Management of diabetes insipidus and adipsia in the child

Imaging in malignant germ cell tumors involving the hypothalamo-neurohypophyseal axis: the evaluation of the posterior pituitary bright spot is essential

PURPOSE

Malignant intracranial germ cell tumors (GCTs) are rare diseases in Western countries. They arise in midline structures and diagnosis is often delayed. We evaluated imaging characteristics and early tumor signs of suprasellar and bifocal GCT on MRI.

METHODS

Patients with the diagnosis of a germinoma or non-germinomatous GCT (NGGCT) who received non-contrast sagittal T1WI on MRI pre-therapy were included. Loss of the posterior pituitary bright spot (PPBS), the expansion and size of the tumor, and the expansion and infiltration of surrounding structures were evaluated. Group comparison for histologies and localizations was performed.

RESULTS

A total of 102 GCT patients (median age at diagnosis 12.3 years, range 4.4-33.8; 57 males; 67 in suprasellar localization) were enrolled in the study. In the suprasellar cohort, NGGCTs (n = 20) were noticeably larger than germinomas (n = 47; p < .001). Each tumor showed involvement of the posterior lobe or pituitary stalk. A PPBS loss (total n = 98) was observed for each localization and entity in more than 90% and was related to diabetes insipidus. Osseous infiltration was observed exclusively in suprasellar GCT (significantly more frequent in NGGCT; p = .004). Time between the first MRI and therapy start was significantly longer in the suprasellar cohort (p = .005), with an even greater delay in germinoma compared to NGGCT (p = .002). The longest interval to treatment had circumscribed suprasellar germinomas (median 312 days).

CONCLUSION

A loss of the PPBS is a hint of tumor origin revealing small tumors in the neurohypophysis. Using this sign in children with diabetes insipidus avoids a delay in diagnosis.

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.

Management of Central Diabetes Insipidus in Disabled Children with Diluted Oral Desmopressin Lyophilisate Formulation Administered Through Nasogastric Tube: A Retrospective Case Series

BACKGROUND

Experience with nasogastric administration of oral DDAVP [desamino-D-arginine-8-vasopressin] lyophilisate (ODL) for central diabetes insipidus (CDI) in disabled children with swallowing coordination difficulties is limited.

OBJECTIVE

We aimed to assess the safety and efficacy of nasogastric use of ODL in disabled children with CDI. Time to serum sodium normalisation was compared with that of children with normal intellect and CDI treated with sublingual DDAVP.

METHODS

Clinical, laboratory and neuroimaging characteristics were evaluated for 12 disabled children with CDI treated with ODL through nasogastric tube at Dr Behcet Uz Children's Hospital, Turkey, between 2012 and 2022.

RESULTS

Six boys and six girls with a mean (±SD) age of 43 (± 40) months were evaluated. These children (mean [±SD] weight standard deviation score [SDS] - 1.2 ± 1.7; mean [±SD] height SDS - 1.3 ± 1.4) presented with failure to thrive, irritability, prolonged fever, polyuria and hypernatraemia (mean serum sodium 162 [±3.6] mEq/L). At diagnosis, mean serum and urine osmolality were 321 (± 14) mOsm/kg and 105 (± 7.8) mOsm/kg, respectively. Arginine vasopressin (AVP) levels were undetectable (< 0.5 pmol/L) at diagnosis in all patients. Nasogastric tube administration of DDAVP lyophilisate (120 µg/tablet) dissolved in water (10 mL) was commenced at a dose of 1-5 µg/kg/day in two divided doses together with controlled water intake to avoid hyponatraemia. The frequency and dose of DDAVP were titrated based on urine output and serum sodium concentration. Serum sodium declined at a rate of 0.11 ± 0.03 mEq/L/h and reached normal range in a mean duration of 174 ± 46.5 h. Serum sodium declined faster in children with normal intellect and CDI treated with sublingual DDAVP (1.28 ± 0.39 mEq/L/h; p = 0.0003). Three disabled children needed rehospitalisation because of hypernatraemia due to unintentional DDAVP omission by caregivers. No episode of hyponatraemia was observed. Weight gain and growth were normal during the median (± interquartile range) follow-up duration of 32 ± 67 months.

CONCLUSIONS

Nasogastric administration of oral DDAVP lyophilised formulation was safe and effective in the treatment of CDI in disabled children in this small retrospective series.

Endocrine Disorders in Children with Brain Tumors: At Diagnosis, after Surgery, Radiotherapy and Chemotherapy

INTRODUCTION

Brain tumors are the second most frequent type of all pediatric malignancies. Depending on their localization, patients with brain tumors may present neurological or ophthalmological symptoms, but also weight anomalies and endocrine disorders ranging from growth hormone deficiency, anomalies of puberty, diabetes insipidus to panhypopituitarism. Immediately at diagnosis, all patients with brain tumors require a complete assessment of the hypothalamic-pituitary function in order to address eventual endocrine disorders. Moreover, children and adolescents undergoing brain surgery must receive peri- and postoperative hydrocortisone stress therapy. Post-operative disorders of water homeostasis are frequent, ranging from transient diabetes insipidus, as well as syndrome of inappropriate antidiuretic hormone secretion to persistent diabetes insipidus. Late endocrine disorders may result from surgery near or within the hypothalamic-pituitary region. Pituitary deficits are frequent after radiotherapy, especially growth hormone deficiency. Thyroid nodules or secondary thyroid cancers may arise years after radiotherapy. Gonadal dysfunction is frequent after chemotherapy especially with alkylating agents.

CONCLUSION

Early detection and treatment of specific endocrine disorders at diagnosis, perioperatively, and during long-term follow-up result in improved general and metabolic health and quality of life.

Imaging response assessment for CNS germ cell tumours: consensus recommendations from the European Society for Paediatric Oncology Brain Tumour Group and North American Children's Oncology Group

Homogeneous and common objective disease assessments and standardised response criteria are important for better international clinical trials for CNS germ cell tumours. Currently, European protocols differ from those of North America (the USA and Canada) in terms of criteria to assess radiological disease response. An international working group of the European Society for Paediatric Oncology Brain Tumour Group and North American Children's Oncology Group was therefore established to review existing literature and current practices, identify major challenges regarding imaging assessment, and develop consensus recommendations for imaging response assessment for patients with CNS germ cell tumours. New clinical imaging standards were defined for the most common sites of CNS germ cell tumour and for the definition of locoregional extension. These new standards will allow the evaluation of response to therapy in patients with CNS germ cell tumours to be more consistent, and facilitate direct comparison of treatment outcomes across international studies.

Approach to the Pediatric Patient: Central Diabetes Insipidus

Central diabetes insipidus (CDI) is a complex disorder in which large volumes of dilute urine are excreted due to arginine-vasopressin deficiency, and it is caused by a variety of disorders affecting the hypothalamic-posterior pituitary network. The differential diagnosis is challenging and requires a detailed medical history, physical examination, biochemical approach, imaging studies, and, in some cases, histological confirmation. Magnetic resonance imaging is the gold standard method for evaluating congenital or acquired cerebral and pituitary stalk lesions. Pituitary stalk size at presentation could be normal, but it may change over time, depending on the underlying condition, while other brain areas or organs may become involved during follow-up. Early diagnosis and treatment are crucial to avoid central nervous system damage and germ cell tumor dissemination and to minimize complications of multiple pituitary hormone defects. We provide a practical update on the diagnosis and management of patients with CDI and highlight several pitfalls that may complicate the differential diagnosis of conditions presenting with polyuria and polydipsia. The need for a careful and close follow-up of patients with apparently idiopathic CDI is particularly emphasized because the underlying condition may be recognized over time. The clinical scenario that we outline at the beginning of this article represents the basis for the discussion about how the etiological diagnosis of CDI can be overlooked and demonstrates how a water intake and urine output improvement can be a sign of progressive damage of both hypothalamus and anterior pituitary gland with associated pituitary hormonal deficiencies.

Variability in Oral Desmopressin Dose Requirements in Children with Central Diabetes Insipidus

There is inconsistency in the amount of oral desmopressin that children with central diabetes insipidus require. We investigated whether clinical characteristics influenced desmopressin dose requirements in 100 children with central diabetes insipidus. Extremely large doses were associated with acquired etiology (P = .04), greater body mass index z score, intact thirst, and additional pituitary hormone deficiencies (P < .001).

Diabetes insipidus

Diabetes insipidus (DI) is a disorder characterized by a high hypotonic urinary output of more than 50ml per kg body weight per 24 hours, with associated polydipsia of more than 3 liters a day [1,2]. Central DI results from inadequate secretion and usually deficient synthesis of Arginine vasopressin (AVP) in the hypothalamus or pituitary gland. Besides central DI further underlying etiologies of DI can be due to other primary forms (renal origin) or secondary forms of polyuria (resulting from primary polydipsia). All these forms belong to the Polyuria Polydipsia Syndrom (PPS). In most cases central and nephrogenic DI are acquired, but there are also congenital forms caused by genetic mutations of the AVP gene (central DI) [3] or by mutations in the gene for the AVP V2R or the AQP2 water channel (nephrogenic DI) [4]. Primary polydipsia (PP) as secondary form of polyuria includes an excessive intake of large amounts of fluid leading to polyuria in the presence of intact AVP secretion and appropriate antidiuretic renal response. Differentiation between the three mentioned entities is difficult [5], especially in patients with Primary polydipsia or partial, mild forms of DI [1,6], but different tests for differential diagnosis, most recently based on measurement of copeptin, and a thorough medical history mostly lead to the correct diagnosis. This is important since treatment strategies vary and application of the wrong treatment can be dangerous [7]. Treatment of central DI consists of fluid management and drug therapy with the synthetic AVP analogue Desmopressin (DDAVP), that is used as nasal or oral preparation in most cases. Main side effect can be dilutional hyponatremia [8]. In this review we will focus on central diabetes insipidus and describe the prevalence, the clinical manifestations, the etiology as well as the differential diagnosis and management of central diabetes insipidus in the out- and inpatient setting.

Clinical Practice Changes After Post-Market Safety Reports on Desmopressin Orally Disintegrating Tablet in Japan: A Single-Center Retrospective Study

Background

Desmopressin orally disintegrating tablet (ODT) was approved in March 2012 in Japan; the post-market safety reports, which warned about adequate initial dose of desmopressin ODT, were published in 2014. However, it is unclear how the warning affected physician and patient behavior.

Methods

We performed a retrospective single-center study to compare the clinical situation of Japanese central diabetes insipidus patients before and after the report.

Results

Thirty-four patients before October 2014 and 16 patients after November 2014 switched from intranasal desmopressin to desmopressin ODT. The mean follow-up period after the switch to desmopressin ODT was 38 ± 3 months. Patients switching after November 2014 tended to have lower ratios of oral to nasal desmopressin dose at switching and 3 months after the switch (at switching; P = 0.20, 3 months; P = 0.42, respectively), and higher ratios from 6 to 12 months than before October 2014 (6 months; P = 0.93, 9 months; P = 0.52, 12 months; P = 0.80, respectively). Relative doses per initial desmopressin ODT at 9 and 12 months were significantly higher in patients switching after November 2014 than in patients switching before October 2014 (9 months; P = 0.02, 12 months; P = 0.04, respectively). Moreover, logistic regression analysis revealed that the incidence of hyponatremia was dependent on the ratio of nasal to oral desmopressin dose (P = 0.02). In addition, in four out of six patients who had serum sodium level reduced below 130 mEq/L, hyponatremia occurred within 1 month after the switch.

Conclusions

A more gradual dose titration after the safety reports was performed, which involved the long-term safety of desmopressin ODT use. Vigilance of hyponatremia in early phase of desmopressin ODT use should be noted.

Evolving pituitary hormone deficits in primarily isolated GHD: a review and experts' consensus

Isolated growth hormone deficiency (GHD) is defined by growth failure in combination with retarded bone age, low serum insulin-like growth factor-1, and insufficient GH peaks in two independent GH stimulation tests. Congenital GHD can present at any age and can be associated with significant malformations of the pituitary-hypothalamic region or the midline of the brain. In rare instances, genetic analysis reveals germline mutations of transcription factors involved in embryogenesis of the pituitary gland and the hypothalamus. Acquired GHD is caused by radiation, inflammation, or tumor growth. In contrast to organic GHD, idiopathic forms are more frequent and remain unexplained.There is a risk of progression from isolated GHD to combined pituitary hormone deficiency (> 5% for the total group), which is clearly increased in children with organic GHD, especially with significant malformation of the pituitary gland. Therefore, it is prudent to exclude additional pituitary hormone deficiencies in the follow-up of children with isolated GHD by clinical and radiological observations and endocrine baseline tests. In contrast to primary disorders of endocrine glands, secondary deficiency is frequently milder in its clinical manifestation. The pituitary hormone deficiencies can develop over time from mild insufficiency to severe deficiency. This review summarizes the current knowledge on diagnostics and therapy of additional pituitary hormone deficits occurring during rhGH treatment in children initially diagnosed with isolated GHD. Although risk factors are known, there are no absolute criteria enabling exclusion of children without any risk of progress to combined pituitary hormone deficiency. Lifelong monitoring of the endocrine function of the pituitary gland is recommended in humans with organic GHD. This paper is the essence of a workshop of pediatric endocrinologists who screened the literature for evidence with respect to evolving pituitary deficits in initially isolated GHD, their diagnosis and treatment.

Endocrine Outcomes In Central Diabetes Insipidus: the Predictive Value of Neuroimaging "Mismatch Pattern"

CONTEXT

The etiology of central diabetes insipidus (CDI) in children is often unknown. Clinical and radiological features at disease onset do not allow discrimination between idiopathic forms and other conditions or to predict anterior pituitary dysfunction.

OBJECTIVE

To evaluate the evolution of pituitary stalk (PS) thickening and the pattern of contrast-enhancement in relation with etiological diagnosis and pituitary function.

METHODS

We enrolled 39 children with CDI, 29 idiopathic and 10 with Langerhans cell histiocytosis (LCH). Brain magnetic resonance images taken at admission and during follow-up (332 studies) were examined, focusing on PS thickness, contrast-enhancement pattern, and pituitary gland size; T2-DRIVE and postcontrast T1-weighted images were analyzed.

RESULTS

Seventeen of 29 patients (58.6%) with idiopathic CDI displayed "mismatch pattern," consisting in a discrepancy between PS thickness in T2-DRIVE and postcontrast T1-weighted images; neuroimaging findings became stable after its appearance, while "mismatch" appeared in LCH patients after chemotherapy. Patients with larger PS displayed mismatch more frequently (P = 0.003); in these patients, reduction of proximal and middle PS size was documented over time (P = 0.045 and P = 0.006). The pituitary gland was smaller in patients with mismatch (P < 0.0001). Patients with mismatch presented more frequently with at least one pituitary hormone defect, more often growth hormone deficiency (P = 0.033).

CONCLUSIONS

The PS mismatch pattern characterizes patients with CDI, reduced pituitary gland size, and anterior pituitary dysfunction. The association of mismatch pattern with specific underlying conditions needs further investigation. As patients with mismatch show stabilization of PS size, we assume a prognostic role of this peculiar pattern, which could be used to lead follow-up.

Central Diabetes Insipidus in a Preterm Neonate Unresponsive to Intranasal Desmopressin

Central or neurogenic diabetes insipidus (DI) is uncommon in the pediatric age group and rarely occurs in neonates. It should be suspected in any neonate presenting with excessive urine output and hypernatremia that persists despite increased fluid administration. Diabetes insipidus may be secondary to asphyxia, intraventricular hemorrhage, infection, and structural abnormalities or may be idiopathic or genetic. Diagnosis includes a careful history, laboratory testing, and magnetic resonance imaging. Management of neonatal DI involves a careful balance between fluid intake and pharmacologic treatment. In this article we report a case of an extremely low birth weight infant presenting with central DI possibly caused by abnormality of the pituitary gland. Persistent hypernatremia was the initial presentation. Increased fluids were given initially but were only partially helpful. Eventually subcutaneous desmopressin (DDAVP) was required. The infant was unresponsive to intranasal DDAVP and required subcutaneous DDAVP upon discharge.

Identification of a Novel Arginine Vasopressin Receptor 2 Mutation (p.V183M) in a Chinese Family with Nephrogenic Diabetes Insipidus

Loss of function of arginine vasopressin receptor 2 (AVPR2) may affect the recognition and binding of arginine vasopressin (AVP) which, in turn, may prevent the activation of Gs/adenylate cyclase and reduce the reabsorption of water by renal tubules and combined tubes. Finally, the organism may suffer from nephrogenic diabetes insipidus (NDI), a kind of kidney disorder featured by polyuria and polydipsia, due to a break of water homeostasis. In this study, we enrolled a Chinese family with polyuria and polydipsia. The proband presented abnormal fluid intake and excessive urine output. A water deprivation and AVP stimulation test further indicated that this patient had NDI. By sequencing known causative genes for diabetes insipidus, we identified a novel mutation in AVPR2 (c.547G>A; p.V183M) in the family. This mutation, located in a conserved site of AVPR2 and predicted to be disease-causing by informatics programs, was absent in our 200 controls and other public databases. Our study not only further confirms the clinical diagnosis, but also expands the spectrum of AVPR2 mutations and contributes to genetic diagnosis and counseling of patients with NDI.

Central diabetes insipidus in children: Diagnosis and management

Central diabetes insipidus (CDI) is a complex disorder in which large volumes of dilute urine are excreted due to arginine-vasopressin deficiency, and it is caused by a variety of conditions (genetic, congenital, inflammatory, neoplastic, traumatic) that arise mainly from the hypothalamus. The differential diagnosis between diseases presenting with polyuria and polydipsia is challenging and requires a detailed medical history, physical examination, biochemical approach, imaging studies and, in some cases, histological confirmation. Magnetic resonance imaging is the gold standard method for evaluating the sellar-suprasellar region in CDI. Pituitary stalk size at presentation is variable and can change over time, depending on the underlying condition, and other brain areas or other organs - in specific diseases - may become involved during follow up. An early diagnosis and treatment are preferable in order to avoid central nervous system damage and the risk of dissemination of germ cell tumor, or progression of Langerhans Cell Histiocytosis, and in order to start treatment of additional pituitary defects without further delay. This review focuses on current diagnostic work-up and on the role of neuroimaging in the differential diagnosis of CDI in children and adolescents. It provides an update on the best approach for diagnosis - including novel biochemical markers such as copeptin - treatment and follow up of children and adolescents with CDI; it also describes the best approach to challenging situations such as post-surgical patients, adipsic patients, patients undergoing chemotherapy and/or in critical care.

Acute onset of central diabetes insipidus during adolescent idiopathic scoliosis surgery

This is a case report of a 12-year-old female with idiopathic scoliosis undergoing posterior scoliosis reconstruction that developed an acute onset of central diabetes insipidus (CDI) during surgery. The diagnosis was made as a result of an intraoperative increase in urine output to 6.82 ml/kg/hour (550 ml), a serum sodium increase from 139 to 147 mmol/L, a serum osmolality of 299 mOsmol/kg, a rapid response to vasopressin administration and a low vasopressin level of < 0.5 picograms/ml (normal, 1-5 picograms/ml). This is the first reported case of CDI with a documented low vasopressin level that has occurred in a pediatric scoliosis surgical patient.

Clinical Approach to Sodium Homeostasis Disorders in Children with Pituitary-Suprasellar Tumors

Children with pituitary-suprasellar tumors are at high risk of developing sodium metabolism disorders since the tumoral mass itself or surgical and medical treatment can damage AVP release circuits. Additional risk factors are represented by the use of hypotonic fluids, the young age, total parenteral nutrition, and obstructive hydrocephalus secondary to tumor pathology. The most frequent hyponatremic disorders related to AVP in these patients are the syndrome of inappropriate ADH secretion and the cerebral/renal salt wasting syndrome, while hypernatremic conditions include central diabetes insipidus (CDI) and adipsic CDI. The main challenge in the management of these patients is to promptly distinguish the AVP release disorder at the base of the sodium imbalance and treat it correctly by avoiding rapid sodium fluctuations. These disorders can coexist or follow each other in a few hours or days; therefore, careful clinical and biochemical monitoring is necessary, especially during surgery, the use of chemotherapeutic agents, or radiotherapy. This monitoring should be performed by experienced healthcare professionals and should be multidisciplinary, including pediatric endocrinologists, neurosurgeons, and oncologists since maintaining sodium homeostasis also plays a prognostic role in terms of disease survival, therapeutic response, hospitalization rate, and mortality. In this review, we analyze the management of sodium homeostasis disorders in children with pituitary-suprasellar tumors and discuss the main challenges in the diagnosis and treatment of these conditions based on literature data and over 30 years of clinical experience at our Department of Pediatric Endocrinology.

Pituitary disease in pediatric brain tumor survivors

INTRODUCTION

Treatment of childhood brain tumors, including surgical resection and especially external beam radiation, often results in endocrine complications manifested by hypopituitarism, which can involve growth hormone deficiency, hypothyroidism, adrenal insufficiency, disorders of puberty, diabetes insipidus, and hypothalamic obesity.

AREAS COVERED

A comprehensive literature search was conducted on Medline (publications from the 1990s to 01/2019) including systematic reviews, meta-analyses, longitudinal controlled studies, retrospective cohort studies, and case reports. Herein, we present an up-to-date review of the current literature regarding endocrine sequellae of childhood brain tumor survivors.

EXPERT OPINION

Late endocrine sequellae can arise many years after the initial treatment of tumor, so at least annual surveillance of growth, puberty, weight, development, and endocrine status is recommended for at least 10 years after tumor therapy. This follow up should encompass childhood and adulthood among survivors. If found early, outcomes of endocrinopathies are favorable when treated appropriately. Newer tumor therapy modalities, such as proton beam radiation, offer the potential for fewer endocrine complications, but such benefit has yet to be demonstrated, and more research into short- and long-term outcomes is needed.

Idiopathic central diabetes insipidus in an extreme premature infant: A case report

CONTEXT

Central diabetes insipidus (CDI) is a rare disease during the neonatal period, making it diagnosis difficult and delaying medical treatment.

CASE REPORT

We report here a case of a premature infant born at 26 weeks gestation who, during his 1st month of life, presented persistent hypernatremia with polyuria despite increased fluid supply and low sodium intake. CDI diagnosis was suspected and then confirmed by the therapeutic test with vasopressin analog, in its oral form. Electrolyte disorders were normalized after treatment, which allowed normal weight and height growth with standard fluid supply. Biological and radiological tests were all normal; this CDI was considered idiopathic.

CONCLUSION

Persistent hypernatremia with excessive diuresis should alert to CDI diagnosis.

Role of MRI T2-DRIVE in the assessment of pituitary stalk abnormalities without gadolinium in pituitary diseases

OBJECTIVE

To investigate the role of T2-DRIVE MRI sequence in the accurate measurement of pituitary stalk (PS) size and the identification of PS abnormalities in patients with hypothalamic-pituitary disorders without the use of gadolinium.

DESIGN

This was a retrospective study conducted on 242 patients who underwent MRI due to pituitary dysfunction between 2006 and 2015. Among 135 eligible patients, 102 showed eutopic posterior pituitary (PP) gland and 33 showed 'ectopic' PP (EPP).

METHODS

Two readers independently measured the size of PS in patients with eutopic PP at the proximal, midpoint and distal levels on pre- and post-contrast T1-weighted as well as T2-DRIVE images; PS visibility was assessed on pre-contrast T1 and T2-DRIVE sequences in those with EPP. The length, height, width and volume of the anterior pituitary (AP), PP height and length and PP area were analyzed.

RESULTS

Significant agreement between the two readers was obtained for T2-DRIVE PS measurements in patients with 'eutopic' PP; a significant difference was demonstrated between the intraclass correlation coefficient calculated on the T2-DRIVE and the T1-pre- and post-contrast sequences. The percentage of PS identified by T2-DRIVE in EPP patients was 72.7% compared to 30.3% of T1 pre-contrast sequences. A significant association was found between the visibility of PS on T2-DRIVE and the height of AP.

CONCLUSION

T2-DRIVE sequence is extremely precise and reliable for the evaluation of PS size and the recognition of PS abnormalities; the use of gadolinium-based contrast media does not add significant information and may thus be avoided.

Copeptin role in polyuria-polydipsia syndrome differential diagnosis and reference range in paediatric age

OBJECTIVE

Plasma arginine-vasopressin (AVP) analysis can help in the differential diagnosis of the polyuria-polydipsia syndrome (PPS), even if such investigation is hampered by technical difficulties, conversely to its surrogate copeptin. This study aims to enlarge the existing data on normal copeptin levels in childhood, to evaluate the correlation between copeptin, serum sodium and plasma and urine osmolality, and to assess the utility of the copeptin analysis in the diagnostic work-up of PPS in the paediatric age.

PATIENTS AND METHODS

Plasma copeptin levels were evaluated in 53 children without AVP disorders (control population), in 12 hypopituitaric children and in 15 patients with PPS after water deprivation test (WDT).

RESULTS

Mean basal copeptin levels were 5.2 ± 1.56 (range 2.4-8.6 pmol/L) in the control population, 2.61 ± 0.49 pmol/L in the hypopituitaric children with complete diabetes insipidus (CDI) (P = .04) and 6.21 ± 1.17 pmol/L in the hypopituitaric patients without DI (P = .02). After WDT, among 15 naïve polyuric/polydipsic children, copeptin values greater than 20 pmol/L allowed to identify nephrogenic diabetes insipidus (NDI), concentrations below 2.2 pmol/L complete central DI (CCDI) and between 5 and 20 pmol/L primary polydipsia (PP). Copeptin cut-off level of 3.5 pmol/L distinguished CDI from PP, with a sensitivity and specificity of 75% and 83.3%, respectively.

CONCLUSION

Copeptin evaluation holds promises as a diagnostic tool in paediatric PPS; its interpretation might be useful to promptly distinguish NDI, even avoiding the WDT need.

A rat model for pituitary stalk electric lesion-induced central diabetes insipidus: application of 3D printing and further outcome assessments

A stable and reproducible rat injury model is not currently available to study central diabetes insipidus (CDI) and the neurohypophyseal system. In addition, a system is needed to assess the severity of CDI and measure the accompanying neurobiological alterations. In the present study, a 3D-printed lesion knife with a curved head was designed to fit into the stereotaxic instrument. The neuro-anatomical features of the brain injury were determined by in vivo magnetic resonance imaging (MRI) and arginine vasopressin (AVP) immunostaining on brain sections. Rats that underwent pituitary stalk electrical lesion (PEL) exhibited a tri-phasic pattern of CDI. MRI revealed that the hyperintenseT1-weighted signal of the pituitary stalk was interrupted, and the brain sections showed an enlarged end proximal to the injury site after PEL. In addition, the number of AVP-positive cells in supraoptic nucleus (SON) and paraventricular nucleus (PVN) decreased after PEL, which confirmed the success of the CDI model. Unlike hand-made tools, the 3D-printed lesion knives were stable and reproducible. Next, we used an ordinal clustering method for staging and the k-means’ clustering method to construct a CDI index to evaluate the severity and recovery of CDI that could be used in other multiple animals, even in clinical research. In conclusion, we established a standard PEL model with a 3D-printed knife tool and proposed a CDI index that will greatly facilitate further research on CDI.

T2*-based MR imaging (gradient echo or susceptibility-weighted imaging) in midline and off-midline intracranial germ cell tumors: a pilot study

PURPOSE

The role of T2*-based MR imaging in intracranial germ cell tumors (GCTs) has not been fully elucidated. The aim of this study was to evaluate the susceptibility-weighted imaging (SWI) or T2* gradient echo (GRE) features of germinomas and non-germinomatous germ cell tumors (NGGCTs) in midline and off-midline locations.

METHODS

We retrospectively evaluated all consecutive pediatric patients referred to our institution between 2005 and 2016, for newly diagnosed, treatment-naïve intracranial GCT, who underwent MRI, including T2*-based MR imaging (T2* GRE sequences or SWI). Standard pre- and post-contrast T1- and T2-weighted imaging characteristics along with T2*-based MR imaging features of all lesions were evaluated. Diagnosis was performed in accordance with the SIOP CNS GCT protocol criteria.

RESULTS

Twenty-four subjects met the inclusion criteria (17 males and 7 females). There were 17 patients with germinomas, including 5 basal ganglia primaries, and 7 patients with secreting NGGCT. All off-midline germinomas presented with SWI or GRE hypointensity; among midline GCT, all NGGCTs showed SWI or GRE hypointensity whereas all but one pure germinoma were isointense or hyperintense to normal parenchyma. A significant difference emerged on T2*-based MR imaging among midline germinomas, NGGCTs, and off-midline germinomas (p < 0.001).

CONCLUSION

Assessment of the SWI or GRE characteristics of intracranial GCT may potentially assist in differentiating pure germinomas from NGGCT and in the characterization of basal ganglia involvement. T2*-based MR imaging is recommended in case of suspected intracranial GCT.

Classical and non-classical causes of GH deficiency in the paediatric age

Growth hormone deficiency (GHD) may result from a failure of hypothalamic GHRH production or release, from congenital disorders of pituitary development, or from central nervous system insults including tumors, surgery, trauma, radiation or infiltration from inflammatory diseases. Idiopathic, isolated GHD is the most common sporadic form of hypopituitarism. GHD may also occur in combination with other pituitary hormone deficiencies, and is often referred to as hypopituitarism, combined pituitary hormone deficiency (CPHD), multiple pituitary hormone deficiency (MPHD) or panhypopituitarism. Children without any identifiable cause of their GHD are commonly labeled as having idiopathic hypopituitarism. MRI imaging is the technique of choice in the diagnosis of children with hypopituitarism. Marked differences in MRI pituitary gland morphology suggest different etiologies of GHD and different prognoses. Pituitary stalk agenesis and ectopic posterior pituitary (EPP) are specific markers of permanent GHD, and patients with these MRI findings show a different clinical and endocrine outcome compared to those with normal pituitary anatomy or hypoplastic pituitary alone. Furthermore, the classic triad of ectopic posterior pituitary gland, pituitary stalk hypoplasia/agenesis, and anterior pituitary gland hypoplasia is generally associated with permanent GHD. T2 DRIVE images aid in the identification of pituitary stalk without the use of contrast medium administration. Future developments in imaging techniques will undoubtedly reveal additional insights. Mutations in a number of genes encoding transcription factors - such as HESX1, SOX2, SOX3, LHX3, LHX4, PROP1, POU1F1, PITX, GLI3, GLI2, OTX2, ARNT2, IGSF1, FGF8, FGFR1, PROKR2, PROK2, CHD7, WDR11, NFKB2, PAX6, TCF7L1, IFT72, GPR161 and CDON - have been associated with pituitary dysfunction and abnormal pituitary gland development; the correlation of genetic mutations to endocrine and MRI phenotypes has improved our knowledge of pituitary development and management of patients with hypopituitarism, both in terms of possible genetic counseling, and of early diagnosis of evolving anterior pituitary hormone deficiencies.

Diabetes insipidus in infants and children

Diabetes insipidus, the inability to concentrate urine resulting in polyuria and polydipsia, can have different manifestations and management considerations in infants and children compared to adults. Central diabetes insipidus, secondary to lack of vasopressin production, is more common in children than is nephrogenic diabetes insipidus, the inability to respond appropriately to vasopressin. The goal of treatment in both forms of diabetes insipidus is to decrease urine output and thirst while allowing for appropriate fluid balance, normonatremia and ensuring an acceptable quality of life for each patient. An infant's obligate need to consume calories as liquid and the need for readjustment of medication dosing in growing children both present unique challenges for diabetes insipidus management in the pediatric population. Treatment modalities typically include vasopressin or thiazide diuretics. Special consideration must be given when managing diabetes insipidus in the adipsic patient, post-surgical patient, and in those undergoing chemotherapy or receiving medications that alter free water clearance.

Central Diabetes Insipidus in Infancy With or Without Hypothalamic Adipsic Hypernatremia Syndrome: Early Identification and Outcome

CONTEXT

Neonatal central diabetes insipidus (CDI) with or without adipsia is a very rare complication of various complex hypothalamic disorders. It is associated with greater morbidity and a high risk of developing both hypernatremia and hyponatremia, due to the condition itself or secondary to treatment with vasopressin analogs or fluid administration. Its outcomes have yet to be evaluated.

OBJECTIVE

To investigate the clinical outcomes of patients with neonatal-onset CDI or adipsic CDI with hypernatremia.

DESIGN, SETTING, AND PARTICIPANTS

All patients diagnosed with neonatal CDI in a university hospital-based observational study and followed between 2005 and 2015 were included and analyzed retrospectively.

MAIN OUTCOME MEASURES

The various causes of CDI were grouped. Clinical outcome and comorbidities were analyzed.

RESULTS

Ten of the 12 patients had an underlying condition with brain malformations: optic nerve hypoplasia (n = 3), septo-optic dysplasia (n = 2), semilobar holoprosencephaly (n = 1), ectopic neurohypophysis (n = 3), and unilateral absence of the internal carotid artery (n = 1). The other two were idiopathic cases. During the median follow-up period of 7.8 (4.9-16.8) years, all but one patient displayed anterior pituitary deficiency. Transient CDI was found in three (25%) patients for whom a posterior pituitary hyperintense signal was observed with (n = 2) and without (n = 1) structural hypothalamic pituitary abnormalities, and with no other underlying cerebral malformations. Patients with permanent CDI with persistent adipsia (n = 4) and without adipsia (n = 5) required adequate fluid intake and various doses of desamino-D-arginine-8-vasopressin. Those with adipsia were more likely to develop hypernatremia (45 vs 33%), hyponatremia (16 vs 4%) (P < .0001), and severe neurodevelopmental delay (P < .05) than those without adipsia. Comorbidities were common. The underlying cause remains unknown at the age of 23 years for one patient with CDI and normal thirst.

CONCLUSION

Neonatal CDI may be transient or permanent. These vulnerable patients have high rates of comorbidity and require careful monitoring.

Adipsia in a Diabetes Insipidus Patient

Central diabetes insipidus is a very common disorder after brain surgery or/trauma or even in the presence of brain inflammatory diseases. Polyuria and polydipsia are the clinical markers, but sometimes clinical situations are presenting with no thirst. These are not frequent but are life-treating conditions. Diagnosis is not easy, and for this reason some cases are treated late. We describe here a very infrequent oncological case of dangerous adipsic diabetes insipidus in a young girl who survived.