1/62. Hypertonic saline test for the investigation of posterior pituitary function.The hypertonic saline test is a useful technique for distinguishing partial diabetes insipidus from psychogenic polydipsia, and for the diagnosis of complex disorders of osmoreceptor and posterior pituitary function. However, there is little information concerning its use in childhood. The experience of using this test in five children (11 months to 18 years) who presented diagnostic problems is reported. In two patients, in whom water deprivation tests were equivocal or impractical, an inappropriately low antidiuretic hormone (ADH) concentration (< 1 pmol/l) was demonstrated in the presence of an adequate osmotic stimulus (plasma osmolality > 295 mosmol/kg). In two children--one presenting with adipsic hypernatraemia and the other with hyponatraemia complicating desmopressin treatment of partial diabetes insipidus--defects of osmoreceptor function were identified. Confirming a diagnosis of idiopathic syndrome of inappropriate ADH secretion (SIADH) was possible in a patient with no other evidence of pituitary dysfunction. The hypertonic saline test was well tolerated, easy to perform, and diagnostic in all cases.- - - - - - - - - - ranking = 1keywords = water (Clic here for more details about this article) |
2/62. Autosomal recessive familial neurohypophyseal diabetes insipidus with continued secretion of mutant weakly active vasopressin.Familial neurohypophyseal diabetes insipidus is an autosomal dominant disorder characterized by post-natal development of arginine vasopressin (AVP) deficiency due to mutations in the AVP gene. All published mutations affect the signal peptide or the neurophysin-II carrier protein and are presumed to interfere with processing of the preprohormone, leading to neuronal damage. We studied an unusual Palestinian family consisting of asymptomatic first cousin parents and three children affected with neurohypophyseal diabetes insipidus, suggesting autosomal recessive inheritance. All three affected children were homozygous and the parents heterozygous for a single novel mutation (C301->T) in exon 1, replacing Pro7 of mature AVP with Leu (Leu-AVP). Leu-AVP was a weak agonist with approximately 30-fold reduced binding to the human V2 receptor. Measured by radioimmunoassay with a synthetic Leu-AVP standard, serum Leu-AVP levels were elevated in all three children and further increased during water deprivation to as high as 30 times normal. The youngest child (2 years old) was only mildly affected but had Leu-AVP levels similar to her severely affected 8-year-old brother, suggesting that unknown mechanisms may partially compensate for a deficiency of active AVP in very young children.- - - - - - - - - - ranking = 1keywords = water (Clic here for more details about this article) |
3/62. Dental fluorosis associated with hereditary diabetes insipidus.Among the characteristics of hereditary pituitary diabetes insipidus are polydipsia and polyuria from early infancy. drinking of large amounts of water, even with lower than accepted fluoride content, can produce fluorosis of the teeth. A mother and her four children affected by this disorder presented different degrees of fluorosis directly related to the stage at which hormonal therapy was introduced.- - - - - - - - - - ranking = 1keywords = water (Clic here for more details about this article) |
4/62. histiocytosis X and compulsive water drinking: report of a case.We describe a patient with histiocytosis X and compulsive water drinking. The association of diabetes insipidus with histiocytosis X is well recognized, and this patient was initially considered to have diabetes insipidus. It was only after further testing that the proper diagnosis was made.- - - - - - - - - - ranking = 5keywords = water (Clic here for more details about this article) |
5/62. cyclophosphamide and water retention: mechanism revisited.We describe an 8 year-old girl with established diabetes insipidus who developed cyclophosphamide-associated antidiuresis. The patient had received cyclophosphamide as part of a high-dose chemotherapy regimen for recurrent suprasellar dysgerminoma prior to autologous bone marrow transplantation. Urinary output decreased and specific gravity increased shortly after a 1 hour i.v. infusion of 50 mg/kg cyclophosphamide and the effect lasted some 5 hours. No other drug could be implicated. This response, occurring in a patient with no ability to secrete vasopressin, suggests a direct tubular effect of one or more cyclophosphamide metabolites. Administering i.v. cyclophosphamide requires careful monitoring of fluid balance in order to avoid water intoxication. Further research is warranted both into the mechanism of this effect and the metabolite responsible for it.- - - - - - - - - - ranking = 5keywords = water (Clic here for more details about this article) |
6/62. diabetes insipidus as a presenting symptom of acute myelogenous leukemia.This report describes a case of diabetes insipidus associated with acute myelogenous leukemia. An 11-year-old boy presented with fatigue, polydipsia and polyuria. His evaluation revealed a diagnosis of acute myelogenous leukemia FAB-M2, and a water deprivation test confirmed the diagnosis of central diabetes insipidus. His brain magnetic resonance imaging (MRI) showed a thickened, enhancing pituitary stalk with absence of the normal hyperintense signal in the posterior pituitary. He was treated with systemic chemotherapy, intensive intrathecal therapy, and 1,000 cGy to the pituitary. The patient achieved a remission but continued to need desmopressin therapy to control his diabetes insipidus. diabetes insipidus is a rare complication of acute myelogenous leukemia that can be caused by leukemic infiltration of the pituitary. The diabetes insipidus is irreversible despite intensive systemic and central nervous system chemotherapy and radiation.- - - - - - - - - - ranking = 1keywords = water (Clic here for more details about this article) |
7/62. hypernatremia in a non insulin dependent (type 2) diabetic patient with central diabetes insipidus.We describe a patient with central diabetes insipidus who presented with hyperosmolar, non-ketotic hyperglycaemia. The role in this case of reduced thirst sensation with decreased water intake and abnormal AVP production illustrates the importance of these protective mechanisms in normal physiology regarding maintenance of normal plasma osmolality. Despite the complex pathophysiology in this patient, fluid resuscitation aimed at normalisation of the water deficit resulted in full recovery.- - - - - - - - - - ranking = 2keywords = water (Clic here for more details about this article) |
8/62. Autosomal dominant neurohypophyseal diabetes insipidus in a Swiss family, caused by a novel mutation (C59Delta/A60W) in the neurophysin moiety of prepro-vasopressin-neurophysin II (AVP-NP II).OBJECTIVE: To study clinical, morphological and molecular characteristics in a Swiss family with autosomal dominant familial neurohypophyseal diabetes insipidus (adFNDI). PARTICIPANTS AND methods: A 15-month-old girl presenting with symptoms of polydipsia and polyuria was investigated by water deprivation test. Evaluation of the family revealed three further family members with symptomatic vasopressin-deficient diabetes insipidus. T1-weighted magnetic resonance images of the posterior pituitary were taken in two affected adult family members and molecular genetic analysis was performed in all affected individuals. RESULTS: The water deprivation test in the 15-month-old child confirmed the diagnosis of vasopressin-deficient diabetes insipidus and the pedigree was consistent with autosomal dominant inheritance. The characteristic bright spot of the normal vasopressin-containing neurophypophysis was absent in both adults with adFNDI. Direct sequence analysis revealed a new deletion (177-179DeltaCGC) in exon 2 of the AVP-NP II gene in all affected individuals. At the amino acid level, this deletion eliminates cysteine 59 (C59Delta) and substitutes alanine 60 by tryptophan (A60W) in the AVP-NP II precursor; interestingly, the remainder of the reading frame remains unchanged. According to the three-dimensional structure of neurophysin, C59 is involved in a disulphide bond with C65. CONCLUSIONS: Deletion of C59 and substitution of A60W in the AVP-NP II precursor is predicted to disrupt one of the seven disulphide bridges required for correct folding of the neurophysin moiety and thus disturb the function of neurophysin as the vasopressin transport protein. These data are in line with the clinical and morphological findings in the reported family with adFNDI.- - - - - - - - - - ranking = 2keywords = water (Clic here for more details about this article) |
9/62. Hypodipsic hypernatremia and diabetes insipidus following anterior communicating artery aneurysm clipping: diagnostic and therapeutic challenges in the amnestic rehabilitation patient.Hypodipsic hypernatremia (HH) represents a pathological increase in serum sodium due to a lack of thirst and defect in hypothalamic osmoreceptors. While 15% of patients with HH have a vascular aetiology, few cases have been described. Moreover, the presence of such abnormalities in the amnestic patient can have particularly threatening implications, as HH tends to recur unless the patient complies with a regimen of water intake. This study reports the case of a 46-year-old male admitted for rehabilitation of functional deficits following subarachnoid haemorrhage (SAH), with clipping of an anterior communicating artery (ACoA) aneurysm. Clinical examination was remarkable for profound short-term memory loss and inability to retain new information. blood chemistry on admission showed a serum sodium level of 160 mEq/L, increasing to 167 mEq/L the following day. The patient denied thirst, and showed no clinical signs of dehydration. Neuroendocrine evaluation revealed diabetes insipidus (DI) and HH. Treatment initially included DDAVP and intravenous hydration, later supplemented with chlorpropramide. Stabilization of serum sodium and osmolality did not ensue until the treatment regimen included hydrochlorothiazide and supervision of enforced fluid intake. Endocrine abnormalities may be encountered among patients with vascular lesions adjacent to the hypothalamus. rehabilitation interventions include establishing a structured medication regimen with fluid administration in the amnestic patient with hypothalamic dysfunction.- - - - - - - - - - ranking = 1keywords = water (Clic here for more details about this article) |
10/62. Infundibulohypophysitis in a man presenting with diabetes insipidus and cavernous sinus involvement.Infundibulohypophysitis is an unusual inflammatory condition that affects the infundibulum, the pituitary stalk, and the neurohypophysis and may be part of a range that includes lymphocytic hypophysitis. Lymphocytic hypophysitis occurs mainly in women and most often presents in the later stages of pregnancy. Infundibulohypophysitis usually presents with diabetes insipidus and the cause remains unclear. The case of a 46 year old man with a 12 week history of polyuria and polydipsia is reported. Cranial diabetes insipidus was diagnosed on the basis of a water deprivation test. Initial cranial and pituitary imaging studies were normal. He subsequently developed symptoms of panhypopituitism over a period of 6-9 months and then, more acutely, developed diplopia secondary to a fourth nerve palsy. Further brain imaging studies disclosed an enhancing pituitary stalk and a left cavernous sinus lesion. An initial trial of immunosuppressive treatment did not help symptoms significantly. The diagnosis of infundibulohypophysitis was made on histological evidence. The patient was treated with prednisolone and methotrexate. At 9 months he is well, without symptoms, and the radiological abnormalities have resolved.- - - - - - - - - - ranking = 1keywords = water (Clic here for more details about this article) |
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