Overnight dexamethasone suppression of cortisol is associated with radiocholesterol uptake patterns in adrenal incidentalomas

Apparent failed and discordant adrenal vein sampling: A potential confounding role of cortisol cosecretion?

OBJECTIVE

Adrenal vein sampling (AVS) and computed tomography (CT) often show confusingly discordant lateralisation results in primary aldosteronism (PA). We tested a biochemical algorithm using AVS data to detect cortisol cosecretion as a potential explanation for discordant cases.

DESIGN

Retrospective analysis from a large PA + AVS database.

PATIENTS

All patients with PA and AVS, 2005-2020.

MEASUREMENTS

An algorithm using biochemical data from paired AVS + CT images was devised from physiological first principles and informed by data from unilateral, AVS-CT concordant patients. The algorithm involved calculations based upon the expectation that low cortisol levels exist in adrenal vein effluent opposite an aldosterone-and-cortisol-producing adrenal mass and may reverse lateralisation due to inflated aldosterone/cortisol ratios.

MAIN OUTCOMES

The algorithm was applied to cases with discordant CT-AVS lateralisation to determine whether this might be a common or explanatory finding. Clinical and biochemical characteristics of identified cases were collected via chart review and compared to CT-AVS concordant cases to detect evidence of biological plausibility for cortisol cosecretion.

RESULTS

From a total of 588 AVS cases, 141 AVS + CT pairs were clear unilateral PA cases, used to develop the three-step algorithm for AVS interpretation. Applied to 88 AVS + CT discordant pairs, the algorithm suggested possible cortisol cosecretion in 40%. Case review showed that the proposed cortisol cosecretors, as identified by the algorithm, had low/suppressed adrenocorticotropic hormone levels, larger average nodule size and lower plasma aldosterone.

CONCLUSIONS

Pending external validation and outcome verification by surgery and tissue immunohistochemistry, cortisol cosecretion from aldosteronomas may be a common explanation for discordant CT-AVS results in PA.

Adrenal (131)I-6β-iodomethylnorcholesterol scintigraphy in choosing the side for adrenalectomy in bilateral adrenal tumors with subclinical hypercortisolemia

Purpose

Adrenal scintigraphy with 131I-6β-iodomethylnorcholesterol is considered by several authors the gold standard for assessing tumors with subclinical hypercortisolemia. However, most of the described series consist mainly of cases with unilateral lesions. The aim of our study was to assess whether scintigraphy is useful in choosing the adrenalectomy side in the case of bilateral adrenal tumors with subclinical hypercortisolemia.

Methods

The study focused on 15 consecutive patients with benign bilateral adrenal tumors and subclinical hypercortisolemia. The scintigraphy with 131I-6β-iodomethylnorcholesterol was performed. Fourteen patients underwent unilateral adrenalectomy; the gland with predominant uptake on scintigraphy was removed. Cortisol and ACTH concentrations were measured one and six months after surgery. Post-dexamethasone cortisolemia was assessed six months after surgery. To date, the patients have been under postoperative observation for 1–4 years.

Results

Four patients showed unilateral uptake of radiotracer, and nine patients showed predominant accumulation of radiotracer in one of the adrenal glands. The smaller tumor was predominant in 2 cases. Percentage of activity on the predominant side correlates positively with the difference between tumors’ diameters. Unilateral uptake of radiotracer predicts long-lasting postoperative insufficiency of the second adrenal gland. Excision of predominating tumor led to cessation of hypercortisolemia in all patients.

Conclusions

The corticoadrenal scintigraphy is useful in choosing the side for operation in the case of bilateral adrenal tumors with subclinical hypercortisolemia.

Update on subclinical Cushing's syndrome

PURPOSE OF REVIEW

The present review summarizes recent findings in the diagnosis and treatment of subclinical Cushing's syndrome, a condition of subtle cortisol dysregulation with a spectrum of clinical and biochemical abnormalities.

RECENT FINDINGS

The diagnosis of subclinical Cushing's syndrome is suggested by abnormal suppression to dexamethasone in a patient with an adrenal mass. The natural history of this disorder includes progression in a minority of cases, and increased cardiovascular disease in patients with more severe and progressive disease, much as is found in overt Cushing's syndrome. In patients with an abnormal response to dexamethasone, additional biochemical and metabolic features increase confidence in the ability of adrenalectomy to reverse clinical abnormalities. In addition, bilateral masses and larger masses are more likely to be associated with hypercortisolism.

SUMMARY

We review the recent literature on subclinical cortisol secretion and suggest that additional studies are needed to define optimal diagnostic and therapeutic approaches.

Subclinical hypercortisolism and CT appearance in adrenal incidentalomas: a multicenter study from Southern Sweden

Evaluation of subclinical hypercortisolism (SH) in patients with adrenal incidentaloma (AI) including its correlation to size, attenuation at unenhanced computed tomography (CT) and unilateral or bilateral adrenal disease. Nine hospitals in Southern Sweden investigated during 2005-2007 consecutively patients with AI with hormonal and CT examinations according a regional protocol. Two hundred and twenty-eight patients with AI with median size 2.0 cm were included. One mg overnight dexamethasone suppression test (DST) was performed in 223 patients and basal P-ACTH measured in 146 patients. SH was defined as cortisol ≥ 50 nmol/l at DST in combination with basal ACTH <2 pmol/l. In patients with unilateral AI 42% (76/180) had inadequate suppression at DST and 23% (27/115) had SH. The probability for SH and inadequate suppression at DST correlated positively to size and inversely to attenuation at CT. Bilateral AI were found in 43 patients and of these 70% (30/43) had inadequate suppression at DST and 42% (13/31) SH. The patients with SH or inadequate suppression at DST had increased frequency of hypertension which increased further in patients with post-DST cortisol ≥ 140 nmol/l. The applied criterion for SH is useful for initial evaluation of patients with AI. SH is common in patients with AI, particular in bilateral disease. In patients with unilateral AI the probability for SH correlated positively to size and inversely to attenuation at CT. Furthermore, SH and the post-DST cortisol concentration was associated with hypertension.

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.

High prevalence of autonomous cortisol and aldosterone secretion from adrenal adenomas

OBJECTIVES

Previous studies based on standard endocrine testing have shown a variable incidence of autonomous cortisol secretion (ACS) or autonomous aldosterone secretion (AAS) in patients with single adrenal adenomas (SAA). We tested whether the use of appropriate controls and modification of standard testing, aiming at eliminating interference from endogenous ACTH, reveals previously undetected subtle ACS and AAS by SAA.

DESIGN

Case control study. Patients We investigated 151 patients with SAA and 72 matched controls with normal adrenal computerized tomography.

MEASUREMENTS

All participants had arterial blood pressure recorded, and serum cortisol and aldosterone measured before and after intravenous administration of 250 mug of ACTH, and following dexamethasone administration. Eighty-three patients and all the controls had serum aldosterone and renin measured before and after saline infusion, and after a second saline infusion following dexamethasone administration.

RESULTS

Using the mean + 2 SD values obtained from controls after dexamethasone administration and saline infusion following dexamethasone administration, normal cut-off values for cortisol (30.11 nM), aldosterone (67.59 pM), and aldosterone/renin ratio (9.74 pM/mU/l) were developed. Using these cut-off values, the estimated incidence of ACS and AAS in patients with SAA was 56.63% and 24.10%, respectively, whereas 12.05% had autonomous secretion of both cortisol and aldosterone. Systolic and diastolic arterial blood pressure correlated significantly with the aldosterone/renin ratio following AlphaCTH stimulation (P < 0.0002 and P < 0.001, respectively), and after saline infusion following dexamethasone administration (P < 0.003 and P < 0.002, respectively).

CONCLUSIONS

By applying new cut-offs, ACS and AAS in patients with a SAA is very common, and aldosterone secretion correlates with arterial blood pressure.

Endogenous subclinical hypercortisolism: Diagnostic uncertainties and clinical implications

Subclinical hypercortisolism (SH) is a newly characterized hormonal disorder that is almost exclusively detected in the context of incidentally discovered adrenal masses. The diagnostic criteria used for the definition of this condition are at present controversial. Amongst the various tests used for the detection of this abnormality (dexamethasone suppression, urinary free cortisol, ACTH levels, midnight serum or salivary cortisol concentrations, ACTH responses to CRH stimulation), the dexamethasone suppression tests (DST) seem to better accomplish the task of unmasking subtle abnormalities of cortisol secretion. Several versions of DST have been used: the 1-mg overnight, the 3-mg overnight and the classical 2-day low-dose DST. This latter test has the theoretical advantage that, by more efficiently suppressing pituitary ACTH secretion, it may provide a measure of the residual (ie non- ACTH-dependent) cortisol secretion from the adrenal mass. In this way, post-dexamethasone cortisol concentrations may quantify the degree of autonomous cortisol hypersecretion. In fact, post-dexamethasone cortisol concentrations have a negative correlation with basal ACTH levels and a positive correlation with midnight cortisol concentrations as well as the size of the incidentally discovered adrenal mass. Most of the existing data indicate that SH detected in the context of adrenal incidentalomas may have some clinically significant implications. In fact, patients with higher post-dexamethasone cortisol concentrations demonstrate higher lipid levels and lower bone mass densities. It has also been suggested that SH may be responsible for biochemical and phenotypic changes reminiscent of the metabolic syndrome. In summary, SH does exist and is associated with a negative impact in patients' health; however, hormonal cut-off criteria for decision-making remain to be defined.

Occult Cushing's syndrome in type-2 diabetes

Subclinical Cushing's syndrome (SCS) caused by adrenal incidentalomas is frequently associated with overweight and insulin resistance. Metabolic syndrome X may therefore be a clue to the presence of CS. However, the incidence of CS in this situation remains unknown. We have conducted a prospective study to evaluate the prevalence of occult CS in overweight, type-2 diabetic patients devoided of specific clinical symptoms of CS. Two hundred overweight, type-2 diabetic patients, consecutively referred for poor metabolic control (HbA(1C) > 8%), were studied as inpatients. A first screening step was performed with the 1-mg overnight dexamethasone suppression test (DST) using a revised criterion for cortisol suppression (60 nmol/liter) to maximize the sensitivity of the procedure. A second confirmatory step of biochemical investigations (midnight plasma cortisol concentration, plasma cortisol circadian rhythm, morning plasma ACTH concentration, 24-h urinary free cortisol, and 4-mg i.v. DST) was performed in patients with impaired 1-mg DST. A third step of imaging studies was performed according to the results of second-step investigations. Fifty-two patients had impaired 1-mg DST. Among these, 47 were further evaluated. Thirty were considered as false positives of the 1-mg DST, whereas 17 displayed at least one additional biological abnormality of the hypothalamic-pituitary-adrenal axis. Definitive occult CS was identified in four patients (2% of the whole series) with Cushing's disease (n = 3) and surgically proven adrenal adenoma (n = 1). Definitive diagnosis remains to be established in seven additional patients (3.5%) with mild occult CS associated with unsuppressed plasma ACTH concentrations and a unilateral adrenal tumor of 10-29 mm in size showing prevalent uptake at radiocholesterol scintigraphy. In conclusion, a relatively high prevalence of occult CS was found in our study. Further studies are needed to evaluate the impact of the cure of occult CS on obesity and diabetes mellitus in these patients. Such studies might provide a rationale for systematic screening of occult CS in this population.