Diagnosis and differential diagnosis of Cushing's syndrome

Distinguishing Cushing's disease from the ectopic ACTH syndrome: Needles in a haystack or hiding in plain sight?

In the context of ACTH-dependent Cushing's syndrome, ectopic ACTH secretion from a neuroendocrine tumour is not uncommon, and needs to be carefully differentiated from pituitary-dependent Cushing's syndrome, Cushing's disease, in order to optimise therapy. Some cases may be quite obvious, while in others the diagnosis may be difficult to confirm and the source of ACTH problematic, as many clinical and biochemical tests may overlap with Cushing's disease. Imaging is essential, but needs to be interpreted in the light of both anatomical as well as functional imaging modalities. In this review we summarise some of the main diagnostic problems, and emphasise the multimodal and interdisciplinary nature of the diagnostic pathways.

The effect of morphological variability of Dorello's canal on surgical procedures - a review

Dorello's canal is an arched structure of bone-fibrous character located in the petroclival venous confluence atop the petrosal bone in the petroclival region. It is bordered by the petrosphenoidal ligament, the petrous part of the temporal bone and the lateral border of the upper part of clivus. Its content in the vast majority of variants comprises the abducens nerve, the inferior petrosal sinus, the venous drainage and the dorsal meningeal artery or its medial branch. With the development of microsurgical techniques, this area has gained huge clinical importance, mainly concerning the order in which the above-mentioned elements (especially the position of the abducens nerve) are arranged in relation to each other. These structures appear in different variant forms and necessitate an individual clinical approach. The main purpose of this review is to present condensed information about possible intercorrelations among them and to indicate, on the basis of the available literature and research, possible surgical approaches and the need to consider the variability when treatments in this region are planned.

Utility of bilateral inferior petrosal sinus sampling for diagnosis and lateralization of Cushing's disease in the pediatric population: case series and review of the literature

OBJECTS

Cushing's disease (CD) is the most common cause of ACTH-dependent hypercortisolism in children age ≥ 7. The utility of bilateral inferior petrosal sinus sampling (BIPSS), an important test in adults, is less defined in children. We present a case series of children with ACTH-dependent hypercortisolemia and review the literature to assess the utility of BIPSS in the diagnosis and localization of CD.

METHODS

We performed an IRB-approved chart review of patients aged ≤ 18 with ACTH-dependent hypercortisolism at MGH between 2000 and 2019 and collected clinical, laboratory, radiographic, BIPSS, surgical, and outcomes data.

RESULTS

In our cohort (n = 21), BIPSS had a sensitivity of 93% and specificity of 100% for diagnosis of CD. Compared to surgery, successful BIPSS correctly predicted adenoma laterality in 69% of cases vs. 70% by MRI. Among patients with lesions ≥ 4 mm (n = 9), BIPSS correctly lateralized in 50% vs. 100% by MRI. In patients with subtle lesions (< 4 mm, n = 7), BIPSS correctly lateralized in 80% vs. 71% by MRI. In patients (n = 4) with CD and negative MRIs, BIPSS correctly lateralized in 75% cases. Surgical cure was achieved in 90% of patients and 95% of patients had long-term disease control.

CONCLUSIONS

In our cohort (n = 21; n = 20 CD, n = 1 ectopic ACTH secretion), BIPSS was sensitive and specific for the diagnosis of CD. Compared to MRI, BIPSS was not additionally helpful for lateralization in patients with lesions ≥ 4 mm on MRI. BIPSS was helpful in guiding surgical exploration and achieving immediate postoperative remission among patients with subtle and negative MRI findings.

A New Clinical Model to Estimate the Pre-Test Probability of Cushing's Syndrome: The Cushing Score

BACKGROUND

Hypercortisolism accounts for relevant morbidity and mortality and is often a diagnostic challenge for clinicians. A prompt diagnosis is necessary to treat Cushing's syndrome as early as possible.

OBJECTIVE

The aim of this study was to develop and validate a clinical model for the estimation of pre-test probability of hypercortisolism in an at-risk population.

DESIGN

We conducted a retrospective multicenter case-control study, involving five Italian referral centers for Endocrinology (Turin, Messina, Naples, Padua and Rome). One hundred and fifty patients affected by Cushing's syndrome and 300 patients in which hypercortisolism was excluded were enrolled. All patients were evaluated, according to current guidelines, for the suspicion of hypercortisolism.

RESULTS

The Cushing score was built by multivariable logistic regression, considering all main features associated with a clinical suspicion of hypercortisolism as possible predictors. A stepwise backward selection algorithm was used (final model AUC=0.873), then an internal validation was performed through ten-fold cross-validation. Final estimation of the model performance showed an average AUC=0.841, thus reassuring about a small overfitting effect. The retrieved score was structured on a 17.5-point scale: low-risk class (score value: ≤5.5, probability of disease=0.8%); intermediate-low-risk class (score value: 6-8.5, probability of disease=2.7%); intermediate-high-risk class (score value: 9-11.5, probability of disease=18.5%) and finally, high-risk class (score value: ≥12, probability of disease=72.5%).

CONCLUSIONS

We developed and internally validated a simple tool to determine pre-test probability of hypercortisolism, the Cushing score, that showed a remarkable predictive power for the discrimination between subjects with and without a final diagnosis of Cushing's syndrome.

Reference ranges of late-night salivary cortisol and cortisone measured by LC-MS/MS and accuracy for the diagnosis of Cushing's syndrome

PURPOSE

International guidelines recommend salivary cortisol for the diagnosis of Cushing's syndrome. Despite mass spectrometry-based assays are considered the analytical gold-standard, there is still the need to define reference intervals and diagnostic accuracy of such methodology.

METHODS

100 healthy volunteers and 50 consecutive patients were enrolled to compare LC-MS/MS and electrochemiluminescence assay for the determination of late-night salivary cortisol and cortisone. Moreover, we aimed to determine reference intervals of salivary steroids in a population of healthy individuals and diagnostic accuracy in patients with suspected hypercortisolism and in a population including also healthy individuals.

RESULTS

Method comparison highlighted a positive bias (51.8%) of immunoassay over LC-MS/MS. Reference intervals of salivary cortisol (0.17-0.97 µg/L), cortisone (0.84-4.85 µg/L) and ratio (0.08-0.30) were obtained. The most accurate thresholds of salivary cortisol for the diagnosis of hypercortisolism were 1.15 µg/L in the population with suspected hypercortisolism (AUC 1) and 1.30 µg/L in the population including also healthy individuals (AUC 1). Cut-off values of salivary cortisone (7.23 µg/L; Se 92.9%, Sp 97.2%, AUC 0.960 and Se 92.9%, Sp 99.1%, AUC 0.985 in suspected hypercortisolism and in overall population, respectively) and cortisol-to-cortisone ratio (0.20; Se 85.7%, Sp 80.6%, AUC 0.820 and Se 85.7%, Sp 85.5%, AUC 0.855 in suspected hypercortisolism and in overall population, respectively) were accurate and similar in both populations.

CONCLUSION

LC-MS/MS is the most accurate analytical platform for measuring salivary steroids. Obtained reference intervals are coherent with previously published data and diagnostic accuracy for diagnosis of overt hypercortisolism proved highly satisfactory.

Cushing´s syndrome: high aggressiveness of low-grade tumors

Cushing´s syndrome is caused by prolonged exposition supraphysiological to endogenous or exogenous cortisol. Ectopic production of adrenocorticotropic hormone by lung carcinoid tumors is relatively rare. Most documented cases have been reported individually. This rare neoplasm low grade that may secrete adrenocorticotropin (ACTH) leading to rapid development of hypercortisolism which is the main mode of discovery, can be a real aggressive form. This report shows a high aggressiveness of this endocrine neoplasia, wich was marked on the general, morphological, bone and psychiatric level. The trivialization of clinical signs had caused the delay in diagnosis with irreparable bone consequences.

Prospective Evaluation of Late-Night Salivary Cortisol and Cortisone by EIA and LC-MS/MS in Suspected Cushing Syndrome

Context

Late-night salivary cortisol (LNSC) measured by enzyme immunoassay (EIA-F) is a first-line screening test for Cushing syndrome (CS) with a reported sensitivity and specificity of >90%. However, liquid chromatography-tandem mass spectrometry, validated to measure salivary cortisol (LCMS-F) and cortisone (LCMS-E), has been proposed to be superior diagnostically.

Objective, Setting, and Main Outcome Measures

Prospectively evaluate the diagnostic performance of EIA-F, LCMS-F, and LCMS-E in 1453 consecutive late-night saliva samples from 705 patients with suspected CS.

Design

Patients grouped by the presence or absence of at least one elevated salivary steroid result and then subdivided by diagnosis.

Results

We identified 283 patients with at least one elevated salivary result; 45 had an established diagnosis of neoplastic hypercortisolism (CS) for which EIA-F had a very high sensitivity (97.5%). LCMS-F and LCMS-E had lower sensitivity but higher specificity than EIA-F. EIA-F had poor sensitivity (31.3%) for adrenocorticotropic hormone (ACTH)-independent CS (5 patients with at least 1 and 11 without any elevated salivary result). In patients with Cushing disease (CD), most nonelevated LCMS-F results were in patients with persistent/recurrent CD; their EIA-F levels were lower than in patients with newly diagnosed CD.

Conclusions

Since the majority of patients with ≥1 elevated late-night salivary cortisol or cortisone result did not have CS, a single elevated level has poor specificity and positive predictive value. LNSC measured by EIA is a sensitive test for ACTH-dependent Cushing syndrome but not for ACTH-independent CS. We suggest that neither LCMS-F nor LCMS-E improves the sensitivity of late-night EIA-F for CS.

Bedtime Salivary Cortisol and Cortisone by LC-MS/MS in Healthy Adult Subjects: Evaluation of Sampling Time

The measurement of late-night salivary cortisol is a mainstay in the diagnosis of Cushing syndrome. Furthermore, the measurement of salivary cortisol is useful in assessing the cortisol awakening response. Because the salivary glands express 11-β-hydroxysteroid dehydrogenase, the measurement of salivary cortisone may improve the performance of salivary corticosteroid measurements. We measured salivary cortisol by enzyme immunoassay (EIA) and salivary cortisol and cortisone by liquid chromatography-tandem mass spectrometry (LC-MS/MS) in only 50 µL of saliva sampled from 54 healthy subjects (aged 20 to 64 years). We allowed patients to sample at their normal bedtime (2025 to 2400 hours) to answer a common question as to whether sampling at the normal bedtime is equivalent to the standard required sampling at 2300 to 2400 hours. We found that the salivary cortisol and cortisone results by LC-MS/MS correlated well with salivary cortisol measured with the US Food and Drug Administration-cleared EIA. Furthermore, the upper limit of normal of salivary cortisol by EIA for bedtime samples was lower than the previously published upper limit of normal with sampling required at 2300 to 2400 hours. There were no significant effects of age or sex on any of the salivary steroid measurements. We conclude that (i) salivary cortisol and cortisone can be reliably measured by LC-MS/MS in small volumes of saliva and (ii) that patients can be evaluated using saliva sampled at their normal bedtime, rather than being required to stay awake until 2300 to 2400 hours.

The Ectopic Adrenocorticotropic Hormone Syndrome: Rarely Easy, Always Challenging

Despite modern imaging techniques, differentiating ectopic adrenocorticotropic hormone (ACTH) syndrome from pituitary-dependent Cushing's syndrome, Cushing's disease, is especially difficult when well-differentiated carcinoids are the source of ACTH secretion, particularly pulmonary carcinoid tumors. ACTH-secreting pulmonary carcinoids, like the corticotroph adenomas causing Cushing's disease, are often small and difficult to detect, and patients present with a gradual onset of the classical signs and symptoms of Cushing's syndrome, indistinguishable from the presentation of Cushing's disease. Hence, the differential diagnosis relies on a combination of clinical assessment, dynamic biochemical tests, inferior petrosal sinus sampling, and multimodal imaging, each with its own caveats and pitfalls.

AN INDIVIDUALIZED APPROACH TO THE EVALUATION OF CUSHING SYNDROME

Cushing syndrome (CS) is caused by chronic exposure to excess glucocorticoids. Early recognition and treatment of hypercortisolemia can lead to decreased morbidity and mortality. The diagnosis of CS and thereafter, establishing the cause can often be difficult, especially in patients with mild and cyclic hypercortisolism. Surgical excision of the cause of excess glucocorticoids is the optimal treatment for CS. Medical therapy (steroidogenesis inhibitors, medications that decrease adrenocorticotropic hormone [ACTH] levels or glucocorticoid antagonists) and pituitary radiotherapy may be needed as adjunctive treatment modalities in patients with residual, recurrent or metastatic disease, in preparation for surgery, or when surgery is contraindicated. A multidisciplinary team approach, individualized treatment plan and long-term follow-up are important for optimal management of hypercortisolemia and the comorbidities associated with CS.

ABBREVIATIONS

ACTH = adrenocorticotropic hormone; BIPSS = bilateral inferior petrosal sinus sampling; CBG = corticosteroid-binding globulin; CD = Cushing disease; CRH = corticotropin-releasing hormone; CS = Cushing syndrome; Dex = dexamethasone; DST = dexamethasone suppression test; EAS = ectopic ACTH syndrome; FDA = U.S. Food & Drug Administration; HDDST = high-dose DST; IPS/P = inferior petrosal sinus to peripheral; MRI = magnetic resonance imaging; NET = neuroendocrine tumor; PET = positron emission tomography; UFC = urinary free cortisol.

DIAGNOSIS OF ENDOCRINE DISEASE: Differentiation of pathologic/neoplastic hypercortisolism (Cushing's syndrome) from physiologic/non-neoplastic hypercortisolism (formerly known as pseudo-Cushing's syndrome)

Endogenous hypercortisolism (Cushing's syndrome) usually implies the presence of a pathologic condition caused by either an ACTH-secreting neoplasm or autonomous cortisol secretion from a benign or malignant adrenal neoplasm. However, sustained or intermittent hypercortisolism may also accompany many medical disorders that stimulate physiologic/non-neoplastic activation of the HPA axis (formerly known as pseudo-Cushing's syndrome); these two entities may share indistinguishable clinical and biochemical features. A thorough history and physical examination is often the best (and sometimes only) way to exclude pathologic/neoplastic hypercortisolism. The presence of alcoholism, renal failure, poorly controlled diabetes and severe neuropsychiatric disorders should always raise suspicion that the presence of hypercortisolism may be related to physiologic/non-neoplastic Cushing's syndrome. As late-night salivary cortisol and low-dose dexamethasone suppression have good sensitivity and negative predictive value, normal studies exclude Cushing's syndrome of any form. However, these tests have imperfect specificity and additional testing over time with clinical follow-up is often needed. When there is persistent diagnostic uncertainty, secondary tests such as the DDAVP stimulation test and the dexamethasone-CRH test may provide evidence for the presence or absence of an ACTH-secreting tumor. This review will define and characterize the numerous causes of physiologic/non-neoplastic hypercortisolism and provide a rational clinical and biochemical approach to distinguish it from pathologic/neoplastic hypercortisolism (true Cushing's syndrome).

Cushing's syndrome: epidemiology and developments in disease management

Cushing’s syndrome is a rare disorder resulting from prolonged exposure to excess glucocorticoids. Early diagnosis and treatment of Cushing’s syndrome is associated with a decrease in morbidity and mortality. Clinical presentation can be highly variable, and establishing the diagnosis can often be difficult. Surgery (resection of the pituitary or ectopic source of adrenocorticotropic hormone, or unilateral or bilateral adrenalectomy) remains the optimal treatment in all forms of Cushing’s syndrome, but may not always lead to remission. Medical therapy (steroidogenesis inhibitors, agents that decrease adrenocorticotropic hormone levels or glucocorticoid receptor antagonists) and pituitary radiotherapy may be needed as an adjunct. A multidisciplinary approach, long-term follow-up, and treatment modalities customized to each individual are essential for optimal control of hypercortisolemia and management of comorbidities.

Clinical Guidelines for the Diagnosis and Treatment of Cushing's Disease in Korea

Cushing's disease (CD) is a rare disorder characterized by the overproduction of adrenocorticotropic hormone due to a pituitary adenoma that ultimately stimulates excessive cortisol secretion from the adrenal glands. Prior to the detection of pituitary adenomas, various clinical signs of CD such as central obesity, moon face, hirsutism, and facial plethora are usually already present. Uncontrolled hypercortisolism is associated with metabolic, cardiovascular, and psychological disorders that result in increased mortality. Hence, the early detection and treatment of CD are not only important but mandatory. Because its clinical manifestations vary from patient to patient and are common in other obesity-related conditions, the precise diagnosis of CD can be problematic. Thus, the present set of guidelines was compiled by Korean experts in this field to assist clinicians with the screening, diagnoses, and treatment of patients with CD using currently available tests and treatment modalities.

Altered circadian patterns of salivary cortisol in low-functioning children and adolescents with autism

BACKGROUND

Reports of higher stress responsivity, altered sleep-wake cycle and a melatonin deficit in autism have stimulated interest in the cortisol circadian rhythm in individuals with autism.

METHODS

The study was conducted on 55 low-functioning children and adolescents with autism (11.3 ± 4.1 years-old) and 32 typically developing controls (11.7 ± 4.9 years-old) matched for age, sex and puberty. Behavioral assessment was performed using the Autism Diagnostic Observation Schedule (ADOS). Salivary samples for measurement of cortisol were collected during a 24-h period (at least 0800 h-Day 1, 1600 h, 0800 h-Day 2 for 46 individuals with autism and 27 controls, and 0800 h-Day 1, 1100 h, 1600 h, 2400 h, 0800 h-Day 2 for 13 individuals with autism and 20 controls). Overnight (2000 h-0800 h) urinary cortisol excretion was also measured.

RESULTS

The autism group displayed significantly higher levels of salivary cortisol at all time-points, flatter daytime and nighttime slopes, higher 0800 h cortisol levels on Day 2 compared to Day 1, and greater variances of salivary and urinary cortisol. There was a significant relationship between salivary cortisol levels and impairments in social interaction and verbal language. Overnight urinary cortisol excretion was similar in the autism and control groups.

CONCLUSION

Anticipation of the stressful collection procedure appears to contribute to the higher 0800 h-Day 2 versus 0800 h-Day 1 salivary cortisol levels in autism. This sensitization to stressors might be as, or even more, important clinically than exposure to novelty in autism. The similar group means for overnight urinary cortisol excretion indicate that basal HPA axis functioning is unaltered in low-functioning autism. The elevated salivary cortisol levels observed in autism over the 24-h period in a repeated stressful condition, flattened diurnal cortisol patterns and the apparent effect of anticipation are consistent with prior findings in high trait anxiety.

Physiological basis for the etiology, diagnosis, and treatment of adrenal disorders: Cushing's syndrome, adrenal insufficiency, and congenital adrenal hyperplasia

The hypothalamic-pituitary-adrenal (HPA) axis is a classic neuroendocrine system. One of the best ways to understand the HPA axis is to appreciate its dynamics in the variety of diseases and syndromes that affect it. Excess glucocorticoid activity can be due to endogenous cortisol overproduction (spontaneous Cushing's syndrome) or exogenous glucocorticoid therapy (iatrogenic Cushing's syndrome). Endogenous Cushing's syndrome can be subdivided into ACTH-dependent and ACTH-independent, the latter of which is usually due to autonomous adrenal overproduction. The former can be due to a pituitary corticotroph tumor (usually benign) or ectopic ACTH production from tumors outside the pituitary; both of these tumor types overexpress the proopiomelanocortin gene. The converse of Cushing's syndrome is the lack of normal cortisol secretion and is usually due to adrenal destruction (primary adrenal insufficiency) or hypopituitarism (secondary adrenal insufficiency). Secondary adrenal insufficiency can also result from a rapid discontinuation of long-term, pharmacological glucocorticoid therapy because of HPA axis suppression and adrenal atrophy. Finally, mutations in the steroidogenic enzymes of the adrenal cortex can lead to congenital adrenal hyperplasia and an increase in precursor steroids, particularly androgens. When present in utero, this can lead to masculinization of a female fetus. An understanding of the dynamics of the HPA axis is necessary to master the diagnosis and differential diagnosis of pituitary-adrenal diseases. Furthermore, understanding the pathophysiology of the HPA axis gives great insight into its normal control.

The inferior petrosal sinus: a comprehensive review with emphasis on clinical implications

INTRODUCTION

The inferior petrosal sinus is an important component of the cerebral venous system with implications in diagnosis and treatment of a variety of diseases such as Cushing's disease, carotid cavernous, and dural arteriovenous fistulas.

METHODS

This manuscript will review the anatomy, embryology, and clinical implications of the inferior petrosal sinus.

CONCLUSIONS

Knowledge of the inferior petrosal sinus is of great importance for open surgical approaches to the skull base and endovascular access to the cavernous sinus and sellar region.

An approach to the evaluation and treatment of Cushing’s disease

Cushing's syndrome is an uncommon disorder involving dysregulation of the hypothalamic-pituitary-adrenal axis resulting in endogenous hypercortisolemia. It has multiple causes, but most commonly is due to hypersecretion of corticotropin from the pituitary gland, called Cushing's disease. The diagnosis of Cushing's syndrome remains a challenge to clinicians because routine hormonal assays can have significant overlap in pathological and normal states. We will review an approach to evaluating patients with suspected cortisol excess. We will also discuss treatment options and post-surgical assessment for those diagnosed with Cushing's disease.

Routine Screening for Cushing's Syndrome Is Not Required in Patients Presenting with Obesity

Background. Cushing's syndrome (CS) is a relatively unusual condition that resembles many of the phenotypic features of obesity. Our aim was to evaluate the frequency of CS in obese patients. Materials and Methods. This study included 354 consecutive patients (87.9% female, age 37.8 ± 13.4 years) who presented with simple obesity. All the patients were evaluated for the clinical signs of CS. Lipid parameters, fasting glucose (FPG) and insulin, 75 gr oral glucose tolerance test, basal cortisol and ACTH were measured. 1 mg overnight DST was performed. Results. The mean weight of the patients was 102.4 ± 20.1 kg and BMI 40 ± 7.35 kg/m². 34.5% of the patients were hypertensive. 36.2% of the patients had central obesity, 72% dorsocervical fat accumulation, 28.8% abdominal striae and 23.2% acne. 49.4% of the women had hirsutism. 46.5% had prediabetes and 12.0% had type 2 diabetes, 72.6% had dyslipidemia. The mean cortisol and ACTH levels were as follows: 9.28 ± 3.53 μg/dL and 17.02 ± 10.43 pg/mL. Seven patients failed to suppress plasma cortisol to less than 1.8 μg/dL. Biochemical confirmation tests were performed in these patients and 2 of them were diagnosed glucocorticoid-secreting adrenal adenoma. Conclusions. Routine screening for CS in obese patients is not required.

Clinical Characteristics of Endogenous Cushing's Syndrome at a Medical Center in Southern Taiwan

From January 1987 to December 2011, over a total of 25 years, 84 patients with Cushing's syndrome (CS) were identified at a medical center in southern Taiwan. We observed a higher incidence of ACTH-independent CS (75%) than ACTH-dependent CS (25%). A higher incidence of adrenocortical adenoma (58.3%) than Cushing's disease (CD, 21.4%) was also found. The sensitivity of the definitive diagnostic tests for CS, including loss of plasma cortisol circadian rhythm, a baseline 24 h urinary free cortisol (UFC) value >80  μ g, and overnight and 2-day low-dose dexamethasone suppression test, was between 94.4% and 100%. For the 2-day high-dose dexamethasone suppression test for the differential diagnosis of CD, the sensitivity of 0800 h plasma cortisol and 24 h UFC was 44.4% and 85.7%, respectively. For the differential diagnosis of adrenal CS, the sensitivities of the 0800 h plasma cortisol and 24 h UFC were 95.5% and 88.9%, respectively. In patients with ACTH-independent CS and ACTH-dependent CS, the baseline plasma ACTH levels were all below 29 pg/mL and above 37 pg/mL, respectively. The postsurgical hospitalization stay following retroperitoneoscopic adrenalectomy was shorter than that observed for transabdominal adrenalectomy (4.3 ± 1.6 versus 8.8 ± 3.7 days, P < 0.001). It was easy to develop retroperitoneal and peritoneal seeding of adrenocortical carcinoma via laparoscopic adrenalectomy.

Reproducibility and performance of one or two samples of salivary cortisol in the diagnosis of Cushing's syndrome using an automated immunoassay system

The purpose of this article is to evaluate the variability and reproducibility of late night salivary cortisol (LNSC) using electrochemiluminescence immunoassay (ECLIA) and compare the accuracy of one or two samples in diagnosis of Cushing's syndrome (CS). We prospectively included 64 healthy volunteers (HV), 35 patients with clinically suspected CS (S), and 26 patients with confirmed CS. Nine patients in the CS group had 24-h urinary free cortisol (UFC) less than two times the upper limit of normal (mild CS). UFC and two consecutive LNSC (LNSC1, LNSC2) were collected at home. All patients in the S group had normal UFC and low-dose dexamethasone suppression test. No differences were found between the HV and S groups in UFC, LNSC1, and LNSC2. Intra-individual variability between the two samples of LNSC was 22% in HV (1.6-91%), 32% in the S group (1.6-144%), and 51% (1.6-156%) in the CS group. Variability was higher in CS patients than those in the HV (P < 0.001) and S groups (P = 0.05). The AUC of LNSC1 was 0.945 (IC 95% 0.880-1.004); when considering the highest LNSC, the AUC was 0.980 (IC 95% 0.954-1.007) (P < 0.01). We found 23% of discordant LNSC in the S group and 11% in the CS group. Three patients with CS had only one elevated LNSC, all of them with mild CS. Our results suggest that LNSC is variable, and reproducibility is affected in both CS and S patients. We found significant improvements in the diagnostic accuracy of the LNSC measurement by obtaining two samples.

Cushing's syndrome: diagnosis and surveillance using salivary cortisol

This short review summarizes the use of late-night salivary cortisol measurement in the diagnosis of Cushing's syndrome, in the evaluation of patients with adrenal incidentalomas, and in monitoring of post-operative patients, with a focus on the different assay methodologies currently in common use. The focus is on recent studies identified by literature searches using Ovid Medline and Google Scholar as well as analysis of several recent review articles on the topic. Measurement of late night salivary cortisol (LNSC) has an excellent sensitivity and specificity for the diagnosis of Cushing's syndrome regardless of the assay methodology used. Immunoassays have the advantage of simplicity, low cost, and small sample volume requirement, while liquid chromatography-tandem mass spectrometry has the advantage of a high specificity for cortisol and the ability to measure cortisone. The overnight dexamethasone suppression test appears to be superior to LNSC measurement in the evaluation of patients with adrenal incidentalomas. LNSC measurement is an excellent approach to monitor post-operative Cushing's disease patients for surgical failure or recurrence. Salivary cortisol is most useful as the initial test when Cushing's syndrome is suspected and for periodic patient monitoring after pituitary surgery for Cushing's disease.

Intraoperative multiple-staged resection and tumor tissue identification using frozen sections provide the best result for the accurate localization and complete resection of tumors in Cushing's disease

The treatment of choice in Cushing's disease (CD) is surgical removal; however, most tumors are too small to be detected. The objective was to establish a method to achieve the complete removal of tumors on the basis of the results of high-resolution magnetic resonance imaging (MRI), inferior petrosal sinus sampling (IPSS), and a surgical resection technique using frozen biopsy. Eighteen patients who underwent transsphenoidal surgery from 2004 to 2010 were included. High-resolution MRI and IPSS, multiple-staged resection, and tumor tissue identification in frozen sections (surgical and histological identification, SHI) were performed. All patients achieved surgical remission, as confirmed by 24 h urinary free cortisol excretion tests. Visible microlesions were identified on the initial MRI in 11 patients (61%). The SHI findings agreed with the MRI findings in 10 of the 11 patients (90.9%) and with IPSS lateralization in 6 of the 11 patients (54.5%). In the 7 patients whose lesions were not visible on the initial MRI, only 1 (14.3%) showed an agreement between IPSS and SHI. In 3 of the 7 patients, the microlesions were identified by additional MRI. The rate of concordance with SHI was 77.8% for the overall MRI and 38.9% for IPSS. High-resolution MRI is better than IPSS for localizing corticotroph adenomas. In patients with lesions not visible on the initial MRI, additional MRI should be performed using a different protocol. Although high-resolution MRI is better for localizing tumors, SHI remains an important approach for removing the tumors completely.

Long-term management with octreotide or cabergoline in ectopic corticotropin hypersecretion: case report and literature review

OBJECTIVE

To describe the corticotropin response to long-term octreotide or cabergoline administration in a patient with ectopic corticotropin secretion who underwent adrenalectomy.

METHODS

We describe the clinical, radiologic, and biochemical findings of the study patient over the course of 18 years.

RESULTS

A 40-year-old woman was evaluated for Cushing syndrome. On the basis of biochemical indices, Cushing disease was diagnosed and pituitary exploration was performed. No cure was achieved. Computed tomography of the chest revealed a right lung nodule due to a lung carcinoid tumor that was then surgically excised. Because of persistent hypercortisolism, total adrenalectomy was performed. Subsequently, corticotropin levels rose dramatically and hyperpigmentation developed while serum cortisol was in the reference range. The patient was treated with octreotide for 3 years and then with cabergoline for 8 years. While taking octreotide, corticotropin values decreased, accompanied by depigmentation and development of signs of adrenal insufficiency, which led to the reinstitution of supplemental hydrocortisone. Cabergoline induced a similar long-lasting effect on the clinical and biochemical parameters observed. Eight years later, she is still treated with cabergoline, and no lung tumor has been detected.

CONCLUSIONS

In this patient with ectopic Cushing syndrome, treatment with either octreotide or cabergoline markedly reduced corticotropin levels and hyperpigmentation.

High prevalence of normal tests assessing hypercortisolism in subjects with mild and episodic Cushing's syndrome suggests that the paradigm for diagnosis and exclusion of Cushing's syndrome requires multiple testing

Many Endocrinologists believe that a single determination of eucortisolism or a single demonstration of appropriate suppression to dexamethasone excluded Cushing's syndrome, except in what was previously thought to be the rare patient with episodic or periodic Cushing's syndrome. We hypothesize that episodic Cushing's syndrome is relatively common and a single test assessing hypercortisolism may not be sufficient to accurately rule out or diagnose Cushing's syndrome and retrospectively examined the number of normal and abnormal tests assessing hypercortisolism performed on multiple occasions in 66 patients found to have mild and/or episodic Cushing's syndrome compared to a similar group of 54 patients evaluated for, but determined not to have Cushing's syndrome. We found that 65 of the 66 patients with Cushing's syndrome had at least one normal test of cortisol status and most patients had several normal tests. The probability of having Cushing's syndrome when one test was negative was 92% for 23:00 h salivary cortisol, 88% for 24-h UFC, 86% for 24-h 17OHS, and 54% for nighttime plasma cortisol. These results demonstrated that episodic hypercortisolism is highly prevalent in subjects with mild Cushing's syndrome and no single test was effective in conclusively diagnosing or excluding the condition. Rather, the paradigm for the diagnosis should be a careful history and physical examination and in those patients in whom mild Cushing's syndrome/disease is strongly suspected, multiple tests assessing hypercortisolism should be performed on subsequent occasions, especially when the patient is experiencing signs and symptoms of short-term hypercortisolism.

Is metabolic syndrome a mild form of Cushing's syndrome?

The Metabolic Syndrome is a diagnosis of increasing prevalence that is noted to share multiple clinical features with Cushing's syndrome. Several studies suggest abnormalities in the Hypothalamic-Pituitary-Adrenal axis to be associated with this disease and tissue-specific hypercortisolemia is being investigated as a possible contributing factor. More research is needed to explore the relation between cortisol and the metabolic syndrome which, if confirmed, will have major therapeutic and public health implications.

Use of the desmopressin test in the differential diagnosis of pseudo-Cushing state from Cushing's disease

CONTEXT

The desmopressin (DDAVP) test has been proposed to discriminate Cushing's disease (CD) from pseudo-Cushing states (PC); however, current information on its value is scarce and contradictory.

OBJECTIVE

The aim of the study was to assess the ability of the DDAVP test in distinguishing between these conditions, with emphasis on subjects with mild hypercortisolism.

DESIGN AND SETTING

We conducted a retrospective/prospective study at the Division of Endocrinology, Polytechnic University of Marche, Ancona, Italy.

PATIENTS

The study included 52 subjects with CD, 28 with PC, and 31 control subjects (CT).

INTERVENTION(S)

We performed the DDAVP test and standard diagnostic procedures for the diagnosis of Cushing's syndrome.

MAIN OUTCOME MEASURE(S)

The diagnosis/exclusion of CD was measured.

RESULTS

Interpretation of the DDAVP test based on percentage and absolute increment of cortisol and ACTH did not afford acceptable values of both sensitivity (SE) and specificity (SP). CD diagnosis based on simultaneous positivity for basal serum cortisol greater than 331 nmol/liter and absolute ACTH increment greater than 4 pmol/liter and its exclusion in subjects negative for one or both measures yielded an SE of 90.3% and an SP of 91.5%. The approach was also highly effective in distinguishing PC from: 1) CD with moderate values of urinary free cortisol (SE, 86.9%; SP, 92.8%); 2) CD with moderate values of serum cortisol after dexamethasone suppression (SE, 86.6%; SP, 92.8%); and 3) CD with moderate values of midnight serum cortisol (SE, 100%; SP, 92.8%).

CONCLUSIONS

Interpretation of the DDAVP test through a combination of parameters allowed effective discrimination of CD from PC, even in subjects with mild hypercortisolism.

Diagnostic efficacy of midnight cortisol and midnight ACTH in the diagnosis and localisation of Cushing's syndrome

Classical tests for diagnosis of Cushing's syndrome (CS) like urine free cortisol and dexamethasone suppression tests have limitations in various clinical settings. This study evaluated the usefulness of sleeping midnight serum cortisol (SMNC) as a diagnostic test for hypercortisolemia. A simultaneously done midnight plasma ACTH level was used to classify the disease as ACTH dependent or independent. Standard biochemical tests, SMNC, midnight plasma ACTH and appropriate imaging evaluated patients with a clinical suspicion of Cushing's syndrome. We evaluated 43 patients with CS comprising of 34 patients with Cushing's disease (CD), 2 patients with thymic carcinoid producing ectopic CS, 5 patients with adrenal carcinoma and 2 with adrenal adenoma. Thirteen patients with clinical suspicion were also evaluated with the above tests and CS was ruled out. SMNC, midnight plasma ACTH and dexamethasone suppressed cortisol was collected from patients with a suspicion of CS. SMNC was evaluated against histopathology as the gold standard. SMNC achieved 100% sensitivity in the diagnosis of endogenous CS at cut offs of 138 nmol/l and below. Raising the cut off to 207 nmol/l resulted in a test sensitivity of 90.5%. At a cut off of 1.65 pmol/l, midnight plasma ACTH could distinguish ACTH independent causes of CS with 100% sensitivity. We concluded that a single midnight collection could identify all patients with CS and classify the ACTH status at the proposed cut offs.

Utility of salivary cortisol measurements in Cushing's syndrome and adrenal insufficiency

CONTEXT

The measurement of cortisol in saliva is a simple, reproducible, and reliable test to evaluate the normal and disordered control of the hypothalamic-pituitary-adrenal (HPA) axis. There are a variety of simple methods to obtain saliva samples without stress, making this a robust test applicable to many different experimental and clinical situations.

EVIDENCE ACQUISITION

Ovid Medline and PubMed from 1950 to present were searched using the following strategies: [<saliva or salivary>and<cortisol or hydrocortisone>and<Cushing or Cushing's>] and [<saliva or salivary>and<cortisol or hydrocortisone>and<adrenal insufficiency or hypoadrenalism or hypopituitarism or Addison's disease>]. The bibliographies of all relevant citations were evaluated for any additional appropriate citations.

EVIDENCE SYNTHESIS

Measurement of an elevated late-night (2300 to 2400 h) salivary cortisol has a greater than 90% sensitivity and specificity for the diagnosis of endogenous Cushing's syndrome. Late-night salivary cortisol measurements are also useful to monitor patients for remission and/or recurrence after pituitary surgery for Cushing's disease. Because it is a surrogate for plasma free cortisol, the measurement of salivary cortisol may be useful during an ACTH stimulation test in patients with increased plasma binding protein concentrations due to increased estrogen, or decreased plasma binding protein concentrations during critical illness. Most reference laboratories now offer salivary cortisol testing.

CONCLUSIONS

It is expected that the use of the measurement of salivary cortisol will become routine in the evaluation of patients with disorders of the HPA axis.

Comparison of 1 mg and 2 mg overnight dexamethasone suppression tests for the screening of Cushing's syndrome in obese patients

OBJECTIVE

Obesity is currently a major public health problem and one of the potential underlying causes of obesity in a minority of patients is Cushing's syndrome (CS). Traditionally, the gold standard screening test for CS is 1 mg dexamethasone overnight suppression test. However, it is known that obese subjects have high false positive results with this test.

DESIGN

We have therefore compared the 1 mg and 2 mg overnight dexamethasone suppression tests in obese subjects. Patients whose serum cortisol after ODST was >50 nM underwent and a low-dose dexamethasone suppression test (LDDST); 24-hour urine cortisol was collected for basal urinary free cortisol (UFC). For positive results after overnight 1-mg dexamethasone suppression test we also performed the overnight 2-mg dexamethasone suppression test.

PATIENTS

We prospectively evaluated 100 patients (22 men and 78 women, ranging in age from 17 to 73 years with a body mass index (BMI) >30 kg/m2 who had been referred to our hospital-affiliated endocrine clinic because of simple obesity. Suppression of serum cortisol to <50 nM (1.8 microg/dL) after dexamethasone administration was chosen as the cut-off point for normal suppression.

MEASUREMENTS

Thyroid function tests, lipid profiles, homocysteine, antithyroglobulin, anti-thyroid peroxidase antibody levels, vitamin B12, folate levels, insulin resistance [by homeostasis model assessment (HOMA)] and 1.0 mg postdexamethasone (postdex) suppression cortisol levels were measured.

RESULTS

We found an 8% false-positive rate in 1 mg overnight test and 2% in 2 mg overnight test (p=0.001). There was no correlation between the cortisol levels after ODST and other parameters.

CONCLUSIONS

Our results indicate that the 2 mg overnight dexamethasone suppression test (ODST) is more convenient and accurate than 1-mg ODST as a screening test for excluding CS in subjects with simple obesity.

Cushing's syndrome in pregnancy: an overview

Cushing's syndrome (CS) during pregnancy is a rare condition with fewer than 150 cases reported in the literature. Adrenal adenomas were found to be the commonest cause, followed by Cushing's disease. The gestation dramatically affects the maternal hypothalamic-pituitary-adrenal axis, resulting in increased hepatic production of corticosteroid-binding globulin (CBG), increased levels of serum, salivary and urinary free cortisol, lack of suppression of cortisol levels after dexamethasone administration and placental production of CRH and ACTH. Moreover, a blunted response of ACTH and cortisol to exogenous CRH may also occur. Therefore, the diagnosis of CS during pregnancy is much more difficult. Misdiagnosis of CS is also common, as the syndrome may be easily confused with preeclampsia or gestational diabetes. Because CS during pregnancy is usually associated with severe maternal and fetal complications, its early diagnosis and treatment are critical. Surgery is the treatment of choice for CS in pregnancy, except perhaps in the late third trimester, with medical therapy being a second choice. There does not seem to be a rationale for supportive treatment alone.

[Endogenous Cushing's syndrome: clinical and laboratorial features in 73 cases]

We studied clinical and laboratorial features of 73 patients with endogenous Cushing's syndrome, subdivided as follows: 46 (63%) with Cushing's disease (CD), 21 (28.7%) with an adrenal tumor and 6 (8.2%) with ectopic ACTH secretion (EAS). The rate of typical manifestations of hypercortisolism was similar regardless its etiology. In 100% of cases of Cushing's syndrome we observed serum cortisol levels greater than 1.8 microg/dL in low-dose dexamethasone (DMS) suppression tests, as well as elevation of serum or salivary midnight cortisol. However, urinary free cortisol was normal in 11.5% of patients. ACTH levels were suppressed in patients with adrenal tumors, normal or high in CD and always high in EAS. In the 8-mg overnight DMS suppression test, serum cortisol suppression > 50% was observed in 78.2% of cases of CD and in 33.3% of subjects with EAS, while an 80% suppression was only seen in CD. After stimulation with CRH or DDAVP an ACTH increase > 35% occurred in 81% of individuals with CD and 16.6% of those with EAS, while an ACTH increase > 50 achieved 100% specificity. Moreover, the combination of serum cortisol suppression > 50% and an ACTH increase > 35% in both tests only occurred in Cushing's disease. Pituitary magnetic resonance imaging identified 100% of macroadenomas and 59.4% of microadenomas in patients with CD. Among 10 patients that underwent bilateral inferior petrosal sinus sampling, a central-to-peripheral ACTH gradient > 3 after CRH or DDAVP had 90% sensitivity and 100% specificity for Cushing's disease.

Late-night salivary cortisol measurement in the diagnosis of Cushing's syndrome

Making a definite diagnosis of Cushing's syndrome is a challenging problem. Unsuspected Cushing's syndrome occurs in 2-3% of patients with poorly controlled diabetes, 0.5-1% with hypertension, 6-9% with incidental adrenal masses, and 11% with unexplained osteoporosis and vertebral fractures. The increasing recognition of this syndrome highlights the need for a simple, sensitive, and specific diagnostic test. Patients with Cushing's syndrome consistently do not reach a normal nadir of cortisol secretion at night. The measurement of late-night salivary cortisol levels might, therefore, provide a new diagnostic approach for this disorder. Salivary cortisol concentrations reflect those of active free cortisol in plasma and saliva samples can easily be obtained in a nonstressful environment (e.g. at home). Late-night salivary cortisol measurement yields excellent overall diagnostic accuracy for Cushing's syndrome, with a sensitivity of 92-100% and a specificity of 93-100%. Several factors can, however, make interpretation of results difficult; these factors include disturbed sleep-wake cycles, contamination of samples (particularly by topical corticosteroids), and illnesses known to cause physiologic activation of the pituitary-adrenal axis. In this Review, we discuss the methods and value of measuring salivary cortisol for the diagnosis of Cushing's syndrome, and put forward some recommendations to maximize accuracy of results.

The role of inferior petrosal sinus sampling in the diagnostic localization of Cushing's disease

Cushing's syndrome can present a complex problem of differential diagnosis. Of cases in which hypercortisolemia results from an adrenocorticotropic hormone (ACTH)-dependent process, approximately 80% are due to a pituitary adenoma (Cushing's disease [CD]), 10% are due to adrenal lesions, and the remaining 10% are secondary to ectopic ACTH secretion. For patients with CD, surgical removal of the pituitary adenoma is the treatment of choice. Thus, localization of the source of ACTH secretion is critical in guiding timely treatment decisions. Inferior petrosal sinus sampling (IPSS) is considered to be the gold standard for confirming the origin of ACTH secretion in patients with Cushing's syndrome. The authors present an overview of IPSS--both the technique and its interpretation--as well as a summary of recent studies. A number of other techniques are discussed including sampling from the cavernous sinus, the jugular vein, and multiple sites to aid the diagnosis and lateralization of ACTH-producing pituitary adenomas. Management is best undertaken by a comprehensive multidisciplinary team taking into account the results of all the biochemical and imaging studies available, to provide the best advice in patient treatment decisions.

"Subclinical Cushing's syndrome" is not subclinical: improvement after adrenalectomy in 9 patients

BACKGROUND

A subgroup of patients with adrenal cortisol hypersecretion fails to meet the biochemical criteria for Cushing's syndrome. Appropriate therapy for this entity, subclinical Cushing's syndrome (subclinical CS), is unclear. We examined outcomes for patients who underwent unilateral adrenalectomy for subclinical CS.

METHODS

Between 2003 and 2006, all patients who underwent adrenalectomy for cortisol hypersecretion caused by an adrenal mass were examined. We analyzed biochemical, metabolic, and clinical outcomes.

RESULTS

Overall, 24 patients underwent adrenalectomy for adrenal cortisol hypersecretion, of which 9 were found to have subclinical CS. Median serum cortisol was 2.0 microg/dL (range, 1.1-6.1) after 1-mg overnight dexamethasone suppression testing. Suspicious clinical findings on preoperative examination included skin bruising, unexplained weight gain, proximal muscle weakness, abnormal fat pads, skin thinning, fatigue, and facial plethora. During a median follow-up period of 5 months (range, 1-30 months), all 8 patients with easy bruising noted resolution postoperatively. Fatigue improved in 4 of 5 patients, muscle weakness in 6 of 8 patients, and weight in 7 of 9 patients, with a median body mass index change of -2.0 kg/m(2) (range, -7.1 to +0.5 kg/m(2)).

CONCLUSION

Adrenalectomy improves clinical and metabolic parameters for many patients with subclinical CS.

Ectopic ACTH syndrome

Ectopic adrenocorticotropic secretion (EAS) is responsible for 12-17% of cases of Cushing's syndrome (CS) and covers a range of tumours, from undetectable benign lesions to widespread metastases. The syndrome is often associated with severe hypercortisolaemia, which aggravates the underlying condition. EAS requires a complete workup that includes the establishment of endogenous CS, diagnosis of adrenocorticotropic hormone (ACTH) dependency, localization of the source of ACTH secretion and rapid biochemical control of hypercortisolaemia. Dynamic endocrine tests should include inferior petrosal sinus sampling with CRH stimulation. Localization studies depend on the availability of reliable high-resolution cross-sectional imaging. This systematic review of the largest published series of patients with EAS (over 380 patients) reveals the common trends in the prevalence and management of this syndrome. The concept of 'occult' EAS has been revisited and the terms 'overt' and 'covert' EAS introduced. In addition to small cell lung carcinoma, the most common causes of ectopic EAS are bronchial carcinoids, thymic tumours, islet cell tumour of the pancreas, medullary thyroid carcinomas, and phaeochromocytomas. Their prevalence and the best localization modalities are presented. Medical and surgical management is discussed on the basis of the extensive experience of major referral centres.

Pitfalls in the diagnosis of Cushing's syndrome

Among endocrine disorders, Cushing's syndrome (CS) is certainly one of the most challenging to endocrinologists due to the difficulties that often appear during investigation. The diagnosis of CS involves two steps: confirmation of hypercortisolism and determination of its etiology. Biochemical confirmation of the hypercortisolaemic state must be established before any attempt at differential diagnosis. Failure to do so will result in misdiagnosis, inappropriate treatment, and poor management. It should also be kept in mind that hypercortisolism may occur in some patients with depression, alcoholism, anorexia nervosa, generalized resistance to glucocorticoids, and in late pregnancy. Moreover, exogenous or iatrogenic hypercortisolism should always be excluded. The three most useful tests to confirm hypercortisolism are the measurement of 24-h urinary free cortisol levels, low-dose dexamethasone-suppression tests, and determination of midnight serum cortisol or late-night salivary cortisol. However, none of these tests is perfect, each one has different sensitivities and specificities, and several are usually needed to provide a better diagnostic accuracy. The greatest challenge in the investigation of CS involves the differentiation between Cushing's disease and ectopic ACTH syndrome. This task requires the measurement of plasma ACTH levels, non-invasive dynamic tests (high-dose dexamethasone suppression test and stimulation tests with CRH or desmopressin), and imaging studies. None of these tests had 100% specificity and their use in combination is usually necessary. Bilateral inferior petrosal sinus sampling is mainly indicated when non-invasive tests do not allow a diagnostic definition. In the present paper, the most important pitfalls in the investigation of CS are reviewed.

Diagnostic approach to Cushing disease

✓ In Cushing disease, a pituitary corticotroph neoplasm causes secondary adrenal hypercortisolism. This condition has known morbidity and mortality, underscoring the need for an efficient and accurate diagnostic approach. An 11 p.m. salivary cortisol level is a modern, simple initial screening tool for the diagnosis of Cushing syndrome. Confirmation with a 24-hour urinary free cortisol test and/or a low-dose dexamethasone suppression test may subsequently be performed. Patients with repeatedly equivocal results should be reevaluated after several months or undergo a corticotropin-releasing hormone (CRH) stimulation test following low-dose dexamethasone suppression to help rule out pseudo-Cushing states. The presence of low morning serum adrenocorticotropic hormone (ACTH) levels then distinguishes primary adrenal hypercortisolism from Cushing disease and the ectopic ACTH syndrome. Patients with moderate ACTH levels can undergo CRH stimulation testing to clarify the underlying disease because those with an ACTH-independent disorder have blunted subsequent ACTH levels. Once ACTH-dependent hypercortisolemia is detected, magnetic resonance (MR) imaging of the pituitary gland can be performed to detect a pituitary neoplasm. Normal or equivocal MR imaging results revealing small pituitary lesions should be followed up with inferior petrosal sinus sampling, a highly specific measure for the diagnosis of Cushing disease in experienced hands. If necessary, body imaging may be used in turn to detect sources of ectopic ACTH.

Assessment of bilateral inferior petrosal sinus sampling (BIPSS) in the diagnosis of Cushing's disease

BACKGROUND

The differential diagnosis of adrenocorticotropin (ACTH)-dependent Cushing's syndrome (CS) remains a challenging issue for clinical endocrinologists. In this respect, bilateral inferior petrosal sinus sampling (BIPSS) appears to be the most sensitive and specific test. Here, we report our 15-year experience of analyzing the performance of BIPSS, both in the correct diagnosis and in the precise lateralization of tumors in patients with Cushing's disease (CD).

METHODS

Between 1992 and 2006, 18 patients with CD (16 females, 2 males; age range, 14-56 years) were admitted to Taipei Veterans General Hospital and subjected to BIPSS plus ovine corticotropin-releasing hormone (oCRH) stimulation. Four of them had previously undergone transsphenoidal hypophysectomy (TSH) and had a recurrence thereafter. BIPSS was performed by inserting a catheter in the right and left inferior petrosal sinus for ACTH assay via a femoral vein puncture. An inferior petrosal sinus/peripheral ACTH ratio (C/P ratio) > or = 2 at baseline > or = 3 after oCRH injection indicated a pituitary origin of ACTH secretion, and an interpetrosal ACTH gradient (IPS ratio) > or = 1.4 at baseline or after oCRH indicated evidence of lateralization.

RESULTS

Positive BIPSS results were found in 16 patients at baseline and in 17 patients after oCRH injection. In 17 out of 18 patients, TSH was subsequently carried out and a pituitary source was confirmed on histopathologic examination. The only 1 false-negative test result was noted in a patient who had undergone previous TSH. Thus, the sensitivities of BIPSS for the diagnosis of CD before and after oCRH stimulation were 89% and 94%, respectively. Moreover, using an IPS ratio > or = 1.4 as a criterion, BIPSS correctly lateralized the tumor in 9 of 17 and 10 of 17 patients at baseline and after oCRH stimulation, respectively, including in 2 patients who had a centrally located tumor and who had an IPS ratio < 1.4. Thus, the sensitivities of lateralization of BIPSS were 53% and 59%, respectively. None of the 4 patients who had previous TSH were precisely localized by BIPSS. If these 4 patients were excluded, the sensitivities of BIPSS for localizing in the patients who had not undergone previous operation increased to 70% (9/13) at baseline and 77% (10/13) after oCRH stimulation, respectively.

CONCLUSION

BIPSS combined with oCRH stimulation is a safe and reliable examination both in the differential diagnosis of CD and in the correct lateralization of pituitary microadenoma in patients without previous pituitary surgery. Nevertheless, this procedure may provide misleading results in patients who have received previous pituitary surgery.

Urinary free cortisol and cortisone excretion in healthy individuals: influence of water loading

The influence of water loading on urinary excretion of free cortisol and cortisone was investigated in healthy men. The results were as follows: water loading tests (intake of 0.25-1.5 L) in a single individual showed that a water load of 1.5 L reliably increased the excretion of urine, free cortisol and cortisone (p < 0.01). Regression analyses gave significant correlations of urine volume with free cortisol and free cortisone, and of free cortisol and free cortisone. Corresponding results were obtained when water loading tests were performed in males who ingested 1.5 L of water (n = 8): the excretion of urine, free cortisol and free cortisone were significantly augmented; correlated was urine volume with free cortisol and free cortisone, and free cortisol with free cortisone. In a third set of tests, volunteers collected one 5 h urine (10:00-15:00 h) after the intake of 3 x 0.1 or 0.5 L at 11:00, 12:00 and 14:00 h. Excretion of urine, free cortisol and free cortisone in males of the low water loading group (3 x 0.1 L) was 0.59 mL/min, and 8.2 or 15.0 microg/5 h; corresponding values in individuals ingesting 3 x 0.5 L of water were 1.5 mL/min (p < 0.01), 12.3 microg/5 h (p > 0.05) and 26.3 microg/5 h (p < 0.02). In summary, urinary free cortisol and cortisone excretion in healthy men depends on urine volume, especially during water diuresis. Thus, interpretation of free cortisol and especially of free cortisone excretion is only possible if subjects strictly control their fluid intake and if urine volume is considered an important pre-analytical parameter-otherwise, interpretation of urinary free cortisol results is difficult and of urinary free cortisone data remains tenuous at best.

Cushing's Syndrome: important issues in diagnosis and management

CONTEXT

The diagnosis, differential diagnosis, and treatment of Cushing's syndrome are challenging problems in clinical endocrinology. We focus on critical questions addressing screening for Cushing's syndrome, differentiation of Cushing's subtypes, and treatment options.

EVIDENCE ACQUISITION

Ovid's MEDLINE (1996 through April 2006) was used to search the general literature. We also relied on previously published reviews and a recent monograph and cite a mix of primary articles and recent reviews.

EVIDENCE SYNTHESIS

Although this article represents our opinion, it draws heavily on a recent consensus statement from experts in the field and a recent monograph on Cushing's syndrome.

CONCLUSIONS

We concluded that: 1) measurement of late-night or bedtime salivary cortisol is a useful approach to screen for Cushing's syndrome; 2) measurement of suppressed plasma ACTH by immunometric assay is useful to differentiate ACTH-dependent and -independent Cushing's syndrome; 3) inferior petrosal sinus sampling for ACTH should be performed in patients with ACTH-dependent hypercortisolism in whom a pituitary magnetic resonance imaging is normal or equivocal (in the absence of a pituitary ACTH gradient, prolactin levels should be measured to confirm the integrity of venous sampling); 4) computed tomography of the chest and abdomen and somatostatin receptor scintigraphy should be performed in patients with the occult ectopic ACTH syndrome; and 5) patients with Cushing's disease should be referred to a neurosurgeon with extensive experience operating on corticotroph microadenomas. Bilateral laparoscopic adrenalectomy should be considered in patients with Cushing's disease who fail therapies directed at the pituitary.

Moderation of psychosocial risk factors through dysfunction of the hypothalamic–pituitary–adrenal stress axis in the onset of chronic widespread musculoskeletal pain : Findings of a population-based prospective cohort study

OBJECTIVE

To test the hypothesis that abnormalities in the hypothalamic-pituitary-adrenal (HPA) stress-response system would act as an effect moderator between HPA function and the onset of chronic widespread pain (CWP).

METHODS

We conducted a population-based prospective cohort study. Current pain and psychosocial status were ascertained in 11,000 subjects. Of the 768 eligible subjects free of CWP but at future risk based on their psychosocial profile, 463 were randomly selected, and 267 (57.7%) consented to assessment of their HPA axis function. Diurnal function was measured by assessing levels of salivary cortisol in the morning (9:00 AM) and evening (10:00 PM). Serum cortisol levels were measured after an overnight low-dose (0.25 mg) dexamethasone suppression test and a potentially stressful clinical examination. All subjects were followed up 15 months later to identify cases of new-onset CWP.

RESULTS

A total of 241 subjects (94.9%) completed the followup study, and 28 (11.6%) reported the new onset of CWP. High levels of cortisol post-dexamethasone (odds ratio [OR] 3.53, 95% confidence interval [95% CI] 1.17-10.65), low levels in morning saliva (OR 1.43, 95% CI 0.52-3.94), and high levels in evening saliva (OR 2.32, 95% CI 0.64-8.42) were all associated with CWP. These 3 factors were found to be independent and additive predictors of CWP (OR for all 3 factors 8.5, 95% CI 1.5-47.9) in analyses controlling for age, sex, depression, sleep disturbance, recent traumatic life events, and pain status. One or more of these 3 HPA factors identified 26 (92.9%) cases of new-onset CWP.

CONCLUSION

Among a group of psychologically at-risk subjects, dysfunction of the HPA axis helps to distinguish those who will and will not develop new-onset CWP.

Evaluation and treatment of Cushing's syndrome

Cushing's syndrome results from sustained pathologic hypercortisolism caused by excessive corticotropin (ACTH) secretion by tumors in the pituitary gland (Cushing's disease, 70%) or elsewhere (15%), or by ACTH-independent cortisol secretion from adrenal tumors (15%). The clinical features are variable, and no single pattern is seen in all patients. Those features most specific for Cushing's syndrome include abnormal fat distribution, particularly in the supraclavicular and temporal fossae, proximal muscle weakness, wide purple striae, and decreased linear growth with continued weight gain in a child. Patients with characteristics of glucocorticoid excess should be screened with measurements of saliva or urine cortisol or dexamethasone suppression testing. The diagnosis of Cushing's syndrome should be followed by the measurement of plasma ACTH concentration to determine whether the hypercortisolism is ACTH-independent. In ACTH-dependent patients, bilateral inferior petrosal sinus sampling with measurement of ACTH before and after administration of ACTH-releasing hormone most accurately distinguishes pituitary from ectopic ACTH secretion. Surgical resection of tumor is the optimal treatment for all forms of Cushing's syndrome; bilateral adrenalectomy, medical treatment, or radiotherapy are sought in inoperable or recurrent cases. The medical treatment of choice is ketoconazole. The prognosis is better for Cushing's disease and benign adrenal causes of Cushing's syndrome than adrenocortical cancer and malignant ACTH-producing tumors.