on patients with CD who underwent TSS between 1990 and 2016.

RESULTS

We analysed 102 TSS that included: 84 first TSS and 18 second and third TSS. The overall remission rate after surgery was 76.5%, with a significant higher percentage of remitted patients after the first TSS compared to the subsequent TSS (82% vs 50%, p = 0.014). The remission after the first TSS was significantly higher when performed by a dedicated surgical team (DST) (89.8% vs 71% p = 0.04) and when the immunohistochemical examination confirmed the adrenocorticotropic adenoma (87% vs 55%, p = 0.04). Neuroradiological findings influenced the surgical outcome in a non-significant manner. Post-TSS complications were reported in 32 patients, with no significant variation when TSS was performed by DST. In case of reintervention, remission of disease was obtained in 72.7% of microadenoma, while no remitted patients were observed in case of macroadenomas. The DST did not significantly improve the outcome.

CONCLUSION

Cushing disease is characterized by a broad spectrum of neuroradiological presentation. Despite the availability of a DST make the TSS a safe and effective first-line treatment among all these patients, a precise pre-treatment evaluation is needed in order to define the aim of neurosurgery and to schedule the management of recurrent disease.

The role of 68Ga-DOTA derivatives PET-CT in patients with ectopic ACTH syndrome

INTRODUCTION AND AIM

Ectopic ACTH secretion (EAS) is mostly secondary to thoracic/abdominal neuroendocrine tumours (NETs) or small cell-lung carcinoma (SCLC). We studied the diagnostic accuracy of CT with 68Ga-Dota derivatives (68Ga-SSTR) PET in localizing ACTH-secreting tumor in patients with EAS.

MATERIALS AND METHODS

68Ga-SSTR-PET/CT was performed and compared with the nearest enhanced CT in 18 cases (16 primary and 2 recurrent neoplasms). Unspecific, indeterminate and false-positive uptakes were assessed using conventional imaging, follow-up or histology.

RESULTS

We diagnosed 13 thoracic (9 primary and 2 recurrent bronchial carcinoids, 2 SCLCs) and 1 abdominal (pancreatic NET) tumors. Eight ACTH-secreting tumors were promptly identified at EAS diagnosis ('overt', four pulmonary carcinoids with two recurrences and two SCLC); six EAS have been discovered during the subsequent follow-up ('covert', five bronchial carcinoids and one pancreatic NET). At the time of EAS diagnosis, imaging was able to correctly detect the ACTH-secreting tumour in 8/18 cases (6 new diagnosis and 2 recurrences). During the follow-up, six out of initially ten 'occult' cases became 'covert'. At last available follow-up, CT and 68Ga-SSTR-PET/CT were able to diagnose 11/18 and 12/18 ACTH-secreting tumours, respectively (11/14 and 12/14 considering only overt and covert cases, respectively). Four cases have never been localized by conventional or nuclear imaging ('occult EAS'), despite an average follow-up of 5 years.

CONCLUSION

The 68Ga-SSTR-PET/CT is useful in localizing EAS, especially to enhance positive prediction of the suggestive CT lesions and to detect occult neoplasms.

Cushing's syndrome: Overview of clinical presentation, diagnostic tools and complications

Cushing's syndrome (CS) is a severe condition that results from chronic exposure to elevated circulating cortisol levels; it is a rare but potentially life-threating condition, especially when not timely diagnosed and treated. Even though the diagnosis can be straightforward in florid cases due to their typical phenotype, milder forms can be missed. Despite the availability of different screening tests, the diagnosis remains challenging as none of the available tools proved to be fully accurate. Due to the ubiquitous effect of cortisol, it is easy understandable that its excess leads to a variety of systemic complications including hypertension, metabolic syndrome, bone damages and neurocognitive impairment. This article discusses clinical presentation of CS with an eye on the most frequent cortisol-related comorbidities and discuss the main pitfalls of first- and second-line tests in endogenous hypercortisolism diagnostic workup.

Sporadic Medullary Thyroid Carcinoma with Paraneoplastic Cushing Syndrome

Medullary thyroid cancer (MTC) is a rare form of neoplasm affecting the thyroid gland. This neuroendocrine tumor is capable of releasing active substances causing systemic manifestation in the form of flushing, diarrhea, and uncommonly, Ectopic Cushing’s syndrome (ECS). MTC can be hereditary as a part of multiple endocrine neoplasm type 2 syndrome (MEN2) or arise sporadically. We report a case of a 74-year-old female presenting with chronic diarrhea, in whom diagnosis of sporadic MTC was delayed due to previous history of gastrointestinal (GI) disturbances. The patient developed liver metastases yielding ACTH dependent Cushing’s Syndrome leading to abnormal clinical presentation and laboratory values driven by elevated cortisol level. Metastatic MTC should be considered in patients presenting with chronic diarrhea and weakness unexplained by other GI related causes.

Measurement of urinary free cortisol by LC-MS-MS: adoption of a literature reference range and comparison with our current immunometric method

PURPOSE

One of the best indicators of adrenal gland dysfunction is the level of free cortisol measured in the 24-h urine (UFC) which faithfully reflects the level of biologically active serum cortisol not subjected to circadian variations. Liquid chromatography coupled with tandem mass spectrometry (LC-MS-MS) is a sensitive, accurate and precise method recently available in routine laboratories that could remedy interference problems of immunoassays.

METHODS

In this study, a literature reference range for UFC measured by LC-MS-MS was verified, and UFC values measured by LC-MS-MS and immunoassay were compared. Immunometric UFC measurement was performed by ACCESS CORTISOL assay without preliminary extraction, using Beckman Coulter UniCel DxI 600 highly automated platform. Liquid chromatography-tandem mass spectrometry UFC measurement was performed by a home-made validated method using cortisol-D₄ as internal standard with preliminary deproteinization of urinary samples by centrifugal filter and injection on reverse-phase column. Cortisol was analyzed in positive ion mode with an ESI interface.

RESULTS

The reference interval from literature (11-70 μg/day) was confirmed by results obtained for healthy study group. Comparison study of the two methods highlighted a constant and proportional systematic error with a general tendency to overestimate results for the in-use method.

CONCLUSIONS

In conclusion, the direct immunometric method overestimates UFC results with respect to liquid chromatography-tandem mass spectrometry which represents the reference method. The literature reference range 11-70 μg/day was confirmed and can be adopted by our lab that will shift all UFC tests performed in routine to the mass spectrometry-based method, satisfying clinicians' request.

Factors Affecting Dexamethasone Suppression Test Results

Dexamethasone suppression tests are basic tools in diagnostics of hypercortisolemia. Low-dose tests play major role in screening and initial assessment. High-dose tests are aimed at more elaborate diagnostics, however their clinical value is questionable. Dexamethasone is a highly potent, synthetic steroid. It is metabolized by cytochrome P450 3A4 (CYP3A4), and so are various other xenobiotics. Due to wide spectrum of substances processed by CYP3A4, interferences and interactions are not uncommon. Physicians should be familiar with drugs modifying dexamethasone metabolism, and therefore the results of dynamic tests. Other important concerns are: drugs enhancing cortisol-binding globulin production, organ dysfunction, pseudo-Cushing states, pregnancy and other physiological conditions leading to elevated blood cortisol, cyclic Cushing disease. To properly assess and assist patients, it is crucial for health professionals to understand and be able to overcome such clinical dilemmas.

RELIABILITY OF THE CORTICOTROPIN RELEASING HORMONE STIMULATION TEST FOR DIFFERENTIATING BETWEEN ACTH DEPENDENT AND INDEPENDENT CUSHING SYNDROME

Context

It is a challenge to determine the origin of Cushing syndrome (CS), especially in patients with low-normal adrenocorticotropic hormone (ACTH) concentrations.

Objective

To evaluate the reliability of the corticotropin-releasing hormone (CRH) stimulation test in patients with CS whose origin of disease was not clearly identified using ACTH values, the high-dose dexamethasone suppression test (HDDST), and imaging in a single tertiary referral center.

Design and Methods

Twenty-one patients with CS who were admitted to the endocrinology-metabolism clinic between 2004 and 2016 whose ACTH concentrations were 5-20 pg/mL and needed CRH stimulation test were retrospectively assessed.

Results

Nine out of 21 patients were diagnosed as having Cushing's disease (CD) and 12/21 had adrenal CS. The CRH stimulation test had a sensitivity and specificity of 100% and 8%, and positive and negative predictive values of 100% and 45% according to the current diagnostic criteria, respectively. An increase in ACTH ≥115% at 15 minutes and cortisol ≥86% at 60 minutes after CRH were associated with the highest likelihood ratio. The sensitivity and specificity of ACTH was 67% and 83% (AUC=0.75±0.12, 95% CI: [0.5-0.9]; p=0.03), and for cortisol it was 75% and 78% (AUC=0.71±0.15, 95% CI: [0.5-0.9]; p=0.03). Cortisol suppression of more than 64% from basal level in the HDDST suggested CD with the highest likelihood ratio. When these cut-off values were used together, both tests were negative in the patients with CD.

Conclusion

The CRH stimulation test has low specificity to localize CS in patients with ACTH concentrations of 5-20 pg/mL according to the current diagnostic criteria. Different diagnostic criteria may be used in the CRH stimulation test and also in the HDDST in this group of patients.