Single-dose dexamethasone suppression in normal subjects and hospital patients

Low-Dose and Standard Overnight and Low Dose-Two Day Dexamethasone Suppression Tests in Patients with Mild and/or Episodic Hypercortisolism

We previously reported on the lack of utility of the 1 mg overnight dexamethasone (DEX) test in mild and/or periodic Cushing's syndrome, as most patients with the condition suppressed to 1 mg DEX. It is possible that a lower dose of DEX as part of an overnight DEX test might be able to distinguish between mild and/or periodic Cushing's syndrome and those without the condition. The objective of the current study is to determine the sensitivity and specificity of a 0.25 mg overnight DEX suppression test, the standard 1 mg overnight DEX suppression test, and the two-day low-dose (Liddle test) DEX suppression test with and without correction for DEX levels in patients evaluated for mild and/or periodic Cushing's syndrome. Thirty patients determined to have Cushing's syndrome by biochemical testing and 14 patients determined not to have the condition had the 0.25 mg and standard 1 mg overnight DEX suppression test and the two-day low-dose DEX suppression tests. Our results show that morning serum cortisol and cortisol/DEX ratios following an overnight dexamethasone suppression test were similar in patients with Cushing's syndrome and those not having Cushing's syndrome. However, a morning cortisol value above 7.6 μg/dl following a dose of DEX of 0.25 mg was found in 12 patients with Cushing's syndrome and none in those not having Cushing's syndrome, suggesting that a high cortisol value after this low dose of dexamethasone can indicate that further testing for Cushing's syndrome is warranted. Our data suggest that the traditional 1 mg overnight or the 2 mg/2 day DEX suppression testing should no longer be used as a screening test in patients who could have mild and/or periodic Cushing's syndrome, while the 0.25 mg dose of DEX may pick up some patients with mild Cushing's syndrome.

Decreased plasma cortisol in response to intramuscular ACTH in ocular hypertensives and primary open-angle glaucomas

PURPOSE

To determine if there is a difference in response of the adrenal gland to intramuscular adrenocorticotropic hormone (ACTH) between normals and ocular hypertensives (OHs) plus primary open-angle glaucomas (POAGs) without pigmented angles.

METHODS

Intramuscular ACTH was given to 29 normals and 24 OH plus POAG hospitalized in a Clinical Study Unit. Blood samples were obtained at baseline (0 hours) before administration of intramuscular ACTH and 4, 8, and 24 hours after administration of intramuscular ACTH for analysis of plasma cortisol/body mass index (BMI).

RESULTS

The OH plus POAG group showed lower cortisol/BMI values compared with the normal group at 4, 8, and 24 hours with a significantly lower peak/BMI value (P=0.030). Multivariate analyses with the peak plasma cortisol/BMI level as the dependent variable showed that a lower peak plasma/BMI was associated with the OH plus POAG group. Also, a lower peak plasma cortisol/BMI level was associated with a lower 0-hour cortisol/BMI (Log).

CONCLUSIONS

Compared with normals, the OH plus POAG subjects showed lower plasma cortisol levels in response to intramuscular ACTH. This observation suggests adrenal suppression in the OH plus OAG group.

Decreased response of plasma cortisol to intravenous metyrapone in ocular hypertension and primary open-angle glaucoma

PURPOSE

To determine if there is a difference in response to metyrapone, which blocks the conversion of 11-deoxycortisol to cortisol in the adrenal gland between normals and ocular hypertensives (OH) plus primary open-angle glaucomas (POAG) without pigmented angles.

METHODS

Intravenous metyrapone was given to 20 normals and 15 ocular hypertensives plus primary open-angle glaucomas without pigmented angles. Blood samples were obtained at 4, 6, and 8 hours after administration of intravenous metyrapone for analyses of 11-deoxycortisol and cortisol.

RESULTS

The ocular hypertensives plus primary open-angle glaucoma group showed significantly lower cortisol values compared with the normal group at 6 hours (P = 0.002) but not at 4 or 8 hours. There were no significant differences between the two groups for 11-deoxycortisol values at 4, 6, or 8 hours. The percent decrease of plasma cortisol from baseline was significantly greater for the ocular hypertensives plus open-angle glaucoma group compared with the normals at 4 hours (P = 0.010) and 6 hours (P = 0.0004). Significant negative correlations were observed for the total group of subjects between levels of plasma cortisol at 6 hours and intraocular pressure, worse eye (P = 0.029), percent area of cupping, worse eye (P = 0.045), pallor, worse eye (P = 0.001), and visual field loss, worse eye (P = 0.048), so that the less the plasma cortisol, the greater the abnormality of the glaucomatous parameters. Multivariate analyses with the 6-hour plasma cortisol level as the dependent variable showed that the only significant (P = 0.0004) independent variable was the percent area of pallor, worse eye, associated with a smaller level of plasma cortisol at 6 hours. Similarly, the multiple regression models using the percent change from baseline of the 6-hour plasma cortisol value showed a significant association of larger percent decreases of plasma cortisol in the ocular hypertensives plus open-angle glaucoma compared with the normals.

CONCLUSIONS

The ocular hypertensives plus primary open-angle glaucoma subjects show greater adrenal inhibition to metyrapone in the synthesis of cortisol from 11-deoxycortisol compared with normals. This observation suggests an adrenal abnormality in the ocular hypertensive plus primary open-angle glaucoma subjects.

Transsphenoidal microsurgical treatment of Cushing disease: postoperative assessment of surgical efficacy by application of an overnight low-dose dexamethasone suppression test

OBJECT

Transsphenoidal adenomectomy with resection of a defined pituitary adenoma has been the treatment of choice for CD for the last 30 years. Surgical resection, however, may not always result in long-term remission of CD. This is particularly important in light of the high risk of morbidity and mortality in patients in the unsuccessfully treated cushingoid state. As such, it is interesting to identify prognostic factors that may predict the likelihood of long-term remission.

METHODS

The authors review their series of 174 patients who have undergone transsphenoidal procedures for CD over a period of 20 years with minimum follow-up periods of 5 years. Selection of these patients was based on clinical, imaging, and laboratory criteria that included serum cortisol levels, loss of diurnal variation in serum cortisol levels, urinary free cortisol concentration, and results of a dexamethasone suppression test, petrosal sinus sampling, and corticotroph-releasing hormone stimulation tests as indicated. All patients who met the biochemical criteria underwent transsphenoidal microsurgery. The authors found an overall rate of remission of 74% at 5 years postoperatively. Patients in whom morning serum cortisol concentrations were lower than 3 microg/dl (83 nmol/L) on postoperative Day 3, following an overnight dexamethasone suppression test, had a 93% chance of remission at the 5-year follow-up examination. Patients with cortisol concentrations higher than this level uniformly failed to achieve long-term remission.

CONCLUSIONS

Transsphenoidal microsurgery is an effective means of control for patients with adrenocorticotrophic hormone-producing microadenomas. Clinical outcome correlated well with the size of the tumor, as measured on preoperative imaging studies, and with postoperative morning cortisol levels following an overnight dexamethasone suppression test. Postoperative cortisol levels can be used as a useful prognostic indicator of the likelihood of future recurrence following transsphenoidal adenomectomy in CD.

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.

Diagnosis of Cushing's syndrome: re-evaluation of midnight plasma cortisol vs urinary free cortisol and low-dose dexamethasone suppression test in a large patient group

We studied plasma cortisol levels at 00:00 h and 08:00 h in 103 patients with Cushing's syndrome and 144 patients in whom this diagnosis had been excluded. These patients were hospitalized in our department from 1975 to 1996. Additionally, we measured these parameters in 20 healthy volunteers and in 5 patients with nonendocrine disease. Corresponding data of urinary free cortisol and low-dose dexamethasone suppression testing were included in the evaluation. Values (mean+/-SD) from patients with Cushing's syndrome: 510+/-232 nmol/l (range 165-1488) for plasma cortisol 00:00 h, 574+/-242 nmol/l (range 236-1612) for plasma cortisol 08:00 h, 991+/-885 nmol/24 h (range 154-4866) for urinary free cortisol and 479+/-304 nmol/l (range 34 - 1,393) for plasma cortisol after 1.5 mg dexamethasone. Values from the patients excluded from Cushing's syndrome: 99+/-76 nmol/l (range 5-371) for plasma cortisol 00:00 h, 393+/-136 nmol/l (range 119-812) for plasma cortisol 08:00 h, 126+/-84 nmol/24 h (range 30-485) for urinary free cortisol, and 64+/-82 nmol/l (range 5-395) for plasma cortisol after 1.5 mg dexamethasone. Values of the healthy volunteers respectively patients with non-endocrine disease: 59+/-30 nmol/l (range 25-130) respectively 127+/-80 nmol/l (range 62-265) for plasma cortisol 00:00 h and 388+/-144 nmol/l (range 157-651) respectively 498+/-113 nmol/l (range 302-581) for plasma cortisol 08:00 h. None of the Cushing patients exhibited a 00:00 h plasma cortisol below 140 nmol/l and only one had a urinary free cortisol below 200 nmol/24 h, whereas 4 were complete dexamethasone suppressors. The diagnostic value of these parameters was examined based on various cutoffs. We recommend determination of midnight plasma cortisol as an efficient and simple additional procedure for the diagnosis of Cushing's syndrome. The sensitivity and specificity of this procedure is similar to urinary free cortisol and slightly above the low-dose dexamethasone suppression testing in our hospitalized patients.

Clinical and biochemical evaluation of Cushing's syndrome

Over the past decade, several advances have been made in our understanding of the molecular pathogenesis of pituitary adenomas, and novel diagnostic tests for the diagnosis and differential diagnosis of Cushing's syndrome have been developed. Although established in the late 1970s, measurement of UFC has emerged as the most sensitive and specific test to screen for and confirm the presence of Cushing's syndrome. The combined CRH/DST is potentially a useful adjunct in patients with probable pseudo-Cushing's syndrome and borderline elevated urinary cortisol levels. Improved assays for circulating ACTH levels are now used as the first test in differentiating ACTH-dependent from ACTH-independent sources. HDDST with the revised reference ranges for UFC currently remains the primary test for differentiating pituitary from ectopic ACTH secretion. However, the CRH test may replace the HDDST in the foreseeable future because of its lower rate of false-positive and false-negative results. IPSS has been established as an integral part of the evaluation of patients with suspected Cushing's disease and no conclusive (> 0.8 to 1 cm) pituitary adenoma. Advances in the radiolabeling of small peptides, such as somatostatin analogs, may facilitate the search for occult ectopic sources.

Different linkage of depression to hypercortisolism early versus late after stroke. A 3-year longitudinal study

BACKGROUND AND PURPOSE

Using the dexamethasone suppression test, we studied the suppressibility of the cortisol axis and its clinical determinants at various time points after stroke. A major aim was to examine the dexamethasone test as a diagnostic tool for the diagnosis of major depression in stroke patients.

METHODS

The dexamethasone suppression test, major depression, functional ability, and disorientation were assessed in a cohort of 70 patients with acute stroke and after 3 months (n = 63) and 3 years (n = 43).

RESULTS

Early after stroke, 24% of the patients were nonsuppressors, with about the same proportion at 3 months (22%) and 3 years (21%). None of the controls (17 healthy elderly volunteers) were nonsuppressors. High cortisol levels early after stroke were significantly associated with functional impairment (r = 0.35; p = 0.003) and disorientation (r = 0.27; p = 0.03). Three years after stroke, high postdexamethasone cortisol levels were significantly associated with major depression (r = 0.57; p < 0.001). The sensitivity of the dexamethasone test was 70% and the specificity 97%. In a longitudinal analysis of the long-term survivors (n = 42), postdexamethasone cortisol values at 3 months predicted major depression at 3 years.

CONCLUSIONS

Hypercortisolism is associated with major depression late (3 years) but not early (0-3 months) after stroke. Patients with hypercortisolism 3 months after stroke are at risk of major depression later in the course and warrant careful follow-up from a psychiatric viewpoint.

Overnight (1 mg) dexamethasone suppression testing reliably distinguishes non-cushingoid obesity from Cushing's syndrome

To determine the sensitivity of the overnight 1-mg dexamethasone suppression test in diagnosing Cushing's syndrome, we evaluated the cortisol responses of 55 subjects (25 non-obese individuals with body mass index less than 25 kg/m2, 20 obese individuals with body mass index greater than 30 kg/m2, and 10 patients with surgically proven Cushing's syndrome) following ingestion of 1 mg dexamethasone at midnight. The basal 8 AM plasma cortisol levels among non-obese and obese individuals and patients with Cushing's syndrome were 310 +/- 85, 377 +/- 91, and 813 +/- 270 nmol/L, respectively. Following 1 mg of dexamethasone, Cushing's syndrome patients showed minimal suppression of cortisol to 609 +/- 180 nmol/L (P = 0.79). Non-obese and obese individuals suppressed to 18.7 +/- 6.0 nmol/L (P less than 0.001) and 22 +/- 7.1 nmol/L (P = 0.003), respectively. The results demonstrated similar cortisol responses to overnight dexamethasone suppression in obese and non-obese groups, and clearly distinguished these subjects from those with Cushing's syndrome. Obesity is not a confounding factor in the 1-mg dexamethasone suppression test.

The overnight dexamethasone test is a worthwhile screening procedure

The overnight low-dose dexamethasone test is a convenient screening procedure for Cushing's syndrome. Claims that the test is associated with a high incidence of 'false positives', rendering it of little value particularly in obese and hospital in-patients, have been investigated in the present study. The data from 100 consecutive subjects undergoing overnight low-dose dexamethasone tests to examine for the possibility of Cushing's syndrome, were reviewed. Cushing's syndrome was identified in four patients, normal suppression of cortisol values occurred in 84 patients and 12 patients exhibited false positive results. Differences in body weights, body mass indices or in-patient status did not distinguish between those subjects with normal suppression of plasma cortisol and those subjects who yielded false positive results. These data indicate that the simple overnight dexamethasone test substituted for the more cumbersome traditional 48-h dexamethasone test in 84 of 96 patients who did not have Cushing's syndrome. Thus the overnight test provides a useful screening procedure but a small percentage of patients, approximately 12.5%, will require additional procedures to exclude Cushing's syndrome.

Effect of concurrent medical illness on dexamethasone suppression test results in depressed inpatients

A retrospective evaluation of the clinical records of 138 depressed patients, who received the dexamethasone suppression test (DST) as part of a standardized physical and psychiatric assessment protocol, revealed that 60 had acute, chronic (mild or severe), stable or remitted medical conditions. The proportion of DST nonsuppressors did not differ between depressed subjects with medical conditions (45% nonsuppressors) and those without (34.6% nonsuppressors; p greater than 0.2). However, all of the six subjects with acute or chronic-severe medical conditions were found to be nonsuppressors (p = 0.003). These results may help clarify the medical exclusion criteria for the clinical application of the DST.

The dexamethasone suppression test in healthy controls

We have summarized the results of 53 studies which examined the dexamethasone suppression test in normal controls. Only 3.6% of 687 0800 hr postdexamethasone cortisol levels were above 5 micrograms/dl. Corresponding figures for 1600 hr and 2300 hr cortisol levels were 7.4% (85/1144) and 6.3% (28/434), respectively. Neither the type of assay (competitive protein binding or radioimmunoassay) nor mean/median age of the subjects was associated with non-suppression rates.

A study of corticotroph adenomas in Cushing's disease: no evidence of intermediate lobe origin

There is little evidence for a separate functional or anatomical intermediate lobe in the adult human pituitary gland. Nevertheless, Lamberts et al. (1982) proposed that a subgroup of corticotroph adenomas in Cushing's disease arise in that lobe and can be identified by the presence of argyrophil (? neural) fibres, and that these tumours are more often associated with corticotroph hyperplasia and hyperprolactinaemia than those arising in the anterior lobe. We have examined a series of corticotroph adenomas from patients with Cushing's disease for evidence of argyrophil fibres, and have correlated this with tumour site, corticotroph distribution in the para-adenomatous gland, serum PRL levels and PRL immunoreactive cells in the tumour. Argyrophil fibres were identified not only in tumours adjacent to the posterior lobe, but also in tumours situated deep in the anterior lobe. There was no correlation between the presence of fibres or the site of the tumour and corticotroph hyperplasia. Whilst the two patients with the highest serum PRL levels did have argyrophil fibres they also had a subpopulation of PRL immunoreactive cells in the tumour. On the basis of these results, we propose that the 'intermediate lobe' hypothesis as outlined above should not be accepted.

Dexamethasone suppression and energy balance in eating disorders

The dexamethasone suppression test (DST) was investigated in 45 female anorectic out-patients (cross sectional study) nine of whom were followed serially as in-patients (longitudinal study). DST non-suppression was strongly associated with negative energy balance (low body weight and low Ponderal Index) but there was no significant association with the presence of affective or neurotic disturbance in these patients. These findings cast doubt on the value of the DST in the management of depressive illness.

Misuse of the dexamethasone suppression test as a diagnostic tool

The diagnostic reliability and appropriateness of use of the Dexamethasone Suppression Test (DST) were assessed by a retrospective chart survey of ninety-nine psychiatric admissions to a community hospital. A change in psychiatric diagnosis between admission and discharge occurred in one-third of the patients. The diagnostic change appeared to be associated with the DST result more than the clinical findings. Such reliance on the test was not justified as the observed diagnostic confidence of the DST in supporting a diagnosis of major depression was only 38 percent. These findings suggest a misuse of the test as a diagnostic tool in routine practice.

Evaluation of depression in a general hospital: utility and limitations of the dexamethasone suppression test

Use of the DST was studied in medically hospitalized, depressed patients. Although complicating medical factors necessarily excluded nearly 60% of referrals, post-dexamethasone plasma cortisol values were significantly higher in 14 major depressives appropriate for the DST as compared to 12 patients with milder, subsyndromal depressive conditions. Using a plasma cortisol criterion of greater than 7 micrograms/dl, the DST identified major depression with 57% sensitivity and 92% specificity in this subsample (p less than 0.005). While limited by a high exclusion rate, the DST may be useful for confirmation of major depression in carefully screened general hospital patients. Implications for research and practice are discussed.

Serum cortisol concentrations during low dose dexamethasone suppression test to screen for Cushing's syndrome

Forty four subjects (23 obese controls, 11 patients with possible Cushing's syndrome, and 10 patients with definite Cushing's syndrome) underwent low dose (0 X 5 mg every six hours for two days) dexamethasone suppression tests during which serum cortisol concentration at 0800 and excretion of urinary free cortisol over 24 hours were measured. Serum cortisol concentration fell to below 60 nmol/1 (2 X 2 micrograms/100 ml) in 31 subjects and remained above 250 nmol/1 (9 X 1 micrograms/100 ml) in the 13 others. Excretion of urinary free cortisol showed a similar response, falling to below 110 nmol (40 micrograms)/24 h in 31 and remaining above 180 nmol (65 micrograms)/24 h in the 13 others. There was complete concordance between the two variables in terms of the pattern of response. Serum cortisol concentration fell to below 60 nmol/1 (2 X 2 micrograms/100 ml) in at least 97% (31 of a possible 32) of subjects without Cushing's syndrome. On the other hand, a serum cortisol concentration of above 250 nmol/1 (9 X 1 micrograms/100 ml) after low dose dexamethasone gave a false positive diagnosis of Cushing's syndrome in at most only one of 13 patients (7 X 7%). Measurement of serum cortisol concentration during the low dose dexamethasone test is simpler than, and as accurate and reliable as, measurements of urinary steroids.

Dexamethasone suppression test in depression: association with duration of illness

Plasma cortisol response to 1 mg dexamethasone suppression test was investigated in 37 patients with primary major depressive illness. Non-suppression of plasma cortisol was found in 14 of 37 (38%) patients. Duration of the index episode of illness was significantly shorter in the non-suppressors (11.1 +/- 9.1 weeks) than in the suppressors (29.7 +/- 25.6 weeks). The two groups were not distinguished by age, sex, polarity or severity of depressive symptoms. Eighty per cent of the non-suppressors (4/5) and 57% of the suppressors (8/14) had severe life events or major difficulties in the 6 months preceding the onset of illness, but this difference failed to reach statistical significance.

Dexamethasone suppression test in acute grief reaction

The authors report a study on the response to the dexamethasone suppression test of bereaved first-degree relatives. Of the 21 subjects who took part two were non-suppressors (plasma cortisol greater than 138 mmol/l), but their grief scores were no higher than the suppressors. Both subjects showed a suppressor response 3 months later.

Cortisol secretion and DST in affective disorders--methodological concerns

In the wake of a large number of studies seeking biological markers for a variety of psychiatric disorders including affective disorders, the enthusiasm over Cortisol Secretion and Dexamethasone Suppression test lead the authors to review critically the data collected so far. The research designs involved, the samples studied and the reliability of the data collected along major variables such as diagnostic criteria, sampling characteristics, procedural differences, length of follow-up and the role of environmental stressors were evaluated. A useful exercise was to compare the literature published in the 50's and 60's with the more recent publications. The potential usefulness of DST as a diagnostic and management tool remains open for scrutiny. Whether the abnormalities in cortisol levels and DST responses evidenced by many researchers are an epiphenomenon or have a diagnostic and management value still remains unclear. From their analysis, the authors point out the lack of well controlled sequential studies using standardized procedures, and large age specific samples. Difficulty arising from the use of various terminologies and criteria for diagnosis of depressive disorders is recognized. The limitations of the use of DST in general clinical practice along with directions for future research are outlined.

The dexamethasone suppression test in demented outpatients with and without depression

The dexamethasone suppression test (DST) was given to 33 elderly, male outpatients, previously diagnosed by DSM-III criteria as having dementia. Fifteen of these patients also had signs and symptoms of depression and, except for the presence of organic mental syndrome, would have met DSM-III criteria for major depressive episode. Of these 15 depressed, demented patients, 40% had abnormal DST results. None of the 18 patients who had dementia alone had abnormal DSTs. Our data suggest that in elderly, demented outpatients, an abnormal DST may be associated with concomitant depression.

Effects of chronic medical illness and dementia on the dexamethasone suppression test

The dexamethasone suppression test (DST) was performed on 26 elderly male outpatients in a geriatric medical clinic. Patients with depression were excluded. All patients had two or more medical diagnoses. Fourteen patients also met DSM-III criteria for dementia. No patient had an abnormal DST result. The authors suggest that neither chronic medical illness nor dementia causes false-positive DST results in this patient population in an outpatient setting, and discuss the findings in relation to previous reports.

Hypothalamic-pituitary-adrenal-axis hyperactivity in bulimia

Hyperactivity of the hypothalamic-pituitary-adrenal axis, demonstrated by nonsuppression of plasma cortisol in the dexamethasone suppression test (DST), has been found in about 50% of patients with major depression. We administered the DST to 47 patients with bulimia and to 22 age- and sex-matched normal controls. Among the bulimics, 47% were nonsuppressors, significantly higher than the 9% prevalence of nonsuppressors in the controls, but similar to the prevalence reported for patients with major depression in other studies. This finding is consistent with evidence from studies of phenomenology, family history, and treatment response which suggest that bulimia may be related to affective disorder.

Mood, vegetative disturbance, and dexamethasone suppression test after stroke

Assessments of mood disturbance and "vegetative" (appetite or sleep) disturbance as well as a single-dose dexamethasone suppression test (DST) were carried out in 25 randomly selected stroke patients and in 13 nonstroke control patients hospitalized in a rehabilitation center. Prevalence rates of moderate-to-serve depression of mood and vegetative disturbance were significantly higher in stroke patients than controls (48% and 52% versus 0% and 8%, respectively), as was the prevalence of abnormal DST results (52% versus 8%). Abnormal DST results were associated with the occurrence of moderate to severe mood, appetite, and sleep disturbances among all patients. in 2 stroke patients, repeated DST results paralleled the clinical course. The DST may be useful as an adjunct to the diagnosis and in monitoring the progress of the common and potentially reversible mood and vegetative disturbances occurring after stroke.

Neuroendocrine tests of monoamine function in man: a review of basic theory and its application to the study of depressive illness

Neuroendocrine tests are now available for studying monoamine function in the brains of patients with mental illness. Great care is required in the selection of drugs which act upon specific monoamine receptors to produce specific hormonal responses. Equal care is required in the control of biological variables which may influence hormonal release. Recently reported neuroendocrine studies of depressive illness are assessed in these terms. The results of these studies support the hypothesis that there is defective noradrenergic function in the brains of some patients with depressive illness.

Cushing's syndrome: a review of diagnostic tests

This review presents an analysis and interpretation of the published experimental data that form the basis for laboratory tests commonly used for screening, definitive diagnosis, and differential diagnosis in Cushing's syndrome. The single-dose overnight dexamethasone suppression test is excellent for screening outpatients since this test has a very low incidence of false-negative results (1.9% of 154 patients with Cushing's syndrome). The definitive diagnosis of Cushing's syndrome is best established by combining basal state measurements of the daily urine-free cortisol excretion and late evening plasma cortisol levels with the 2-mg low-dose dexamethasone suppression test. The etiology of Cushing's syndrome is best determined by combining measurements of basal state plasma adrenocorticotropin (ACTH) levels with the 8-mg high-dose dexamethasone suppression test. Under certain conditions, the basal state daily urine excretion of 17-hydroxycorticosteroids and 17-ketogenic steroids, the insulin tolerance test, and the metyrapone test may be useful in the definitive or differential diagnosis of Cushing's syndrome.

Evaluation of steroid laboratory tests and adrenal gland imaging with radiocholesterol in the aetiological diagnosis of Cushing's syndrome

Basal values of the urinary excretion of 17-oxogenic steroids and serum levels of cortisol were not satisfactory in the differentiation of 'suspected' subjects from patients with true Cushing's syndrome. With an RIA method for serum cortisol determination, the overnight dexamethasone suppression test provided the most reliable single test in establishing adrenocortical hyperfunction. Thirty-five normal subjects, fifty-nine obese patients, thirteen 'suspected' patients, and thirteen patients with disease states other than Cushing's syndrome had suppressed values below 4.0 microgram/100 ml. None of the ten patients with Cushing's syndrome had a cortisol concentration less than 16.3 microgram/100 ml. Adrenal gland scintigraphy after radiocholesterol injection is a more valuable tool than the metyrapone test and the high-dose dexamethasone suppression test in the localization and differential diagnosis of adrenocortical lesions causing Cushing's syndrome. It obviates the need for angiographic procedure in the localization of adenomas. It is a reliable technique for identifying functioning adrenal remnants. We therefore propose a schedule for studying patients with suspected adrenocortical hyperfunction.

Steroid-induced glaucoma: A. Persistent elevation of intraocular pressure B. Histopathological aspects

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Neuroendocrine identification of depressed patients

Recent studies of hypothalamo--pituitary--adrenal (HPA) suppression in depressed patients indicate that these subjects often show abnormal early escape of plasma cortisol levels following an initial suppression. Non-depressed psychiatric inpatients usually show normal sustained HPA suppression. The responses of 49 depressed and 30 non-depressed patients have been analysed to develop criteria which can make the dexamethasone suppression test suitable for outpatient studies. The cortisol levels measured in a 24-hour urine collection and a single blood sample post-dexamethasone were sufficient to enable 61% of the depressed patients to be identified correctly at a confidence level of 90%, on the basis of at least one abnormal cortisol value. When both cortisol values were abnormal 35% of the depressed patient were identified correctly at a confidence level of 100%. Patients with "endogenous" depressive profiles had the most abnormal results. A normal response to this test will not necessarily exclude the diagnosis of primary depressive illness. An abnormal response to the test may be of help in confirming the diagnosis. With the simplified procedure outpatient studies may become possible.

Plasma and urinary 11-hydroxycorticosteroids in differential diagnosis of Cushing's syndrome

Morning plasma 11-hydroxycorticoids, urinary 11-hydroxycorticoids, and urinary 17-oxogenic steroids were measured before and during a dexamethasone suppression test. This consisted in the administration by mouth of 2 mg of dexamethasone daily for 48 hours, followed by 8 mg daily for 48 hours. In addition midnight plasma 11-hydroxycorticoids were measured before the start of the test. The subjects investigated were 21 patients with Cushing's syndrome, 27 obese female patients, 10 female patients with the Stein-Leventhal syndrome, and 8 female patients with idiopathic hirsutism.The results showed that the clearest distinction between the groups was made by measurement of the basal urinary 11-hydroxycorticoid excretion, where, in the group of patients with Cushing's syndrome, all the levels were well above the upper limit of normal. In addition raised midnight plasma 11-hydroxycorticoid levels were of great diagnostic value. By using these results together with those of the dexamethasone suppression tests it was possible to make a firm preoperative diagnosis of pituitary-dependent Cushing's syndrome in 90% of patients in this series.

Plasma "cortisol" levels in right and left ventricular failure

Plasma ;cortisol' values are reported in 36 patients during or following right ventricular failure, and 12 during or following left ventricular failure. In patients with right ventricular failure the normal circadian rhythm was abolished with elevation of midnight values. Disturbance of rhythm was less marked in left ventricular failure, although midnight values were usually raised. Dexamethasone suppression of plasma ;cortisol' levels was abolished or reduced in right ventricular failure. These results confirm our earlier findings and further support our contention that the disturbance of circadian rhythm is not due to a simple stress mechanism. The results are of importance in the differential diagnosis of Cushing's syndrome based on plasma ;cortisol' values, if there is concomitant right ventricular failure.