The low-dose dexamethasone suppression test: a reevaluation in patients with Cushing’s syndrome

Posted on July 9, 2015 by MaryO

J Clin Endocrinol Metab. 2004 Mar;89(3):1222-6.

Findling JW1, Raff H, Aron DC.

Abstract

Low-dose dexamethasone suppression testing has been recommended for biochemical screening when Cushing’s syndrome is suspected. The criterion for normal suppression of cortisol after dexamethasone is controversial.

To assess diagnostic utility (sensitivity), we report the results of low-dose dexamethasone suppression testing in 103 patients with spontaneous Cushing’s syndrome. There were 80 patients with Cushing’s disease (78%), 13 with the ectopic ACTH syndrome (13%), and 10 with cortisol-producing adrenocortical adenomas (10%). Fourteen (18%) of 80 patients with Cushing’s disease suppressed serum cortisol to less than 5 micro g/dl (<135 nmol/liter) after the overnight 1-mg test, whereas six patients (8%) actually showed suppression of serum cortisol to less than 2 micro g/dl (<54 nmol/liter). In addition, the 2-d, low-dose dexamethasone suppression test yielded false-negative results in 38% of patients when urine cortisol was used and 28% when urinary 17-hydroxycorticosteroids were used. Serum cortisol after the 1-mg test correlated with baseline urinary free cortisol (r = 0.705, P < 0.001), plasma ACTH level (r = 0.322, P = 0.001), and urinary free cortisol after the 2-d test (r = 0.709, P = 0.001).

This study provides evidence that low-dose dexamethasone may suppress either plasma cortisol or urinary steroids to levels previously thought to exclude Cushing’s syndrome and that these tests should not be used as the sole criterion to exclude the diagnosis of endogenous hypercortisolism.

PMID:
15001614
[PubMed – indexed for MEDLINE]

From http://www.ncbi.nlm.nih.gov/pubmed/15001614

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Moderately impaired renal function increases morning cortisol and cortisol levels at dexamethasone suppression test in patients with incidentally detected adrenal adenomas

Posted on June 26, 2015 by MaryO
Clin Endocrinol (Oxf). 2015 May 23. doi: 10.1111/cen.12823. [Epub ahead of print]
Olsen H1, Mjöman M2.

Author information

Abstract

OBJECTIVE:

Patients with incidentally detected adrenal adenomas may have subclinical hypercortisolism. We hypothesized that impaired renal function could lead to increased cortisol levels in these patients.

DESIGN:

Descriptive retrospective study of consecutive patients.

PATIENTS:

A total of 166 patients with incidentally detected unilateral adrenal adenomas were examined during 2008-2013.

MEASUREMENTS:

Levels of cortisol, ACTH and cortisol at 1 mg overnight dexamethasone suppression test (DST) were measured. The estimated glomerular filtration rate (eGFR) was calculated using the MDRD equation.

RESULTS:

Renal function was normal, mildly impaired, moderately impaired or severely impaired (eGFR >90, 60-90, 30-60 and 15-30 ml/min/1·73 m2 ) in 34, 54, 10 and 1% of the patients, respectively. Patients with normal and mildly impaired renal function had similar cortisol levels. Patients with moderately impaired renal function, compared to all the patients with eGFR >60 ml/min/1·73 m2 , exhibited increased cortisol (541 vs 456 nmol/l, P = 0·02), increased cortisol at DST (62 vs 37 nmol/l, P = 0·001), but similar ACTH levels (4·1 vs 2·9 pmol/l, P = 0·21). Patients with moderately impaired renal function thus exhibited cortisol at DST ≥50 nmol/l, more often than patients with eGFR >60 ml/min/1·73 m2 (76% vs 30%, P = 0·000), while the prevalence of ACTH below 2 pmol/l was similar (24% vs 31%, P = 0·51).

CONCLUSIONS:

Moderately impaired renal function increases cortisol and cortisol at DST in patients with adrenal adenomas, while mildly impaired renal function has no such effect. Cortisol level at DST ≥50 nmol/l therefore seems to have low specificity in diagnosing subclinical adrenal hypercortisolism, and an additional criterion, for example low ACTH, is required.

© 2015 John Wiley & Sons Ltd.

PMID:
26010731
[PubMed – as supplied by publisher]

From http://www.ncbi.nlm.nih.gov/pubmed/26010731

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Cushing’s Syndrome | Seeking Alpha

Posted on May 14, 2015 by MaryO

Looking at the dizzying volatility in the government bond space and in continuation of our recent theme dealing with “alkaloids,” we remembered Cushing’s syndrome when choosing our title analogy, also known as “hypercortisolism” which is a collection of signs and symptoms due to prolonged exposure to cortisol (or QEs). Cushing’s syndrome is generally associated with rapid weight gain (bond prices), moodiness, irritability or depression to name a few.

The most common cause of Cushing’s syndrome is “exogenous” administration of glucortocoides prescribed by a health practitioner to treat other diseases such as asthma and rheumatoid arthritis. In our “market case,” one could argue that the most common cause of the sudden rise in government bond yields could be linked to the exogenous administration of “QEs” prescribed by central bankers in order to treat weak aggregate demand (AD). Strictly, Cushing’s syndrome refers to excess cortisol of any etiology (as syndrome means a group of symptoms).

 

Government bonds and Cushing’s Syndrome analogy from Cushing’s Syndrome | Seeking Alpha.

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Cushing’s syndrome vs simple obesity. How can a needle be found in the haystack?

Posted on April 2, 2015 by MaryO

Endocrinology Today 02/2015; 4(1):30-35.

Clinical recognition of Cushing’s syndrome should generally follow from the observation of a constellation of compatible clinical features that progress over time. Screening for Cushing’s syndrome in patients with individual features of the metabolic syndrome, such as obesity, hypertension and hyperglycaemia, is not recommended.

Early diagnosis reduces unnecessary suffering and the ultimate lifetime sequelae of Cushing’s syndrome. Confirmation involves the demonstration of biochemical hypercortisolism, and the extent of diagnostic testing needs to be based on the degree of clinical suspicion.
Read the whole article here, in PDF format

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Screening for Cushing’s syndrome: Is it worthwhile?

Posted on March 5, 2015 by MaryO

The data suggests that Cushing is not frequent enough to support the use of routine screening in patients with morbid obesity and type 2 DM. Also only 1 % of hypertensive patients have secondary hypertension due to CS. However, screening should be considered in young patients with resistant DM and/or hypertension. Among patients with osteoporosis and vertebral fractures up to 5 % were diagnosed with subclinical hypercortisolism; most of these had adrenal adenoma. Screening for CS is important in subjects with adrenal incidentaloma, and many studies show a high prevalence (~10 %) of Cushing or subclinical CS in these patients.

Abstract

Introduction

Cushing’s syndrome (CS) is a rare disease characterized by a collection of signs and symptoms, also common in the general population without elevated cortisol secretion. During the last years more patients with CS are identified earlier and with milder disease. Many of these patients are diagnosed during screening efforts performed for certain or isolated complaints like weight gain, diabetes mellitus (DM), hypertension, osteoporosis, elevated white blood cell counts and more.

Methods

In this review article the most popular screening test performed in the studies cited was the 1-mg dexamethasone suppression test.

Conclusions

Cushing is not frequent enough to support the use of routine screening in patients with morbid obesity and type 2 DM. Also only 1 % of hypertensive patients have secondary hypertension due to CS. However, screening should be considered in young patients with resistant DM and/or hypertension. Among patients with osteoporosis and vertebral fractures up to 5 % were diagnosed with subclinical hypercortisolism; most of these had adrenal adenoma. Screening for CS is important in subjects with adrenal incidentaloma, and many studies show a high prevalence (~10 %) of Cushing or subclinical CS in these patients.

Buy this article for $39.00 at http://link.springer.com/article/10.1007%2Fs11102-015-0634-9

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