Purpose: The precise effects of non-steroidal anti-inflammatory drugs on the neuroendocrine hydro-electrolytic regulation are not precisely understood. The aim of this pilot study was to evaluate, in healthy subjects, the neuroendocrine response of the antidiuretic system to intravenous diclofenac infusion. Methods: For this single-blinded, cross-over study, we recruited 12 healthy subjects (50% women). Test sessions were divided into three observation times (pre-test; test; 48 h post-test), which were repeated equally on two different occasions, with the administration of diclofenac (75 mg in saline solution 0.9% 100 cc) on 1 day, or placebo (saline solution 0.9% 100 cc) on another day. The night before the test the subjects were asked to collect a salivary cortisol and cortisone sample, which was repeated on the night of the procedure session. Serial urine and blood samples were collected on the test day (for osmolality, electrolytes, ACTH, cortisol, copeptin, MR-proADM, MR-proANP; the last three represent more stable and analytically reliable molecules than their respective active peptides). Moreover, the subjects were evaluated with the bioimpedance vector analysis (BIVA) before and after the test. Forty-eight hours after the end of the procedure urine sodium, urine potassium, urine osmolality, serum sodium and copeptin were revaluated together with BIVA. Results: No significant changes in circulating hormone levels were observed; anyway, 48 h after diclofenac, BIVA showed a significant water retention (p < 0.00001), especially in extracellular fluid (ECF) (16.47 ± 1.65 vs 15.67 ± 1.84, p < 0.001). Salivary cortisol and cortisone tended to increase only the night after placebo administration (p = 0.054 cortisol; p = 0.021 cortisone). Conclusion: Diclofenac resulted in an increased ECF at 48 h, but this phenomenon seems to be associated with a greater renal sensibility to the action of vasopressin rather than with an increase in its secretion. Moreover, a partial inhibitory effect on cortisol secretion can be hypothesized.

Background: Long QT syndrome (LQTS) is characterized by delayed myocardial repolarization, predisposing to malignant arrhythmias such as torsades de pointes, ventricular fibrillation, and cardiac arrest. Recent reports suggest that acquired LQTS (aLQTS) may represent an early manifestation of hypopituitarism, potentially contributing to its increased cardiovascular mortality, although evidence remains limited to 16 published case reports. Objective: The objective was to investigate the relationship between hypopituitarism and corrected QT (QTc) interval. Methods: We retrospectively analyzed data from 185 patients (121 males) with hypothalamic–pituitary disorders who underwent a 12-lead electrocardiogram between April 2023 and September 2024. Clinical characteristics, hormone replacement therapy, and same-day laboratory parameters (electrolytes, fT3, fT4, IGF-I, testosterone) were recorded. QTc was calculated using Bazett’s formula. Multivariate logistic regression identified predictors of QTc prolongation. Results: Age (OR 1.07–1.09, p = 0.02) was a significant predictor in 5 of 8 models. The presence of expansive lesions other than pituitary adenomas, craniopharyngiomas, and Rathke’s cleft cysts was also associated with QTc prolongation (OR 8.35–17.73, p < 0.05 and p = 0.03). Potassium (OR 0.14–0.17, p = 0.09) and albumin-corrected calcium levels (OR 0.0003, p = 0.06) showed consistent, though borderline, associations. Conclusions: Age and the presence of expansive lesions other than pituitary adenomas, craniopharyngiomas, and Rathke’s cleft cysts are the main predictors of QTc duration in patients with hypothalamic–pituitary disease. Electrolyte imbalances—particularly low potassium and albumin-corrected calcium—may further contribute. The influence of specific pituitary deficiencies remains uncertain, likely due to adequate replacement therapy in most patients.

Background: The diagnosis of adult growth hormone (GH) deficiency (GHD) relies on demonstrating a reduced GH response to stimulation tests. Excess body weight, an increasingly prevalent condition, is associated with a blunted GH response to all types of stimulation tests. Therefore, establishing body mass index (BMI)-dependent cut-offs is essential for accurate interpretation. This study aimed to identify BMI-specific diagnostic thresholds for the insulin tolerance test (ITT), using residual pituitary function as the clinical gold standard. Methods: We retrospectively analyzed 105 patients with hypothalamic-pituitary disorders who underwent ITT. GHD was defined by the presence of at least three pituitary hormone deficiencies, while preserved somatotropic function was defined by the absence of other pituitary deficits and an insulin-like growth factor-I (IGF-I) standard deviation score ≥ 0. Receiver operating characteristic (ROC) curve analysis was used to determine optimal BMI-stratified cut-offs, defined as those maximizing sensitivity (SE) and specificity (SP). Results: The optimal GH cut-off was 2.8 μg/L for patients with normal weight (SE 84.6%, SP 97.4%) and those with overweight (SE 100%, SP 92.3%), and 2.1 μg/L for patients with obesity (SE 88.2%, SP 87.5%). The area under the ROC curve was 0.968, 0.957, and 0.897 for patients with normal weight, overweight, and obesity, respectively. Conclusions: This is the first study to define GH diagnostic thresholds for the ITT according to BMI, using a clinical definition of GHD as reference. More restrictive cut-offs in patients with obesity are needed to avoid GHD overdiagnosis and potential overtreatment. These findings should be considered hypothesis-generating and require prospective external validation before routine clinical implementation.

Introduction Stiff-person syndrome (SPS) is a rare neurological disorder that causes progressive muscle rigidity, gait disturbances and functional impairment; type 1 is autoimmune, with postitive anti-GAD antibodies (Ab) while type 2 is paraneoplastic, associated with anti-amphiphysin Ab. Case presentation A 41-year-old man with silent medical history presented with stiffness and functional impairment; after numerous rheumatological and neurological investigations he was diagnosed with SPS, with evidence of high titer anti-GAD Ab. After treatment with benzodiazepines was started, the patient began to experience episodes of confusion, which persisted even after reducing the dosage. During one of these episodes, he was admitted to the emergency department and a glucose level of 26 mg/dL was found. Differential diagnosis led to an insulin secreting neuroendocrine tumor of the pancreas, thus a paraneoplastic origin of SPS was hypothesized. However, anti- amphiphysin Ab were negative, anti-GAD were persistently elevated and symptoms only transiently improved after removal of the tumor. Conclusion This is the first case, to our knowledge, of association between type 1 SPS and insulinoma, with partial and transient improvement of neurological symptoms after resolution of the associated hypoglycemic syndrome.