Diagnosis and management of diabetes insipidus for the internist: an update

Diabetes insipidus is a disorder characterized by excretion of large amounts of hypotonic urine. Four entities have to be differentiated: central diabetes insipidus resulting from a deficiency of the hormone arginine vasopressin (AVP) in the pituitary gland or the hypothalamus, nephrogenic diabetes insipidus resulting from resistance to AVP in the kidneys, gestational diabetes insipidus resulting from an increase in placental vasopressinase and finally primary polydipsia, which involves excessive intake of large amounts of water despite normal AVP secretion and action. Distinguishing between the different types of diabetes insipidus can be challenging. A detailed medical history, physical examination and imaging studies are needed to detect the aetiology of diabetes insipidus. Differentiation between the various forms of hypotonic polyuria is then done by the classical water deprivation test or the more recently developed hypertonic saline or arginine stimulation together with copeptin (or AVP) measurement. In patients with idiopathic central DI, a close follow-up is needed since central DI can be the first sign of an underlying pathology. Treatment of diabetes insipidus or primary polydipsia depends on the underlying aetiology and differs in central diabetes insipidus, nephrogenic diabetes insipidus and primary polydipsia. This review will discuss issues and newest developments in diagnosis, differential diagnosis and treatment, with a focus on central diabetes insipidus.     

遗传性肾性尿崩症的药物治疗

遗传性肾性尿崩症由精氨酸加压素受体2 (AVPR2)或水通道蛋白-2(AQP2)基因突变引起.目前临床治疗主要是改善多饮、多尿的症状.随着对发病机制研究的不断深入,新型药物如AVPR2激动剂和拮抗剂、磷酸二酯酶抑制剂、他汀类、前列腺素E受体激动剂等,通过改善突变的AVPR2/AQP2在细胞内的合成、修饰、表达等达到治疗的目的.     

Copeptin and its role in the diagnosis of diabetes insipidus and the syndrome of inappropriate antidiuresis

Copeptin is secreted in an equimolar amount to arginine vasopressin (AVP) but can easily be measured in plasma or serum with a sandwich immunoassay. The main stimuli for copeptin are similar to AVP, that is an increase in osmolality and a decrease in arterial blood volume and pressure. A high correlation between copeptin and AVP has been shown. Accordingly, copeptin mirrors the amount of AVP in the circulation. Copeptin has, therefore, been evaluated as diagnostic biomarker in vasopressin‐dependent disorders of body fluid homeostasis. Disorders of body fluid homeostasis are common and can be divided into hyper‐ and hypoosmolar circumstances: the classical hyperosmolar disorder is diabetes insipidus, while the most common hypoosmolar disorder is the syndrome of inappropriate antidiuresis (SIAD). Copeptin measurement has led to a “revival” of the direct test in the differential diagnosis of diabetes insipidus. Baseline copeptin levels, without prior thirsting, unequivocally identify patients with nephrogenic diabetes insipidus. In contrast, for the difficult differentiation between central diabetes insipidus and primary polydipsia, a stimulated copeptin level of 4.9 pmol/L upon hypertonic saline infusion differentiates these two entities with a high diagnostic accuracy and is clearly superior to the classical water deprivation test. On the contrary, in the SIAD, copeptin measurement is of only little diagnostic value. Copeptin levels widely overlap in patients with hyponatraemia and emphasize the heterogeneity of the disease. Additionally, a variety of factors lead to unspecific copeptin elevations in the acute setting further complicating its interpretation. The broad use of copeptin as diagnostic marker in hyponatraemia and specifically to detect cancer‐related disease in SIADH patients can, therefore, not be recommended.     

一例精氨酸加压素受体2基因突变的先天性肾性尿崩症患者的临床及家系研究

报道1例精氨酸加压素受体2( arginine vasopressin receptor2,AVPR2)基因突变导致的先天性肾性尿崩症.提取患者及家属的基因组DNA,PCR扩增AVPR2的全部外显子,扩增产物经纯化后行双向测序,测序结果与基因库中序列进行比对,找出突变位点,利用同源结构模型探讨突变点对AVPR2结构的影响.发现AVPR2基因第6 036位核苷酸碱基T突变为C,导致基因产物的168位氨基酸由亮氨酸突变为精氨酸,该突变点尚未报道.患者母亲和姐姐基因为杂合子,父亲为正常基因型.     

Diabetes insipidus complicating apoplexy during pregnancy: the potential use of copeptin

Pituitary apoplexy during pregnancy is rare but important to recognise, particularly in the hyperoestrogenaemic state when known lactotroph hyperplasia occurs. Untreated, the complication rates from pituitary adenomas depend on the size of the adenoma before pregnancy. A history of thirst plus polydipsia during pregnancy raises suspicion for diabetes insipidus and a 24‐h urine collection quantifying polyuria with an inappropriately low urine osmolality confirms the diagnosis. Further evaluation for assessing diabetes insipidus in pregnancy may be facilitated by the use of a copeptin.     

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.     

Genoa syndrome and central diabetes insipidus: a case report

Genoa syndrome was first described by Camera et al in 1993 in two patients with semilobar holoprosencephaly (HPE), craniosynostosis and abnormal small hands with cone-shaped epiphyses and hypoplastic terminal phalanges of fingers (OMIM: 601370). In 2001, Lapunzina et al reported a case of craniosynostosis and HPE associated with several other malformations and suggested that these findings could be attributed to a severe form of Genoa syndrome or to a newly recognized syndrome. Endocrinopathies in association with HPE are frequently reported in the literature. Diabetes insipidus, hypothyroidism, hypocortisolism, and growth hormone deficiency are frequently associated with HPE. We here report a case of semilobar HPE, craniosynostosis and cleft lip/palate, possibly a case of Genoa syndrome, associated with central diabetes insipidus.     

A case of central diabetes insipidus with spontaneous remission after 8 years of the disease

Abstract. A 55-year-old male smoker developed polyuria and polydipsia in November 1983. A water deprivation study revealed a defect in the urine concentrating function, which was corrected by vasopressin. Plasma antidiuretic hormone (ADH) was not increased by smoking. His condition was well controlled by deamino-d -arginine vasopressin. However, since February 1992 he has become completely free from the need for medication to control his urine volume. Re-evaluation studies with water deprivation and smoking revealed dramatic improvements in the urine concentrating function and ADH response. A patient with idiopathic diabetes insipidus with spontaneous remission after 8 years is reported.     

The value of urine specific gravity in detecting diabetes insipidus in a patient with uncontrolled diabetes mellitus

When a patient with diabetes mellitus presents with worsening polyuria and polydipsia, what is a sensible, cost-effective approach? We report the unique coincidence of type 2 diabetes mellitus and diabetes insipidus. A 46-year-old woman with poorly controlled type 2 diabetes complained of polyuria with a daily output of 5 L. Although urinalysis demonstrated significant glucosuria, diabetes insipidus was suspected owing to a low urine specific gravity (1.008). The low specific gravity persisted during a water deprivation test. Ultimately, diabetes insipidus was confirmed when urine specific gravity and urine osmolaity normalized following desmopressin administration. This case emphasizes the importance of accurately interpreting the urine specific gravity in patients with polyuria and diabetes mellitus to detect diabetes insipidus.     

Acute myeloid leukaemia presenting with diabetes insipidus

A 41‐year‐old man was diagnosed with hypogonadotropic hypogonadism managed with gonadotropins after routine fertility review. Eight months later he presented with new polydipsia and polyuria, lethargy and easy bruising. A full blood count showed 28% circulating blasts. A bone marrow biopsy confirmed a diagnosis of acute myeloid leukaemia with inv(3)(q21.3q26.2) with additional monosomy 7. Central diabetes insipidus (DI) was diagnosed following a water deprivation test. Pituitary magnetic resonance imaging showed a slightly thickened pituitary stalk, stable Rathke’s cyst, and new absence of the pituitary bright spot. The patient was commenced on desmopressin and induction chemotherapy, subsequently requiring a bone marrow transplant. Bone marrow examination at 100 days post‐transplant revealed cytogenetic remission. All symptoms of DI resolved and magnetic resonance imaging showed return of the posterior bright spot and a pituitary stalk of normal thickness. Biochemical hypogonadotropic hypogonadism persisted but was uninterpretable in the context of systemic illness and recent chemotherapy. DI is a rare complication of haematological malignancies, and the prevalence and pathophysiology of DI in this context are poorly understood. Pathogenic mechanisms proposed include leukaemic infiltration of the pituitary, interference with antidiuretic hormone synthesis, and abnormal thrombopoiesis influencing hormone levels. Particular cytogenetic abnormalities such as inv(3)(q21.3q26.2) and monosomy 7 appear to be more commonly associated with DI and also appear to confer worse outcomes. Aetiologies in the literature remain elusive but as DI is a recognised association of haematological malignancies it should be considered in a patient presenting with polydipsia and polyuria.     

以中枢性尿崩为首发表现的朗格汉斯细胞组织细胞增生症的临诊应对

报道3例以中枢性尿崩为首发表现的朗格汉斯细胞组织细胞增生症(LCH)患者,总结其临床表现、实验室检查、影像学检查、病理结果、诊断过程和治疗反应。3例患者早期均以中枢性尿崩症起病,垂体磁共振成像(MRI)均表现为垂体柄增粗,垂体后叶正常高信号消失。2例患者表现为孤立性下丘脑-垂体病变,1例表现为垂体和甲状腺多系统受累。病理结果显示典型的朗格汉斯细胞,免疫组织化学示S-100、CD1a、Langerin阳性。LCH临床表现呈现明显的异质性,容易误诊和漏诊。确诊依赖病理结果,孤立性下丘脑-垂体病变活检难度较大,建议积极筛查其他器官增加活检概率。LCH导致的神经垂体损害通常需要终生激素替代治疗。