Cortisol cut-points for the glucagon stimulation test in the evaluation of hypothalamic pituitary adrenal axis.

Diagnosis of adrenal insufficiency requires evaluation by dynamic stimulation tests. The insulin tolerance test (ITT) is accepted as the gold-standard test for the evaluation of hypothalamo-pituitary-adrenal (HPA) axis but the test is unpleasant and dangerous. Although it takes more time, glucagon stimulation test (GST) is a good alternative to ITT. The primary aim of this study was to compare the ITT and GSTs in the evaluation of HPA axe in patients with pituitary disorders. We conducted a prospective study in which ITT and GST were performed within 7 days in 81 patients. Serum cortisol was measured. We divided our population in Group 1 (G1): Adrenal Insufficiency (Peak cortisol under ITT <200 ng/mL) and Group 2 (G2): normal response (Peak cortisol under ITT >200 ng/mL). Receiver-operating characteristic (ROC) analysis was performed to identify the thresholds for GST. The mean peak of cortisol under GST was not significantly different from that obtained after ITT in the whole cohort (182.67 ± 89.07 ng/mL vs. 179.75 ± 79.01 ng/mL), and it was significantly reduced in patients of G1 (p < 10-3). ROC curve analysis showed that the best diagnostic accuracy was obtained with a peak cortisol cut-off to GST of 167 ng/mL (sensitivity, 89%; specificity, 79%). Using this cut-off, 86.4% of the patients were correctly classified. In our prospective series, GST is a potential accurate and safe alternative test for the assessment HPA. Test-specific cut-offs should be applied to avoid misinterpretation.

Disorders of sodium balance in COVID-19 patients: two Tunisian patients report.

Coronavirus disease 2019 (COVID-19) was first reported in December 2019. The disease is caused by severe acute respiratory syndrome virus corona virus 2 (SARS-CoV-2). Mild respiratory symptoms are the most common manifestations of SARS-CoV-2, but new signs are constantly being discovered as it spreads. Disorders of sodium balance are increasingly described in patients with SARS-CoV-2. We report, here, the cases of two patients presented with COVID-19 and in whom we discovered sodium disorders. The first patient is a 74-year-old man who presented with fatal hypernatremia. The second patient is a 66-years-old man presented with COVID-19 and euvolemic hyponatremia attributed to syndrome of inappropriate anti-diuretic hormone secretion (SIADH). This hyponatremia persisted long after the respiratory signs disappeared. Sodium balance disorders are increasingly described in the literature; special attention should be paid to the electrolyte status of COVID-19 patients. Pathophysiological mechanisms associating SARS-CoV-2 with these disorders are being studied.

Assessing the adrenal axis by the glucagon stimulation test in children with idiopathic growth hormone deficiency.

Approximately 30% of children with idiopathic growth hormone deficiency (IGHD) also suffer from other pituitary hormone deficien-cies. Of children with IGHD, approximately 10% are unable to generate appropriate ACTH levels in response to stress. This study was prospectively designed to test the integrity of the adrenal axis in patients with an established diagnosis of IGHD using the glucagon stimulation test (GST). The study population comprised 39 patients with established childhood-onset IGHD. The diagnosis of GHD was established on the basis of failure of GH to increase over 10 ng/ml after two stimulation tests. The GST was performed by intra-muscular injection of 1 mg glucagon. The criteria followed to define adrenal deficiency was cortisol less than 167 ng/l in response to GST. The mean peak blood glucose level was 8.64 ±1.71 mmol/l. Analysing the cohort using the cut-off of 167 ng/ml to define adrenal insufficiency under GST, there were 25.64% of children diagnosed: 20% among males and 35.7% among females. Subjects with GH and ACTH deficiency had a mean peak GH of 2.07 ±1.79 ng/ml - significantly lower than GH peak of children with IGHD alone (p < 0,001). The frequency of children with combined somatotroph and corticotroph deficiencies with a GH peak < 3 ng/ml was 21% (p < 0,001). The current study identified a prevalence of adrenal insufficiency of 25.64%, which could predict greater risk for children if untreated, especially because a substantial proportion of patients do not present clinical symptoms.

Macroprolactinemia and Empty Sella Syndrome.

Macroprolactinemia is a polymeric form of prolactin-release, causing mildly symptomatic clinical pictures. The former can be isolated or associated with other causes of hyperprolactinemia. The association with an empty sella syndrome is rare. We report a case of a female patient discovered with this association. It's about a female patient 47 years old, followed up since the age of 31 years for bilateral galactorrhea and a spaniomenorrhea. There has been no associated drug intake. Her exploration has showed a serum prolactin level of 635 mIU/L. Thyroid test results were normal T4 = 10,2ng/L and TSH = 1.76 mIU/L. A brain scan has showed an empty sella turcica. Despite the unchanged levels of prolactinemia, the evolution under dopaminergic 5 mg /D has been marked by the occurrence of a pregnancy with persistent moderate hyperprolactinemia in the postpartum. Chromatography has showed a predominance of the macroprolactin form with: Prolactin monomer at 4.8%, Big Prolactin at 5% and Big Big Prolactin at 83%, thus stopping bromocriptine. Our observation suggests that macroprolactinemia can be associated with conventional etiologies of moderate hyperprolactinemia as the empty sella syndrome. Its detection would prevent the use of dopaminergic therapy which seems not useful.