Discrepancies in results of low-and high-dose dexamethasone suppression tests for diagnosing preclinical Cushing's syndrome

Association of urinary free cortisol with bone formation in patients with mild autonomous cortisol secretion

CONTEXT

Mild autonomous cortisol secretion (ACS) is associated with an increased risk of vertebral fractures (VFx). However, the influence of this condition on bone turnover or its association with mild ACS is still controversial.

OBJECTIVE

This study aimed to evaluate the impact of mild ACS on bone quality among patients living with the disease.

DESIGN AND SETTING

A retrospective study was conducted using data from 55 mild ACS and 12 nonfunctioning adrenal tumour (NFT) patients who visited Chiba University Hospital, Japan, from 2006 to 2018.

PATIENTS AND MAIN OUTCOME MEASURES

We analysed clinical features and bone-related factors, including bone mineral density (BMD) and VFx, performed blood tests to assess bone metabolism markers in patients with mild ACS and NFT, and assessed the associations between bone-related markers and endocrinological parameters in patients with mild ACS.

RESULTS

No significant differences between mild ACS and NFT patients were observed with respect to the presence or absence of VFx and BMD. Urinary free cortisol (UFC) was higher in mild ACS patients with VFx than those without (p = .037). The T-score and young adult mean (YAM) of the BMD of the femoral neck in mild ACS patients with a body mass index <25 were positively correlated with dehydroepiandrosterone sulphate levels (ρ: 0.42, p = .017; ρ: 0.40, p = .024, respectively). Pearson's correlation analysis showed that bone-specific alkaline phosphatase was negatively correlated with UFC in the patients with mild ACS (ρ: -0.37, p = .026).

CONCLUSIONS

These results suggest that urinary free cortisol may be useful for predicting bone formation in mild ACS patients.

Autonomous cortisol secretion in adrenal incidentalomas

Adrenal incidentalomas (AI) are one of the most frequent reasons for consultation in Endocrinology, as they are present in 3-10% of the general population. Up to 20% of them may have autonomous cortisol secretion (ACS), a term that refers to AI carriers with biochemical evidence of excess cortisol, but without the "specific" clinical signs of Cushing's syndrome. As ACS is associated with an increased risk of diabetes, obesity, high blood pressure (HBP), osteoporosis, cardiovascular events, and global mortality; its correct identification is of great importance. There are different laboratory assays to detect ACS, but all of them have some limitations. The dexamethasone suppression test is the most accepted for screening. However, there is no consensus on the cutoff point that should be used. Low levels of ACTH and DHEA-S and high urinary free cortisol are also associated with ACS, but in isolation they are of little value to establish the diagnosis. Considering its clinical implications and the lack of consensus in the diagnosis and in which is the most appropriate management of these patients, this review offers a quick reference guide of ACS, presenting an exhaustive review of the topic: its definition, epidemiology, diagnosis, clinical implications, treatment, and follow-up.

Clinical Investigation of Adrenal Incidentalomas in Japanese Patients of the Fukuoka Region with Updated Diagnostic Criteria for Sub-clinical Cushing's Syndrome

Objectives We retrospectively investigated the clinical and endocrinological characteristics of adrenal incidentalomas. Methods We studied 61 patients who had been diagnosed with adrenal incidentalomas and had undergone detailed clinical and endocrinological evaluations while hospitalized. We used common criteria to diagnose the functional tumors, but for sub-clinical Cushing's syndrome, we used an updated set of diagnosis criteria: serum cortisol ≥1.8 μg/dL after a positive response to a 1-mg dexamethasone suppression test if the patient has a low morning adrenocorticotropic hormone (ACTH) level (<10 pg/mL) and a loss of the diurnal serum cortisol rhythm. Results Of the 61 patients, none (0%) had malignant tumors, 8 (13.1%) had pheochromocytoma, and 15 (24.6%) had primary aldosteronism; when diagnosed by our revised criteria, 13 (21.3%) had cortisol-secreting adenomas (Cushing's syndrome and sub-clinical Cushing's syndrome), and 25 (41.0%) had non-functional tumors. Compared with the non-functional tumor group, the primary aldosteronism group and the cortisol-secreting adenoma group were significantly younger and had significantly higher rates of hypokalemia, whereas the pheochromocytoma group had significantly larger tumors and a significantly lower body mass index. Conclusion Our study found a larger percentage of functional tumors among adrenal incidentalomas than past reports, partly because we used a lower serum cortisol level after a dexamethasone suppression test to diagnose sub-clinical Cushing's syndrome and because all of the patients were hospitalized and could therefore receive more detailed examinations. Young patients with hypokalemia or lean patients with large adrenal tumors warrant particularly careful investigation.

New diagnostic criteria of adrenal subclinical Cushing's syndrome: opinion from the Japan Endocrine Society

New diagnostic criteria and the treatment policy for adrenal subclinical Cushing's syndrome (SCS) are proposed on behalf of the Japan Endocrine Society. The Japanese version has been published, and the essential contents are presented in this English-language version. The current diagnostic criteria for SCS have elicited two main problems: (i) the relatively low reliability of a low range of serum cortisol essential for the diagnosis by an overnight 1-mg dexamethasone suppression test (DST); (ii) different cutoff values for serum cortisol after a 1-mg DST compared with those of other countries. Thus, new criteria are needed. In the new criteria, three hierarchical cortisol cutoff values, 5.0, 3.0 and 1.8 μg/dL, after a 1-mg DST are presented. Serum cortisol ≥5 μg/dL after a 1-mg DST alone is considered sufficient to judge autonomous cortisol secretion for the diagnosis of SCS, and the current criterion based on serum cortisol ≥3 μg/dL after a 1-mg DST can continue to be used. Clinical evidence suggests that serum cortisol ≥1.8-2.9 μg/dL after a 1-mg DST is not always normal, so cases who meet the cutoff value as well as a basal adrenocorticotropic hormone (ACTH) level <10 pg/mL (or poor ACTH response to corticotropin-releasing hormone (CRH)) and nocturnal serum cortisol ≥5 μg/dL are proposed to have SCS. We suggest surgery if cases show serum cortisol ≥5 μg/dL after a 1-mg DST (or are disheartened by treatment-resistant problems) or suspicious cases of adrenal cancer according to tumor imaging.

DHEAS for the prediction of subclinical Cushing's syndrome: perplexing or advantageous?

The diagnostic accuracy of dehydroepiandrosterone sulfate (DHEAS) to predict subclinical Cushing's syndrome (sCS) has been a matter of debate. The primary objective of this study was to assess the diagnostic power of DHEAS in predicting sCS. This retrospective study was conducted in a tertiary referral center and based on subjects referred between 2004 and 2014. Data of 249 subjects with adrenal incidentalomas were evaluated. We also reviewed 604 DHEAS measurements from adults, which were performed during the same period in our laboratory (LB group). Adrenocortical function, tumor size, and clinical characteristics were assessed. We diagnosed sCS in 15.2 % of the participants in the presence of ≥2 of the following; 1 mg dexamethasone suppression test >3.0 μg/dl, urinary free cortisol >70 μg/24 h, and corticotrophin (ACTH) <10 pg/ml. DHEAS levels were significantly reduced in patients with sCS (n = 38) compared to sCS (-) (n = 141) and LB groups (n = 604) (27.95, 65.90, and 66.80 µg/dl, respectively, p < 0.001) while age was comparable. The ROC curve analysis showed that the cut-off of the DHEAS with the best diagnostic accuracy for detecting sCS was 40.0 μg/dl (SN, 68 %; SP, 75; PPV, 43 %; NPV, 90 %, AUC: 0.788, p < 0.001). Logistic regression assessed the impact of age, BMI, low DHEAS (<40 μg/dl), bilateral tumors, and tumor size on the likelihood of having sCS. The strongest predictor was low DHEAS, recording an OR of 9.41. DHEAS levels are inversely associated with the extent of cortisol excess. In subjects with intermediate laboratory findings, detection of low DHEAS could be advantageous for distinguishing sCS.

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.

Characterization of lipid-rich adrenal tumors by FDG PET/CT: Are they hormone-secreting or not?

OBJECTIVES

The purpose of this study was to evaluate the diagnostic ability of FDG PET/CT to predict the hormone-secretion status of lipid-rich adrenal tumors.

METHODS

This study included 29 lipid-rich (CT number <10 HU) adrenal tumors 2 cm or larger in diameter in 28 patients who underwent FDG PET/CT. The diagnoses were based on endocrine examinations, including adrenal venous sampling and subsequent surgical resection, or on the endocrinological and morphological imaging follow-up during a period of at least 6 months. The FDG uptake of the adrenal tumors was evaluated semi-quantitatively using maximum standardized uptake values (SUVmax) and a ratio of the adrenal SUVmax compared to the liver SUVmax (SUVratio) was used for comparison. The statistical significance of differences was assessed using the Mann-Whitney U test, and a p value <0.05 was considered to be statistically significant.

RESULTS

The lipid-rich adrenal tumors were proved to be 16 non-hormone-secreting tumors (15 adenomas and one myelolipoma) and 13 hormone-secreting tumors (five subclinical cortisol-producing adenomas, six aldosterone-producing adenomas and two adenomas that produced both cortisol and aldosterone). None of the patients had pheochromocytoma or a malignant adrenal tumor. The SUVmax (median, range) of the hormone-secreting tumors (3.2, 2.0-8.3) was higher than that of the non-hormone-secreting tumors (2.4, 1.8-3.3) (p < 0.05). Similarly, the SUVratio of the hormone-secreting tumors (0.95, 0.70-3.10) was higher than that of the non-hormone-secreting tumors (0.72, 0.54-0.95) (p < 0.01). There was no significant difference in the tumor diameter between the two groups (p = 0.8). The sensitivity, specificity and accuracy of FDG PET/CT for differentiating hormone-secreting tumors from non-hormone-secreting tumors were 0.69, 0.81 and 0.76 for cutoff SUVratio of 0.8, and were 0.46, 1 and 0.76 for the cutoff SUVratio of 1.0, respectively.

CONCLUSIONS

A lipid-rich adrenal tumor presenting increased FDG uptake compared with that of the liver is likely to be a hormone-secreting adenoma. Therefore, additional endocrinological investigations are strongly recommended when an FDG-avid lipid-rich incidentaloma is detected on FDG PET/CT.

Proposed diagnostic criteria for subclinical Cushing's syndrome associated with adrenal incidentaloma

Subclinical Cushing's syndrome (SCS) associated with adrenal incidentaloma is usually characterized by autonomous cortisol secretion without overt symptoms of Cushing's syndrome (CS). Although the diagnostic criteria for SCS differ among countries, the 1 mg dexamethasone suppression test (DST) is essential to confirm the presence and the extent of cortisol overproduction. Since 1995, SCS has been diagnosed in Japan based on serum cortisol levels ≥3 μg/dL (measured by radioimmunoassay [RIA]) after a 1 mg DST. However, the increasing use of enzyme immunoassays (EIA) instead of RIA has hindered the diagnosis of SCS because of the differing sensitivities of commercially available assays, particularly for serum cortisol levels of around 3 μg/dL. One way to overcome this problem is to lower the cortisol threshold level after a 1 mg DST. In the present study, we examined the clinical applicability of lowering the cortisol threshold to 1.8 μg/dL, similar to the American Endocrine Society's guidelines for CS, by reanalyzing 119 patients with adrenal incidentaloma. Our findings indicate that serum cortisol levels ≥1.8 μg/dL after 1 mg DST are useful to confirm the diagnosis of SCS if both of the following criteria are met: (1) basal ACTH level <10 pg/mL (or poor plasma ACTH response to corticotrophin-releasing hormone) and (2) serum cortisol ≥5 μg/dL at 21:00 to 23:00 h. If only one of (1) and (2) are met, we recommend that other clinical features are considered in the diagnosis of SCS, including serum dehydroepiandrosterone sulfate levels, urine free cortisol levels, adrenal scintigraphy, and clinical manifestation.

Subclinical Cushing's syndrome

The routine use of abdominal procedure has significantly increased the incidental finding of adrenal masses. The prevalence of these tumors, commonly defined as adrenal incidentalomas, ranges between 2-3% in autopsy and 4% in radiological series, reaching 5-8% in oncological studies and increasing with patients age. Although clinically silent, in 5-20% of cases, adrenal incidentalomas are responsible for a subtle cortisol overproduction, commonly defined as "subclinical Cushing's syndrome" (SCS). This term is used to describe autonomous cortisol secretion in patients who don't have the typical signs and symptoms of hypercortisolism. The optimal strategy for identification and management of SCS is unknown; the standard biochemical tests used to screen for overt Cushing's syndrome are generally ill-suited to the assessment of patients who have no, or only very mild signs of cortisol excess, then many tests aimed to study the hypothalamus-pituitary-adrenal axis (HPA) axis do not have sufficient sensitivity to recognize very mild degree of cortisol excess. An increased frequency of hypertension, central obesity, impaired glucose tolerance or diabetes, hyperlipemia and osteoporosis has been described in patients with SCS since patients are exposed to a chronic albeit slight, cortisol excess; however, there is not evidence-based demonstration of long term complications and, consequently, the management of this condition is largely empirical. Adrenalectomy or medical management of associated disease has been indicated as therapeutic options due to lack of data demonstrating the superiority of a surgical or non-surgical treatment.

Subclinical Cushing's syndrome: definition and management

Subclinical Cushing's syndrome is an ill-defined endocrine disorder that may be observed in patients bearing an incidentally found adrenal adenoma. The concept of subclinical Cushing's syndrome stands on the presence of ACTH-independent cortisol secretion by an adrenal adenoma, that is not fully restrained by pituitary feed-back. A hypercortisolemic state of usually minimal intensity may ensue and eventually cause harm to the patients in terms of metabolic and vascular diseases, and bone fractures. However, the natural history of subclinical Cushing's syndrome remains largely unknown. The present review illustrates the currently used methods to ascertain the presence of subclinical Cushing's syndrome and the surrounding controversy. The management of subclinical Cushing's syndrome, that remains a highly debated issue, is also addressed and discussed. Most of the recommendations made in this chapter reflects the view and the clinical experience of the Authors and are not based on solid evidence.

Clinical review: Diagnosis and treatment of subclinical hypercortisolism

CONTEXT

Subclinical hypercortisolism (SH) is a condition of biochemical cortisol excess without the classical signs or symptoms of overt hypercortisolism. It is thought to be present in the 5-30% of patients with incidentally discovered adrenal mass (adrenal incidentalomas), which in turn are found in 4-7% of the adult population. Therefore, SH has been suggested to be present in 0.2-2.0% of the adult population. Some studies suggested that this condition is present in 1-10% of patients with diabetes or established osteoporosis. The present manuscript reviews the literature on diagnostic procedures and the metabolic effect of the recovery from SH.

EVIDENCE ACQUISITION

A PubMed search was used to identify the available studies. The most relevant studies from 1992 to November 2010 have been included in the review.

EVIDENCE SYNTHESIS

The available data suggest that SH may be associated with chronic complications, such as hypertension, diabetes mellitus, overweight/obesity, and osteoporosis. The available intervention studies suggest that the recovery from SH may lead to the improvement of hypertension and diabetes mellitus. A retrospective study suggests that this beneficial effect could be predicted before surgery.

CONCLUSIONS

SH is suggested to be associated with some chronic complications of overt cortisol excess. Recovery from this condition seems to improve these complications. However, a large, prospective, randomized study is needed to confirm this hypothesis and to establish the best diagnostic approach to identify patients with adrenal incidentalomas who can benefit from surgery.

A case of ACTH-independent macronodular adrenal hyperplasia associated with multiple endocrine neoplasia type 1

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant neoplasia syndrome characterized by the occurrence of tumors in the parathyroid glands, pancreas, and anterior pituitary. Approximately 30-40% of MEN1 patients also have adrenal lesions, such as hyperplasia, benign adenoma, and adrenocortical carcinoma. Most of the cases are hormonally silent. We describe the case of a 60-year-old man with bilateral macronodular adrenal lesions, in addition to parathyroid tumors, multiple insulinomas, and non-functioning pituitary microadenoma. Endocrinological tests revealed subclinical hypercortisolism; midnight cortisol level rose slightly (8.0 µg/dL), although basal plasma ACTH and cortisol levels were within the normal range (19.5 pg/mL and 12.0 µg/dL, respectively). One and 8 mg dexamethasone suppression tests showed cortisol levels of 2.3 and 9.8 µg/dL, respectively. (131)I-adosterol scintigraphy under dexamethasone suppression revealed bilateral adrenal uptake with right-sided predominance. The histological features of the removed right adrenal gland were consistent with ACTH-independent macronodular adrenal hyperplasia (AIMAH): immunoreactivity of 17α-hydroxylase was predominantly observed in the small compact cells, while that of 3β-hydroxysteroid dehydrogenase was exclusively expressed in the large clear cells. The glucose-dependent insulinotropic polypeptide (GIP) receptor was expressed at high levels in compact cells, suggesting that GIP is responsible for the development of AIMAH. Unilateral small adrenal lesions were detected in the patient's 2 children, who also presented with MEN1 symptoms. Genetic abnormalities in the MEN1, p27, and p18 genes were not found, however, the present case may provide a clue to the understanding of the etiology of MEN1 and AIMAH.

Approach to the patient with an adrenal incidentaloma

Unsuspected adrenal masses, or incidentalomas, are increasingly found with the widespread use of thoracic and abdominal imaging. These masses may be hormonally active or nonfunctional and malignant or benign. Clinicians must determine the nature of the mass to decide what treatment, if any, is needed. Measurement of precontrast Hounsfield units (HU) and contrast washout on computed tomography scan provide useful diagnostic information. All patients should undergo biochemical testing for pheochromocytoma, either with plasma or urinary catecholamine measurements. This is particularly important before surgical resection, which is routinely recommended for masses larger than 4 cm in diameter without a clear-cut diagnosis and for others with hormonal secretion or ominous imaging characteristics. Hypertensive patients should undergo biochemical testing for hyperaldosteronism. Patients with features consistent with Cushing's syndrome, such as glucose intolerance, weight gain, and unexplained osteopenia, should be evaluated for cortisol excess. Here, the dexamethasone suppression test and late-night salivary cortisol may be preferred over measurement of urine cortisol. The ability of surgical resection to reverse features of mild hypercortisolism is not well established. For masses that appear to be benign (<10 HU; washout, >50%), small (<3 cm), and completely nonfunctioning, imaging and biochemical reevaluation (pheochromocytoma and hypercortisolism only) at 1-2 yr (or more) is appropriate. For more indeterminate lesions, repeat evaluation for growth after 3-12 months is useful, with subsequent testing intervals based on the rate of growth.

A new illicit opioid dependence outbreak, evidence for a combination of opioids and steroids

Opioid abuse is common in Iran. In 2005, a new version of locally produced illicit opioid vials, so called Norgesic, appeared in the illicit market, which gained popularity rapidly and led to an improvement of stigmatizing the general appearance of dependent cases. Later, some cases suffered Cushing's-like problems. A prospective case series was designed to evaluate 18 Norgesic-dependent subjects who volunteered for abstinence therapy in a rehabilitation clinic from November 1, 2005, to December 30, 2005. In this study, we aimed to describe the clinical and paraclinical findings in detail and define the potential determinants of this Cushing's syndrome outbreak. History, physical examination, plasma cortisol level, and urine screen tests were used to describe the patients. All subjects were male with a mean (SEM) age of 29.8 +/- 1.6 years. The opioid-dependence period was 8.4 +/-0.9 years. In an average of 4.7 +/- 0.3 months, subjects increased their usage to 5.5 +/- 0.5 vials a day. Patients claimed to gain weight. Striae were seen in 38.9%, previously documented psychological problems in 33.3%, weakness in 27.8%, high systolic blood pressure in 22.2%, moon face in 16.7%, hirsutism in 11.1%, extensive dermal infection in 11.1%, gynecomastia in 5.6%, back pain in 5.6%, insomnia in 5.6%, and lack of potency in 5.6%. Their cortisol level, on average, was 4.8 +/- 1.1 microg/dL. Hepatitis C virus was positive in 22.2%. Urine-screening tests were positive for morphine and negative for buprenorphine. In conclusion, these new vials contain steroids as well as opioids. This combination could be more dangerous than opioids themselves.

Primary Aldosteronism Caused by a Unilateral Adrenal Adenoma Accompanied by Autonomous Cortisol Secretion

A 35-year-old Japanese woman was referred for further examination of persistent hypertension with hypokalemia. Her serum aldosterone levels were high and her plasma renin activity markedly suppressed. Radiological examinations revealed the presence of a 3-cm diameter left adrenal tumor. (131)I-adosterol was specifically accumulated in the left adrenal tumor, whereas the accumulation in the right adrenal was completely suppressed. Low-dose dexamethasone failed to suppress cortisol secretion although the serum cortisol levels were within the normal range. Urinary excretion of 17-hydroxycorticosteroids but not 17-ketosteroids was increased. Levels of plasma adrenocorticotropin (ACTH) and serum dehydroepiandrosterone sulfate (DHEAS) were decreased. Upon diagnosis of left aldosteronoma with autonomous secretion of cortisol, left adrenalectomy was performed by laparoscopy. In the resected adenoma tissues, clear cells expressed P450c17 protein and the ratio of CYP17/CYP11B2 mRNA evaluated by quantitative real-time polymerase chain reaction (PCR) was apparently higher than that of typical aldosteronomas. Based on the corticotropin-releasing hormone (CRH) loading tests, the contra-lateral adrenal functions were restored 3 months after surgery. These results indicate that evaluation for autonomy of cortisol secretion and contra-lateral adrenal function is clinically important to avoid the risk of adrenal failure after surgery for primary aldosteronism.