Absence of anti-rabphilin-3A antibodies in children and young adults with idiopathic central diabetes insipidus: a potential clue to elucidating a tumor etiology

BACKGROUND

Central diabetes insipidus (CDI) is a rare condition caused by various underlying diseases, including neoplasms, autoimmune diseases, and infiltrative diseases. Differentiating between CDI etiologies is difficult. What has initially been classified as "idiopathic" central diabetes insipidus might in fact underlie various pathogenic mechanisms that are less understood to date and/or are not obvious at initial presentation. Therefore, even if idiopathic CDI is diagnosed at the time of onset, it is common for tumors such as germinoma to develop during surveillance. Crucially, a delayed diagnosis of germinoma may be associated with a worse prognosis. Recently, the presence of anti-rabphilin-3A antibodies has been found to be a highly sensitive and specific marker of lymphocytic infundibuloneurohypophysitis, an autoimmune-mediated CDI.

CASE PRESENTATION

We herein present two cases, namely, a 13-year-old boy (patient 1) and a 19-year-old young man (patient 2) who were diagnosed with idiopathic CDI. In both patients, panhypopituitarism developed. Magnetic resonance imaging revealed pituitary stalk thickening and pituitary swelling approximately 1 1/2 years after the onset of CDI. Western blotting did not reveal the presence of anti-rabphilin-3A antibodies in serum in either patient, suggesting that autoimmune mechanisms might not be involved. Both patients were subsequently diagnosed with germinoma on pathological examination. They received chemotherapy, followed by radiation therapy. Notably, testosterone and insulin-like growth factor-1 levels normalized, and libido and beard growth recovered after chemoradiotherapy in patient 2.

CONCLUSION

Our data suggest that the absence of anti-rabphilin-3A antibodies in young patients clinically diagnosed with idiopathic CDI may increase the probability of the development of non-lymphocytic lesions, including germinoma. We thus recommend a more attentive approach at the onset of these diseases.

Pituitary Stalk Thickening: Causes and Consequences. The Children's Memorial Health Institute Experience and Literature Review

BACKGROUND

Pituitary stalk thickening (PST) is a rare abnormality in the pediatric population. Its etiology is heterogeneous. The aim of the study was to identify important clinical, radiological and endocrinological manifestations of patients with PST and follow the course of the disease.

MATERIALS AND METHODS

It is a study conducted in 23 patients (13 boys) with PST with/without central diabetes insipidus (CDI) diagnosed between 1990 and 2020 at Children's Memorial Health Institute (CMHI) in Warsaw, Poland. We analyzed demographic data, clinical signs and symptoms, radiological findings, tumor markers, hormonal results, treatment protocols and outcomes.

RESULTS

The median age at the diagnosis of PST was 9.68 years (IQR: 7.21-12.33). The median time from the onset of the symptoms to the diagnosis was 2.17 years (IQR: 1.12-3.54). The most common initially reported manifestations were polydipsia, polyuria and nocturia (82.6%); most of the patients (56.5%) also presented decreased growth velocity. Hormonal evaluation at the onset of PST revealed: CDI (91.3%), growth hormone deficiency (GHD) (56.5%), hyperprolactinemia (39%), central hypothyroidism (34.8%), adrenal insufficiency (9%), precocious puberty (8.7%). The majority of the patients were diagnosed with germinoma (seventeen patients - 73.9%, one of them with teratoma and germinoma). Langerhans cell histiocytosis (LCH) was identified in three patients (multisystem LCH in two patients, and unifocal LCH in one patient). A single case of atypical teratoid rhabdoid tumor, suspected low-grade glioma (LGG) and lymphocytic infundibuloneurohypophysitis (LINH). The overall survival rate during the observational period was 87.0%.

CONCLUSIONS

The pituitary infundibulum presents a diagnostic imaging challenge because of its small size and protean spectrum of disease processes. Germinoma should be suspected in all children with PST, especially with CDI, even when neurological and ophthalmological symptoms are absent.

Central Diabetes Insipidus Caused by Arginine Vasopressin Gene Mutation: Report of a Novel Mutation and Review of Literature

Familial neurohypophyseal diabetes insipidus (FNDI) is an autosomal dominant hereditary disorder characterized by severe polydipsia and polyuria that usually presents in early childhood. In this study, we describe a new arginine vasopressin (AVP) gene mutation in an ethnic German family with FNDI and provide an overview of disease-associated AVP-gene mutations that are already described in literature. Three members of a German family with neurohypophyseal diabetes insipidus were studied. Isolated DNA from peripheral blood samples was used for mutation analysis by sequencing the whole coding region of AVP-NPII gene. Furthermore, we searched the electronic databases MEDLINE (Pubmed) as well as HGMD, LOVD-ClinVar, db-SNP and genomAD in order to compare our cases to that of other patients with FNDI. Genetic analysis of the patients revealed a novel heterozygote missense mutation in exon 2 of the AVP gene (c.274T>G), which has not yet been described in literature. We identified reports of more than 90 disease-associated mutations in the AVP gene in literature. The novel mutation of the AVP gene seems to cause FNDI in the presented German family. Similar to our newly detected mutation, most mutations causing FNDI are found in exon 2 of the AVP gene coding for neurophysin II. Clinically, it is important to think of FNDI in young children presenting with polydipsia and polyuria.

Central diabetes insipidus and pituitary stalk thickening in adults: distinction of neoplastic from non-neoplastic lesions

CONTEXT

Association of central diabetes insipidus (CDI) and pituitary stalk thickening (PST) may have several etiologies (including malignancies) and differential diagnosis remains often difficult.

OBJECTIVE

The purpose of this study was to identify which clinical, biochemical or radiological features could help clinicians to make an etiological diagnosis, especially distinguishing neoplastic from non-neoplastic pituitary stalk lesions.

DESIGNS AND METHODS

We retrospectively analyzed clinical, biochemical, radiological and histological data of 38 adult patients diagnosed with CDI and PST of proven etiology.

RESULTS

Of the 38 pituitary stalk lesions included, 11 (29%) were neoplastic. A histopathological diagnosis was obtained in 22/38 (58%) patients. The three most frequently observed etiologies of PST were neuroinfundibulitis (34%), germinoma (21%) and histiocytosis (18%). Pituitary stalk thickness was larger for neoplastic lesions, particularly germinomas. Male gender and a very young age were statistically associated with a risk of germinoma. At least one anterior pituitary deficit was observed in nearly 60% of patients. Patients with neoplastic PST were more affected by multiple anterior pituitary dysfunction than patients with benign PST. A high serum prolactin level was individually the best predictor of a neoplastic origin (90% sensitivity and 60% specificity for a serum prolactin level 1.27-fold above the normal upper limit (ULN)).

CONCLUSION

We confirm a relatively high risk of malignancy in adult patients presenting with the association of CDI and PST. Young age, male gender, a very large thickening of the stalk, multiple anterior pituitary deficits and prolactin above 1.3× ULN increase the likelihood of a neoplastic origin.

Forty-One Individuals With Mutations in the AVP-NPII Gene Associated With Familial Neurohypophyseal Diabetes Insipidus

CONTEXT

Familial neurohypophyseal diabetes insipidus is a rare disease produced by a deficiency in the secretion of antidiuretic hormone and is caused by mutations in the arginine vasopressin gene.

OBJECTIVE

Clinical, biochemical, and genetic characterization of a group of patients clinically diagnosed with familial neurohypophyseal diabetes insipidus, 1 of the largest cohorts of patients with protein neurophysin II (AVP-NPII) gene alterations studied so far.

DESIGN

The AVP-NPII gene was screened for mutations by PCR followed by direct Sanger sequencing in 15 different unrelated families from Spain.

RESULTS

The 15 probands presented with polyuria and polydipsia as the most important symptoms at the time of diagnosis. In these patients, the disease was diagnosed at a median of 6 years of age. We observed 11 likely pathogenic variants. Importantly, 4 of the AVP-NPII variants were novel (p.(Tyr21Cys), p.(Gly45Ser), p.(Cys75Tyr), p.(Gly88Cys)).

CONCLUSIONS

Cytotoxicity seems to be due to consequences common to all the variants found in our cohort, which are not able to fold correctly and pass the quality control of the ER. In concordance, we found autosomal dominant familial neurohypophyseal diabetes insipidus in the 15 families studied.

Role of protein aggregation and degradation in autosomal dominant neurohypophyseal diabetes insipidus

This review focuses on the cellular and molecular aspects underlying familial neurohypophyseal diabetes insipidus (DI), a rare disorder that is usually transmitted in an autosomal-dominant fashion. The disease, manifesting in infancy or early childhood and gradually progressing in severity, is caused by fully penetrant heterozygous mutations in the gene encoding prepro-vasopressin-neurophysin II, the precursor of the antidiuretic hormone arginine vasopressin (AVP). Post mortem studies in affected adults have shown cell degeneration in vasopressinergic hypothalamic nuclei. Studies in cells expressing pathogenic mutants and knock-in rodent models have shown that the mutant precursors are folding incompetent and fail to exit the endoplasmic reticulum (ER), as occurs normally with proteins that have entered the regulated secretory pathway. A portion of these mutants is eliminated via ER-associated degradation (ERAD) by proteasomes after retrotranslocation to the cytosol. Another portion forms large disulfide-linked fibrillar aggregates within the ER, in which wild-type precursor is trapped. Aggregation capacity is independently conferred by two domains of the prohormone, namely the AVP moiety and the C-terminal glycopeptide (copeptin). The same domains are also required for packaging into dense-core secretory granules and regulated secretion, suggesting a disturbed balance between the physiological self-aggregation at the trans-Golgi network and avoiding premature aggregate formation at the ER in the disease. The critical role of ERAD in maintaining physiological water balance has been underscored by experiments in mice expressing wild-type AVP but lacking critical components of the ERAD machinery. These animals also develop DI and show amyloid-like aggregates in the ER lumen. Thus, the capacity of the ERAD is exceeded in autosomal dominant DI, which can be viewed as a neurodegenerative disorder associated with the formation of amyloid ER aggregates. While DI symptoms develop prior to detectable cell death in transgenic DI mice, the eventual loss of vasopressinergic neurons is accompanied by autophagy, but the mechanism leading to cell degeneration in autosomal dominant neurohypophyseal DI still remains unknown.

Clinical Characteristics of Pediatric Patients With Sellar and Suprasellar Lesions Who Initially Present With Central Diabetes Insipidus: A Retrospective Study of 55 Cases From a Large Pituitary Center in China

Purpose: To increase knowledge for the early differential diagnosis and accurate therapeutic strategies for pediatric patients with sellar or suprasellar region (SSR) lesions who initially present with central diabetes insipidus (CDI). Methods: This is a retrospective review of 55 pediatric patients (≤14 years old) with identified lesions in the SSR who initially presented with CDI at a large pituitary center between 2012 and 2018. The following data were summarized: demographic, clinical, endocrine, and neuroimaging data, intraoperative findings, histopathological findings, treatments, and prognosis. Results: In our group, the etiologies of the SSR lesions included germ cell tumors (GCTs, 74.5%), Langerhans cell histiocytosis (LCH, 18.2%), and craniopharyngioma (CP, 7.3%). Almost all patients (50/55, 90.9%) showed anterior pituitary dysfunction [multiple axes dysfunction (38), and isolated axis dysfunction (14)], while the GH/IGF-I axis was the most affected. Most GCT patients presented with various clinical manifestations besides CDI and had elevated β-HCG, whereas LCH and CP patients mostly presented few non-specific symptoms besides CDI and most had normal level tumor markers. Sellar MRI demonstrated that posterior pituitary bright spot disappearance occurred in all patients, and pituitary stalk thickening was observed in 96.7% of patients. Treatment varied due to the different etiologies of the SSR lesions. After follow-up for 35.4 ± 20.2 months, the proportions of patients who needed AVP (arginine vasopressin) for GCT, LCH, and CP were 86.5, 100, and 75%, respectively, and the proportions of patients who needed HRT were 89.2, 50, and 75%, respectively. Conclusion: For pediatric SSR lesions that first manifest as CDI, we should comprehensively consider clinical characteristics and imaging features to aid in their early differential diagnosis. Tumor markers and surgical histopathology are also great complements for the differential diagnosis. Additionally, various treatment strategies should be adopted according to different causes to improve the child's prognosis and quality of life.

Isolated Langerhans cell histiocytosis in the hypothalamic-pituitary region: a case report

BACKGROUND

Langerhans cell histiocytosis (LCH) is a rare disease that mainly affects children, but this disease is significantly rarer in patients who are older than 15 years. In this disease, any organ can be involved. The skeleton, skin and lung are commonly affected, and isolated hypothalamic-pituitary (HP) involvement is relatively rare. Here we report a 17-year-old adolescent with isolated HP-LCH of enlarged pituitary stalk presented with central diabetes insipidus (CDI).

CASE PRESENTATION

A 17-year-old male adolescent with polydipsia and polyuria accompanied with elevated serum sodium level and low urine osmolality for 3 weeks was referred to our hospital. After admission, hormonal evaluation showed that his growth hormone (GH) was slightly elevated, and serum osmolality and glucose were normal. The fluid deprivation-vasopressin test demonstrated CDI. Imaging examination showed an obvious thickening of the pituitary stalk. Lymphocytic hypophysitis, sarcoidosis and granulation tissue lesions were suspected. After oral 1-deamino-8-Darginine vasopressin (DDAVP) and prednisone were administered for 2 months, symptoms were relieved, and he discontinued taking the drugs by himself. On reexamination, imaging revealed changes in the size and shape of the pituitary stalk, with thickened nodules. Then, a diagnostic biopsy of the pituitary stalk lesion was performed. Immunohistochemistry confirmed the definitive diagnosis of LCH. The clinical symptoms subsided with oral hormone replacements.

CONCLUSION

CDI is a rare symptom in children and adolescents. Most of the causes are idiopathic, while others are caused by central nervous system (CNS) disorders. Meanwhile, lymphocytic hypophysitis, germinoma, LCH and other CNS disorders can all present as thickening of the pituitary stalk, diffuse enlargement of the pituitary gland, and weakening of high signal intensity in the neurohypophysis on magnetic resonance imaging (MRI). The differential diagnosis among these diseases depends on immunohistochemistry evidence.

Clinical presentation and outcome of children with central diabetes insipidus associated with a self-limited or transient pituitary stalk thickening, diagnosed as infundibuloneurohypophysitis

OBJECTIVE

Despite lymphocytic or autoimmune infundibuloneurohypophysitis (INH) is an increasingly recognized aetiology in children with central diabetes insipidus (CDI); clinical data on epidemiology (clinical evolution, predisposing factors, complications), diagnosis and management of this entity are limited and mostly based on published case reports. The aim of this study was to gain a broader insight in the natural history of this disease by analysing the clinical presentation, radiological pituitary stalk changes, associated autoimmunity and hormonal deficiencies in children with CDI and a self-limiting or transient stalk thickening (ST), diagnosed as autoimmune infundibuloneurohypophysitis, during the last 15 years in four Belgian university hospitals.

DESIGN AND PATIENTS

The medical files of nine CDI patients with a ST at initial presentation and no signs of Langerhans cell histiocytosis or germinoma at presentation and/or during follow-up of more than 1.5 years were reviewed.

RESULTS

Age at presentation ranged from 3 to 14 years. Two patients had a positive family history of autoimmunity. Three children presented with associated growth failure, two with nausea and one with long-standing headache. Median maximal diameter of the stalk was 4.6 mm (2.7-10 mm). Four patients had extra-pituitary brain anomalies, such as cysts. One patient had central hypothyroidism, and another had a partial growth hormone deficiency at diagnosis. Within a mean follow-up of 5.4 (1.5-15) years, stalk thickening remained unchanged in two patients, regressed in one and normalized in six children. CDI remained in all, while additional pituitary hormone deficiencies developed in only one patient.

CONCLUSIONS

In this series of children INH with CDI as initial presentation, CDI was permanent and infrequently associated with anterior pituitary hormone deficiencies, despite a frequent association with nonstalk cerebral lesions.

Genetic forms of neurohypophyseal diabetes insipidus

Neurohypophyseal diabetes insipidus is characterized by polyuria and polydipsia owing to partial or complete deficiency of the antidiuretic hormone, arginine vasopressin (AVP). Although in most patients non-hereditary causes underlie the disorder, genetic forms have long been recognized and studied both in vivo and in vitro. In most affected families, the disease is transmitted in an autosomal dominant manner, whereas autosomal recessive forms are much less frequent. Both phenotypes can be caused by mutations in the vasopressin-neurophysin II (AVP) gene. In transfected cells expressing dominant mutations, the mutated hormone precursor is retained in the endoplasmic reticulum, where it forms fibrillar aggregates. Autopsy studies in humans and a murine knock-in model suggest that the dominant phenotype results from toxicity to vasopressinergic neurons, but the mechanisms leading to cell death remain unclear. Recessive transmission results from AVP with reduced biologic activity or the deletion of the locus. Genetic neurohypophyseal diabetes insipidus occurring in the context of diabetes mellitus, optic atrophy, and deafness is termed DIDMOAD or Wolfram syndrome, a genetically and phenotypically heterogeneous autosomal recessive disorder caused by mutations in the wolframin (WFS 1) gene.

From cerebral salt wasting to diabetes insipidus with adipsia: case report of a child with craniopharyngioma

Craniopharyngioma is associated with a wide and interesting variety of sodium states both by itself and following surgical resection. These are often challenging to diagnose, especially given their dynamic nature during the perioperative course. We present the case of a boy with craniopharyngioma who had hyponatremia due to cerebral salt wasting preoperatively, developed diabetes insipidus (DI) intraoperatively and proceeded to develop hypernatremia with adipsic DI.

CONCLUSION

Cerebral salt wasting is a rare presenting feature of craniopharyngioma. Postoperative DI can be associated with thirst abnormalities including adipsia due to hypothalamic damage; careful monitoring and a high index of suspicion are required for its detection. Adipsic DI is a difficult condition to manage; hence a conservative surgical approach is suggested.

Hypothalamic type of hypopituitarism and central diabetes insipidus probably linked to Rathke's cleft cyst

A 73-year-old woman was admitted due to weight loss and generalized malaise. The basal levels of all the anterior pituitary hormones, except for prolactin, were reduced. However, they were all elevated in response to exogenous hypothalamic hormones. After starting hydrocortisone replacement, the patient had polyuria of >5,000 mL/day. T1-weighted MRI depicted a low signal of an oval mass in the sella turcica and an iso-intense signal of another mass at the pituitary stalk. These findings indicate a hypothalamic type of hypopituitarism and masked central diabetes insipidus which possibly derived from the atypical occupation of Rathke's cleft cyst at the pituitary stalk.

Surgical biopsies in patients with central diabetes insipidus and thickened pituitary stalks

Thickened pituitary stalks (TPSs) on magnetic resonance imaging (MRI) result from diverse pathologies; therefore, it is essential to make specific diagnoses for clinical decision-making. The diagnoses and indications for surgical biopsies in patients with central diabetes insipidus (CDI) and TPSs are thoroughly discussed in this paper. Thirty-seven patients with CDI and TPSs were retrospectively reviewed. The mean age at the diagnosis of CDI was 29.0 ± 15.9 years (range 8.0-63.3), and the median duration of follow-up was 5.5 ± 2.8 years (range 0.7-13.0). Anterior pituitary hormone deficiencies were documented in 26 (70.3 %) patients. All patients had a TPS on MRI at the diagnosis of CDI, and 21 (56.8 %) patients exhibited radiological changes during the follow-up. Of these 21 patients, 11 exhibited increases in the thickness of the stalk, and two patients exhibited reversals of the TPSs. Involvements of the hypothalamus, pituitary gland, basal ganglia or supersellar, and pineal gland were found in four, three, one, and 1 patient, respectively. Ultimately, clear diagnoses were established in 17 patients who underwent biopsies, nine of whom had germinomas, six of whom had Langerhans cell histiocytosis, one of whom had a granular cell tumor, and one of whom had Erdheim-Chester disease. Patients with CDI and TPSs should submit to periodic clinic follow-ups with serial MRI assessments to establish anterior pituitary deficiencies and to detect radiological progressions that are appropriate for surgical biopsies. Endoscopic-assisted microsurgery via the supraorbital keyhole approach is a good choice for the biopsy of pituitary stalk lesions.

Erdheim-Chester disease and pituitary involvement: a unique case and the literature

An early thirties man diagnosed with Erdheim-Chester disease (ECD) was simultaneously disclosed to have hypogonadotropic hypogonadism, central adrenal insufficiency, and GH deficiency in addition to central diabetes insipidus (CDI). Pituitary magnetic resonance imaging (MRI) showed swelling in the stalk, enlargement of the anterior lobe with delayed enhancement, and loss of high intensity of the posterior lobe on T1-weighted images, suggesting of pituitary involvement of ECD. Three months after starting treatment with interferon α and zoledronic acid, polyuria and polydipsia were ameliorated without DDAVP, accompanied with improvement of MRI. Simultaneously technetium-99m bone scintigraphy showed improvement, accompanied with a relief of bone pain and high fever. In contrast, he developed secondary hypothyroidism with slight enlargement of anterior pituitary gland without relapse of CDI, suggesting of different responses to treatment with interferon α between anterior pituitary lobe and posterior one. So far he continues to be replaced with deficient hormone replacement therapy. As for bone pain, it remains to be controlled with the decreased levels of bone resorption marker with decreased abnormal uptake in bone scintigraphy although zoledronic acid was discontinued for osteonecrosis of the jaw. For four years, he has not showed new involvement at other organs besides bones and the pituitary. While CDI is known to be very common in ECD, improvement of CDI has been reported in a few cases. Other endocrine manifestations, especially with detailed endocrine status, have been also reported in limited cases. Thus we report this case and review the literature.

Prednisolone markedly reduced serum IgG4 levels along with the improvement of pituitary mass and anterior pituitary function in a patient with IgG4-related infundibulo-hypophysitis

In 2011 a 76 year-old man with a medical history of diabetes, hypertension and autoimmune pancreatitis was admitted to our hospital because of anorexia, general malaise and repeated hypoglycemia. When he was 72 years old, he suffered from pancreatitis, and pancreas head tumor was operated. IgG4-related pancreatitis was diagnosed histopathologically. On admission anterior pituitary function test revealed impaired response of ACTH and cortisol to CRH, and no response of GH, TSH and gonadotropin to GHRH, TRH and LHRH, respectively. Baseline PRL level was elevated. Serum IgG and IgG4 levels were markedly elevated. Pituitary MRI showed significant enlargement of pituitary gland and stalk. Chest CT suggested IgG4-related lung disease. IgG4-related infundibulo-hypophysitis was diagnosed based on the above mentioned past history and results of present examinations. Twenty mg of hydrocortisone, followed by 20 mg of prednisolone (PSL) and 25 μg of levothyroxine markedly reduced serum IgG4 levels and ameliorated the symptom, the size of pituitary and stalk, and anterior pituitary function (TSH, GH and gonadotropin), although diabetes insipidus became apparent due to glucocorticoid administration. This is a typical case of IgG4-related hypophysitis in which PSL causes marked improvement of pituitary mass and pituitary function along with the reduction of serum IgG4 levels.

Late onset of familial neurogenic diabetes insipidus in monozygotic twins

OBJECTIVE

Autosomal dominant familial diabetes insipidus (FNDI) is a rare disease characterized by polydipsia and polyuria due to deficiency of the antidiuretic hormone, arginine vasopressin (AVP). We report the first Slovak family with the disease. Noteworthy is the concordantly belated debut of the disease symptoms in two monozygotic twin proband girls in the age of 17 years. Because of inconclusive results of water deprivation test consistent with partial diabetes insipidus (DI), missing "bright spot" of posterior pituitary gland in T1-weighted magnetic resonance imaging and family occurrence of polyuria and polydipsia on anamnestic evaluation.

METHODS

Molecular genetic testing of the AVP gene was proceeded, because of the inconclusive results of water deprivation test consistent with partial diabetes insipidus, missing "bright spot" of posterior pituitary gland in T1-weighted magnetic resonance imaging and family occurrence of polyuria and polydipsia on anamnestic evaluation.

RESULTS

Genetic analysis revealed a heterozygous g.279G>A substitution that predicts a p.Ala19Thr substitution in the signal peptide of the AVP prohormone. The wide intrafamiliar variations (3 to 17 years) in disease onset together with the concordantly delayed debut of polyuria in two monozygotic twin girls suggest that individual differences in genetic influences family environmental factors may modify the penetrance of the mutation of the AVP gene.

CONCLUSIONS

The present paper supports the notion that molecular genetic evaluation should be performed in all patients with familial occurrence of DI regardless of the clinical results.

Hypothalamic pituitary complications in Kabuki syndrome

Kabuki syndrome is characterized by distinctive facial features, multiple anomalies and mental retardation. In this syndrome, structural CNS abnormalities are commonly observed, but congenital abnormalities in the pituitary gland or hypothalamus have rarely been reported. We searched the published medical literature on the complications in hypothalamic pituitary axis in this syndrome. As a result, only nine patients with Kabuki syndrome had been reported to have complications in hypothalamic pituitary axis in previous papers. Among the nine reported patients and one presented case in this report, GH deficiency was the most frequent complication and found in six patients. Precocious puberty and central diabetes insipidus (DI) was identified in two cases, respectively, and ACTH deficiency was found in one. One case had combination of GH deficiency and central DI. Three of the 10 patients demonstrated abnormal pituitary findings in MRI study. Two of the six patients with GH deficiency were accompanied with premature thelarche. This review highlights that patients with Kabuki syndrome could present various clinical manifestations due to abnormalities in hypothalamic pituitary axis.

Subclinical diabetes insipidus

Subclinical central diabetes insipidus (CDI) can be the outcome of a number of diseases that affect the hypothalamus-infundibulum-post hypophysis axis. One of the most common forms of subclinical CDI is linked to an autoimmune pathogenesis even if other causes may be also responsible. Among these, pregnancy, traumatic and surgical brain injury and some infiltrative, vascular, infectious and neoplastic diseases have been reported with increasing frequency. The natural history of autoimmune CDI seems to evolve through 4 functional stages according to the presence of antibodies to vasopressin-secreting cells (AVPcAb) and the relationship between their behavior overtime, the variations of posterior pituitary function and the characteristics of hypothalamic-hypophyseal region on magnetic resonance imaging. This staging is of crucial importance for the therapeutic strategy, taking into account that some stages could be still reversible. Several medical treatments have been suggested to interrupt the progression toward clinical CDI but the results are still discussed.

Pituitary and systemic autoimmunity in a case of intrasellar germinoma

Germinomas arising in the sella turcica are difficult to differentiate from autoimmune hypophysitis because of similar clinical and pathological features. This differentiation, nevertheless, is critical for patient care due to different treatments of the two diseases. We report the case of an 11-year-old girl who presented with diabetes insipidus and growth retardation, and was found to have an intra- and supra-sellar mass. Initial examination of the pituitary biopsy showed diffuse lymphocytic infiltration of the adenohypophysis and absent placental alkaline phosphatase expression, leading to a diagnosis of hypophysitis and glucocorticoid treatment. Because of the lack of clinical and radiological response, the pituitary specimen was re-examined, revealing this time the presence of scattered c-kit and Oct4 positive germinoma cells. The revised diagnosis prompted the initiation of radiotherapy, which induced disappearance of the pituitary mass. Immunological studies showed that the patient's serum recognized antigens expressed by the patient's own germinoma cells, as well as pituitary antigens like growth hormone and systemic antigens like the Sjögren syndrome antigen B and alpha-enolase. The study first reports the presence of pituitary and systemic antibodies in a patient with intrasellar germinoma, and reminds us that diffuse lymphocytic infiltration of the pituitary gland and pituitary antibodies does not always indicate a diagnosis of autoimmune hypophysitis.

Central diabetes insipidus as the inaugural manifestation of Langerhans cell histiocytosis: natural history and medical evaluation of 26 children and adolescents

CONTEXT

Isolated central diabetes insipidus (CDI) can be the first manifestation of Langerhans cell histiocytosis (LCH), creating diagnostic dilemmas such as dysgerminoma and other inflammatory lesions.

METHOD

In 2010, the French national LCH registry had enrolled 1236 LCH patients under 18 yr of age. Isolated CDI was the initial presentation of LCH in 26 patients. We reviewed their clinical and magnetic resonance imaging (MRI) features.

RESULTS

Median age at the diagnosis of CDI was 9.6 yr (1.8-16.3), and median follow-up after CDI diagnosis was 9.9 yr (3.5-26.6). In addition to CDI, two patients had visual field defects, four had secondary amenorrhea, and 11 had anterior pituitary deficiency. Cerebral imaging (including computed tomography in two cases), performed in 22 patients within 3 months of CDI diagnosis, showed pituitary stalk thickening in 14 patients, which was moderate (3.0-7 mm) in nine cases and marked (>7 mm) in five cases. In eight cases, the lesion extended to the floor of the third ventricle. One child with LCH presented with a mild enlarged sellar content. During follow-up, 22 patients developed extrapituitary involvement, mainly of bone (n = 15), lung (n = 9), and skin (n = 9). Pituitary biopsy was performed in eight cases and was conclusive in six cases.

CONCLUSIONS

Pituitary stalk thickening can be observed in LCH as well as lesions extending to the floor of the third ventricle. In all cases but one, the intrasellar content was not enlarged. Long-term follow-up with close attention to bone, skin, and lung disorders may lead to the diagnosis of LCH.

A case of central diabetes insipidus following probable type A/H1N1 influenza infection

The major causes of central diabetes insipidus (CDI) are neoplastic or infiltrative lesions of the hypothalamus or pituitary gland, severe head injuries, or pituitary or hypothalamic surgery. Lymphocytic infundibuloneurophysitis (LINH) is associated with autoimmune inflammatory disease of the pituitary gland, but the exact etiology is unknown. CDI caused by viral infections has been rarely reported. Here, we describe the case of a 22-year-old man who was in good health until 2 months prior to admission, presented with acute development of polyuria and polydipsia, and showed increased urinary volume up to 9000 mL/day. The patient showed elevated serum osmolality and low urine osmolality, with a low level of antidiuretic hormone. Endocrinological findings revealed CDI, but his arterial pituitary function appeared normal. Magnetic resonance imaging revealed significant enlargement of the pituitary stalk. We suspected CDI due to LINH based on non-transsphenoidal biopsy findings. He was diagnosed as type A influenza,and given oral therapeutic agents. However, acute onset of polyuria and polydipsia occurred 10 days after the influenza diagnosis. The available epidemiological information regarding the outbreak of influenza around that time strongly suggested that the patient was infected with the A/H1N1 influenza virus, although this virus had not been detected on polymerase chain reaction testing. In the present case, the autoimmune mechanism of LINH may have been associated with novel influenza A/H1N1 virus infection.

Mechanisms underlying progressive polyuria in familial neurohypophysial diabetes insipidus

Familial neurohypophysial diabetes insipidus (FNDI), an autosomal dominant disorder, is mostly caused by mutations in the gene of neurophysin II (NPII), the carrier protein of arginine vasopressin (AVP). The analyses of knock-in mice expressing a mutant NPII that causes FNDI in humans demonstrated that polyuria progressed substantially in the absence of loss of AVP neurones. Morphological analyses revealed that inclusion bodies were present in the AVP neurones in the supraoptic nucleus and that the size and numbers of inclusion bodies gradually increased in parallel with the increases in urine volume. Electron microscopic analyses showed that aggregates existed in the endoplasmic reticulum (ER) of AVP neurones. These data suggest that cell death is not the primary cause of polyuria in FNDI, and that the aggregate formation in the ER is likely to be related to the pathogenesis of the progressive polyuria.

Lymphocytic hypophysitis with a long latent period from onset of central diabetes insipidus to development of pituitary enlargement

A 61-year-old man presented with central lymphocytic hypophysitis. Initial pituitary MRI imaging was normal, except for loss of the "bright spot" of the posterior lobe. A diagnosis of idiopathic diabetes insipidus was made. Two years later, pituitary gland enlargement with panhypopituitarism was detected. Eight months after commencing a replacement dose of corticosteroid, the pituitary enlargement was reduced in size. These findings resulted in a diagnosis of lymphocytic hypophysitis. In patients with idiopathic diabetes insipidus, it is important to suspect lymphocytic hypophysitis and to perform a long follow-up to repeat endocrinological examinations and pituitary imaging.

Myelodysplastic syndrome complicated by central diabetes insipidus and cerebral salt wasting syndrome with peculiar change in magnetic resonance images

Central diabetes insipidus (CDI) could occurs in patients with myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML), because of infiltration of leukemic cells into the neurohypophysis or some other reason and it is closely associated with abnormalities of chromosome 7. We report a case of MDS with abnormalities of chromosome 7, presenting as CDI followed by deterioration of polyuria and hyponatremia with a decreased extracellular fluid volume. Magnetic resonance imaging (MRI) revealed symmetrically enhanced lesions in the hypothalamus. Fludrocortisone treatment normalized his serum sodium level and cerebral salt wasting syndrome (CSWS) was suspected.

Transient polyuria related to central diabetes insipidus caused by lymphocytic infundibulo-neurohypophysitis in a patient treated for Graves' disease

A 45-year-old man was hospitalized because of weight loss, finger tremor, thirst, polydipsia and increased urinary frequency. He was diagnosed with Graves' disease (GD) and central diabetes insipidus (CDI). Magnetic resonance imaging revealed the enlarged posterior pituitary with thickened stalk. Histological examination obtained from biopsy of the pituitary revealed lymphocytic infundibulo-neurohypophysitis. He received treatment with thiamazole (MMI) for GD and desmopressin acetate (DDAVP) for CDI. However, DDAVP administration could be discontinued as GD was gradually improved. This course indicates that not only the recovered renal response to arginine-vasopressin but also the immunomodulative effects of MMI might attribute to the improvement of polyuria.

Spontaneous regression of isolated neurohypophyseal langerhans cell histiocytosis with diabetes insipidus

In pediatric and adolescent patients, the most common causes for a thickened pituitary stalk with central diabetes insipidus are germ cell tumors, lymphocytic infundibuloneurohypophysitis (LIN), and Langerhans cell histiocytosis (LCH). We describe here a 13-year-old girl who had an abrupt onset of polyuria and polydipsia. Magnetic resonance imaging of the brain revealed thickening of the pituitary stalk, and loss of the physiological hyperintense signal of the posterior pituitary gland. Based on a histopathology, she was diagnosed as having LCH. Another LCH lesion was not detected. The prognoses for LCH patients with single-system and single-site are generally good so we decided on only simple observation. The lesion spontaneously regressed 3 months later, resembling a typical self-limiting course of LIN. In conclusion, the present case suggests that 1) radiological differential diagnosis between LIN and LCH is so difficult that histological confirmation is crucial for correct diagnosis, 2) some past cases of histologically-unconfirmed LIN can include LCH, 3) solitary neurohypophyseal LCH can shrink spontaneously up to near remission level.

Pituitary involvement in Wegener's granulomatosis

Wegener's granulomatosis (WG) is an anti-neutrophil cytoplasmic antibody (ANCA)-associated systemic vasculitis of small and medium-sized vessels. Pituitary involvement in WG is rare with only 22 previous case reports in the English medical literature between 1966 and 2006. Herein we report another patient with WG-related diabetes insipidus (DI) and partial disruption of the anterior pituitary axes. We also review the clinical features, imaging findings, treatment and outcome of WG-related pituitary involvement. Isolated pituitary involvement in the absence of lung or renal complications in WG is rare and described in only one previous patient. Pituitary involvement in WG is usually associated with other organ involvement (96% of cases)-commonly upper respiratory tract (93%), lungs (73%) and kidneys (67%). Abnormalities are often seen in the hypothalamo-pituitary region on magnetic resonance imaging (MRI) or computed tomography (CT) of the head (90% of cases). In 65% of reported cases, cyclophosphamide-based induction therapy was used with a subsequent relapse rate of 27%, occurring at a median of 10.5 months (range: 7-36 months) after initiation of treatment. In comparison, induction treatment without cyclophosphamide was associated with relapse in 50% at a median of 4.5 months (range: 4-18 months after starting treatment) suggesting more frequent and earlier relapse. Therefore, we recommend treatment with cyclophosphamide-based regimen. Despite treatment of WG, only 17% (4 patients) had full recovery in their pituitary function. The long-term prognosis of patients with WG and pituitary involvement is not known.

Medullary thyroid carcinoma metastatic to the pituitary gland: an unusual site of metastasis

We present a case of metastatic medullary thyroid carcinoma involving the pituitary gland of a 23-year-old woman with multiple endocrine neoplasia type 2b who presented with diabetes insipidus and visual loss. The diagnostic features, including cytomorphology and immunohistochemistry, used to differentiate pituitary adenoma from metastatic medullary carcinoma are discussed. Pituitary metastases and tumor-to-tumor metastases in this region are also highlighted.

The diagnosis of children with central diabetes insipidus

Central diabetes insipidus is the end result of a number of different diseases that affect the hypothalamic-neurohypophyseal system. In many patients, especially children and young adults, it is caused by the destruction or degeneration of neurons that originate in the supraoptic and paraventricular nuclei of the hypothalamus. The known causes of these lesions include germinoma or craniopharyngioma; Langerhans cell histiocytosis; local inflammatory, autoimmune or vascular diseases; trauma resulting from surgery or an accident; sarcoidosis; metastases; and midline cerebral and cranial malformations. In rare cases, genetic defects in AVP synthesis that are inherited as autosomal dominant, autosomal recessive or X-linked recessive traits are the underlying cause. Accurate diagnostic differentiation is essential for both safe and effective disease management. Proper etiological diagnosis can be achieved via a series of steps that start with clinical observations and then progress, as needed, to more sophisticated methods. Indeed, magnetic resonance imaging (MRI) represents the examination method of choice for evaluating hypothalamic-pituitary-related endocrine diseases due to its ability to provide strongly-contrasted high-resolution multi-planar and spatial images. Specifically, MRI allows a detailed and precise anatomical study of the pituitary gland by differentiating between the anterior and posterior pituitary lobes. MRI identification of pituitary hyperintensity in the posterior part of the sella, now considered to be a clear marker of neurohypophyseal functional integrity, together with careful analysis of pituitary stalk shape and size, have provided the most striking recent findings contributing to the diagnosis and understanding of some forms of 'idiopathic' central diabetes insipidus.

Central nervous system-related permanent consequences in patients with Langerhans cell histiocytosis

BACKGROUND

Permanent consequences in Langerhans cell histiocytosis (LCH) are irreversible late sequelae related to the disease that may severely impair the quality of life of survivors. The frequency and pattern of permanent consequences affecting the central nervous system (CNS) remains to be determined.

PROCEDURE

In this single center study, 25 LCH patients observed for a median time of 10 years 3 months underwent a uniform thorough follow-up program including neuropsychological testing and electrophysiological evaluation.

RESULTS

Overall permanent consequences were seen in 9 of 25 patients. Intracranial abnormalities were the most frequent including diabetes insipidus (DI) in seven patients, anterior pituitary deficiencies in five patients, and neurodegenerative CNS disease in five patients. No patient had overt neurological symptoms upon neurological evaluation, but psychological testing revealed subtle deficits in short-term auditory memory (STAM) in 14 patients. Brain stem evoked potentials showed abnormalities in four of nine tested patients, all of these four had neurodegeneration on MRI.

CONCLUSION

Psychoneuroendocrine sequelae were found in an unexpectedly high number of patients in this single center study. Long-term follow-up focusing on such sequelae are important in LCH survivors, in order to detect early deficits, to monitor the evolution of the disease, and to provide specific support.

Masking of central diabetes insipidus and hypogonadotrophic hypogonadism by germ cell tumour in suprasellar--pineal region

A patient with beta hCG-secreting germ cell carcinoma of the pineal and suprasellar regions presented with hydrocephalus, Parinaud's syndrome, hypopituitarism and polyuria. Central diabetes insipidus was strongly suspected although the water deprivation test was not diagnostic. The polyuria however, responded to ADH analogue when the hypothyroidism and hypocortisolism were treated. Pubertal development was evident and serum testosterone was normal despite the low FSH/LH, suggesting hCG stimulation of Leydig cells. This case illustrates that a beta hCG-germ cell tumour of the suprasellar region causing hypopituitarism can mask the presence of central diabetes insipidus and hypogonadotrophic hypogonadism.

Familial neurohypophyseal diabetes insipidus--an update

Although molecular research has contributed significantly to our knowledge of familial neurohypophyseal diabetes insipidus (FNDI) for more than a decade, the genetic background and the pathogenesis still is not understood fully. Here we provide a review of the genetic basis of FNDI, present recent progress in the understanding of the molecular mechanisms underlying its development, and survey diagnostic and treatment aspects. FNDI is, in 87 of 89 kindreds known, caused by mutations in the arginine vasopressin (AVP) gene, the pattern of which seems to be largely revealed as only few novel mutations have been identified in recent years. The mutation pattern, together with evidence from clinical, cellular, and animal studies, points toward a pathogenic cascade of events, initiated by protein misfolding, involving intracellular protein accumulation, and ending with degeneration of the AVP producing magnocellular neurons. Molecular research has also provided an important tool in the occasionally difficult differential diagnosis of DI and the opportunity to perform presymptomatic diagnosis. Although FNDI is treated readily with exogenous administration of deamino-D-arginine vasopressin (dDAVP), other treatment options such as gene therapy and enhancement of the endoplasmic reticulum protein quality control could become future treatment modalities.

Idiopathic central diabetes insipidus in children and young adults is commonly associated with vasopressin-cell antibodies and markers of autoimmunity

OBJECTIVES

Autoimmune targeting of hypothalamic-neurohypophyseal structures in children and young adults with posterior pituitary and anterior pituitary dysfunction, as well as pituitary stalk involvement, are not yet completely understood.

DESIGN

We aimed to (1) evaluate the presence of circulating vasopressin-cell autoantibodies (AVPc-Abs) in young patients with central diabetes insipidus (CDI), (2) detect organ-specific autoantibodies as markers of autoimmunity, and (3) define the relationship between immune markers and neuroimaging findings.

PATIENTS

Twenty patients were evaluated at a median age of 16.3 years. Twelve patients had idiopathic CDI, six had Langerhans cell histiocytosis (LCH) and two had germinoma. AVPc-Abs were evaluated in 40 healthy children. Magnetic resonance imaging (MRI) of the hypothalamic-pituitary region was performed longitudinally in all subjects.

MEASUREMENTS

Circulating arginine vasopressin (AVP), protein tyrosine phosphatase (IA2), glutamic acid decarboxylase (GAD), 21-hydroxylase (21-OH), endomysium antibodies (EMA), parietal cell (PCA), thyroid peroxidase (TPO), thyroglobulin (TG) and TSH-receptor (TSHr) autoantibodies were evaluated.

RESULTS

Circulating AVPc-Abs were found in 15 patients (75%), nine with idiopathic CDI, four with LCH and two with germinoma; the pituitary stalk was involved in most of them. Five patients with idiopathic CDI showed a persistence of AVPc-Abs during follow-up and one became positive subsequently. Serum IA2 autoantibodies were demonstrated in 14 patients (70%) and 21-OH autoantibodies in three of them.

CONCLUSION

In idiopathic CDI, circulating AVPc-Abs suggest an autoimmune involvement of the neurohypophyseal system. The identification of AVPc-Abs in subjects who could have either idiopathic CDI or LCH or germinoma, however, indicates that AVPc-Abs cannot be considered a completely reliable marker of autoimmune CDI. Thus, close clinical and MRI follow-up are needed because AVPc-Abs may mask germinoma or LCH.

[Cranial diabetes insipidus in Wegener's granulomatosis]

We describe three cases of cranial diabetes insipidus (CDI) caused by Wegener's granulomatosis (WG). Panhypopituitarism was the presenting symptom in one patient. Magnetic resonance imaging (MRI) showed enlargement of the pituitary gland with an intrasellar mass lesion and absence of posterior pituitary lobe hyperintensity. Follow-up MRI disclosed reduction of the intrasellar lesion but sustained loss of posterior lobe hyperintensity. The patients still have CDI despite a marked clinical response to the treatment of WG. Pituitary dysfunction may be the presenting symptom as well as a complication of WG.

A novel heterozygous missense mutation in the vasopressin moiety is identified in a Japanese person with neurohypophyseal diabetes insipidus

The autosomal dominant familial neurohypophyseal diabetes insipidus (adFNDI) is caused by diverse mutations in one allele of the gene that encodes the arginine vasopressin (AVP) precursor protein, AVP-neurophysin II (AVP-NP II). Most of the mutations identified so far are located in either the signal peptide or NP II moiety. Two recently published mutations in the AVP gene identified in kindreds with adFNDI predict a substitution of histidine for tyrosine at position 2 and a deletion of phenylalanine at position 3 in AVP. They are unique among adFNDI mutations in that they are the only adFNDI mutations that affect amino acid residues in the AVP moiety of the pro-hormone. Here, we report a novel heterozygous missense mutation in the AVP moiety of the AVP-NP II gene in a Japanese person with neurohypophyseal diabetes insipidus (DI). This mutation occurs at position 2 in AVP and predicts a substitution of serine for tyrosine (Y21S). It is expected to interfere with normal binding of AVP with NP II, and thus result in misfolding of the precursor proteins. The data of this study support the notion that mutations affecting the AVP moiety can result in the initiation of the pathological processes.

Central diabetes insipidus: Is it Langerhans cell histiocytosis of the pituitary stalk? A diagnostic pitfall

Central diabetes insipidus (CDI) is a rare disorder that may be caused by a variety of diseases. In pediatric and adolescent patients the most common causes for CDI are Langerhans cell histiocytosis (LCH) and germinoma. To avoid a potentially hazardous biopsy of the hypothalamic pituitary region it is recommended to evaluate patients with CDI carefully to identify potential extracranial lesions. Since LCH is the most common systemic disease that may cause CDI, special focus is paid to the identification of LCH lesions. We report on a 9(1/2) year old girl who presented with central diabetes insipidus and a thickening of the pituitary stalk on magnetic resonance imaging. Diagnostic workup revealed a history of recurrent ear infections and a compressed 6th thoracic vertebral body on radiographs. Based on these findings LCH was anticipated. Upon growth of the pituitary stalk lesion the patient was treated with LCH standard chemotherapy. After an initial shrinkage of the lesion, a further growth of the pituitary stalk lesion was observed and the tumor was resected. Histopathology revealed germinoma. This case underscores the importance of a istopathologically proven diagnosis in patients with HPR tumors before the initiation of a specific therapy, even if the clinical findings are highly suggestive.

Risk factors for diabetes insipidus in langerhans cell histiocytosis

BACKGROUND

Diabetes insipidus (DI) is the most frequent central nervous system (CNS)-related permanent consequence in Langerhans cell histiocytosis (LCH), which mostly requires life-long hormone replacement therapy. In an attempt to define the population at risk for DI, 1,741 patients with LCH registered on the trials DALHX 83 and DALHX 90, LCH I and LCH II were studied.

RESULTS

Overall 212 of 1,741 patients (12%) was reported to have DI. In 102 of 1,741 patients (6%) DI was present at diagnosis of LCH. One thousand one hundred eighty three of 1,539 patients without DI at diagnosis had follow up information. One hundred ten of these (9%) later developed DI. The risk of developing DI was 20% at 15 years after diagnosis. Multisystem disease patients at diagnosis carried a 4.6-fold risk for DI compared to single system patients. Craniofacial lesions, in particular in the "ear," "eye," and oral region were associated with a significantly increased risk for DI (relative hazard rate, RHR 1.7), independent of the extent of disease. No influence of the duration of therapy could be determined, but the duration of initial disease activity (RHR 1.5) and the occurrence of reactivations (RHR 3.5) significantly increased the risk for DI.

CONCLUSIONS

Patients with multisystem disease and craniofacial involvement at diagnosis, in particular of the "ear," "eye," and the oral region carry a significantly increased risk to develop DI during their course. This risk is augmented when the disease remains active for a longer period or reactivates.

Pituitary infarction resulting from intranasal cocaine abuse

OBJECTIVE

To report a case of pituitary infarction attributable to long-term intranasal cocaine use.

METHODS

We present the clinical findings, laboratory results, and imaging studies in a woman with hypopituitarism, diabetes insipidus, and a palsy of cranial nerve VI, associated with cocaine-induced destruction of her nasal and paranasal structures and the anterior base of her skull.

RESULTS

A 55-year-old woman, a long-term cocaine abuser, presented with delirium, nausea, vomiting, hypoglycemia, hypercalcemia, and hypotension as manifestations of adrenal insufficiency (cortisol levels <1 mg/dL before and after administration of cosyntropin). She was found to have a deficiency of adrenocorticotropic hormone (<1 pg/mL), gonadotropin deficiency (estradiol <20 pg/mL, luteinizing hormone 1.7 mIU/mL, and follicle-stimulating hormone 4.9 mIU/mL), and diabetes insipidus. She also had a palsy of right cranial nerve VI. Computed tomography and magnetic resonance imaging of the head demonstrated extensive destruction of the paranasal sinuses, extending into the base of the skull. Serial magnetic resonance images showed reduction of pituitary volume. Nasal biopsy specimens disclosed findings consistent with cocaine-induced ischemic necrosis.

CONCLUSION

To our knowledge, this is the first case of hypopituitarism and diabetes insipidus due to prolonged intranasal cocaine abuse.

Etiologies of central diabetes insipidus in Thai children

In order to determine the etiologies of central diabetes insipidus (DI) among Thai children, we retrospectively reviewed records of 67 patients (44 male and 23 female) between the age of 0.1 and 15.6 years (mean age 5.5 years) who were diagnosed with central DI at the Pediatric Endocrinology Unit, Siriraj Hospital, Bangkok, Thailand between 1996 and 2003. Etiologies were found to be central nervous system (CNS) malformations in 20 patients (29.8%), post resection of intracranial tumors and cysts in 17 patients (25.4%), intracranial tumors in 11 patients (16.4%), cerebral palsy of unknown cause in five patients (7.5%), infection in four patients (6%), and Langerhans cell histiocytosis in three patients (4.5%). In another seven patients (10.4%), the cause was considered to be idiopathic. This study revealed that CNS malformation was the most common etiology, followed by intracranial tumors and their treatment. A thorough investigation to rule out CNS lesions needs to be done before considering the diagnosis of idiopathic central DI.

Autophagy is a prosurvival mechanism in cells expressing an autosomal dominant familial neurohypophyseal diabetes insipidus mutant vasopressin transgene

Autosomal dominant familial neurohypophyseal diabetes insipidus (adFNDI) is a progressive, inherited neurodegenerative disorder that presents as polydipsia and polyuria as a consequence of a loss of secretion of the antidiuretic hormone vasopressin (VP) from posterior pituitary nerve terminals. VP gene mutations cause adFNDI. Rats expressing an adFNDI VP transgene (Cys67stop) show a neuronal pathology characterized by autophagic structures in the cell body. adFNDI has thus been added to the list of protein aggregation diseases, along with Alzheimer's, Parkinson's and Huntington's, which are associated with autophagy, a bulk process that delivers regions of cytosol to lysosomes for degradation. However, the role of autophagy in these diseases is unclear. To address the relationships between mutant protein accumulation, autophagy, cell survival, and cell death, we have developed a novel and tractable in vitro system. We have constructed adenoviral vectors (Ads) that express structural genes encoding either the Cys67stop mutant protein (Ad-VCAT-Cys67stop) or an epitope-tagged wild-type VP precursor (Ad-VCAT). After infection of mouse neuroblastoma Neuro2a cells, Ad-VCAT encoded material enters neurite processes and accumulates in terminals, while the Cys67stop protein is confined to enlarged vesicles in the cell body. Similar to the intracellular derangements seen in the Cys67stop rats, these structures are of ER origin, and colocalize with markers of autophagy. Neither Ad-VCAT-Cys67stop nor Ad-VCAT expression affected cell viability. However, inhibition of autophagy or lysosomal protein degradation, while having no effect on Ad-VCAT-expressing cells, significantly increased apoptotic cell death following Ad-VCAT-Cys67stop expression. These data suggest that activation of autophagy by the stress of the expression of an adFNDI mutant protein is a prosurvival mechanism.

Autophagy‐dependent cell survival and cell death in an autosomal dominant familial neurohypophyseal diabetes insipidus in vitro model

Mutations in the human gene encoding the antidiuretic hormone vasopressin (VP) cause autosomal dominant familial neurohypophyseal diabetes insipidus (adFNDI), a rare inherited disorder that presents as polydipsia and polyuria as a consequence of a loss of secretion of VP from posterior pituitary nerve terminals. Work from our laboratories has shown that adFNDI, like other neurodegenerative diseases such as Alzheimer's, Parkinson's and Huntington's, is associated with autophagy. We have recently shown that the activation of autophagy in mouse neuroblastoma Neuro2a cells after adenoviral vector-mediated delivery of an adFNDI mutant VP transgene (Cys67stop) is a cell survival mechanism; its inhibition induces apoptosis. We now show that expression of Cys67stop sensitizes Neuro2a cells to the lethal effects of dopamine. This mode of cell death exhibits features typically associated with classical apoptosis. Yet inhibition of autophagy reversed these effects and rescued cell viability. We propose that autophagy-mediated cell death is a "two-hit" process: Following the cellular stress of the accumulation of a misfolded mutant protein, autophagy is prosurvival. However, a second insult triggers an autophagy-dependent apoptosis.

Idiopathic Neurohypophysial Diabetes Insipidus: Reversibility of Structural and Functional Renal Abnormalities after Treatment

OBJECTIVE

To present a case of untreated long-term idiopathic neurohypophysial diabetes insipidus (DI) with structural and functional renal abnormalities that regressed after treatment.

METHODS

We describe the clinical course, biochemical data, and imaging findings in a man with idiopathic neurohypophysial DI in whom structural and functional abnormalities involving the urinary tract diminished after treatment. The patient underwent intravenous pyelography, retrograde pyelography, computed tomographic (CT) scanning of the kidneys and abdomen, iodohippurate renal scanning, and voiding cystourethrography. Ultrasonography of the kidneys at presentation and at 8-year followup and serial determinations of serum creatinine for a period of 9 years were also done.

RESULTS

A 43-year-old man had polyuria for 30 years attributable to untreated idiopathic neurohypophysial DI. He presented with bilateral flank pain and a high serum creatinine level (156 mmol/L). Ultrasonography, intravenous pyelography, retrograde pyelography, and CT scan of the kidneys demonstrated severe bilateral hydronephrosis, notably dilated and tortuous ureters, a distended bladder, and atrophy of the left renal cortex. Retrograde pyelography and voiding cystourethrography confirmed the absence of mechanical obstruction or urinary reflux. A renal scan study showed bilaterally impaired function. Treatment with intranasally administered desmopressin and clean intermittent straight bladder catheterization resulted in resolution of flank pain, improvement of renal function, normalization of serum creatinine levels, and decreased hydronephrosis during 9 years of follow-up.

CONCLUSION

This case provides information about renal abnormalities in the natural history of a long-term polyuric state, idiopathic neurohypophysial DI, before and after treatment. Reversibility of renal structural and functional abnormalities after treatment is documented. Recognition of renal abnormalities associated with untreated neurohypophysial DI is important for prevention and treatment of such complications.

Course and clinical impact of magnetic resonance imaging findings in diabetes insipidus associated with Langerhans cell histiocytosis

BACKGROUND

Diabetes insipidus (DI) is the most frequent sequela in Langerhans cell histiocytosis (LCH). The clinical relevance and therapeutic impact of brain magnetic resonance imaging (MRI) findings in LCH patients with LCH during the disease course is unclear.

PROCEDURE

In this retrospective study, we reviewed 113 brain MRIs from 59 DI patients, in 17 of these serial follow up MR-examination findings were correlated to the clinical course and therapy.

RESULTS

At DI diagnosis, 71% patients showed a thickened stalk, in 24% the stalk was still thickened on MRIs done more than 5 years after DI onset, and in two patients the stalk was already thickened several months before DI onset. The changes of the pituitary stalk thickness were highly variable and did not clearly correlate with the treatment. Regression of pituitary thickness on MRI did not concur with clinical recovery of DI, which persisted in all but one patient with initially partial DI. The occurrence of anterior pituitary hormone deficiencies appeared to be linked to a thickening of the stalk at DI diagnosis. LCH-lesions in the craniofacial bones were seen in 75% DI patients, and 76% of DI patients with follow up MRIs done 5 years or longer after DI diagnosis had parenchymal neurodegenerative brain changes.

CONCLUSIONS

Our study indicates that repeated MR-examinations in DI patients are of limited value for assessing a response to therapy in the pituitary stalk, but are important for the monitoring of craniofacial bone lesions and for the detection of parenchymal CNS disease.

Myelodysplastic syndrome with central diabetes insipidus manifesting hypodipsic hypernatremia and dehydration

Central diabetes insipidus (DI) is a rare but recognized complication of myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) that is caused by leukemic infiltration to the hypothalamo-neurohypophyseal system. In rare patients in whom a wide region of the hypothalamus is involved, central DI results in hypodipsic hypernatremia and dehydration. Typical DI symptoms such as polydipsia, polyuria, and marked thirst are concealed in these cases, because the hypothalamic "thirst center" cannot send thirst stimuli to the cerebral cortex. Herein we describe a patient with MDS developing into AML, who presented with hypodipsic hypernatremia and dehydration. A diagnosis of central DI was made on the ground of a low level of serum anti-diuretic hormone (ADH) despite high serum osmolality. A magnetic resonance imaging study revealed attenuation of a physiological "bright spot" of the neurohypophysis. An induction course chemotherapy including regular-dose cytarabine and daunorubicin produced a rapid improvement of hypernatremia. The bone marrow aspirate after two courses of chemotherapy showed complete remission. At that point, ADH release and the "bright spot" were recovered. In order to correctly diagnose central DI in association with hematological malignancies, we should not overlook this atypical type of DI.

Dominant-negative diabetes insipidus and other endocrinopathies

Familial neurohypophyseal diabetes insipidus (FNDI) in humans is an autosomal dominant disorder caused by a variety of mutations in the arginine vasopressin (AVP) precursor. A new report demonstrates how heterozygosity for an AVP mutation causes FNDI (see the related article beginning on page 1697). Using an AVP knock-in mutation in mice, the study shows that FNDI is caused by retention of AVP precursors and progressive loss of AVP-producing neurons.

A murine model of autosomal dominant neurohypophyseal diabetes insipidus reveals progressive loss of vasopressin-producing neurons

Familial neurohypophyseal diabetes insipidus (FNDI) is an autosomal dominant disorder caused by mutations in the arginine vasopressin (AVP) precursor. The pathogenesis of FNDI is proposed to involve mutant protein-induced loss of AVP-producing neurons. We established murine knock-in models of two different naturally occurring human mutations that cause FNDI. A mutation in the AVP signal sequence [A(-1)T] is associated with a relatively mild phenotype or delayed presentation in humans. This mutation caused no apparent phenotype in mice. In contrast, heterozygous mice expressing a mutation that truncates the AVP precursor (C67X) exhibited polyuria and polydipsia by 2 months of age and these features of DI progressively worsened with age. Studies of the paraventricular and supraoptic nuclei revealed induction of the chaperone protein BiP and progressive loss of AVP-producing neurons relative to oxytocin-producing neurons. In addition, Avp gene products were not detected in the neuronal projections, suggesting retention of WT and mutant AVP precursors within the cell bodies. In summary, this murine model of FNDI recapitulates many features of the human disorder and demonstrates that expression of the mutant AVP precursor leads to progressive neuronal cell loss.