Total and free cortisol levels during 1 μg, 25 μg, and 250 μg cosyntropin stimulation tests compared to insulin tolerance test: results of a randomized, prospective, pilot study

Diagnostic strategies in adrenal insufficiency

PURPOSE OF REVIEW

Adrenal insufficiency (AI) is the clinical manifestation of deficient production of glucocorticoids with occasionally deficiency also in mineralocorticoids and adrenal androgens and constitutes a fatal disorder if left untreated. The aim of this review is to summarize the new trends in diagnostic methods used for determining the presence of AI.

RECENT FINDINGS

Novel aetiologies of AI have emerged; severe acute respiratory syndrome coronavirus 2 infection was linked to increased frequency of primary AI (PAI). A new class of drugs, the immune checkpoint inhibitors (ICIs) widely used for the treatment of several malignancies, has been implicated mostly with secondary AI, but also with PAI. Salivary cortisol is considered a noninvasive and patient-friendly tool and has shown promising results in diagnosing AI, although the normal cut-off values remain an issue of debate depending on the technique used. Liquid chromatography-mass spectrometry (LC-MS/MS) is the most reliable technique although not widely available.

SUMMARY

Our research has shown that little progress has been made regarding our knowledge on AI. Coronavirus disease 2019 and ICIs use constitute new evidence on the pathogenesis of AI. The short synacthen test (SST) remains the 'gold-standard' method for confirmation of AI diagnosis, although salivary cortisol is a promising tool.

Cortisol values during the standard-dose cosyntropin stimulation test: Personal experience with Elecsys cortisol II assay

PURPOSE

There has been debate regarding the appropriate cortisol cutoff during the cosyntropin stimulation test (CST) when newer cortisol assays are used. We aimed to evaluate the proper cortisol values during the standard dose CST in patients with normal hypothalamic-pituitary-adrenal (HPA) axis when the Elecsys^® Cortisol II assay from Roche Diagnostics is used.

METHODS

We retrospectively reviewed the medical records of patients evaluated for possible adrenal insufficiency using the standard-dose (250 mcg) CST from January 2018 to December 2020 and eventually judged to have a normal HPA axis. All the CSTs were done in the outpatient setting. Evaluation by an endocrinologist, restrictive exclusion criteria including prior glucocorticoid and opioid use, and lack of glucocorticoid treatment for at least 6 months after the CST was used to define normal HPA axis. The results are reported in the median (range).

RESULTS

We identified 63 patients who met the inclusion criteria and were considered to have a normal HPA axis. The median age was 54.7 (27.6-89.1) years; 32 (51%) were female, and 27 (43%) were white. The duration of follow-up after the CST without any glucocorticoid replacement was 13.9 (6.3-43.9) months. Cortisol levels were 21.7 (15.7-29.1) µg/dl and 24.4 (17.9-35.8) µg/dl at 30- and 60-minutes after cosyntropin administration, respectively. The lowest cortisol levels at 30 and 60 minutes for patients with either normal TSH or gonadal axis (n=47) or in whom both axes were normal (n=18) were similar to the ones of the entire cohort.

CONCLUSION

Our study supports using a lower than previously recommended cortisol cutoff value at 30 minutes after Cosyntropin using the Roche Elecsys^® Cortisol II assay. The lowest cortisol levels in our cohort were 15.7 and 17.9 µg/dL at 30 and 60 minutes after the CST, respectively. Therefore, it is essential to consider the time of cortisol draw after cosyntropin administration.

Investigation of the Hypothalamo-pituitary-adrenal (HPA) axis: a contemporary synthesis

The hypothalamo-pituitary-adrenal (HPA) axis is one of the main components of the stress system. Maintenance of normal physiological events, which include stress responses to internal or external stimuli in the body, depends on appropriate HPA axis function. In the case of severe cortisol deficiency, especially when there is a triggering factor, the patient may develop a life-threatening adrenal crisis which may result in death unless early diagnosis and adequate treatment are carried out. The maintenance of normal physiology and survival depend upon a sufficient level of cortisol in the circulation. Life-long glucocorticoid replacement therapy, in most cases meeting but not exceeding the need of the patient, is essential for normal life expectancy and maintenance of the quality of life. To enable this, the initial step should be the correct diagnosis of adrenal insufficiency (AI) which requires careful evaluation of the HPA axis, a highly dynamic endocrine system. The diagnosis of AI in patients with frank manifestations is not challenging. These patients do not need dynamic tests, and basal cortisol is usually enough to give a correct diagnosis. However, most cases of secondary adrenal insufficiency (SAI) take place in a gray zone when clinical manifestations are mild. In this situation, more complicated methods that can simulate the response of the HPA axis to a major stress are required. Numerous studies in the assessment of HPA axis have been published in the world literature. In this review, the tests used in the diagnosis of secondary AI or in the investigation of suspected HPA axis insufficiency are discussed in detail, and in the light of this, various recommendations are made.

Continuous Glucose Monitoring to Diagnose Hypoglycemia Due to Late Dumping Syndrome in Children After Gastric Surgeries

Gastrostomy tubes (G-tubes) and Nissen fundoplication are common surgical interventions for feeding difficulties and gastroesophageal reflux disease in children. A potential yet often missed, complication of these procedures is dumping syndrome. We present 3 pediatric patients with postprandial hypoglycemia due to late dumping syndrome after gastric surgeries. All patients received gastrostomy tubes for feeding intolerance: 2 had Nissen fundoplication for gastroesophageal reflux disease, and 1 had tracheoesophageal repair. All patients underwent multiple imaging studies in an to attempt to diagnose dumping syndrome. Continuous glucose monitoring (CGM) was essential for detecting asymptomatic hypoglycemia and glycemic excursions occurring with feeds that would have gone undetected with point-of-care (POC) blood glucose checks. CGM was also used to monitor the effectiveness of treatment strategies and drive treatment plans. These cases highlight the utility of CGM in diagnosing postprandial hypoglycemia due to late dumping syndrome, which is infrequently diagnosed by imaging studies and intermittent POC blood glucose measurements.

Morning Serum Cortisol as a Predictor for the HPA Axis Recovery in Cushing's Disease

BACKGROUND

The suppressed hypothalamic-pituitary-adrenal (HPA) axis after successful surgery for Cushing's disease (CD) will recover in almost all patients. We aimed to identify the predictive factors for HPA axis recovery in CD patients with postoperative remission. Design and Methods. This observational retrospective cross-sectional study enrolled 69 CD patients with postoperative remission in Huashan Hospital from 2015 to 2019. All subjects had a detailed clinical evaluation. The low-dose ACTH stimulation test (LDT) was conducted as the gold standard for assessing the HPA axis function.

RESULTS

Peak cortisol in LDT was found only to be positively correlative with morning serum cortisol (MSC) (ρ=0.451, p < 0.001). The MSC was higher (p < 0.001), and the median postoperative course was significantly longer (p=0.025) in the patients with the recovered HPA axis function compared with unrecovered patients. The AUC value of MSC for predicting the recovery of the HPA axis was 0.701, and the optimal cutoff was 6.25 μg/dl (sensitivity 85.19% and specificity 47.62%). Other useful cutoff values were 10.74 μg/dl (specificity 100%) and 4.18 μg/dl (sensitivity 100%). Besides, combined with the postoperative course, the AUC values were higher than MSC alone (0.935 vs. 0.701, p < 0.001).

CONCLUSIONS

MSC is a viable first-step diagnostic predictor for HPA axis recovery in CD patients with postoperative remission. For the patients with cortisol levels between 4.18 and 10.74 μg/dl, a confirmatory test should be conducted. When the MSC level was 10.74 μg/dl or greater, the replacement therapy could be discontinued.

Plasma Free Cortisol in States of Normal and Altered Binding Globulins: Implications for Adrenal Insufficiency Diagnosis

CONTEXT

Accurate diagnosis of adrenal insufficiency is critical because there are risks associated with overdiagnosis and underdiagnosis. Data using liquid chromatography tandem mass spectrometry (LC/MS/MS) free cortisol (FC) assays in states of high or low cortisol-binding globulin (CBG) levels, including cirrhosis, critical illness, and oral estrogen use, are needed.

DESIGN

Cross-sectional.

OBJECTIVE

Determine the relationship between CBG and albumin as well as total cortisol (TC) and FC in states of normal and abnormal CBG. Establish the FC level by LC/MS/MS that best predicts TC of <18 μg/dL (497 nmol/L) (standard adrenal insufficiency diagnostic cutoff) in healthy individuals.

SUBJECTS

This study included a total of 338 subjects in four groups: healthy control (HC) subjects (n = 243), patients with cirrhosis (n = 38), intensive care unit patients (ICU) (n = 26), and oral contraceptive (OCP) users (n = 31).

MAIN OUTCOME MEASURE(S)

FC and TC by LC/MS/MS, albumin by spectrophotometry, and CBG by ELISA.

RESULTS

TC correlated with FC in the ICU (R = 0.91), HC (R = 0.90), cirrhosis (R = 0.86), and OCP (R = 0.70) groups (all P < 0.0001). In receiver operator curve analysis in the HC group, FC of 0.9 μg/dL (24.8 nmol/L) predicted TC of <18 μg/dL (497 nmol/L; 98% sensitivity, 91% specificity; AUC, 0.98; P < 0.0001). Decreasing the cutoff to 0.7 μg/dL led to a small decrease in sensitivity (92%) with similar specificity (91%).

CONCLUSIONS

A cutoff FC of <0.9 μg/dL (25 nmol/L) in this LC/MS/MS assay predicts TC of <18 μg/dL (497 nmol/L) with excellent sensitivity and specificity. This FC cutoff may be helpful in ruling out adrenal insufficiency in patients with binding globulin derangements.

Pitfalls in the interpretation of the cosyntropin stimulation test for the diagnosis of adrenal insufficiency

PURPOSE OF REVIEW

Adrenal insufficiency is a rare disease characterized by cortisol deficiency. The evaluation of patients suspected of having adrenal insufficiency can be challenging because of the rarity of the disease and limitations in the biochemical assessment of the cortisol status by either basal or dynamic testing [adrenocorticotropic hormone (ACTH) stimulation test]. Prompt and adequate diagnosis is of paramount importance to avoid adverse outcomes. We aimed to summarize the recent developments in the conduction and interpretation of the ACTH stimulation test for the diagnosis of adrenal insufficiency.

RECENT FINDINGS

The ACTH stimulation test is commonly performed in patients suspected of having adrenal insufficiency when the basal serum cortisol levels are inconclusive. Recent literature has evaluated the impact of technical aspects such as time of the day the test is performed, type of assay and sample source used for cortisol measurement on the clinical value of this test, as well as the feasibility of reliable low dose ACTH testing.

SUMMARY

Clinicians evaluating patients with suspected adrenal insufficiency should take into consideration the clinical presentation (likelihood of adrenal insufficiency before testing) when interpreting the results of the ACTH stimulation test and be aware of clinical and technical factors that can affect cortisol values and diagnostic accuracy of this test.

SERUM FREE CORTISOL DURING GLUCAGON STIMULATION TEST IN HEALTHY SHORT-STATURED CHILDREN AND ADOLESCENTS

OBJECTIVE

The total cortisol (TC) response may be measured during the glucagon stimulation test (GST) for growth hormone (GH) reserve in order to assess the integrity of the hypothalamic-pituitary-adrenal (HPA) axis. Measurements of TC are unreliable in conditions of albumin and cortisol-binding globulin (CBG) alterations (e.g., hypoproteinemia or CBG deficiency). We aimed to measure the serum free cortisol (sFC) response to the GST in children and adolescents and determine whether it could predict the GH response to glucagon stimulation.

METHODS

Infants and children with either short stature or growth attenuation who were referred for evaluation of GH reserve underwent the GST.

RESULTS

The study population consisted of 103 subjects (62 females), median age 3.9 years (range, 0.5-14). The mean basal and peak TC levels were 13.3 ± 6.7 μg/dL and 29.6 ± 8.8 μg/dL, respectively. The mean basal and peak sFC levels were 0.7 ± 0.8 μg/dL and 1.7 ± 1.1 μg/dL, respectively. There was a negative correlation between peak TC and age ( r = -0.3, P = .007) but not between peak sFC and age ( r = -0.09, P = .36). Ninety-five percent of the patients had peak TC levels >15.8 μg/dL and peak sFC levels >0.6 μg/dL.

CONCLUSION

Our results on a cohort of healthy short-statured children can serve as reference values for the sFC response during GST. Based on these results, we propose peak TC levels >15.8 μg/dL and peak sFC levels >0.6 μg/dL for defining normalcy of the HPA axis during the GST in children and adolescents.

ABBREVIATIONS

ACTH = adrenocorticotrophic hormone BMI = body mass index CBG = cortisol-binding globulin GH = growth hormone GST = glucagon stimulation test HPA = hypothalamic-pituitary-adrenal SDS = standard deviation score sFC = serum free cortisol TC = total cortisol.