The influence of insulin-induced hypoglycemia on copeptin concentrations

Plasma copeptin is a biomarker that reflects arginine vasopressin (AVP) secretion. In this study we measured copeptin during insulin tolerance test (ITT) in 65 patients referred to our department for evaluation of anterior pituitary function. Plasma for measurements of copeptin were collected at the start of the test and regurarly up to 120 minutes thereafter. Of 60 patients who developed significant hypoglycemia and were included in the analyses, 13 (22%) had corticotropic deficiency, 11 (18%) had thyreotropic deficiency, 33 (55%) had growth hormone deficiency and 4 (6%) had AVP deficieny (AVPD). Thirty-seven (62%) patients had at least one anterior pituitary deficiency. In patients without AVPD, median (range) copeptin increased from 4.5 pmol/L (1.3-33.0) to a maximum of 6.2 pmol/L (2.0-34.4; p<0.001). Baseline copeptin was similar in men and women, but maximal copeptin during ITT was higher in men. Copeptin concentrations were not affected by age, BMI, somatotropic, or corticotropic function. Copeptin concentrations were lower in patients with AVPD than patiets without AVPD, and in patients with thyrotropic deficiency, compared to patients with intact thyrotropic function, both at baseline and during ITT. In conclusion, copeptin increases significantly during insulin induced hypoglycemia but is of limited value in predicting anterior pituitary hormonal function.

Preoperative peripheral inflammatory markers are predictors of postoperative central diabetes insipidus in craniopharyngioma patients: a retrospective study

BACKGROUND

Postoperative central diabetes insipidus (CDI) is commonly observed in craniopharyngioma (CP) patients, and the inflammatory response plays an important role in CPs. We aimed to evaluate the predictive value of preoperative peripheral inflammatory markers and their combinations regarding CDI occurrence in CPs.

METHODS

The clinical data including preoperative peripheral inflammatory markers of 208 CP patients who underwent surgical treatment were retrospectively collected and analyzed. The preoperative peripheral white blood cells (WBC), neutrophils, lymphocytes, monocytes, platelet (PLT), neutrophil-to-lymphocyte ratio (NLR), derived-NLR (dNLR), monocyte-to-lymphocyte ratio (MLR) and PLT-to-lymphocyte ratio (PLR) were assessed in total 208 CP patients and different age and surgical approach CP patient subgroups. Their predictive values were evaluated by the receiver operator characteristic curve analysis.

RESULTS

Preoperative peripheral WBC, neutrophils, NLR, dNLR, MLR, and PLR were positively correlated and lymphocyte was negatively associated with postoperative CDI occurrence in CP patients, especially when WBC ≥ 6.66 × 109/L or lymphocyte ≤ 1.86 × 109/L. Meanwhile, multiple logistic regression analysis showed that WBC > 6.39 × 109/L in the > 18 yrs age patients, WBC > 6.88 × 109/L or lymphocytes ≤ 1.85 × 109/L in the transcranial approach patients were closely associated with the elevated incidence of postoperative CDI. Furthermore, the area under the curve obtained from the receiver operator characteristic curve analysis showed that the best predictors of inflammatory markers were the NLR in total CP patients, the MLR in the ≤ 18 yrs age group and the transsphenoidal group, the NLR in the > 18 yrs age group and the dNLR in the transcranial group. Notably, the combination index NLR + dNLR demonstrated the most valuable predictor in all groups.

CONCLUSIONS

Preoperative peripheral inflammatory markers, especially WBC, lymphocytes and NLR + dNLR, are promising predictors of postoperative CDI in CPs.

The diagnostic role of arginine-stimulated copeptin in the differential diagnosis of polyuria-polydipsia syndrome (PPS) in pediatric age

PURPOSE

In recent years, copeptin stimulation through arginine administration has been evaluated as a new potential tool in the differential diagnosis of polyuria-polydipsia syndrome (PPS) in adults; to date very few data, all retrospective, exist in pediatric age. The aim of this prospective study is to evaluate the diagnostic performance of the arginine-stimulation test for copeptin in a cohort of pediatric patients affected by PPS.

METHODS

All children (<18 years) referred to the Department of Pediatric Endocrinology of the Regina Margherita Children Hospital for polyuria-polydipsia in the period January 2021-June 2023 were enrolled. The Arginine-stimulation test for copeptin was performed in all patients presenting PPS after water deprivation test (WDT). Patients with polyuria-polydipsia were then classified as having primary polyuria (PP), complete and partial central diabetes insipidus (CDI), according to the standardized interpretation. Arginine-stimulation test for copeptin was also performed in a control cohort.

RESULTS

A significant difference in arginine-stimulated copeptin values was observed at baseline (p = 0.005), at 60 min (p = 0.01), and at 90 min (p = 0.005) in 7 subjects presenting PP, 6 patients affected by CDI and 50 subjects of the control cohort. Plasma osmolality values remained stable at all measurements. The arginine-stimulated copeptin test demonstrated sensitivity and specificity of 100%, whereas the sensitivity of the WDT test was 83.3% and the specificity was 85.7%.

CONCLUSION

Given the reliability and the minor adverse effects and costs, the copeptin level after arginine administration could replace the WDT in the diagnostic workup of these in pediatric age.

Diagnosis and management of congenital hypopituitarism in children

Hypopituitarism (or pituitary deficiency) is a rare disease with an estimated prevalence of between 1/16,000 and 1/26,000 individuals, defined by insufficient production of one or several anterior pituitary hormones (growth hormone [GH], thyroid-stimulating hormone [TSH], adrenocorticotropic hormone [ACTH], luteinizing hormone [LH], follicle-stimulating hormone [FSH], prolactin), in association or not with diabetes insipidus (antidiuretic hormone [ADH] deficiency). While in adults hypopituitarism is mostly an acquired disease (tumors, irradiation), in children it is most often a congenital condition, due to abnormal pituitary development. Clinical symptoms vary considerably from isolated to combined deficiencies and between syndromic and non-syndromic forms. Early signs are non-specific but should not be overlooked. Diagnosis is based on a combination of clinical, laboratory (testing of all hormonal axes), imaging (brain magnetic resonance imaging [MRI] with thin slices centered on the hypothalamic-pituitary region), and genetic (next-generation sequencing of genes involved in pituitary development, array-based comparative genomic hybridization, and/or genomic analysis) findings. Early brain MRI is crucial in neonates or in cases of severe hormone deficiency for differential diagnosis and to inform syndrome workup. This article presents recommendations for hormone replacement therapy for each of the respective deficient axes. Lifelong follow-up with an endocrinologist is required, including in adulthood, with multidisciplinary management for patients with syndromic forms or comorbidities. Treatment objectives include alleviating symptoms, preventing comorbidities and acute complications, and optimal social and educational integration.

Diabetes insipidus: Vasopressin deficiency…

Diabetes insipidus is a disorder characterized by hypo-osmotic polyuria secondary to abnormal synthesis, regulation, or renal action of antidiuretic hormone. Recently, an expert group, with the support of patient associations, proposed that diabetes insipidus be renamed to avoid confusion with diabetes mellitus. The most common form of diabetes insipidus is secondary to a dysfunction of the neurohypophysis (central diabetes insipidus) and would be therefore named â€̃vasopressin deficiency’. The rarer form, which is linked to renal vasopressin resistance (nephrogenic diabetes insipidus), would then be named â€̃vasopressin resistance’. The etiology of diabetes insipidus is sometimes clear, in the case of a neurohypophyseal cause (tumoral or infiltrative damage) or a renal origin, but in some cases diabetes insipidus can be difficult to distinguish from primary polydipsia, which is characterized by consumption of excessive quantities of water without any abnormality in regulation or action of antidiuretic hormone. Apart from patients’ medical history, physical examination, and imaging of the hypothalamic-pituitary region, functional tests such as water deprivation or stimulation of copeptin by hyperosmolarity (induced by infusion of hypertonic saline) can be proposed in order to distinguish between these different etiologies. The treatment of diabetes insipidus depends on the underlying etiology, and in the case of a central etiology, is based on the administration of desmopressin which improves patient symptoms but does not always result in an optimal quality of life. The cause of this altered quality of life may be oxytocin deficiency, oxytocin being also secreted from the neurohypophysis, though this has not been fully established. The possibility of a new test using stimulation of oxytocin to identify alterations in oxytocin synthesis is of interest and would allow confirmation of a deficiency in those patients presenting with diabetes insipidus linked to neurohypophyseal dysfunction.

Coronavirus as a trigger of lymphocytic hypophysitis in an adolescent girl: An exceptional case report

INTRODUCTION AND IMPORTANCE

Lymphocytic hypophysitis is an underestimated disease and the pathogenesis is still poorly elucidated. Post-coronavirus lymphocytic hypophysitis is a new emerging entity.

CASE PRESENTATION

A 16-year-old previously healthy girl presented with pituitary tumor syndrome. She suffered from frontal headaches, polyuria-polydipsic syndrome, and impaired visual acuity. She was diagnosed with COVID-19 infection three weeks before. Contrast-enhanced magnetic resonance imaging (MRI) revealed pituitary enlargement with intense homogenous enhancement postgadolinium on T1 weighted images. The diagnosis of lymphocytic hypophysitis was made after ruling out other differential diagnosis. She was started on methylprednisolone. Improvement of clinical symptoms was seen on day 5 with a significant decrease in headache intensity.

CLINICAL DISCUSSION

The article summarizes data from cases reported in the literature and our case to highlight coronavirus as a new trigger of lymphocytic hypophysitis. Despite the rarity of this complication, patients with a suspicion of hypophysitis after a recent COVID-19 infection should be carefully evaluated.

CONCLUSION

COVID-19 infection can cause lymphocytic hypophysitis. However, it seems premature to conclude on the causal link between COVID-19 and endocrine diseases. Further studies on larger samples are needed to comprehend the pathogenesis of autoimmune endocrinopathies after COVID-19 infection.

[Panhypopituitarism, Diabetes Insipidus and Bone Pain - Is There a Systemic Disease Behind it?]

INTRODUCTION

A 27-year-old man presented due to unilateral leg pain. He had a history of diabetes insipidus and panhypopituitarism. Laboratory analysis revealed hormonal undersupply. MRI showed a large contrast medium-absorbing mass in the pituitary gland extending into the hypothalamus. FDG-PET/CT examination revealed a hypermetabolic soft tissue lesion around the left femoral shaft. After biopsy of the lesion, a diagnosis of multisystemic Langerhans cell histiocytosis was made.

An Unusual Cause of Fever, Bilateral Ear Discharge, Lung Nodules, and Polyuria in a Young Male Post Coronavirus Disease 19

We present a case of a young male with pyrexia of unknown origin, bilateral ear discharge, lung nodules and polyuria within four weeks of recovering from a moderate Coronavirus disease-19 infection. To the best of our knowledge, this is the first case of post- Coronavirus disease-19 Granulomatosis with Polyangiitis with overlapping large vessel vasculitis with a favorable outcome.

Mechanisms of hyponatremia and diabetes insipidus after acute spinal cord injury: a critical review

The incidence of hyponatremia after spinal cord injury was reported to be between 25 and 80%. Hyponatremia can lead to a variety of clinical symptoms, from mild to severe and even life-threatening. Hyponatremia is often associated with diabetes insipidus, which refers to insufficient arginine vasopressin (AVP) secretion or defective renal response to AVP, with clinical manifestations of syndromes such as hypoosmolality, polydipsia, and polydipsia. Recent mechanistic studies on hyponatremia and diabetes insipidus after acute spinal cord injury have been performed in isolation, without integrating the above two symptoms into different pathological manifestations that occur in the same injury state and without considering the acute spinal cord injury patient's condition as a whole. The therapeutic principles of CSWS and SIADH are in opposition to one another. It is not easy to identify the mechanism of hyponatremia in clinical practice, which makes selecting the treatment difficult. According to the existing theories, treatments for hyponatremia and diabetes insipidus together are contraindicated, whether the mechanism of hyponatremia is thought to be CSWS or SIADH. In this paper, we review the mechanism of these two pathological manifestations and suggest that our current understanding of the mechanisms of hyponatremia and diabetes insipidus after high acute cervical SCI is insufficient, and it is likely that there are other undetected pathogenetic mechanisms.

A case of pituitary metastasis discovered when diabetes insipidus developed in a patient 20 years after breast cancer treatment

The patient was a 52-year-old woman. She had a history of left breast cancer at age 32 years, with no recurrences. She was examined for a feeling of oral dryness and nocturia, and central diabetes insipidus was diagnosed. A mass was seen in the posterior pituitary on magnetic resonance imaging, and multiple pulmonary nodules were seen on computed tomography. Breast cancer metastases were diagnosed in both tissues. Since this patient had no cancer other than the breast cancer treated 20 years earlier, it was difficult to reach a diagnosis of pituitary metastasis with pituitary gland imaging alone. In estrogen receptor-positive breast cancer, there may be recurrences after a long period of time. It may be that recommending a full body examination could be useful in the differential diagnosis of metastasis even in patients who have had a long disease-free period, if they had undergone surgery for breast cancer.

Executive summary of the expert consensus document from the Spanish Society of Neurosurgery and the Spanish Society of Endocrinology and Nutrition: Clinical recommendations on the perioperative management of pituitary tumors

Pituitary tumors (PT) account for 15% of intracranial tumors affect 10.7%-14.4% of the population although the incidence of clinically relevant PT is 5.1 cases/100,000 inhabitants. Surgical treatment is indicated in PTs with hormone hypersecretion (except for prolactin-producing PTs) and those with local compressive or global neurological symptoms. Multidisciplinary care, is essential for patients with PTs, preferably delivered in a center of excellence and based on a well-defined care protocol. In order to facilitate and standardize the clinical procedures for this type of tumor, this document gathers the positioning of the Neuroendocrinology Knowledge Area of the Spanish Society of Endocrinology and Nutrition (SEEN) and the Spanish Society of Neurosurgery (SENEC) on the management of patients with PTs and their preoperative, surgical and postoperative follow-up.

Executive summary of the expert consensus document from the Spanish Society of Neurosurgery and the Spanish Society of Endocrinology and Nutrition: clinical recommendations on the perioperative management of pituitary tumors

Pituitary tumors (PT) account for 15% of intracranial tumors affect 10.7-14.4% of the population although the incidence of clinically relevant PT is 5.1 cases/100,000 inhabitants. Surgical treatment is indicated in PTs with hormone hypersecretion (except for prolactin-producing PTs) and those with local compressive or global neurological symptoms. Multidisciplinary care, is essential for patients with PTs, preferably delivered in a center of excellence and based on a well-defined care protocol. In order to facilitate and standardize the clinical procedures for this type of tumor, this document gathers the positioning of the Neuroendocrinology Knowledge Area of the Spanish Society of Endocrinology and Nutrition (SEEN) and the Spanish Society of Neurosurgery (SENEC) on the management of patients with PTs and their preoperative, surgical and postoperative follow-up.

A case of ifosfamide-induced acute kidney injury, Fanconi syndrome, and nephrogenic diabetes insipidus

Ifosfamide, a cytotoxic antineoplastic drug, can induce rare complications of Fanconi syndrome and nephrogenic diabetes insipidus (DI). Ifosfamide-induced Fanconi syndrome tends to occur in patients with certain risk factors including young age, high cumulative ifosfamide dose, and coadministration of cisplatin. Nephrogenic DI causes polyuria from impaired urinary concentrating ability due to resistance to arginine vasopressin (AVP) at the collecting duct. These complications are serious and potentially fatal. Here, we describe a case of a middle-aged man without risk factors who was admitted for the management of acute kidney injury and electrolyte derangements after his fourth cycle of chemotherapy including ifosfamide for synovial sarcoma. He was found to have hypokalemia, hypophosphatemia, renal glycosuria, and aminoaciduria, likely from Fanconi syndrome, which were managed by electrolyte replacement therapy. In addition, polyuria and hypernatremia were considered due to nephrogenic DI, which partially responded to desmopressin treatment. This case highlights the importance of the routine electrolytes monitoring after ifosfamide treatment.

Neurogenic diabetes insipidus in a critical patient with COVID-19 pneumonia in treatment with extracorporeal membrane oxygenation: a case report

The following case report analyses a patient with extracorporeal membrane oxygenation (ECMO), who suffered from a severe Acute Respiratory Distress Syndrome (ARDS) due to COVID-19 pneumonia. ARDS is defined as a diffuse and inflammatory injury of the lungs; classifying this as severe when the ratio of arterial oxygen tension to a fraction of inspired oxygen (PaO2/FiO2) is equal to or lower than 100 mmHg. To decide if the patient was suitable for the use of ECMO therapy, the ELSO criteria were used; and in this case, the patient matched with the criteria of hypoxemic respiratory failure (with a PaO2/FiO2 < 80 mmHg) after optimal medical management, including, in the absence of contraindications, a trial of prone positioning. During hospitalization, the patient presented a Central Diabetes Insipidus (CDI), probably explained by the damage hypoxia generated on the central nervous system. There are few reports of this complication produced by COVID-19. The case is about a 39-year-old woman, who started with ECMO 6 days after the beginning of Invasive Mechanical Ventilation (IMV), because of a severe ARDS. On the fifth day of ECMO, the patient started with a polyuria of 7 L in 24 h. A series of paraclinical studies were made, but no evidence of central nervous system lesions was found. After treatment with desmopressin was initiated and the ARDS was solved, polyuria stopped; with this, CDI was diagnosed. There are many complications secondary to the evolution of COVID-19 infection, and some of them are not yet well explained.

[Diagnosis of germ cell tumors]

CLINICAL/METHODICAL ISSUE

Intracranial germ cell tumors are rare central nervous system (CNS) diseases in Europa and America. Because of their low frequency and lack of typical imaging features, they represent a difficult diagnosis for any radiologist.

STANDARD RADIOLOGICAL METHODS

Magnetic resonance imaging (MRI) is a sensible diagnostic tool for the initial diagnosis of germ cell tumors, although it has limitations.

METHODOLOGICAL INNOVATIONS

So far, no typical morphologic pattern as a red flag for germ cell tumors has been identified. Correlation with clinical symptoms and laboratory results is mandatory.

PERFORMANCE

In certain cases, combining the location of the tumor and clinical findings may allow a diagnosis to be made even without histologic confirmation.

PRACTICAL RECOMMENDATIONS

In addition to imaging, the radiologist needs the age, background, and laboratory findings to be able to make an accurate diagnosis.

Craniofacial involvement in Langerhans cell histiocytosis: A review of 44 cases at a single medical center

BACKGROUND

Craniofacial bones are the most commonly involved site of Langerhans cell histiocytosis (LCH). The main purpose of this study was to clarify the relation between subsites of craniofacial bone and clinical presentation, treatment modalities, outcomes, and permanent consequences (PCs) in patients with LCH.

METHODS

Forty-four patients diagnosed with LCH involving the craniofacial region presenting at a single medical center during 2001-2019 were collected and divided into four groups: single system with unifocal bone lesion (SS-LCH, UFB); single system with multifocal bone lesions (SS-LCH, MFB); multisystem without risk organ involvement (MS-LCH, RO-); and multisystem with risk organ involvement (MS-LCH, RO+). Data including demographics, clinical presentation, treatments, outcomes, and the development of PC were retrospectively reviewed.

RESULTS

Temporal bone (66.7% versus 7.7%, p = 0.001), occipital bone (44.4% versus 7.7%, p = 0.022), and sphenoid bone (33.3% versus 3.8%, p = 0.041) involvement were more common in SS-LCH, MFB than they were in SS-LCH, UFB. No difference of reactivation rate was noted among the four groups. The most common PC is diabetes insipidus (DI), reported in 9 of the 16 (56.25%) patients with PC. The single system group was reported with the lowest incidence of DI (7.7%, p = 0.035). The reactivation rate was also higher in patients with PC (33.3% versus 4.0%, p = 0.021) or DI (62.5% versus 3.1%, p < 0.001).

CONCLUSION

An increased risk of multifocal or multisystem lesions was associated with temporal bone, occipital bone, sphenoid bone, maxillary bone, eye, ear, and oral involvement, which may indicate poor outcomes. Longer follow-up may be indicated if there is the presence of PC or DI due to the high risk of reactivation. Therefore, multidisciplinary evaluation and treatment according to risk stratification are vital for patients diagnosed with LCH involving the craniofacial region.

Age-Associated Abnormalities of Water Homeostasis

Deficits in renal function, thirst, and responses to osmotic and volume stimulation have been repeatedly demonstrated in older populations. The lessons learned over the past six decades serve to emphasize the fragile nature of water balance characteristic of aging. Older individuals are at increased risk for disturbances of water homeostasis due to both intrinsic disease and iatrogenic causes. These disturbances have real-life clinical implications in terms of neurocognitive effects, falls, hospital readmission and need for long-term care, incidence of bone fracture, osteoporosis, and mortality.

Diabetes insipidus related to sedation in the intensive care unit: A review of the literature

PURPOSE

To identify cases of diabetes insipidus (DI) related to sedation in the ICU to determine which medications pose the greatest risk and understand patterns of presentation.

MATERIALS AND METHODS

We searched PubMed, Embase, Scopus, Google Scholar, and Web of Science. Search terms included "polyuria," "diabetes insipidus," "hypnotics and sedatives," "sedation," as well as individual medications. Case reports or series involving DI or polyuria related to sedation in the ICU were identified.

RESULTS

We identified 21 cases of diabetes insipidus or polyuria in the ICU attributed to a sedative. Dexmedetomidine was implicated in 42.9% of cases, followed by sevoflurane (33.3%) and ketamine (23.8%). Sevoflurane was implicated in all 7 cases in which it was used (100%; 95% CI 59.0%, 100.0%), dexmedetomidine in 9 of 11 cases (81.8%; 95% CI 48.2, 97.7), and ketamine in 5 of 9 cases (55.6%; 95% CI 21.2%, 86.3%).

CONCLUSIONS

Awareness of the potential for sedatives to cause DI may lead to greater identification with swifter medication discontinuation and subsequent resolution of DI.

Mineralocorticoids induce polyuria by reducing apical aquaporin-2 expression of the kidney in partial vasopressin deficiency

The symptoms of diabetes insipidus may be masked by the concurrence of adrenal insufficiency and emerge after the administration of hydrocortisone, occasionally at high doses. To elucidate the mechanism underlying polyuria induced by the administration of high-dose corticosteroids in the deficiency of arginine vasopressin (AVP), we first examined the secretion of AVP in three patients in whom polyuria was observed only after the administration of high-dose corticosteroids. Next, we examined the effects of dexamethasone or aldosterone on water balance in wild-type and familial neurohypophyseal diabetes insipidus (FNDI) model mice. A hypertonic saline test showed that AVP secretion was partially impaired in all patients. In one patient, there were no apparent changes in AVP secretion before and after the administration of high-dose corticosteroids. In FNDI mice, unlike dexamethasone, the administration of aldosterone increased urine volumes and decreased urine osmolality. Immunohistochemical analyses showed that, after the administration of aldosterone in FNDI mice, aquaporin-2 expression was decreased in the apical membrane and increased in the basolateral membrane in the collecting duct. These changes were not observed in wild-type mice. The present data suggest that treatment with mineralocorticoids induces polyuria by reducing aquaporin-2 expression in the apical membrane of the kidney in partial AVP deficiency.

Postpartum gestational diabetes insipidus related to preeclampsia: A case report

Gestational diabetes insipidus (GDI) is a rare complication of pregnancy thought to be due to increased vasopressinase produced by the placenta. It typically occurs at the end of the second or in the third trimester. This report describes a case of GDI diagnosed postpartum in the setting of newly diagnosed superimposed preeclampsia. A 39-year-old Hispanic woman (gravida 2 para 2) presented ten days postpartum with a persistent headache and elevated blood pressures in the setting of a history of chronic hypertension, meeting criteria for superimposed preeclampsia. Repeat lab work was notable for mild elevation of liver function enzymes. Despite normalization of blood pressures, her headache persisted and further workup revealed polyuria, suspected to be vasopressinase-induced diabetes insipidus. The patient was started on oral desmopressin with improvement of polyuria and symptoms.

Salt and Water: A Review of Hypernatremia

Serum sodium disorders are generally a marker of water balance in the body. Thus, hypernatremia is most often caused by an overall deficit of total body water. Other unique circumstances may lead to excess salt, without an impact on the body's total water volume. Hypernatremia is commonly acquired in both the hospital and community. As hypernatremia is associated with increased morbidity and mortality, treatment should be initiated promptly. In this review, we will discuss the pathophysiology and management of the main types of hypernatremia, which can be categorized as either a loss of water or gain of sodium that can be mediated by renal or extrarenal mechanisms.

Post-pituitary surgery copeptin analysis as a 'rule-out' test for post-operative diabetes insipidus

BACKGROUND

Diabetes insipidus (DI) is a recognised complication of pituitary surgery, with diagnosis requiring clinical observation aided by plasma and urine electrolytes and osmolalities. Copeptin is a stable surrogate marker of AVP release and has potential to facilitate prompt diagnosis of post-operative DI. This assay has been shown to accurately predict which patients are likely to develop DI following pituitary surgery.

OBJECTIVE

To determine whether copeptin analysis can be used to predict which patients are at risk of developing DI following trans-sphenoidal surgery (TSS).

METHODS

Seventy-eight patients undergoing TSS had samples taken for copeptin pre-operatively and at day 1 post-TSS. The majority of patients also had samples from day 2, day 8, and week 6 post-TSS. Results from patients who developed post-operative DI (based on clinical assessment, urine and plasma biochemistry and the need for treatment with DDAVP) were compared to those who did not. Patients with any evidence of pre-operative DI were excluded.

RESULTS

Of 78 patients assessed, 11 were clinically determined to have developed DI. Differences were observed between patients with DI and those without in post-operative samples. Of note, there was a significant difference in plasma copeptin at day 1 post-operation (p = 0.010 on Kruskal-Wallis test), with copeptin levels greater than 3.4 pmol/l helping to rule out DI (91% sensitivity, 55% specificity at this cut off).

CONCLUSION

In the post-TSS setting, copeptin is a useful rule-out test in patients with values above a defined threshold, which may facilitate earlier decision making and shorter hospital stays.

Aquaporins in Diabetes Insipidus

Disruption of water and electrolyte balance is frequently encountered in clinical medicine. Regulating water metabolism is critically important. Diabetes insipidus (DI) presented with excessive water loss from the kidney is a major disorder of water metabolism. To understanding the molecular and cellular mechanisms and pathophysiology of DI and rationales of clinical management of DI is important for both research and clinical practice. This chapter will first review various forms of DI focusing on central diabetes insipidus (CDI) and nephrogenic diabetes insipidus (NDI). This is followed by a discussion of regulatory mechanisms underlying CDI and NDI, with a focus on the regulatory axis of vasopressin, vasopressin receptor 2 (V2R) and the water channel molecule, aquaporin 2 (AQP2). The clinical manifestation, diagnosis, and management of various forms of DI will also be discussed with highlights of some of the latest therapeutic strategies that are developed from in vitro experiments and animal studies.

PINEAL GERMINOMA PRESENTED WITH PARALYSIS OF UPWARD GAZE AND DIABETES INSIPIDUS

Intracranial germ cell tumors (GCTs) include two categories: germinoma and non germinoma. The pineal gland and suprasellar are the most common site of involvement. The patient is a 14-year-old boy who presented with paralysis of upward gaze, polyuria, polydipsia and diplopia. Examination of vertical eye movements was impaired. Puberty then progressed to stage 3 of Marshall - Tanner and had stopped. In laboratory studies, the patient had anterior hypopituitarism and diabetes insipidus (DI). In pituitary and hypothalamic MRIs, a mass-like enlargement of the pituitary stalk and pineal region was seen, but due to the small size of the lesions, stereotactic biopsy was not possible. During this time, the patient developed recurrent attacks of hydrocephalus. Serum and CSF β-subunit of Human chorionic gonadotropin levels were negative. Treatment was not started because different lesions could cause disease in this area. After one year, a biopsy was performed and the germ cell tumor was diagnosed. Chemotherapy was started and after treatment the vision disorder and diplopia disappeared, but DI and pituitary dysfunction remained. Treatment of intracranial germinoma is multidisciplinary. GCTs are very sensitive to radiation therapy. They are treated with combination of chemotherapy, radiotherapy, surgery, endocrine therapy and have a good prognosis.

Combined Arginine and Insulin Stimulation Elicits a Robust and Consistent Copeptin Response in Short Children

INTRODUCTION

Copeptin, co-secreted with arginine vasopressin, is regulated by osmotic and volume stimuli but also responds to intravenous arginine and insulin-induced hypoglycemia. The serum copeptin response to the latter agents has been studied in adults but only to a limited extent in children. The objective of this study was to describe the copeptin response to combined arginine and insulin in children with normal posterior pituitary function.

METHODS

We conducted a prospective, single-arm assessment of serum copeptin concentrations in children (age 7-16 years, n = 38) undergoing growth hormone stimulation testing with an arginine-insulin tolerance test (AITT) for short stature or growth deceleration in a tertiary referral center. After overnight fasting, arginine (500 mg/kg) was administered between 0 and 30 min intravenously (IV) followed by insulin (0.1 units/kg IV) at 60 min. Copeptin serum concentrations were measured at baseline (0 min), at the post-arginine peak (60 min), and at the post-insulin peak (90 min; 30 min post-insulin), respectively. The main outcome was the peak copeptin concentration.

RESULTS

Mean ± SD copeptin concentrations increased from 9.9 ± 5.0 pmol/L at 0 min to 13.2 ± 5.8 pmol/L at 60 min (p < 0.0001 vs. 0 min) and 27.7 ± 14.2 pmol/L at 90 min (p < 0.0001 vs. 0 and 60 min). There was no significant correlation between copeptin concentrations and age, BMI, pubertal status, cortisol, growth hormone, or glucose concentrations.

DISCUSSION/CONCLUSION

Arginine and insulin appear to have an additive and consistent effect resulting in significant stimulation of copeptin secretion in children. The AITT may be a useful tool to evaluate for normal posterior pituitary function in this age-group, with potential implications for the evaluation of polyuria-polydipsia syndrome.

Idiopathic central diabetes insipidus in a large cohort of patients: the hypopituitarism ENEA rare observational (HEROS) study

Central Diabetes Insipidus (CDI) is mainly associated with structural pathologies of the hypothalamic-pituitary area. Etiologies underlying CDI are identified in most patients, however idiopathic CDI is reported in 13-17% of cases after excluding other etiologies. The Hypopituitarism ENEA Rare Observational Study (HEROS study) retrospectively collected data of patients with idiopathic CDI from 14 pituitary centers in 9 countries. The cohort included 92 patients (59 females 64%), mean age at diagnosis was 35.4 ± 20.7 years, and a mean follow up of 19.1 ± 13.5 years following CDI diagnosis. In 6 women, diagnosis was related to pregnancy. Of 83 patients with available data on pituitary imaging, 40(48%) had normal sellar imaging, and 43(52%) had pathology of the posterior pituitary or the stalk, including loss of the bright spot, posterior pituitary atrophy or stalk enlargement. Anterior pituitary hormone deficiencies at presentation included hypogonadism in 6 (6.5%) patients (5 females), and hypocortisolism in one; during follow-up new anterior pituitary deficiencies developed in 6 patients. Replacement treatment with desmopressin was given to all patients except one, usually with an oral preparation. During follow up, no underlying disease causing CDI was identified in any patient. Patients with idiopathic CDI following investigation at baseline are stable with no specific etiology depicted during long-term follow-up.

Changing the name of diabetes insipidus: a position statement of The Working Group for Renaming Diabetes Insipidus

"What's in a name? That which we call a rose/By any other name would smell as sweet." (Juliet, from Romeo and Juliet by William Shakespeare). Shakespeare's implication is that a name is nothing but a word and it therefore represents a convention with no intrinsic meaning. Whilst this may be relevant to romantic literature, disease names do have real meanings, and consequences, in medicine. Hence, there must be a very good rational for changing the name of a disease that has a centuries-old historical context. A working group of representatives from national and international endocrinology and pediatric endocrine societies now proposes changing the name of "diabetes insipidus" to "Arginine Vasopressin Deficiency (AVP-D)" for central etiologies, and "Arginine Vasopressin Resistance (AVP-R)" for nephrogenic etiologies. This editorial provides both the historical context and the rational for this proposed name change.

Impact of surgical factors on delayed hyponatremia in patients with nonfunctioning pituitary adenoma after endonasal endoscopic transsphenoidal procedure

PURPOSE

Delayed hyponatremia can occur after pituitary surgery, resulting in prolonged hospitalization. However, the influence of surgical factors after such a procedure has not been well established. The impact of surgery and related factors on delayed hyponatremia was investigated.

METHODS

This was a retrospective analysis of 137 consecutive patients who underwent transsphenoidal surgery for a nonfunctioning pituitary adenoma between 2008 and 2019. Preoperative (demographics, comorbidities), intraoperative (resection extent, operation time, blood loss volume, cerebrospinal fluid leak, tumor consistency), and postoperative [hematoma, meningitis, diabetes insipidus (DI), hormonal assessment] data were collected, with statistical analysis of each factor performed.

RESULTS

Among the 137 patients, delayed hyponatremia occurred in 31 (22.6%). Multivariate analysis revealed that those with hypertension had a significantly higher likelihood of avoiding delayed hyponatremia (p = 0.004). Although no correlations of direct surgical factors with delayed hyponatremia were found, multivariate analysis of indirect surgical factors showed that presence of a firm tumor, transient DI, and meningitis were significantly associated with delayed hyponatremia (p = 0.014, 0.001, and 0.047, respectively). There was also a significant association of severe hyponatremia with appearance of symptoms (p = 0.002).

CONCLUSION

There was a tendency for hypertension to be associated with delayed hyponatremia avoidance, with indirect surgical factors including tumor consistency, transient DI, and meningitis found to have an influence on delayed hyponatremia. It was concluded that attention should be given to non-hypertensive patients with a firm tumor, transient DI, or meningitis after pituitary surgery, as delayed hyponatremia may occur.

Central diabetes insipidus and burn trauma

Diabetes insipidus (DI) is characterized by polyuria and polydipsia. In most cases, the condition results from either an inadequate release or resistance to the activity of antidiuretic hormone in the renal collecting tubules. The underlying pathophysiology may be related to destruction the destruction or degeneration of neurons from inflammatory, autoimmune diseases, vascular diseases, Langerhans cell histiocytosis, sarcoidosis, or trauma. However, a large majority of diabetes insipidus cases (50%) are considered idiopathic. An exceedingly rare cause of idiopathic central DI occurs in burn injuries, which has only been reported in eight cases. We present an extremely rare case of idiopathic DI in a 15-year-old male with 76% total body surface area (TBSA) burns with the development of idiopathic central DI. An extensive literature review was accomplished to compare this case with the small number of previously reported case reports of idiopathic DI in burn patients.

Lay Summary

Diabetes insipidus (DI) is a rare complication of burn injuries that results from the destruction of neurons involved in the secretion of antidiuretic hormone from the pituitary gland. Only eight cases of DI have been reported in the literature in association to burn injuries. The patient in this case report received immediate fluid resuscitation, burn treatment, and intensive observation after the initial burn injury. The rapid response was likely the main reason for the absence of neurological damage as reported in the CT image. Therefore, the treatment of burn injuries remains an important step for reducing neurological damage and hormonal dysregulation leading to diabetes insipidus.

Erdheim-Chester disease: Typical radiologic findings of a multisystemic disease

Erdheim-Chester disease is a rare and multisystemic entity. It results from the infiltration of tissues by foamy histiocytes. The etiology is unknown, but there are mutations in the MAPK pathway in over 80% of patients, more frequently BRAF mutation. The most commonly affected organs and systems are the skeleton, central nervous system, cardiovascular system, kidney, lungs, and skin. The most common clinical manifestations are bone pain, usually in the lower limbs, and diabetes insipidus. The diagnosis is challenging. It requires a combination of clinical, radiological, histopathological, and molecular findings. We present the case of a patient with typical clinical and radiological manifestations: bone pain and diabetes insipidus at presentation, bilateral long bone cortical sclerosis, hairy kidney appearance, coated aorta, right atrium pseudotumor, and periorbital masses.

Endocrine manifestations of paediatric intracranial germ cell tumours: from diagnosis to long-term follow-up

PURPOSE

We examined endocrine manifestations in a cohort of paediatric patients with IC-GCTs at diagnosis and during follow-up, integrating clinical, radiological, histopathological and laboratory data.

METHODS

Diabetes insipidus (DI), growth hormone deficiency (GHD), hypothyroidism, adrenal insufficiency, precocious puberty (PP)/hypogonadism were diagnosed clinically and biochemically. The prevalence of endocrine manifestations was compared to survival rates.

RESULTS

Our population included 55 children (37 males, 18 females) diagnosed with IC-GCT with a median follow-up of 78.9 months from diagnosis (range 0.5-249.9). At tumour diagnosis, 50.9% patients displayed endocrinopathies: among them, 85.7% were affected by DI, 57.1% central adrenal insufficiency, 50% central hypothyroidism, 28.5% GHD, 10.7% hypogonadotrophic hypogonadism, 10.7% PP. These patients presented predominantly with suprasellar germinoma. If not diagnosed previously, endocrine disorders arose 15.15 months (1.3-404.2) after end of treatment (EOT) in 16.4% patients. At least one endocrinopathy was identified in 67.3% of subjects at last follow-up visit, especially GHD and adrenal insufficiency. DI, hypothyroidism, and adrenal insufficiency occurred earlier than other abnormalities and frequently preceded tumour diagnosis. Subjects with and without endocrine manifestations who survived beyond 12 months after EOT did not show significant difference in overall survival and progression-free survival (p = 0.28 and p = 0.88, respectively).

CONCLUSION

Endocrinopathies were common presenting symptoms in our population. If present at diagnosis, they often persisted hence after. The spectrum of endocrinopathies expanded during follow-up up to 33.7 years after EOT. Although they did not seem to affect survival rate in our cohort, close lifelong surveillance is mandatory to provide the best care for these patients.

Renal water transport in health and disease

Saving body water by optimal reabsorption of water filtered by the kidney leading to excretion of urine with concentrations of solutes largely above that of plasma allowed vertebrate species to leave the aquatic environment to live on solid ground. Filtered water is reabsorbed for 70% and 20% by proximal tubules and thin descending limbs of Henle, respectively. These two nephron segments express the water channel aquaporin-1 located along both apical and basolateral membranes. In the proximal tubule, the paracellular pathway accounts for at least 30% of water reabsorption, and the tight-junction core protein claudin-2 plays a key role in this permeability. The ascending limb of Henle and the distal convoluted tubule are impermeant to water and are responsible for urine dilution. The water balance is adjusted along the collecting system, i.e. connecting tubule and the collecting duct, under the control of arginine-vasopressin (AVP). AVP is synthesized by the hypothalamus and released in response to an increase in extracellular osmolality or stimulation of baroreceptors by decreased blood pressure. In response to AVP, aquaporin-2 water channels stored in subapical intracellular vesicles are translocated to the apical plasma membrane and raise the water permeability of the collecting system. The basolateral step of water reabsorption is mediated by aquaporin-3 and -4, which are constitutively expressed. Drugs targeting water transport include classical diuretics, which primarily inhibit sodium transport; the new class of SGLT2 inhibitors, which promotes osmotic diuresis and the non-peptidic antagonists of the V2 receptor, which are pure aquaretic drugs. Disturbed water balance includes diabetes insipidus and hyponatremias. Diabetes insipidus is characterized by polyuria and polydipsia. It is either related to a deficit in AVP secretion called central diabetes insipidus that can be treated by AVP analogs or to a peripheral defect in AVP response called nephrogenic diabetes insipidus. Diabetes insipidus can be either of genetic origin or acquired. Hyponatremia is a common disorder most often related to free water excess relying on overstimulated or inappropriate AVP secretion. The assessment of blood volume is key for the diagnosis and treatment of hyponatremia, which can be classified as hypo-, eu-, or hypervolemic.

Diabetes Insipidus after Vasopressin Withdrawal: A Scoping Review

Objectives

The objective of this study is to synthesize the current literature about the relationship between the occurrence of diabetes insipidus (DI), its diagnosis criteria, and management after withdrawal of vasopressin (VP) in critically ill.

Data sources

This scoping review followed the recommendations of Preferred Reporting Items for Systematic Review and Meta-Analyses for Scoping Review (PRISMA-ScR). The search literature was conducted in MEDLINE and EMBASE databases, until March 2022. A manual search was also conducted in order to include articles that were not identified in the initial search performed in the databases.

Study selection and data extraction

The selection of studies and extraction of data were carried out in a paired and independent manner. There was no restriction regarding the language of publication of the included manuscripts.

Data synthesis

The analysis included 17 studies (16 case reports and one retrospective cohort). All studies used VP, with a median time of drug infusion of 48 hours (IQR: 16-72) and DI incidence of 1.53%. The diagnosis of DI was based on diuresis output and concomitant hypernatremia or changes in serum sodium concentration, with median time to symptoms onset after discontinuation of VP of 5 hours (IQR: 3-10). The treatment of DI consisted mainly of fluid management and the use of desmopressin.

Conclusions

DI after VP withdrawal was present in 51 patients described in 17 studies, but diagnosis and management varied among each report. Using the available data, we propose a diagnosis suggestion and a flowchart for managing patients with DI after withdrawal of VP in the Intensive Care Unit. Multicentric collaborative research is urgently needed to obtain more quality data on this topic.

How to cite this article

Pérsico RS, Viana MV, Viana LV. Diabetes Insipidus after Vasopressin Withdrawal: A Scoping Review. Indian J Crit Care Med 2022;26(7):846-852.

Change in cephalocaudal tumor cavity diameter after transsphenoidal surgery is a predictor of diabetes insipidus in pituitary adenoma

Objective

To assess the factors influencing the development of diabetes insipidus after transsphenoidal surgery for pituitary adenomas.

Methods

We retrospectively analyzed the clinical data of patients with pituitary adenoma who underwent transsphenoidal surgery. The pituitary gland was assessed using a 3.0 T magnetic resonance imaging, and the predictors of postoperative diabetes insipidus were determined through univariate and multivariate analyses.

Results

A total of 212 eligible patients with pituitary adenomas were included; 82 (38.7%) cases developed postoperative diabetes insipidus while 130 cases (61.3%) did not. Diabetes insipidus was transient in 80 (37.7%) patients and permanent in 2 (0.9%) patients. The results of logistic regression analyses showed that the change in cephalocaudal tumor cavity diameter after transsphenoidal surgery was associated with the occurrence of postoperative diabetes insipidus.

Conclusions

Change in cephalocaudal tumor cavity diameter after transsphenoidal surgery may play an important role in predicting diabetes insipidus onset in patients with a pituitary adenoma.

The value of intraoperative MRI for resection of functional pituitary adenomas-a critical assessment of a consecutive single-center series of 114 cases

This series sought to evaluate the role of intraoperative MRI (iMRI) for resection of functional pituitary adenomas (FPAs). We retrospectively reviewed clinical data of 114 consecutive FPAs with excessive hormone secretion treated with transsphenoidal surgery and iMRI during 01/2010–12/2017. We focused on iMRI findings, extend of resection and postoperative hormonal remission. Variables of incomplete resections and persistent hormone excess were evaluated by binary regression. Patients with FPAs presented with hypercortisolism (n = 23, 20%), acromegaly (n = 56, 49%), and as prolactinomas (n = 35, 31%) resistant to medical treatment. Preoperative MRI showed 81 macroadenomas (71%) and optic system involvement in 41 cases (36%). IMRI was suggestive for residual tumor in 51 cases (45%). Re-inspection of the cavity cleared equivocal findings in 16 cases (14%). Additional tumor was removed in 22 cases (19%). Complete resection was achieved in 95 cases (83%). Postoperative morbidity was low (1.7% revision surgeries, 0.8% permanent diabetes insipidus). Overall hormonal remission-rate was 59% (hypercortisolism 78%, acromegaly 52%, prolactinoma 57%). Supra- and parasellar invasion and preoperative visual impairment were significant predictors for incomplete resections despite use of iMRI. Risk for persistent hormone excess was increased sevenfold after incomplete resections. IMRI enabled reliable identification of tumor remnants during surgery and triggered further resection in a considerable proportion of cases. Nevertheless, tumor size and invasiveness set persistent boundaries to the completeness of resections. The low rate of surgical complications could point at a less invasive iMRI-guided surgical approach while achieving a complete tumor resection was a crucial determinant for hormonal outcome.

Copeptin in fluid disorders and stress

Copeptin, a glycosylated peptide of 39 amino acids, is the C-terminal segment of arginine vasopressin (AVP) precursor peptide, which is consisted of two other fragments, vasopressin and neurophysin Ⅱ. The main physiological functions of AVP are fluid and osmotic balance, cardiovascular homeostasis and regulation of the endocrine stress response. Numerous studies have demonstrated that the endogenous AVP in plasma is a meaningful biomarker to guide diagnosis and therapy of diseases associated with fluids disorders and stress. However, due to its instability, short half-time life in circulation and lack of readily available AVP assays, clinical measurement of AVP is restricted. In contrast to AVP, copeptin which is released in an equimolar mode with AVP from the pituitary, has emerged as a stable and simple-to-measure surrogate marker of AVP and displays excellent potential in diagnosis, differentiation and prognosis of various diseases. This review will discuss the studies on the clinical value of copeptin in different diseases, especially in AVP-dependent fluids disorders, as well as issues and prospects of the application of this potential biomarker.

Predictive factors of postoperative diabetes insipidus in 333 patients undergoing transsphenoidal surgery for non-functioning pituitary adenoma

PURPOSE

Diabetes insipidus (DI) following transsphenoidal surgery (TSS) is a common complication. Although postoperative DI often occurs in patients with craniopharyngioma and Rathke's cleft cyst, postoperative DI in patients with non-functioning pituitary adenoma (NFPA) has not been fully examined. We clarified the clinical characteristics and magnetic resonance imaging (MRI) findings predicting postoperative DI in NFPAs.

METHODS

A total of 333 patients undergoing initial TSS for NFPA were included in this retrospective study. Hyperintensity (HI) in the posterior pituitary lobe was evaluated on preoperative T1-weighted MRI. Based on the findings of HI patients were divided into three groups as follows: HI was not detected (Disappearance group), HI located intrasellarly (Intrasellar group), and HI located suprasellarly (Suprasellar group).

RESULTS

The overall rate of DI was 21.9%, including permanent DI in 0.6%. DI occurred at postoperative day 1 (72.6%) or day 2 (19.2%) and improved within 7 days in most cases (87.7%). Univariable and multivariable analyses showed that the predictive factors of DI were a younger age (odds ratio [OR] 0.97, 95% confidence interval [CI] 0.95-0.99, P = 0.0037) and larger tumor diameter (OR 1.04, 95% CI 1.01-1.08, P = 0.0155). The rate of DI was highest in the Disappearance group (43.8%) followed by the Intrasellar group (26.0%). The OR was 2.17 in the Intrasellar group compared with the Suprasellar group (95% CI 1.17-4.02, P = 0.0141).

CONCLUSIONS

Factors predicting DI following TSS for NFPA were a younger age, larger tumor size, and the location of intrasellar HI on preoperative T1-weighted MRI.

Pulmonary Langerhans cell histiocytosis and multiple system involvement: A case report

BACKGROUND

Pulmonary Langerhans cell histiocytosis (PLCH) is a relatively rare type of lung disease, common in middle-aged smoking men. It is characterized by proliferation and infiltration of Langerhans cells, and the formation of multiple parabronchial mesenchymal nodules in lung tissue, and may lead to organ dysfunction. There are no typical symptoms and signs, and it is easily misdiagnosed or missed, and therefore deserves clinical attention and further discussion.

CASE SUMMARY

We describe the case of a nonsmoking 46-year-old man with PLCH diagnosed based on clinical manifestations of fever and dry cough, with a history of hypothyroidism and diabetes insipidus for 9 years. Computed tomography (CT)- and CT-guided puncture examinations revealed no abnormalities, and he ultimately underwent thoracoscopic biopsy to confirm the diagnosis. The pathological diagnosis was PLCH. Thyroid function was maintained by medication. Pituitary magnetic resonance imaging showed that the pituitary stalk had become thinner.

CONCLUSION

LCH often involves multiple systems. Moreover, the pathogenesis is not clear, clinical manifestations lack specificity, and diagnosis requires special attention. Diagnosis of PLCH can significantly benefit from comprehensive multidisciplinary analysis.

The cascade to a serendipitous discovery of lithium-induced nephrogenic diabetes insipidus

Lithium therapy is a common treatment for affective disorders and is widely regarded as a lifesaving drug. However, because its elimination is almost wholly unchanged via the kidneys, both acute and long-term adverse effects relating to toxicity may occur, including declining renal function and nephrogenic diabetes insipidus (DI). DI may be difficult to detect and is frequently preceded by dehydration and which, in our patient, was discovered by chance. We describe a case of an elderly woman on chronic lithium therapy for bipolar affective disorder who initially presented with dehydration from vomiting but possibly developed extra-pontine myelinolysis (EPM) after over-zealous correction of hyponatraemia. Steroids administered appeared to have prevented further progression but a persisting hyperosmolar state then alerted us to the presence of nephrogenic DI. Although both conditions were later successfully reversed with no obvious chronic sequelae, the recovery of the patient was protracted. Clinicians should be vigilant for complications of managing dehydration states in people prescribed with lithium.

Functional analyses of three different mutations in the AVP-NPII gene causing familial neurohypophyseal diabetes insipidus

PURPOSE

Familial neurohypophyseal diabetes insipidus (FNDI), a rare disorder, which is clinically characterized by polyuria and polydipsia, results from mutations in the arginine vasopressin-neurophysin II (AVP-NPII) gene. The aim of this study was to perform functional analyses of three different mutations (p.G45C, 207_209delGGC, and p.G88V) defined in the AVP-NPII gene of patients diagnosed with FNDI, which are not included in the literature.

METHODS

For functional analysis studies, the relevant mutations were created using PCR-based site-directed mutagenesis and restriction fragment replacement strategy and expressed in Neuro2A cells. AVP secretion into the cell culture medium was determined by radioimmunoassay (RIA) analysis. Fluorescence imaging studies were conducted to determine the differences in the intracellular trafficking of wild-type (WT) and mutant AVP-NPII precursors. Molecular dynamics (MD) simulations were performed to determine the changing of the conformational properties of domains for both WT and 207-209delGGC mutant structures and dynamics behavior of residues.

RESULTS

Reduced levels of AVP in the supernatant culture medium of p.G45C and p.G88V transfected cells compared to 207_209delGGC and WT cells were found. Fluorescence imaging studies showed that a substantial portion of the mutant p.G45C and p.G88V AVP-NPII precursors appeared to be located in the endoplasmic reticulum (ER), whereas 207_209delGGC and WT AVP-NPII precursors were distributed throughout the cytoplasm.

CONCLUSIONS

The mutations p.G45C and p.G88V cause a failure in the intracellular trafficking of mutant AVP-NPII precursors. However, 207_209delGGC mutation does not result in impaired cellular trafficking, probably due to not having any significant effect in processes such as the proper folding, gain of three-dimensional structure, or processing. These results will provide valuable information for understanding the influence of mutations on the function of the AVP precursor hormone and cellular trafficking. Therefore, this study will contribute to elucidate the mechanisms of the molecular pathology of AVP-NPII mutations.

Diabetes insipidus after endoscopic transsphenoidal surgery: multicenter experience and development of the SALT score

OBJECTIVE

To identify risk factors for the development of postoperative diabetes insipidus (DI) in a modern cohort of endoscopic endonasal transsphenoidal surgery.

METHODS

Analysis of prospectively collected data of 449 consecutive patients operated on for anterior skull base pathology. DI was defined as a polyuria (> 250 ml/h for ≥ 2 consecutive hours) polydipsia syndrome associated with hypotonic urine with or without hypernatraemia. Multivariate logistic regression was used to identify predictors of postoperative DI. A simple scoring system was then created.

RESULTS

Postoperative DI occurred in 46 (10.2%) patients. The development of DI did not affect quality of life. Predictors of DI on multivariate analysis included suprasellar extension (OR 2.2; p = 0.04), age < 50 years (OR 2.8; p = 0.003), craniopharyngioma histology (OR 6.7; p = 0.002), and Kelly grade 3 intraoperative CSF leak (OR 2.1; p = 0.04). The SALT score was created based on these characteristics, with one point awarded for each feature present, and predicted DI with fair to good predictive value in our cohort (AUROC 0.735 (95%CI 0.65-0.82)). The rates of postoperative DI were 4.0%, 6.5%, 15.0%. 36.8% and 85.7% for SALT scores of zero, one, two, three, and four, respectively.

CONCLUSIONS

The SALT score predicts postoperative DI with fair to good accuracy, and now requires prospective external validation. Improved prediction of DI could optimize resource allocation and facilitate individualised preoperative patient counselling. We also provide our algorithm for diagnosis and treatment of DI.

Intraoperative Cerebrospinal Fluid Leak Graded by Esposito Grade Is a Predictor for Diabetes Insipidus After Endoscopic Endonasal Pituitary Adenoma Resection

BACKGROUND

Diabetes insipidus (DI) is a well-known complication of transsphenoidal surgery. However, the risk factors for DI remain controversial.

METHODS

We conducted a retrospective study of patients who underwent endoscopic transsphenoidal surgery for pituitary adenoma at our institution during a 5-year period. The patients were divided into a DI group and a non-DI group. Logistic regression analyses were used to identify risk factors for postoperative DI. In subgroup analysis, the DI group was divided into transient DI and permanent DI groups, and perioperative factors were compared between groups.

RESULTS

Of 101 patients, 58 were in the non-DI group (57.4%) and 43 were in the DI group (42.6%). Permanent DI occurred in 7 patients (6.9%). In univariate analyses, statistically significant risk factors were suprasellar extension, tumor functionality, and intraoperative cerebrospinal fluid leaks by Esposito grade. In multivariate logistic regression analysis, Esposito grade was the only statistically significant risk factor (P = 0.015). The frequency of DI increased as the Esposito grade increased (P = 0.0002 for the trend). In subgroup analysis, postoperative nadir sodium concentration was lower in the permanent DI group (128.1 ± 2.78 mmol/L) than in the transient DI group (135 ± 1.22 mmol/L; P = 0.035), and the optimal cutoff value was 124.5 mmol/L, with a sensitivity of 57.1% and a specificity of 91.7% (area under the curve = 0.76, P = 0.034).

CONCLUSIONS

Intraoperative cerebrospinal fluid leak by Esposito grade is associated with postoperative DI. These data can be applied to help identify high-risk patients who need more aggressive follow-up and fluid management.

Role of copeptin in the diagnosis of traumatic neuroendocrine dysfunction

Traumatic neuroendocrine dysfunction may present with diabetes insipidus (DI) or with the syndrome of inappropriate antidiuretic hormone secretion (SIADH). Both these pathologies involve a disturbance in the antidiuretic hormone (ADH) secretion, causing dysnatremias. Diagnosis of posttraumatic ADH dysfunction is hampered by technical difficulties in ADH assessment, and relies mostly on non-specific serum sodium, serum and urine osmolality and diuresis, often leading to misdiagnosis in the acute care setting. Research now focuses on the diagnostic role of copeptin, a peptide secreted together with ADH in an equimolar fashion, and which can be accurately evaluated. Recent studies identified cut-off values of 2.6 pmol/L for baseline copeptin and of 4.9 and 3.8 pmol/L for hypertonic saline infusion and arginine infusion stimulated copeptin, respectively, for the diagnosis of DI in patients with polyuria-polydipsia syndrome. Although SIADH is more difficult to be explored due to its heterogeneity, a ratio of copeptin to urinary sodium below 30 pmol/mmol identifies euvolemic hyponatremia. Exploring the role of copeptin assessment in patients with traumatic brain injury (TBI) in the acute phase may improve their diagnosis accuracy, management and outcome.