Clinical and biochemical evaluation of Cushing's syndrome

Utility of Simple and Non-Invasive Strategies Alternative to Inferior Petrosal Sinus Sampling and Peripheral CRH Stimulation in Differential Diagnosis of ACTH-Dependent Cushing Syndrome

We aimed to evaluate the utility of simple, cost-effective, and non-invasive strategies alternative to BIPSS and peripheral CRH stimulation in differential diagnosis of ACTH-dependent CS. First, we performed ROC analysis to evaluate the performance of various tests for differential diagnosis of ACTH-dependent CS in our cohort (CD, n=76 and EAS, n=23) and derived their optimal cut-offs. Subsequently, combining various demographic (gender), clinical (hypokalemia), biochemical (plasma ACTH, HDDST, peripheral CRH stimulation) and imaging (MRI pituitary) parameters, we derived non-invasive models with 100% PPV for CD. Patients with pituitary macroadenoma (n=14) were excluded from the analysis involving non-invasive models. Relative percent ACTH (AUC: 0.933) and cortisol (AUC: 0.975) increase on peripheral CRH stimulation demonstrated excellent accuracy in discriminating CD from EAS. Best cut-offs for CD were plasma ACTH<97.3 pg/ml, HDDST≥57% cortisol suppression, CRH stimulation≥77% ACTH increase and≥11% cortisol increase. We derived six models that provided 100% PPV for CD and precluded the need for BIPPS in 35/85 (41.2%) patients with ACTH-dependent CS and no macroadenoma (in whom BIPSS would have otherwise been recommended). The first three models included basic parameters and avoided both peripheral CRH stimulation and BIPSS in 19 (22.4%) patients, while the next three models included peripheral CRH stimulation and avoided BIPSS in another 16 (18.8%) patients. Using simple and non-invasive alternative strategies, BIPSS can be avoided in 41% and peripheral CRH stimulation in 22% of patients with ACTH-dependent CS and no macroadenoma; such patients can be directly referred for a pituitary surgery.

Clinical profile and treatment outcomes of patients with ectopic ACTH syndrome compared to Cushing disease: a single-center experience

PURPOSE

We aimed to evaluate and compare the clinical, biochemical and radiological profile and outcomes of patients with ectopic ACTH syndrome (EAS) and Cushing disease (CD) treated over a period of 10 years (2013-2022).

METHODS

In this ambispective observational study, we collected data for 146 patients with ACTH-dependent CS (EAS, n = 23; CD, n = 94; occult ACTH source, n = 29). Relevant details were filled in a predesigned proforma and outcomes were ascertained at the most recent visit.

RESULTS

EAS was more common in males (65.2 vs. 27.6%, p < 0.001). Patients with EAS had a shorter duration of symptoms [12 (6-12) vs. 31.5 (15-48) months, p < 0.001] and were more likely to have hypokalemia (82.6 vs. 21.0%, p = 0.001), pedal edema (65.2 vs. 34.2%, p = 0.015), weight loss (34.8 vs. 4.0%, p < 0.001) and systemic infection (30.4 vs. 6.5%, p = 0.006). They also had significantly higher 8 a.m. serum cortisol, midnight serum and salivary cortisol and 8 a.m. plasma ACTH levels. Bronchial carcinoid (n = 10, 43.5%) was the most common etiology of EAS. Bilateral adrenalectomy was performed in 11 (47.8%) patients with EAS. Eight patients (34.8%) with EAS died at the last follow-up, of whom 7 (87.5%) had metastatic disease. In CD group, overall remission rate was 69.4% (56.1%, early and 13.3%, delayed) and 26.3% of patients with an initial remission had recurrence.

CONCLUSIONS

Bronchial carcinoid was the most common cause of EAS in our cohort. Bilateral adrenalectomy was performed in approximately every 1 in 2 patients with EAS and approximately every 1 in 3 patients expired till the last follow-up.

Development and validation of an LC-MS/MS method for profiling 39 urinary steroids (estrogens, androgens, corticoids, and progestins)

Abnormal production or metabolism of steroid hormones is responsible for the development of endocrine diseases. Thus, accurate quantification of steroid hormones is needed for both research into clinical conditions and diagnostic and monitoring purposes. An improved analytical method for profiling 39 steroids in urine using LC-MS/MS was developed. As a pre-treatment procedure prior to LC-tandem mass spectrometry (LC-MS/MS) analysis, hydrolysis using β-glucuronidase and solid-phase extraction for purifying the samples were performed. Steroids were separated using Waters ACQUITY BEH C₁₈ column (2.1 × 100 mm, 1.7 μm) and a mobile phase consisting of eluent A (0.01% formic acid and 1 mm ammonium formate in water) and eluent B (0.01% formic acid and 1 mm ammonium formate in methanol) with a gradient program at a flow rate of 0.4 mL/min. Under the optimized method, the linearity of calibration curves was higher than 0.992. The limits of detection at signal-to-noise ratio of 3 were 0.03-90 ng/mL. The developed novel LC-MS/MS method can quantitatively profile 39 steroids in a single analytical run. Steroid profiling based on quantitative results could improve the diagnosis and monitoring of hormone-dependent diseases.

Intraocular pressure and its correlation with midnight plasma cortisol level in Cushing's disease and other endogenous Cushing's syndrome

Purpose:

The purpose of this study is to measure intraocular pressure (IOP) and evaluate the correlation between IOP and midnight plasma cortisol (MPC) level in patients with Cushing's disease (CD) and other endogenous Cushing's syndrome (ECS).

Methods:

This is a cross-sectional study from a single center including newly diagnosed patients with CD or ECS. All patients underwent detailed ophthalmological evaluation. IOP was measured by Goldmann applanation tonometry in the morning and evening on two consecutive days. MPC value was obtained for each patient. The data were compared using paired and unpaired t-test, Mann–Whitney U-test, and Spearman's rank correlation coefficient.

Results:

Among 32 patients, 22 were CD (68.75%) and 10 patients were other ECS (31.25%). A total of 25 patients (78.12%) in our study group had normal IOP (<22 mmHg), and seven patients (21.88%) had increased IOP (≥22 mmHg). The percentage of patients with normal IOP was found to be significantly higher compared to percentage of patients with high IOP (P = 0.001) using one-sample Chi-square test. Mean MPC value was 468.6 ± 388.3 nmol/L in patients having IOP ≥22 mmHg and 658.5 ± 584 nmol/L in those with IOP <22 mmHg from both CD and ECS groups, but the difference was not statistically significant. No correlation was found between IOP and MPC (Spearman's rank correlation rho = −0.16 [P = 0.38]).

Conclusion:

In CD and ECS patients, IOP elevation is an uncommon feature, and high IOP in either group does not correlate with MPC level.

Bilateral inferior petrosal sinus sampling

Simultaneous bilateral inferior petrosal sinus sampling (BIPSS) plays a crucial role in the diagnostic work-up of Cushing's syndrome. It is the most accurate procedure in the differential diagnosis of hypercortisolism of pituitary or ectopic origin, as compared with clinical, biochemical and imaging analyses, with a sensitivity and specificity of 88-100% and 67-100%, respectively. In the setting of hypercortisolemia, ACTH levels obtained from venous drainage of the pituitary are expected to be higher than the levels of peripheral blood, thus suggesting pituitary ACTH excess as the cause of hypercortisolism. Direct stimulation of the pituitary corticotroph with corticotrophin-releasing hormone enhances the sensitivity of the procedure. The procedure must be undertaken in the presence of hypercortisolemia, which suppresses both the basal and stimulated secretory activity of normal corticotrophic cells: ACTH measured in the sinus is, therefore, the result of the secretory activity of the tumor tissue. The poor accuracy in lateralization of BIPSS (positive predictive value of 50-70%) makes interpetrosal ACTH gradient alone not sufficient for the localization of the tumor. An accurate exploration of the gland is recommended if a tumor is not found in the predicted area. Despite the fact that BIPSS is an invasive procedure, the occurrence of adverse events is extremely rare, particularly if it is performed by experienced operators in referral centres.

Silent corticotroph adenomas

PURPOSE

Silent corticotroph adenomas (SCAs) comprise 20% of all corticotroph adenomas and 3-19% of nonfunctioning adenomas (NFAs). As they do not manifest clinical or biochemical hypercortisolism, they are diagnosed after pathologic examination of resected tumor tissue demonstrates positive ACTH expression. While preoperative features are similar to those of NFAs, SCAs may have more cavernous sinus invasion. Further, patients with SCAs tend to have more frequent and earlier recurrences than those with NFAs, often necessitating multiple surgeries and other modalities of treatment. This article reviews the incidence, pathogenesis, and clinical behavior of SCAs.

METHODS

A systematic literature review was performed using PubMed for information regarding SCAs.

RESULTS

Up to date findings regarding epidemiology, pathogenesis, pathology, clinical presentation, postoperative course, and management of patients with SCAs are presented.

CONCLUSION

This review highlights the necessity of rigorous monitoring for recurrences and hypopituitarism in patients with SCAs.

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.

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.

Subclinical hyperfunctioning pituitary adenomas: the silent tumors

Pituitary adenomas are classified by function as defined by clinical symptoms and signs of hormone hypersecretion with subsequent confirmation on immunohistochemical staining. However, positive immunostaining for pituitary cell types has been shown for clinically nonfunctioning adenomas, and this entity is classified as silent functioning adenoma. Most common in these subtypes include silent gonadotroph adenomas, silent corticotroph adenomas and silent somatotroph adenomas. Less commonly, silent prolactinomas and thyrotrophinomas are encountered. Appropriate classification of these adenomas may affect follow-up care after surgical resection. Some silent adenomas such as silent corticotroph adenomas follow a more aggressive course, necessitating closer surveillance. Furthermore, knowledge of the immunostaining characteristics of silent adenomas may determine postoperative medical therapy. This article reviews the incidence, clinical behavior, and pathologic features of clinically silent pituitary adenomas.

Diagnosis and therapy for Cushing's disease with negative dynamic MRI finding: a single-centre experience

OBJECTIVE

Most patients with Cushing's disease (CD) will have evidence of an adenoma on high-resolution magnetic resonance imaging (MRI). However, a significant minority of patients with CD and biochemical hypercortisolaemia have no visible adenoma on MRI. The purpose of this study was to evaluate the diagnostic value of preoperative biochemical assessment and accuracy of MRI findings on surgical outcome.

DESIGN

Retrospective data set analyses. PATIENTS AND MEASUREMENT: The clinical, endocrinological, histopathological and surgical outcomes of 24 consecutive CD patients with negative MRI findings were compared with those of 95 consecutive age- and sex-matched CD patients with pituitary adenomas on MRI.

RESULTS

The total remission rate was 86.6%. Among all patients, 87 had concordant positive endocrine tests and underwent neurosurgery, while bilateral inferior petrosal sinus sampling (BIPSS) was performed in 12 and 50 other patients with negative and positive MRI, respectively. A pituitary adenoma, confirmed by pathological examination, was found in 83.3% and 93.6% of patients with negative and positive MRI, respectively. The remission rate was not different between patients with negative and positive MRI (87.5 % and 86.3%, respectively; P > 0.05) or between patients who did not undergo BIPSS with negative MRI and patients with positive MRI (P > 0.05). The remission rate of patients who underwent BIPSS with negative MRI was not different from those not undergoing BIPSS (P > 0.05). The recurrence rate was higher, although not statistically different, in patients with negative MRI compared to positive ones.

CONCLUSIONS

Based on the findings outlined, MRI-negative CD may be a surgically remediable syndrome, with a pathophysiological basis that primarily involves a pituitary cause of the hypercortisolaemia.

Silent corticogonadotroph adenomas: clinical and cellular characteristics and long-term outcomes

Silent corticotrophins adenomas (SCAs) are clinically silent and non-secreting but immunostain positively for ACTH. We hypothesize that SCAs comprise both corticotroph and gonadotroph characteristics. Cohort analysis from 1994-2008 with follow-up time ranging from 1-15 years in a tertiary referral center. We compared preoperative and postoperative clinical results and tumor cytogenesis in 25 SCAs and 84 nonfunctioning adenomas in 109 consecutive patients diagnosed pre-operatively with nonfunctioning pituitary adenomas. Clinical outcomes were radiologic and hormonal measures. Pathologic outcomes were expression of relevant pituitary hormones, tissue-specific transcription factors, and electron microscopy features. Preoperative SCA presentation was similar to that observed for nonfunctioning adenomas. However, SCAs recurred postoperatively at a median of 3 years vs. 8 years for nonfunctioning adenomas (p<0.0001). Fifty-four percent of patients with SCAs had new onset postoperative hypopituitarism vs. 17% of nonfunctioning adenomas (p<0.025). SCAs (n=18) were immunopositive for ACTH, cytoplasmic and nuclear SF-1, NeuroD1, DAX-1, and alpha-gonadotropin subunit, but Tpit negative, and co-expression of tumor ACTH with either SF-1 or LH was detected. In contrast, functional corticotroph adenomas (n=11) were immunopositive for ACTH, nuclear SF-1, NeuroD1, and Tpit, but negative for DAX-1, a gonadotroph cell transcription factor. Gonadotroph adenomas (n=23) were immunonegative for ACTH and Tpit but positive for nuclear SF-1, NeuroD1, and DAX-1. SCA electron microscopy demonstrated ultrastructural features consistent with corticotroph and gonadotroph cells. As SCAs exhibit features consistent with both corticotroph and gonadotroph cytologic origin, we propose a pathologic and clinically distinct classification of SCAs as silent corticogonadotroph adenomas.

The determination of urinary free and conjugated cortisol using UPLC–MS/MS

Background: To develop an UPLC–MS/MS method to replace the in-house immunoassay for the analysis of urinary cortisol. Results: Cortisol was extracted from human urine by ethyl acetate and analyzed on a Waters ACQUITY TQD system using a BEH C18 column. Linear calibration curves were generated over the range of 27.6 to 1380 nmol/l and exhibited consistent linearity and reproducibility with a correlation coefficient greater than 0.9950. Intra-day coefficients of variation were between 3.74 and 5.10% and inter-day coefficients of variations were between 4.22 and 6.73%. The extraction recovery of cortisol was greater than 83%. Conclusion: An accurate, rapid and robust UPLC–MS/MS method for the determination of urinary cortisol has been developed and validated. With a lower flow rate (0.4 ml/min), a shorter running time per sample and a simple and cost-effective sample preparation, this method is a desirable option for clinical laboratories.

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.

The ectopic ACTH syndrome

Ectopic Cushing's syndrome usually relates to the ectopic ACTH syndrome (EAS) and represents ∼20% of ACTH-dependent and ∼10% of all types of Cushing's syndrome (CS). Nearly any neuroendocrine or non-endocrine tumours may be associated with EAS, but the more prevalent tumours are bronchial carcinoids, small cell lung carcinomas, pancreatic carcinoids, thymic carcinoids, medullary carcinomas of the thyroid, and phaeochromocytomas. Occult tumours are highly represented in all the series (12-38%) and constitute the more challenging cases of EAS, requiring long term follow-up. The lack of any completely reliable diagnostic test procedure and imaging to clearly reveal the source of EAS suggests that we should adopt a step-by-step multidisciplinary approach for their diagnosis and therapeutic management. Clinical features are often similar in ACTH-dependent CS, but the rapid onset and progress may suggest an ectopic source. A combination of biochemical tests and imaging studies seems the most appropriate approach for the prompt identification of EAS, even if there are several pitfalls to be avoided along the way. The most appropriate management for cure of EAS, when its source is identified, is surgical excision after controlling the hypercortisolaemia by inhibitors of cortisol secretion and other newer modalities alone or in combination; bilateral adrenalectomy remains an alternative option. Tumour histology, the presence of metastases and the effective control of hypercortisolaemia affect mortality and morbidity. If a source repeatedly fails to be found, the prognosis is often favourable but the identification of a malignant tumour should still be sought during life-long follow-up to avoid the calamity of misdiagnosis.

Selective use of bilateral inferior petrosal sinus sampling in patients with adrenocorticotropin-dependent Cushing's syndrome prior to transsphenoidal surgery

CONTEXT

Few data are available on the selective use of bilateral inferior petrosal sinus sampling (BIPSS) in the presurgical evaluation of patients with ACTH-dependent Cushing's syndrome, so we investigated whether its use only in patients without a clear adenoma on magnetic resonance imaging and/or inconsistent biochemical testing affected remission and long-term outcome after surgery in patients with Cushing's disease (CD).

SETTING

This was a retrospective review of patients treated for CD by one pituitary neurosurgeon at tertiary medical centers in New York City.

PATIENTS

A total of 193 consecutive adult patients who underwent initial transsphenoidal surgery (TS) for presumed CD between 1987 and 2005 were included.

MAIN OUTCOME MEASURES

We examined preoperative pituitary imaging and biochemical data, results of BIPSS and surgical pathology, and outcome based on biochemical tests after initial TS and long term after subsequent therapies.

RESULTS

Remission rate after the first TS was 80.8% overall, 79.1% in the BIPSS group (n = 105), and 83.0% in the No-BIPSS group (n = 88). Recurrences occurred in 13.5% after the first TS at a mean of 4.8 +/- 3.5 yr (range, 0.7-12.4 yr) with no difference between BIPSS and No-BIPSS groups. Long-term remission was achieved after surgeries and radiotherapy in 85% (86.7% of BIPSS group, 83.0% of No-BIPSS group). CD was ultimately confirmed in all but one patient in each group.

CONCLUSIONS

Selective use of BIPSS in the preoperative evaluation of patients with presumed CD did not lead to misdiagnosis in the No-BIPSS group or adversely affect remission rates or long-term outcome.

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.

The role of non-invasive dynamic tests in the diagnosis of Cushing's syndrome

OBJECTIVE

To evaluate the role of non-invasive dynamic tests in the diagnosis and differential diagnosis of Cushing's syndrome (CS).

METHODS

We studied laboratory features of 74 patients with endogenous CS, subdivided as follows: 46 (62.1%) with Cushing's disease (CD), 21 (28.3%) with an adrenal tumor, and 7 (9.5%) with ectopic ACTH syndrome (EAS).

RESULTS

In 100% of cases of CS we found serum cortisol levels greater than 1.8 microg/dl after low-dose dexamethasone suppression tests (LDDST), as well as elevation of midnight serum or salivary 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 invariably increased in EAS. After the 8-mg overnight dexamethasone suppression test (HDDST), serum cortisol suppression >50% was observed in 79.5% of cases of CD and in 28.6% of subjects with EAS, whereas cortisol suppression >80% was only found in CD. After stimulation with CRH or desmopressin an ACTH rise > or =35% occurred in 86.5% of individuals with CD and 14.3% of those with EAS, whereas an ACTH rise > or =50 achieved 100% specificity. Moreover, the combination of serum cortisol suppression >50% after HDDST and an ACTH increase > or =35% after the administration of CRH or desmopressin only occurred in CD.

CONCLUSION

Our findings demonstrate that LDDST had 100% sensitivity for the diagnosis of CS and that HDDST and stimulation tests with CRH or desmopressin may be very useful for confirmation of CS etiology when analyzed together or when more stringent cut-offs are used.

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.

[The value of corticotropin-releasing hormone (CRH) test for differential diagnosis of Cushing's syndrome]

INTRODUCTION

Diagnosis and differential diagnosis of Cushing's syndrome (CS) remain considerable challenge in endocrinology. For more than 20 years, CRH has been widely used as differential diagnostic test. Following the CRH administration, the majority of patients with ACTH secreting pituitary adenoma show a significant rise of plasma cortisol and ACTH, whereas those with ectopic ACTH secretion characteristically do not.

OBJECTIVE

The aim of our study was to assess the value of CRF test for differential diagnosis of CS using the ROC (receiver operating characteristic) curve method.

METHOD

A total of 30 patients with CS verified by pathological examination and postoperative testing were evaluated. CRH test was performed within diagnostic procedures. ACTH secreting pituitary adenoma was found in 18, ectopic ACTH secretion in 3 and cortisol secreting adrenal adenoma in 9 of all patients with CS. Cortisol and ACTH were determined -15.0, 15, 30, 45, 60, 90 and 120 min. after i.v. administration of 100 microg of ovine CRH. Cortisol and ACTH were determined by commercial RIA. Statistical data processing was done by ROC curve analysis. Due to small number, the patients with ectopic ACTH secretion were excluded from test evaluation by ROC curve method.

RESULTS

In evaluated subgroups, basal cortisol was (1147.3 +/- 464.3 vs. 1589.8 +/- 296.3 vs. 839.2 +/- 405.6 nmol/L); maximal stimulated cortisol (1680.3 +/- 735.5 vs. 1749.0 +/- 386.6 vs. 906.1 +/- 335.0 nmol/L); and maximal increase as a percent of basal cortisol (49.1 +/- 36.9 vs. 9.0 +/- 7.6 vs. 16.7 +/- 37.3%). Consequently, basal ACTH was (100.9 +/- 85.0 vs. 138.0 +/- 123.7 vs. 4.8 +/- 4.3 pg/mL) and maximal stimulated ACTH (203.8 +/- 160.1 vs. 288.0 +/- 189.5 vs. 7.4 +/- 9.2 pg/mL). For cortisol, determination area under ROC curve was 0.815 +/- 0.083 (CI 95% 0.652-0.978). For cortisol increase cut-off level of 20%, test sensitivity was 83%, with specificity of 78%. For ACTH, determination area under ROC curve was 0.637 +/- 0.142 (CI 95% 0.359-0.916). For ACTH increase cut-off level of 30%, test sensitivity was 70%, with specificity of 57%.

CONCLUSION

Determination of cortisol and ACTH levels in CRH test remains reliable tool in differential diagnosis of Cushing's syndrome.

Specificity assessment of immunoassay kits for determination of urinary free cortisol concentrations

BACKGROUND

In immunoassay kits for determination of urinary free cortisol (UFC) concentrations, the results vary markedly from kit to kit, so we compared in this study the reaction specificity among 4 commercially available immunoassay kits to determine the applicability of these assays in routine determination of UFC concentrations.

METHOD

Using 4 commercially available kits, cross-reaction was investigated. In addition, urine samples were fractionated by HPLC to investigate endogenous immunoreactive cortisol responses. HPLC fractions were subjected to gas chromatography-mass spectrometry (GCMS) to identify substances causing inter-kit assay discrepancies.

RESULTS

Among the 4 kits, cortisol Kit "TFB" (Immunotech; IOT-RIA method) showed the lowest cross-reaction (2.5%) for prednisolone. Furthermore, on HPLC, 87.8% of the reaction of the entire fraction was seen in the fractions corresponding to the elution position of standard cortisol with the IOT-RIA method; this was the highest percentage among the 4 kits. GCMS revealed that the substance that showed a cross-reaction with the other 3 kits was 5alpha-tetrahydrocortisol (5alpha-THF) glucuronide.

CONCLUSIONS

The IOT-RIA method was found to be the most specific for UFC. The other 3 commercially available kits showed cross-reaction with a conjugate of 5alpha-THF, found to be one of the causes of inter-kit assay discrepancies.

Laparoscopic adrenalectomy of an adrenal adenoma with myelolipoma relieves severe hypertension in a 16-year-old patient

Adrenal adenoma with myelolipoma is extremely rare in pediatrics. Although the tumor is usually asymptomatic, sometimes it may result in serious manifestations. A 16-year-old patient was diagnosed with severe hypertension associated with a right adrenal mass. The laboratory work-up was inconclusive of the nature of the tumor. Plasma and urinary hormonal studies were not diagnostic. Magnetic resonance imaging (MRI) of the brain and meta-iodobenzylguanidine (MIBG) scanning were normal. MRI of the abdomen showed a heterogeneous adrenal mass 4.2x3.3 cm. Laparoscopic resection of the mass was done, and the pathology revealed an adrenal adenoma with myelolipoma. After tumor resection the hypertension resolved, and within 1 month the patient was off medications. At 2-year follow-up the patient's blood pressure remained normal at 120/73 mmHg. This is a case in which an adrenal adenoma with myelolipoma, a benign and usually asymptomatic tumor, presented as severe hypertension resolving with surgical resection of the tumor.

Dexamethasone infusion testing in the diagnosis of Cushing's syndrome

Cushing's syndrome and its various aetiologies is a markedly difficult diagnosis to make given its subtle signs, sometime cyclical nature, and the lack of a single definitive diagnostic test. Although a great variety of diagnostic tests have been developed to assist in the diagnosis, even with the best clinical acumen, biochemistry and medical imaging the diagnosis can remain elusive. The long low and high dose oral dexamethasone suppression test is cumbersome, costly and often requiring an extended inpatient stay. The utility of the dexamethasone suppression test would be greatly enhanced if it could be performed as a short outpatient procedure. In this study we sought to confirm and refine the clinical utility of the high dose 4 mg intravenous dexamethasone suppression test as an alternative diagnostic test for Cushing's syndrome. There were a total of 31 subjects: 8 patients with proven pituitary Cushing's disease, 3 with primary adrenal tumors, 10 with pseudo-Cushing's syndrome and 10 healthy controls. All subjects with pseudo-Cushing's syndrome suppress serum cortisol at +5 and at +24 hours. In subjects with pituitary Cushing's disease, 7 out of 8 (88%) had serum cortisol suppressed at +5 hours but rebounded at +24 hours to at least 70% of the original serum level. Primary adrenal tumors showed a pattern of non-suppression throughout. The 4 mg intravenous dexamethasone suppression test is excellent in ruling out pseudo-Cushing's syndrome. This test is much simpler and more convenient than the oral dexamethasone suppression test in confirming clinical suspicion of pituitary Cushing's disease.

Value of assessing adrenocorticotropic hormone (ACTH) levels in differential diagnosis of hypercorticism

Diagnosis and differential diagnosis of Cushing's syndrome remains a challenge in clinical endocrinology. The aim of this study was to establish the value of assessing adrenocorticotropic hormone (ACTH) levels in differential diagnosis of hypercorticism using receiver operating characteristic (ROC) curve. We have evaluated 114 patients with Cushing's syndrome testing the value of pathohistological examination and postoperative testing. The control group consisted of 53 obese healthy persons. ACTH level was determined using a commercial RIA (CIS, France). ACTH secreting pituitary adenoma was found in 56.14% examinees, ectopic secretion in 6.14%, cortisol secreting adrenal adenoma in 37.57%, and adrenal carcinoma in 6.14% of all patients with Cushing's syndrome. Basal ACTH level for pituitary adenoma was 107.29 +/- 75.69 pg/mL; for ectopic secretion 181.63 +/- 149.84 pg/mL; for adrenal adenoma 4.22 +/- 2.32 pg/mL; for adrenal carcinoma 5.50 +/- 7.72 pg/mL; and 34.76 = 10.07 pg/mL in control group. Testing the value of assessing ACTH the area under ROC curve was 0.9965 +/- 0.0071. Test sensitivity was 99.89% and test specificity was 97%. For ACTH cut-off level of 8 pg/mL, test sensitivity was 88.50%, with specificity of 99%. For ACTH cut-off level of 22 pg/mL, test sensitivity was 99.30%, with specificity of 98%. Our intermediate zone from 8 to 22 pg/mL confirms that assessment of ACTH level is a reliable tool in differential diagnosis of Cushing's syndrome.

[Cushing's disease caused by pituitary macroadenoma]

Cushing's syndrome comprises the symptoms and signs associated with prolonged exposure to inappropriately elevated levels of free plasma glucocorticoids. When iatrogenic causes are excluded, the commonest cause of Cushing's syndrome is Cushing's disease, accounting for approximately 70% of cases. We present the case of a 20-year-old male patient with central obesity, moon face and purple-red striae, whose diagnostic investigation shows a pituitary macroadenoma. The patient was submitted to transsphenoidal hypophysectomy, but developed early recurrence. He was submitted to a second transsphenoidal intervention followed by pituitary radiation. Presently, the patient is in clinical and laboratory remission.

Cavernous and inferior petrosal sinus sampling in the evaluation of ACTH-dependent Cushing's syndrome

OBJECTIVE

Central venous sampling (CVS) is used frequently in the evaluation of ACTH-dependent Cushing's syndrome. However, several controversies exist including the diagnostic accuracy, the sampling site of choice (cavernous sinus vs. inferior petrosal sinus) and the use of lateralization data in tumour localization. We have analysed our experience with CVS to address these controversies.

DESIGN

We retrospectively reviewed CVS data in patients with ACTH-dependent Cushing's syndrome, in whom cavernous sinus sampling (CSS), inferior petrosal sinus sampling (IPSS) and IPSS after administration of ovine corticotrophin releasing hormone (oCRH) were performed.

PATIENTS

Data on 95 patients were analysed, including 79 patients with suspected Cushing's disease (CD) and 16 patients with suspected ectopic ACTH syndrome (EAS).

RESULTS

For the differential diagnosis of ACTH-dependent Cushing's syndrome, the diagnostic accuracy of IPSS after oCRH stimulation was 97% compared to 86% for CSS. While no single sampling site was perfect in diagnostic accuracy, sampling both CS and IPS achieved a combined diagnostic accuracy of 100%. Lateralization data predicted tumour location in 62-68% of the patients with various central venous drainage patterns and in 77-80% of the patients with symmetrical drainage. CSS was not significantly superior to IPSS in tumour lateralization. In patients with suspected CD based on CVS and in whom an adenoma was not found on magnetic resonance imaging (MRI) and not located by the surgeon intraoperatively, hemihypophysectomy based on lateralization data was successful in only 10 of the 18 patients (56%) with various central venous drainage patterns and in 5 of 10 patients with symmetrical drainage.

CONCLUSION

CVS is a powerful method for differentiating CD from the EAS. CSS without oCRH was not superior to IPSS after oCRH stimulation; however, we achieved a 100% diagnostic accuracy if at least two sites were sampled. Tumour localization by CVS did not accurately predict the tumour site at surgery and should not be used to guide surgical resection.

Steroid hormones: relevance and measurement in the clinical laboratory

Steroid hormones are synthesized in the adrenal cortex, the gonads, and the placenta; are all derived from cholesterol and many are of clinical importance. This article addresses the relevance and methods of measurement of steroid hormones in the clinical laboratory.

Issues in the diagnosis of Cushing's syndrome for the primary care physician

The diagnosis of Cushing's syndrome is one of the most difficult and yet one of the most important ones a primary care physician can make. The clinical presentation overlaps that of many other common diseases, but more specific signs such as unexplained osteoporosis, muscle weakness, ecchymoses, hypokalemia, and central obesity, the presence of multiple symptoms affecting different body systems, and a demonstrated change over time should prompt the screening evaluation. We recommend a step-wise approach to the diagnostic evaluation. Step 1 involves demonstrating pathologic hypercortisolemia and thus making the diagnosis of Cushing's syndrome. In step 2, distinguishing ACTH-independent disease from ACTH-dependent disease and then adrenal imaging is done. Finally, for patients with ACTH-dependent disease, step 3 entails anatomic localization of the ACTH source by MRI, if unequivocal, or by IPSS or CSS. Only when the evaluation is done in a step-wise fashion can the clinician be assured that appropriate treatment recommendations can be made. Although a fair amount of the testing is complex, requiring special facilities and usually the assistance of an endocrinologist, the most critical step is that done by the primary care physician--considering the diagnosis and initiating the screening algorithm.

Cushing's syndrome due to ectopic production of corticotropin-releasing hormone in an infant with ganglioneuroblastoma

OBJECTIVE

To report the first recognized case of Cushing's syndrome due to a corticotropin-releasing hormone (CRH)-secreting ganglioneuroblastoma, which was found in an 18-month-old boy with hypertensive encephalopathy.

METHODS

The clinical, biochemical, and immunohistochemical characteristics of this rare syndrome are described, and the relevant literature is reviewed.

RESULTS

An 18-month-old boy with a history of recent weight gain was admitted because of sudden onset of right fixed esotropia and left facial palsy after episodes of emesis. Magnetic resonance imaging showed old left frontal lobe and right hypothalamic infarcts. The patient had generalized obesity, decelerated linear growth, hypertrichosis, hypertension (144/103 mm Hg), hypokalemia, and proteinuria. The 24-hour urinary excretion of free cortisol, catecholamines, and metanephrines was increased. The serum cortisol concentration after a 1-mg overnight dexamethasone suppression test (DST) was 53.7 mg/dL (normal, <5). The serum adrenocorticotropic hormone (ACTH) concentration was 7 pg/mL (normal, 10 to 60), and the CRH level was 439 pg/mL (normal, 24 to 40). An overnight high-dose DST (8 mg) failed to suppress serum cortisol; however, both cortisol and ACTH were responsive to ovine CRH stimulation. Despite discordant dynamic endocrine testing and negative somatostatin receptor scintigraphy, computed tomography showed a right 3.6- by 3.0-cm extra-adrenal retroperitoneal mass with central calcification extending 7 cm cephalocaudally. The patient underwent exploratory laparotomy, followed by chemotherapy. Findings on light microscopic and immunohistochemical examination of the retroperitoneal mass were consistent with a ganglioneuroblastoma that expressed CRH, pro-opiomelanocortin, and ACTH.

CONCLUSION

The evaluation of Cushing's syndrome is one of the most complex endocrine challenges. In this case, it was due to ectopic production of CRH by a ganglioneuroblastoma. Because most CRH-producing tumors also secrete ACTH, the ectopic production may represent a paracrine phenomenon in addition to an endocrine phenomenon. The ectopic CRH may also indirectly provoke pituitary ACTH secretion. This dual mechanism may explain the resistance of the tumor to feedback inhibition and a CRH-stimulation response indistinguishable from that observed in pituitary-dependent Cushing's syndrome.

The biochemical investigation of Cushing syndrome

Cushing syndrome is an insidious illness that warrants an early diagnosis to avoid the effects of prolonged hyper-cortisolism. The variability in the clinical features of the disease and the occasional inconsistencies between different biochemical tests performed to identify it render the diagnosis challenging. In this paper the author discusses the various biochemical tests that are useful for the diagnoses of Cushing syndrome and Cushing disease, with an emphasis on the respective sensitivities and specificities of these tests. The measurement of evening salivary cortisol and the combined low-dose dexamethasone–corticotropin-releasing hormone stimulation test have improved overall sensitivity and specificity in the evaluation of Cushing syndrome and Cushing disease.

The clinically inapparent adrenal mass: update in diagnosis and management

Clinically inapparent adrenal masses are incidentally detected after imaging studies conducted for reasons other than the evaluation of the adrenal glands. They have frequently been referred to as adrenal incidentalomas. In preparation for a National Institutes of Health State-of-the-Science Conference on this topic, extensive literature research, including Medline, BIOSIS, and Embase between 1966 and July 2002, as well as references of published metaanalyses and selected review articles identified more than 5400 citations. Based on 699 articles that were retrieved for further examination, we provide a comprehensive update of the diagnostic and therapeutic approaches focusing on endocrine and radiological features as well as surgical options. In addition, we present recent developments in the discovery of tumor markers, endocrine testing for subclinical disease including autonomous glucocorticoid hypersecretion and silent pheochromocytoma, novel imaging techniques, and minimally invasive surgery. Based on the statements of the conference, the available literature, and ongoing studies, our aim is to provide practical recommendations for the management of this common entity and to highlight areas for future studies and research.

Nonpeptide corticotropin-releasing hormone receptor type 1 antagonists and their applications in psychosomatic disorders

Overproduction of corticotropin-releasing hormone (CRH) and stress system abnormalities are seen in psychiatric diseases such as depression, anxiety, eating disorders, and addiction. Investigations of CRH type 1 receptor (CRHR1) nonpeptide antagonists suggest therapeutic potential for treatment of these and other neuropsychiatric diseases. However, overproduction of CRH in the brain and on its periphery and disruption of the hypothalamic-pituitary-adrenal axis are also found in 'somatic' disorders. Some rare forms of Cushing's disease and related pituitary/adrenal disorders are obvious applications for CRHR1 antagonists. In addition, however, these antagonists may also be effective in treating more common somatic diseases. Patients with obesity and metabolic syndrome who often have subtle, but chronic hypothalamic-pituitary-adrenal hyperactivity, which may reflect central dysregulation of CRH and consequently glucocorticoid hypersecretion, could possibly be treated by administration of CRHR1 antagonists. Hormonal, autonomic, and immune aberrations are also present in chronic inflammatory, autoimmune, and allergic diseases, with considerable evidence linking CRH with the observed abnormalities. Furthermore, autonomic dysregulation is a prominent feature of common gastrointestinal disorders, such as irritable bowel syndrome and peptic ulcer disease. Patients with irritable bowel syndrome and other gastrointestinal disorders frequently develop altered pain perception and affective symptoms. CRH acts peripherally to modulate bowel activity both directly through the autonomic system and centrally by processing viscerosensory and visceromotor neural signals. This review presents clinical and preclinical evidence for the role of CRH in the pathophysiology of these disorders and for potential diagnostic and therapeutic applications of CRHR1 antagonists. Recognition of a dysfunctional stress system in these and other diseases will alter the understanding and treatment of 'psychosomatic' disorders.

Stress hormone responses to corticotropin-releasing hormone in substance abusers without severe comorbid psychiatric disease

BACKGROUND

Preclinical data indicate a crucial role of stress in the acute effects of drugs of abuse, maintenance of self-administration, and susceptibility to relapse. Stress system activation may serve as a marker for a neurochemical dysfunction with prognostic significance in patients with addiction.

METHODS

We tested pituitary adrenocorticotrophin (ACTH) and adrenal cortisol response to ovine corticotropin-releasing hormone (oCRH) to assess the reactivity of the hypothalamic-pituitary-adrenal (HPA) axis in seven nonsubstance-abusing subjects, 31 polysubstance-abusing subjects without depressive symptoms, and seven subjects with substance abuse and depressive symptoms. No subject met diagnostic criteria for depression or other severe psychiatric disease.

RESULTS

Compared with normal control subjects, substance abusers showed significantly lower ACTH and cortisol responses over the course of oCRH stimulation (p <.0001). Substance abusers with depressive symptoms showed similarly blunted responses.

CONCLUSIONS

Polysubstance abusers with no past or current diagnosis of other Axis I disorders show blunted ACTH and cortisol responses to oCRH administration. The finding of an activated HPA axis in this population suggests an overlapping role of central CRH and HPA axis activation in affective disorders and substance abuse, which is likely to constitute an endocrine milieu necessary for the maintenance of addictive behavior. These data support the role of future therapeutic trials with nonpeptide CRH receptor 1 antagonists in these patients.

Cutaneous manifestations of endocrine disorders: a guide for dermatologists

Dermatologists may commonly see skin lesions that reflect an underlying endocrine disorder. Identifying the endocrinopathy is very important, so that patients can receive corrective rather than symptomatic treatment. Skin diseases with underlying endocrine pathology include: thyrotoxicosis; hypothyroidism; Cushing syndrome; Addison disease; acromegaly; hyperandrogenism; hypopituitarism; primary hyperparathyroidism; hypoparathyroidism; pseudohypoparathyroidism and manifestations of diabetes mellitus. Thyrotoxicosis may lead to multiple cutaneous manifestations, including hair loss, pretibial myxedema, onycholysis and acropachy. In patients with hypothyroidism, there is hair loss, the skin is cold and pale, with myxedematous changes, mainly in the hands and in the periorbital region. The striking features of Cushing syndrome are centripetal obesity, moon facies, buffalo hump, supraclavicular fat pads, and abdominal striae. In Addison disease, the skin is hyperpigmented, mostly on the face, neck and back of the hands. Virtually all patients with acromegaly have acral and soft tissue overgrowth, with characteristic findings, like macrognathia and enlarged hands and feet. The skin is thickened, and facial features are coarser. Conditions leading to hyperandrogenism in females present as acne, hirsutism and signs of virilization (temporal balding, clitoromegaly).A prominent feature of hypopituitarism is a pallor of the skin with a yellowish tinge. The skin is also thinner, resulting in fine wrinkling around the eyes and mouth, making the patient look older. Primary hyperparathyroidism is rarely associated with pruritus and chronic urticaria. In hypoparathyroidism, the skin is dry, scaly and puffy. Nails become brittle and hair is coarse and sparse. Pseudohypoparathyroidism may have a special somatic phenotype known as Albright osteodystrophy. This consists of short stature, short neck, brachydactyly and subcutaneous calcifications. Some of the cutaneous manifestations of diabetes mellitus include necrobiosis lipoidica diabeticorum, diabetic dermopathy, scleredema adultorum and acanthosis nigricans.

Pituitary tumor endocrinopathies and their endocrine evaluation

Pituitary tumors, depending on their respective cell type, manifest various endocrinopathies. Prolactinomas may present as hypogonadism and galactorrhea and can be diagnosed by measuring morning prolactin levels. Gonadotropinomas rarely cause gonadal hyperstimulation, and dynamic thyrotropin-releasing hormone stimulation testing is often required to elicit a diagnostic gonadotropin and/or subunit secretory response. Acromegaly is a multisystemic debilitating disease for which early diagnosis and treatment are crucial. Diagnostic criteria include a lack of plasma growth hormone suppression during the oral glucose tolerance test and elevation of age- and sex-matched insulin growth factor-1 levels. Patients harboring corticotropin-secreting adenomas characheristically present with signs and symptoms of hypercortisolism. Inferior petrosal sinus sampling for corticotropin may be required for microadenoma localization. Thyrotropinomas produce inappropriate thyrotropin (TSH) secretion and hyperthyroidism. The new third-generation TSH assay has improved the rate of detection of these lesions at an earlier stage.

Clinical laboratory findings and results of therapy in 55 patients with Cushing's syndrome

In this study, 55 patients with Cushing's syndrome (CS) (50 female, 5 male; mean age 34 +/- 12.3 yr) who attended our clinics between the years 1983 and 2000 were retrospectively evaluated for clinical and laboratory features and modalities and results of therapy, due to a few similar studies over the last ten years. Cushing's disease was diagnosed in 39 patients (71%), adrenal adenoma in 13 patients (23.6%) and adrenal carcinoma in 3 patients (5.5%). Centripedal obesity, moon face, hypertension, hirsutism and purplish stria were the most frequent findings. Loss of normal serum F circadian rhythm was found in all patients with CS. The overnight 1 mg oral dexamethasone suppression test and low-dose dexamethasone suppression test (LDDST) yielded 100% and 100% diagnostic sensitivity for CS, respectively. Sensitivity and specivity of the high-dose dexamethasone suppression test (HDDST) in distinguishing Cushing's disease was found to be 82% and 100%, respectively. All of the patients with adrenal CS were not suppressed with HDDST. Sellar CT and/or MRI accurately identified the tumor in 58% of these patients. Recurrence was observed in 3 (11%) of the 28 patients with Cushing's disease, treated by transsphenoidal adenomectomy. Recurrence was diagnosed 1.5, 3 and 6 yr after the operation in these 3 patients. One patient had residue tumor. In our case series, bilateral adrenalectomy plus pituitary irradiation achieved the highest remission rate (100%) in Cushing's disease. In 2 out of 4 patients (50%) treated by left adrenalectomy associated with pituitary irradiation, recurrence was observed. Panhypopituitarism due to tumor apoplexy was observed in one of the patients with Cushing's disease. All of the patients with adrenal CS, the tumor was accurately localized with imaging methods before the operation. The appropriate operative procedure resulted in complete remission in patients with adrenal adenoma. Consequently, Cushing's disease was the most common form of CS. The overnight 1 mg oral DST and 24-h urine free F excretion (UFC) as screening tests, 2-day LDDST as diagnostic test and 2-day HDDST as differential diagnostic test were good studies. More successful outcomes have been achieved in treatment of Cushing's disease with the development of pituitary surgery in the recent years, as well as in our case series. Surgery is also curative for adrenal adenoma patients. Survival remains poor among carcinoma patients.

Overnight dexamethasone suppression test: a reliable screen for Cushing's syndrome in the obese

OBJECTIVE

Reevaluation of the validity of the 1-mg overnight dexamethasone suppression test (ODST) as a screening test for Cushing's syndrome in obese patients.

RESEARCH METHODS AND PROCEDURES

Eighty-six obese patients (body mass index, 30 to 53 kg/m(2)) that were referred to a general endocrine outpatient clinic for evaluation of simple obesity, diabetes mellitus, hypertension, polycystic ovary disease, or pituitary tumor. One milligram dexamethasone was administered orally at 11:00 PM, and serum cortisol levels were measured the following morning between 8:00 AM and 9:00 AM. Suppression of serum cortisol to <80 nM (3 micro g/dL) was chosen as the cut-off point for normal suppression. Patients with serum cortisol levels > or =80 nM were evaluated for Cushing's syndrome.

RESULTS

Suppression of morning cortisol levels to <80 nM occurred in 79 of the 86 obese patients. Seven patients had serum cortisol levels higher than 80 nM; five were eventually diagnosed with Cushing's syndrome and two were considered false positive results in view of normal 24-hour free urinary cortisol and normal suppression on a low dose dexamethasone suppression test (0.5 mg of dexamethasone every 6 hours for 2 days). We found a false positive rate of 2.3% for the ODST using a cut-off serum cortisol of 80 nM.

DISCUSSION

The ODST is a valid screening test for Cushing's syndrome in the obese population. The false positive rate was 2.3%, even when using a strict cut-off serum cortisol of 80 nM. Abnormal cortisol suppression in obese patients should be investigated and not be considered false positive results.

Validation of a High-Throughput Liquid Chromatography–Tandem Mass Spectrometry Method for Urinary Cortisol and Cortisone

Background: Urinary free cortisol and cortisone measurements are useful in evaluation of Cushing syndrome, apparent mineralocorticoid excess, congenital adrenal hyperplasia, and adrenal insufficiency. To reduce analytical interference, improve accuracy, and shorten the analysis time, we developed a liquid chromatography–tandem mass spectrometry (LC-MS/MS) method for urinary cortisol and cortisone.

Methods: We added 190 pmol (70 ng) of stable isotope cortisol-9,11,12,12-d4 to 0.5 mL of urine as an internal standard before extraction. The urine was extracted with 4.5 mL of methylene chloride, washed, and dried, and 10 μL of the reconstituted extract was injected onto a reversed-phase C18 column and analyzed using a tandem mass spectrometer operating in the positive mode.

Results: Multiple calibration curves for urinary cortisol and cortisone exhibited consistent linearity and reproducibility in the range 7–828 nmol/L (0.25–30 μg/dL). Interassay CVs were 7.3–16% for mean concentrations of 6–726 nmol/L (0.2–26.3 μg/dL) for cortisol and cortisone. The detection limit was 6 nmol/L (0.2 μg/dL). Recovery of cortisol and cortisone added to urine was 97–123%. The regression equation for the LC-MS/MS (y) and HPLC (x) method for cortisol was: y = 1.11x + 0.03 μg cortisol/24 h (r2 = 0.992; n = 99). The regression equation for the LC-MS/MS (y) and immunoassay (x) methods for cortisol was: y = 0.66x − 12.1 μg cortisol/24 h (r2 = 0.67; n = 99).

Conclusion: The sensitivity and specificity of the LC-MS/MS method for urinary free cortisol and cortisone offer advantages over routine immunoassays or chromatographic methods because of elimination of drug interferences, high throughput, and short chromatographic run time.

Classification of the spectrum of Coats' disease as subtypes of idiopathic retinal telangiectasis with exudation

PURPOSE

An increasing variety of eponymous terms have been used to describe atypical cases of Coats' disease. A group of typical cases of Coats' disease and other cases of differing severity were classified as one of four subtypes of idiopathic retinal telangiectasis with exudation and compared with regard to clinical outcome.

METHODS

In a retrospective clinical review patients with typical and atypical Coats' disease were classified as severe, focal, juxtafoveal or associated (with another disease) forms of idiopathic retinal telangiectasis with exudation.

RESULTS

53 eyes in 50 patients were examined of which 62% (n=31) were male. 12 eyes were classified as severe (group 1), 22 focal (group 2), 12 juxtafoveal (group 3) and 7 associated (group 4). The mean age at diagnosis was lowest in group 1 eyes (6.8 years). The best visual acuity at presentation was 6/60 in group 1 whereas high proportions of eyes in the other groups had initial visual acuities of 6/24 or better. In group 1 only one eye was treated, the majority of eyes were blind or had been enucleated whereas 34 (79%) of eyes in the other groups were suitable for treatment and 29 eyes (67%) retained pre-treatment visual acuity or better at last follow-up.

CONCLUSIONS

Idiopathic retinal telangiectasis with exudation is a spectrum of disease, which is synonymous with Coats' disease. In this retrospective study eyes with severe idiopathic retinal telangiectasis with exudation corresponding to typical Coats' disease, have poorer vision at presentation, are less suitable for treatment and have worse outcomes than eyes with other subtypes. The spectrum of disease severity seen in idiopathic retinal telangiectasis with exudation may be due to second somatic mutations in genes with an existing germline mutation (the two hit theory) and a mosaic phenotype.

Cushing's syndrome

During the past 30 years, there have been advances in understanding of the pathogenesis of Cushing's syndrome and in differential diagnosis of its various forms. Improved diagnostic tests and procedures have increased the ability to recognise even mild hypercortisolism and have provided the means to obtain an accurate diagnosis. Despite these advances, the occurrence of unusual clinical presentations and laboratory shortcomings may produce diagnostic problems and challenge clinical intuition. This article reviews recent pathogenic views, new tests, and new diagnostic problems in the evaluation of Cushing's syndrome. Atypical clinical presentations of hypercortisolism and some laboratory shortcomings that may confuse the diagnosis of Cushing's syndrome are also reported.

Polycystic ovary syndrome and ovulation induction

Before initiating treatment to induce ovulation in cases of PCOS, an appropriate evaluation of the patient and her partner, based on individual considerations, is important to optimize outcome. For obese patients with PCOS, weight-loss measures should be pursued before pharmacologic treatment is initiated. For most patients, the pharmacologic agent of choice to induce ovulation is clomiphene citrate, alone or in combination with a glucocorticoid. Treatment with metformin, alone or in combination with clomiphene citrate, may also be beneficial. For patients not responsive to clomiphene citrate, injectable gonadotropin treatment is usually warranted, although, depending on individual circumstances, laparoscopic ovarian drilling may be appropriate.

Maximizing Efficacy of Endocrine Tests: Importance of Decision-focused Testing Strategies and Appropriate Patient Preparation

The efficacy of endocrine tests depends on the choice of tests, the preparation of the patients, the integrity of the specimens, the quality of the measurements, and the validity of the reference data. Close dialogue among the clinicians, the laboratory, and the patients is a key factor for optimal patient care. The characteristics of urine and plasma samples and the advantages and limitations of paired test measurements are presented. The importance of test sequence strategies, provocative or inhibitory procedures, and elimination of drug interferences is illustrated with four cases involving Cushing syndrome, pheochromocytoma, primary aldosteronism, and hypercalcemia. For each of these scenarios, key clinical issues are highlighted, along with discussions of the best test strategies, including which medications are likely to interfere. The importance of targeting laboratory tests to answer well-focused clinical decisions is emphasized. The roles of some time-honored provocative procedures are questioned in light of more sensitive and specific analytic methods. The importance of decision-focused analytical tolerance limits is emphasized by demonstrating the impact of analytic bias on downstream medical resource utilization. User-friendly support systems to facilitate the implementation of test strategies and postanalytic tracking of patient outcomes are presented as essential requirements for quality medical practice.

The neuroendocrine protein 7B2 is required for peptide hormone processing in vivo and provides a novel mechanism for pituitary Cushing's disease

The neuroendocrine protein 7B2 has been implicated in activation of prohormone convertase 2 (PC2), an important neuroendocrine precursor processing endoprotease. To test this hypothesis, we created a null mutation in 7B2 employing a novel transposon-facilitated technique and compared the phenotypes of 7B2 and PC2 nulls. 7B2 null mice have no demonstrable PC2 activity, are deficient in processing islet hormones, and display hypoglycemia, hyperproinsulinemia, and hypoglucagonemia. In contrast to the PC2 null phenotype, these mice show markedly elevated circulating ACTH and corticosterone levels, with adrenocortical expansion. They die before 9 weeks of severe Cushing's syndrome arising from pituitary intermediate lobe ACTH hypersecretion. We conclude that 7B2 is indeed required for activation of PC2 in vivo but has additional important functions in regulating pituitary hormone secretion.