Diagnosis and management of central diabetes insipidus in adults

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.

Management of Diabetes Insipidus following Surgery for Pituitary and Suprasellar Tumours

Central diabetes insipidus (CDI) is a common complication after pituitary surgery. However, it is most frequently transient. It is defined by the excretion of an abnormally large volume of dilute urine with increasing serum osmolality. The reported incidence of CDI after pituitary surgery ranges from 0–90%. Large tumour size, gross total resection and intraoperative cerebrospinal fluid leak usually pose an increased risk of CDI as observed with craniopharyngioma and Rathke’s cleft cysts. CDI can be associated with high morbidity and mortality if not promptly recognised and treated on time. It is also essential to rule out other causes of postoperative polyuria to avoid unnecessary pharmacotherapy and iatrogenic hyponatremia. Once the diagnosis of CDI is established, close monitoring is required to evaluate the response to treatment and to determine whether the CDI is transient or permanent. This review outlines the evaluation and management of patients with CDI following pituitary and suprasellar tumour surgery to help recognise the diagnosis, consider the differential diagnosis, initiate therapeutic interventions and guide monitoring and long-term management.

Acquired Idiopathic Generalized Anhidrosis (AIGA) and Its Complications: Implications for AIGA as an Autoimmune Disease

Acquired idiopathic generalized anhidrosis (AIGA) is a rare disorder in which systemic anhidrosis/hypohidrosis occurs without causative dermatological, metabolic or neurological disorder. Most cases of AIGA have been reported in Asia, especially in Japan, but there have been only a few reports in Europe and the United States. Severe AIGA may result in heatstroke and can reduce quality of life due to restriction of exercise and outdoor works. AIGA is often accompanied by cholinergic urticaria (CholU), and it is thought that AIGA and CholU with anhidrosis/hypohidrosis belong to the same spectrum of the disease. However, the pathophysiology of AIGA has not yet been clarified. Decreased expression of cholinergic receptor M3 on the epithelial cells of eccrine sweat glands is often accompanied by T cell infiltration around eccrine apparatus, suggesting an immunological mechanism of disordered perspiration. AIGA is occasionally associated with various complications indicative of autoimmune disorders. The association of autoimmune complications further suggests that AIGA is an autoimmune disorder. Studies on complications may lead to a better understanding of the pathophysiology of AIGA.

Incidence and Possible Predictors of Sodium Disturbance After Craniopharyngioma Resection Based on QST Classification

OBJECTIVE

Serum sodium abnormalities are one of the most common manifestations after radical craniopharyngioma (CP) excision. The aim of this study was to report the incidence and possible predictors of serum sodium disturbance and explore features of sodium destabilization manifestation among QST classification results after CP resection.

METHODS

A retrospective analysis was performed of clinical, biochemical, radiologic, and operative data for 134 successive patients who underwent primary CP removal between September 2016 and March 2018. Univariate and multivariate analyses were conducted to determine predictors.

RESULTS

Sixty patients (44.8%) experienced hyponatremia and 67 patients (50%) hypernatremia; the median time of onset was 6 days and the first day after surgery, respectively. The incidence, onset, severity, and type of sodium disturbance among different types of CP differed significantly based on statistical tests (P < 0.05). Sodium disturbance was more common and severe in patients with type T tumors (P < 0.05). Age, tumor type, and preoperative diabetes insipidus were independent prognostic factors for obvious disorders of serum sodium.

CONCLUSIONS

Hyponatremia/hypernatremia is common after primary CP resection. The site of tumor origin has a direct effect on the growth pattern of CP, which may serve as a useful index for anticipating sodium perturbation after surgery. The level of sodium in children and patients with type T tumors, preoperative diabetes insipidus should be monitored closely throughout hospitalization.

Perioperative management of cranial diabetes insipidus in a patient requiring a tracheostomy

Cranial diabetes insipidus (DI), which can cause life-threatening dehydration, is treated with desmopressin, often intranasally. This is challenging in patients whose nasal airflow is altered, such as those requiring tracheostomy. We report the case of a patient, taking intranasal desmopressin for cranial DI, who underwent partial glossectomy, free-flap reconstruction and tracheostomy. Postoperatively, she could not administer nasal desmopressin due to reduced nasal airflow. She developed uncontrollable thirst, polyuria and hypernatraemia. Symptoms were relieved by switching to an enteric formulation. A literature review showed no cases of patients with DI encountering difficulties following tracheostomy. The Royal Society of Endocrinology recommends perioperative planning for such patients, but gives no specific guidance on medication delivery in the context of altered airway anatomy. Careful perioperative planning is required for head and neck patients with DI, particularly for those undergoing airway alteration that may necessitate a change in the mode of delivery of critical medications.

Outcomes of endoscopic transsphenoidal surgery for Cushing's disease

BACKGROUND

Transsphenoidal surgery (TSS) to resect an adrenocorticotropic hormone (ACTH)-secreting pituitary adenoma is the first-line treatment for Cushing's disease (CD), with increasing usage of endoscopic transsphenoidal (ETSS) technique. The aim of this study was to assess remission rates and postoperative complications following ETSS for CD.

METHODS

A retrospective analysis of a prospective single-surgeon database of consecutive patients with CD who underwent ETSS between January 2012-February 2020. Post-operative remission was defined, according to Endocrine Society Guidelines, as a morning serum cortisol < 138 nmol/L within 7 days of surgery, with improvement in clinical features of hypercortisolism. A strict cut-off of < 50 nmol/L at day 3 post-op was also applied, to allow early identification of remission.

RESULTS

A single surgeon (MJ) performed 43 ETSS in 39 patients. Pre-operative MRI localised an adenoma in 22 (56%) patients; 18 microadenoma and 4 macroadenoma (2 with cavernous sinus invasion). IPSS was carried out in 33 (85%) patients. The remission rates for initial surgery were 87% using standard criteria, 58% using the strict criteria (day 3 cortisol < 50 nmol/L). Three patients had an early repeat ETSS for persistent disease (day 3 cortisol 306-555 nmol/L). When the outcome of repeat early ETSS was included, the remission rate was 92% (36/39) overall. Remission rate was 94% (33/35) when patients with macroadenomas were excluded. There were no cases of CSF leakage, meningitis, vascular injury or visual deterioration. Transient and permanent diabetes insipidus occurred in 33 and 23% following first ETSS, respectively. There was one case of recurrence of CD during the follow-up period of 24 (4-79) months.

CONCLUSION

Endoscopic transsphenoidal surgery produces satisfactory remission rates for the primary treatment of CD, with higher remission rates for microadenomas. A longer follow-up period is required to assess recurrence rates. Patients should be counselled regarding risk of postoperative diabetes insipidus.

Concurrent Central Diabetes Insipidus and Acute Myeloid Leukemia

Central diabetes insipidus (CDI) is a rare reported complication of acute myeloid leukemia (AML). The onset of AML-associated CDI often precedes the diagnosis of AML by weeks or months and is considered an adverse prognostic indicator in this setting. The mechanism of AML-associated CDI is not known; however, it is often reported in the setting of cytogenetic events resulting in MDS1 and EVI1 complex locus protein (MECOM) gene overexpression. Here, we describe a case of new onset CDI which preceded a diagnosis of AML by 1 month. We detail the clinical and laboratory evaluation of the patient's CDI, and we describe the pathological and laboratory workup of their AML, which ultimately yielded a diagnosis of AML with myelodysplasia-related changes. Additional cytogenetic findings included the identification of the t (2;3)(p23;q27), which leads to MECOM gene overexpression and which to our knowledge has not previously been reported in the setting of AML-associated CDI. The patient received induction chemotherapy followed by allogeneic hematopoietic stem cell transplantation but experienced disease relapse and passed away nine months after initial diagnosis. We emphasize that new onset CDI can occur as a rare complication of AML where it portends a poor prognosis and may be related to AML subtypes displaying MECOM gene dysregulation.

Diabetes Insipidus: A Pragmatic Approach to Management

Diabetes insipidus (DI) is a disorder of water balance characterized by polyuria and polydipsia. It can occur due to genetic and acquired causes that affect the secretion or action of arginine vasopressin (AVP) or antidiuretic hormone (ADH).Markedly increased thirst and urination are not only quite distressing but also increases the risk of volume depletion and hypernatremia in severe situations. A careful diagnosis of the type of DI and its etiology is based on careful clinical evaluation, measurement of urine and serum osmolality, and water deprivation test. Management includes the correction of any water deficit and the use of specific pharmacological agents, including desmopressin, thiazides, and amiloride.

Approach to the Management of Hypernatraemia in Older Hospitalised Patients

Hypernatraemia is associated with high morbidity and mortality and is more common in patients of older age, nursing home residents and those with cognitive impairment and restricted mobility. The most common cause in hospital settings is water dehydration due to reduced intake although other causes should be identified. Once identified, prompt management is necessary to avoid delayed correction as prolonged hypernatremia is associated with increased hospital stay and mortality. Comprehensive history-taking and physical examination, basic investigations and medication review are essential to identify causative and remediable factors in those admitted with hypernatraemia. Accurate calculation of fluid deficit and ongoing losses is essential in order to ensure adequate fluid replacement, The administration of appropriate, usually hypotonic, fluids is also essential to the timely restoration of eunatraemia. Although evidence of definite harm resulting from rapid correction is lacking, a serum sodium reduction rate of <12 mmol/l day is advised with the caveat that close monitoring of electrolytes is required to ensure the desired correction rate is being achieved. Medical and nursing professionals should have access to a local hospital protocol to guide management of patients with hypernatraemia to improve patient outcomes and mitigate the risk of harm, particularly from under-recognition and slow correction.

When polyuria does not stop: a case report on an unusual complication of hantavirus infection

Background

The clinical features, course and outcome of hantavirus infection is highly variable. Symptoms of the central nervous system may occur, but often present atypically and diagnostically challenging. Even though the incidence of hantavirus infection is increasing worldwide, this case is the first to describe diabetes insipidus centralis as a complication of hantavirus infection in the Western world.

Case presentation

A 49-year old male presenting with severe headache, nausea and photophobia to our neurology department was diagnosed with acute haemorrhage in the pituitary gland by magnetic resonance imaging. In the following days, the patient developed severe oliguric acute kidney failure. Diagnostic workup revealed a hantavirus infection, so that the pituitary haemorrhage resulting in hypopituitarism was seen as a consequence of hantavirus-induced hypophysitis. Under hormone replacement and symptomatic therapy, the patient’s condition and kidney function improved considerably, but significant polyuria persisted, which was initially attributed to recovery from kidney injury. However, water deprivation test revealed central diabetes insipidus, indicating involvement of the posterior pituitary gland. The amount of urine production normalized with desmopressin substitution.

Conclusion

Our case report highlights that neurological complications of hantavirus infection should be considered in patients with atypical clinical presentation.

Gut Microbiota and Serum Biomarker Analyses in Obese Patients Diagnosed with Diabetes and Hypothyroid Disorder

Background: Variations of serum biomarkers and bacterial diversity of the gastrointestinal tract in obese patients with diabetes or hypothyroid are poorly understood. The aim of this study was to provide recent findings in this regard. Methods: A total of 119 obese patients [17 with diabetes, 23 with hypothyroid, and 79 patients without either diabetes or hypothyroid (control)] were recruited in this study. Serum biomarkers such as biochemical, hormonal (insulin and glucagon), and cytokine levels [interleukin (IL)-6, IL-1β, tumor necrosis factor-alpha, IL-10, and transforming growth factor beta-1 (TGF-β1)] were measured under fasting conditions. Bacterial abundance of gut microbiota was also quantitated by real-time polymerase chain reaction using 16S rRNA gene-based specific primers. Results: Average value of blood sugar (P: 0.0184), hemoglobin A1c, insulin, homeostasis model assessment insulin resistance, TGF-β 1, IL-6, IL-1β, interferon gamma (P_{for each} < 0.001), and phylum Actinobacteria [odds ratio (OR): 1.5, P: 0.032] was significantly higher in diabetic versus control group. In contrast, the levels of IL-10 (P < 0.001), Firmicutes (OR: 0.6, P: 0.058), and Akkermansia muciniphila (OR: 0.4, P: 0.053) were significantly lower in diabetic versus control group. However, there was no statistically significant difference between the values in hypothyroid versus control group either in crude or adjusted models. Conclusion: While there are some relationships between serum biomarkers or bacterial abundance with diabetes prediction in obese patients, this prognostication is less likely in obese patients with hypothyroid. Further investigation is warranted in the application of identified preclinical biomarkers in the diagnosis of diabetes or hypothyroid in obese patients.

Hypothalamic-Pituitary Axis Dysfunction, Central Diabetes Insipidus, and Syndrome of Inappropriate Antidiuretic Hormone Secretion as the First Clinical Presentation of Neurosarcoidosis: Why Early Diagnosis and Treatment is Important?

Sarcoidosis is defined by granuloma formation in a multitude of organs. Despite its rare involvement in the nervous system, there are a number of cases that identify neurological symptoms to be the initial clinical manifestation of sarcoidosis. The involvement of the hypothalamic-pituitary (HP) axis presented most frequently with hormone deficiencies. Studies have reported that damage to the pituitary gland may be irreversible, and hormone abnormalities were generally permanent. Neurosarcoidosis has been described as the underlying cause of central diabetes insipidus (DI) and syndrome of inappropriate antidiuretic hormone (SIADH) secretion. The pathological mechanism that can lead both to deficiency and excess of antidiuretic hormone (ADH) secretion is still not fully understood. It has been shown that diagnosis of neurosarcoidosis remains challenging, as symptoms can be inconclusive and diagnostic tools are not sufficiently sensitive and specific. Early treatment may potentially reverse pituitary deficiencies, although studies to confirm this hypothesis are minimal. This review article aims to increase knowledge about central DI and SIADH caused by neurosarcoidosis, identify possible difficulties in diagnosis, and discuss the importance of early management. Clinical trials investigating the long-term therapeutic response in patients with HP sarcoidosis are essential, as there are currently no established guidelines for the treatment of neurosarcoidosis.

Diabetes exacerbates brain pathology following a focal blast brain injury: New role of a multimodal drug cerebrolysin and nanomedicine

Blast brain injury (bBI) is a combination of several forces of pressure, rotation, penetration of sharp objects and chemical exposure causing laceration, perforation and tissue losses in the brain. The bBI is quite prevalent in military personnel during combat operations. However, no suitable therapeutic strategies are available so far to minimize bBI pathology. Combat stress induces profound cardiovascular and endocrine dysfunction leading to psychosomatic disorders including diabetes mellitus (DM). This is still unclear whether brain pathology in bBI could exacerbate in DM. In present review influence of DM on pathophysiology of bBI is discussed based on our own investigations. In addition, treatment with cerebrolysin (a multimodal drug comprising neurotrophic factors and active peptide fragments) or H-290/51 (a chain-breaking antioxidant) using nanowired delivery of for superior neuroprotection on brain pathology in bBI in DM is explored. Our observations are the first to show that pathophysiology of bBI is exacerbated in DM and TiO₂-nanowired delivery of cerebrolysin induces profound neuroprotection in bBI in DM, not reported earlier. The clinical significance of our findings with regard to military medicine is discussed.

Pharmacological modulation of the hydrogen sulfide (H2 S) system by dietary H2 S-donors: A novel promising strategy in the prevention and treatment of type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) represents the most common age-related metabolic disorder, and its management is becoming both a health and economic issue worldwide. Moreover, chronic hyperglycemia represents one of the main risk factors for cardiovascular complications. In the last years, the emerging evidence about the role of the endogenous gasotransmitter hydrogen sulfide (H₂ S) in the pathogenesis and progression of T2DM led to increasing interest in the pharmacological modulation of endogenous "H₂ S-system". Indeed, H₂ S directly contributes to the homeostatic maintenance of blood glucose levels; moreover, it improves impaired angiogenesis and endothelial dysfunction under hyperglycemic conditions. Moreover, H₂ S promotes significant antioxidant, anti-inflammatory, and antiapoptotic effects, thus preventing hyperglycemia-induced vascular damage, diabetic nephropathy, and cardiomyopathy. Therefore, H₂ S-releasing molecules represent a promising strategy in both clinical management of T2DM and prevention of macro- and micro-vascular complications associated to hyperglycemia. Recently, growing attention has been focused on dietary organosulfur compounds. Among them, garlic polysulfides and isothiocyanates deriving from Brassicaceae have been recognized as H₂ S-donors of great pharmacological and nutraceutical interest. Therefore, a better understanding of the therapeutic potential of naturally occurring H₂ S-donors may pave the way to a more rational use of these nutraceuticals in the modulation of H₂ S homeostasis in T2DM.

Central diabetes insipidus unveiled by glucocorticoid therapy in a patient with an empty sella: A case report and literature review

RATIONALE

Some diseases contribute to hypopituitarism without clinical manifestations and the glucocorticoid therapy may unveil central diabetes insipidus. The condition is rare and usually causes problems for clinical physicians.

PATIENT CONCERNS

A 59-year-old woman presented to our hospital due to facial numbness and persistent eyelid heaviness.

DIAGNOSIS

Physical examination and cerebrospinal fluid examination supported a diagnosis of Guillain-Barre[Combining Acute Accent] syndrome. Magnetic resonance imaging showed an empty sella. Hormone test indicated hypopituitarism.

INTERVENTIONS

The patient received intravenous immunoglobulin and glucocorticoid. Central diabetes insipidus appeared after 20 days. Subsequently, the patient was prescribed 1-desamino-8-D-arginine vasopressin and prednisone.

OUTCOMES

During 6 months' follow-up, the patient's urine output was gradually reduced to normal level.

LESSONS

This case indicated that hypopituitarism may be caused by an empty sella and be masked by adrenal insufficiency. Central diabetes insipidus may present after glucocorticoid therapy.

Management of central diabetes insipidus

The treatment of central diabetes insipidus has not changed significantly in recent decades, and dDAVP and replacement of free water deficit remain the cornerstones of treatment. Oral dDAVP has replaced nasal dDAVP as a more reliable mode of treatment for chronic central diabetes insipidus. Hyponatraemia is a common side effect, occurring in one in four patients, and should be avoided by allowing a regular break from dDAVP to allow a resultant aquaresis. Hypernatraemia is less common, and typically occurs during hospitalization, when access to water is restricted, and in cases of adipsic DI. Management of adipsic DI can be challenging, and requires initial inpatient assessment to establish dose of dDAVP, daily fluid prescription, and eunatraemic weight which can guide day-to-day fluid targets in the long-term.

Electrolyte Disorders and the Nervous System

PURPOSE OF REVIEW

This article provides an overview of the major electrolyte disorders and discusses in detail the homeostasis, etiologies, neurologic manifestations, and treatment of these disorders.

RECENT FINDINGS

The diagnosis and management of hyponatremia continue to evolve. Diagnostic accuracy is improved by assessing serum and urine osmolality as well as urinary sodium. Avoiding overcorrection of hyponatremia is crucial to avoid osmotic demyelination syndrome, although even careful correction can cause osmotic demyelination syndrome in patients who have other risk factors. The clinical presentation of osmotic demyelination syndrome has expanded, with many patients presenting with extrapontine myelinolysis in addition to central pontine myelinolysis.

SUMMARY

Electrolyte disorders often present with neurologic manifestations. Whereas disorders of some electrolytes, such as sodium, preferentially affect the central nervous system, disorders of others, such as potassium and calcium, have significant neuromuscular manifestations. An understanding of the pathophysiology of these disorders and recognition of these manifestations are crucial for the practicing neurologist as the symptoms are reversible with correct management.

Diabetes Insipidus After Discontinuation of Vasopressin Infusion for Treatment of Shock

OBJECTIVES

Vasopressin has achieved common usage for the treatment of catecholamine-requiring and catecholamine-resistant shock. Diabetes insipidus is a syndrome characterized by excretion of abnormally large volumes of dilute urine. To date, very few reports of diabetes insipidus after discontinuation of vasopressin infusion have been published; the majority of previous reports describe neurosurgical patients. The purpose of the present study was to investigate the occurrence rate of diabetes insipidus after discontinuation of vasopressin infusion among patients treated with vasopressin infusion for shock.

DESIGN

Retrospective analysis of electronic health records of patients receiving continuous vasopressin infusion for the treatment of shock within a 5-year period (2012-2016).

SETTING

Medical, surgical, and cardiothoracic ICUs within one academic medical center.

PATIENTS

One-thousand eight-hundred ninety-six patients received vasopressin infusion for the treatment of shock.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The occurrence rate of diabetes insipidus after discontinuation of vasopressin infusion was 1.53% among all patients. Sixteen of 29 patients with diabetes insipidus after discontinuation of vasopressin infusion had undergone cardiothoracic intervention, such as coronary artery bypass graft and valve replacement surgery, extracorporeal membrane oxygenation, and placement of ventricular assist devices. No neurosurgical patients were identified in our cohort. In a control group of patients receiving norepinephrine but not vasopressin infusion for treatment of shock, criteria for diabetes insipidus were observed in two of 1,320 subjects (0.15%).

CONCLUSIONS

Despite a paucity of published reports, diabetes insipidus after discontinuation of vasopressin infusion appears not to be a rare phenomenon, and is likely to be encountered by intensivists who regularly employ vasopressin for the treatment of vasoplegic shock. Previous reports consisted predominantly of neurosurgical patients. Our findings demonstrate the occurrence of diabetes insipidus after discontinuation of vasopressin infusion among patients with septic shock as well as vasoplegic shock after cardiothoracic intervention. The mechanism of diabetes insipidus after discontinuation of vasopressin infusion remains to be elucidated but may involve transient downregulation of V2 receptors induced by exposure to supraphysiological doses of vasopressin.

Optimisation of the organ donor and effects on transplanted organs: a narrative review on current practice and future directions

Mortality remains high for patients on the waiting list for organ transplantation. A marked imbalance between the number of available organs and recipients that need to be transplanted persists. Organs from deceased donors are often declined due to perceived and actual suboptimal quality. Adequate donor management offers an opportunity to reduce organ injury and maximise the number of organs than can be offered in order to respect the donor's altruistic gift. The cornerstones of management include: correction of hypovolaemia; maintenance of organ perfusion; prompt treatment of diabetes insipidus; corticosteroid therapy; and lung protective ventilation. The interventions used to deliver these goals are largely based on pathophysiological rationale or extrapolations from general critical care patients. There is currently insufficient high-quality evidence that has assessed whether any interventions in the donor after brain death may actually improve immediate post-transplant function and long-term graft survival or recipient survival after transplantation. Improvements in our understanding of the underlying mechanisms following brain death, in particular the role of immunological and metabolic changes in donors, offer promising future therapeutic opportunities to increase organ utilisation. Establishing a UK donor management research programme involves consideration of ethical, logistical and legal issues that will benefit transplanted patients while respecting the wishes of donors and their families.

Early Copeptin Determination Allows Prompt Diagnosis of Post-Neurosurgical Central Diabetes Insipidus

INTRODUCTION

Central diabetes insipidus (CDI) is a frequent complication of pituitary surgery, but its diagnosis lacks standardized criteria. Copeptin, a surrogate marker of arginine vasopressin release, is triggered by psycho-physical stresses such as pituitary surgery. Low postoperative copeptin could predict CDI onset. The aims of this study were the validation of copeptin as a predictor of post-neurosurgical CDI and the identification of the optimal timing for its determination.

METHODS

Sixty-six consecutive patients operated for a hypothalamic-pituitary lesion were evaluated. Copeptin was determined preoperatively and at 1, 6, 12, 24 and 48 h post-extubation. Fifty-eight patients were reassessed after 3-6 months post-surgery to confirm transient (3 cases) or permanent CDI (5 cases) diagnosis.

RESULTS

A marked copeptin peak was identified at 1 h after extubation, when a value below or equal to 12.8 pmol/L had a good accuracy in identifying CDI cases (AUC 0.866, 95% CI 0.751-0.941). Moreover, a copeptin peak above 4.2 pmol/L excluded permanent forms (AUC 1, 95% CI 0.629-1). Regression analysis identified copeptin as the only significant predictor of CDI (OR 0.86, 95% CI 0.75-0.98, p = 0.02). A copeptin T1/T0 ratio below or equal to 1.47 identified patients at risk of isolated biochemical alterations even in the absence of an overt CDI.

CONCLUSIONS

A prompt increase of copeptin is expected at 1 h after extubation. The absence of this peak is a reliable predictor of post-neurosurgical CDI.

Transient Central Diabetes Insipidus after Discontinuation of Vasopressin

Central diabetes insipidus (CDI) is an uncommon condition resulting from lack of vasopressin secretion from the posterior pituitary gland typically caused by some form of destruction of the gland. Here we present a case of transient CDI after discontinuation of vasopressin used for septic shock without evidence of overt pituitary damage. Serum sodium concentration peaked at 160 mmol/L in the setting of polyuria within days of vasopressin discontinuation without identified alternative etiologies. Sodium levels and urine output normalized with administration of desmopressin with continued stability after desmopressin was discontinued. This is one of few reported cases of diabetes insipidus occurring after discontinuation of vasopressin and the rapid and profound response to desmopressin in this case proves a central etiology. This case allows for speculation into predisposing risk factors for this phenomenon including preexisting neurological disease.

Delayed Onset of Central Diabetes Insipidus With Ketamine Sedation: A Report of 2 Cases

Ketamine is being prescribed with greater frequency due to an emphasis on multimodal analgesia. With increasing use, uncommon adverse effects associated with ketamine are likely to surface. Limited reports of transient central diabetes insipidus (DI) occurring early after initiation (ie, within 10 hours) of ketamine have been reported. We present 2 cases of delayed onset (32 hours or more after initiation), ketamine-induced, transient central DI in patients cannulated for venovenous extracorporeal membranous oxygenation. No other causes of central DI were determined based upon physical examination or laboratory data, and both patients responded to treatment with desmopressin/vasopressin. The Naranjo adverse drug reaction probability scale noted a probable causation for each case. These cases demonstrate the possibility of a rare but serious complication of ketamine. Improvement after discontinuation of ketamine and administration of desmopressin/vasopressin appear to support a drug-effect association.

Central diabetes insipidus associated with refeeding in anorexia nervosa: A case report

Anorexia nervosa (AN) has been associated with a multitude of hypothalamic pituitary abnormalities, although it is unknown which aberrations reflect disease causation and which are the consequences of severe malnutrition. Among these endocrinopathies, hypothalamic-posterior pituitary aberrations have been described, including disorders of osmoregulation. We report the case of an adolescent female with a history of severe AN, restricting subtype, treated aggressively with multiple hospitalizations. During hospitalization for severe weakness and lethargy, her course of medical stabilization was complicated by significant polyuria, ultimately diagnosed as central diabetes insipidus (DI). This is the first reported case, to our knowledge, of a severely malnourished adolescent with AN-restricting subtype developing central DI during the refeeding process for medical stabilization, thus adding to the small body of existing literature on disordered osmoregulation in this patient population. This case report raises the question as to whether the frequency of central DI during refeeding is greater than that previously recognized. Additional research should focus on how neuroendocrine dysregulation of water balance might impact the clinical course of AN and its treatment.

Permanent central diabetes insipidus after mild head injury

We report a case of a patient with mild traumatic brain injury (TBI) who was diagnosed with permanent central diabetes insipidus (DI). A 21-year-old man was admitted to our outpatient clinic with polyuria and polydipsia 1 week after a mild head injury. He was well, except for these complaints. The initial laboratory workup was consistent with DI. There was no abnormality with other laboratory and hormone values. MRI showed lack of neurohypophyseal hyperintensity with no other abnormal findings. The patient responded well to desmopressin therapy. At the first year of the diagnosis, the patient still needed to use desmopressin treatment as we concluded that DI is permanent. DI is not uncommon after TBI, but it is often seen after severe TBI. We present here an extraordinary case of developing permanent DI after mild TBI with the absence of neurohypophyseal bright spot on MRI with no other abnormal findings.

Syndrome of Inappropriate Antidiuretic Hormone Secretion (SIADH) and Subsequent Central Diabetes Insipidus: A Rare Presentation of Pituitary Apoplexy

Pituitary apoplexy (PA) is a rare endocrine emergency that occasionally presents with sodium disturbances. Here we present a rare case with a previously healthy 41-year-old female who presented with acute onset headache and nausea without visual impairment or overt pituitary dysfunction. Plasma sodium concentrations declined abruptly during the first two days of admission to a nadir of 111 mmol/l. Urine and blood chemistry were consistent with syndrome of inappropriate antidiuretic hormone secretion (SIADH). Magnetic resonance imaging revealed recent bleeding into a pituitary cystic process. Hyponatremia was successfully corrected with fluid restriction and both visual function and anterior pituitary function remained intact. Subsequently, the patient developed central diabetes insipidus (CDI), which responded well to desmopressin substitution. To our knowledge, this is the first case of PA presenting predominantly with posterior pituitary dysfunction that transitioned from SIADH to permanent CDI.

Sickle cell disease up-regulates vasopressin, aquaporin 2, urea transporter A1, Na-K-Cl cotransporter 2, and epithelial Na channels in the mouse kidney medulla despite compromising urinary concentration ability

Sickle cell disease (SCD)-induced urinary concentration defect has been proposed as caused by impaired ability of the occluded vasa recta due to red blood cell sickling to serve as countercurrent exchangers and renal tubules to absorb water and solutes. However, the exact molecular mechanisms remain largely unknown. The present studies were undertaken to determine the effects of SCD on vasopressin, aquaporin2 (AQP2), urea transporter A1 (UTA1), Na-K-Cl co-transporter 2 (NKCC2), epithelial Na channels (ENaC), aquaporin1 (AQP1), nuclear factor of activated T cells 5 (NFAT5) and Src homology region-2 domain-containing phosphatase-1 (SHP-1), an important regulator of NFAT5, in the Berkeley SCD mouse kidney medulla. Under water repletion, SCD only induced a minor urinary concentration defect associated with increased urinary vasopressin level alone with the well-known effects of vasopressin: protein abundance of AQP2, UTA1 and ENaC-β and apical targeting of AQP2 as compared with non-SCD. SCD did not significantly affect AQP1 protein level. Water restriction had no further significant effect on SCD urinary vasopressin. NFAT5 is also critical to urinary concentration. Instead, water restriction-activated NFAT5 associated with inhibition of SHP-1 in the SCD mice. Yet, water restriction only elevated urinary osmolality by 28% in these mice as opposed to 104% in non-SCD mice despite similar degree increases of protein abundance of AQP2, NKCC2 and AQP2-S256-P. Water-restriction had no significant effect on protein abundance of ENaC or AQP1 in either strain. In conclusion, under water repletion SCD, only induces a minor defect in urinary concentration because of compensation from the up-regulated vasopressin system. However, under water restriction, SCD mice struggle to concentrate urine despite activating NFAT5. SCD-induced urinary concentration defect appears to be resulted from the poor blood flow in vasa recta rather than the renal tubules' ability to absorb water and solutes.