Diabetes Insipidus Presenting with Oligohydramnios and Polyuria During Pregnancy

New developments and concepts in the diagnosis and management of diabetes insipidus (AVP-deficiency and resistance)

Diabetes insipidus (DI) is a disorder characterised by the excretion of large amounts of hypotonic urine, with a prevalence of 1 per 25,000 population. Central DI (CDI), better now referred to as arginine vasopressin (AVP)-deficiency, is the most common form of DI resulting from deficiency of the hormone AVP from the pituitary. The less common nephrogenic DI (NDI) or AVP-resistance develops secondary to AVP resistance in the kidneys. The majority of causes of DI are acquired, with CDI developing when more than 80% of AVP-secreting neurons are damaged. Inherited/familial CDI causes account for approximately 1% of cases. Although the pathogenesis of NDI is unclear, more than 280 disease-causing mutations affecting the AVP2 protein or AVP V2 receptor, as well as in aquaporin 2 (AQP2), have been described. Although the cAMP/protein kinase A pathway remains the major regulatory pathway of AVP/AQP2 action, in vitro data have also revealed additional cAMP independent pathways of NDI pathogenesis. Diagnosing partial forms of DI, and distinguishing them from primary polydipsia, can be challenging, previously necessitating the use of the water deprivation test. However, measurements of circulating copeptin levels, especially after stimulation, are increasingly replacing the classical tests in clinical practice because of their ease of use and high sensitivity and specificity. The treatment of CDI relies on desmopressin administration, whereas NDI requires the management of any underlying diseases, removal of offending drugs and, in some cases, administration of diuretics. A better understanding of the pathophysiology of DI has led to novel evolving therapeutic agents that are under clinical trial.

Pregnancy complicated by central diabetes insipidus and oligohydramnios

This is the fourth reported case of central diabetes insipidus with oligohydramnios. Central diabetes insipidus does not adversely affect pregnancy; it can present with oligohydramnios, which can be improved by treating central diabetes insipidus.

Multifactorial diabetes insipidus during pregnancy: a challenging diagnosis

Diabetes insipidus (DI) is characterised by thirst and polydipsia with hypotonic polyuria. Several forms exist, namely, central or pituitary, nephrogenic and gestational and must be differentiated for adequate treatment. We describe the case of a 41-year-old woman chronically infected with HIV who had been recently medicated with a tenofovir-based antiretroviral treatment and who, at 22 weeks of pregnancy, presented with transient gestational DI. Obstetric ultrasound revealed oligohydramnios and foetal growth restriction that did not improve despite serum sodium correction. The severity of the case suggested the presence of an underlying disorder and elevated copeptin levels indicated that an underlying subclinical form of nephrogenic DI, possibly induced by HIV-related nephropathy or tenofovir use, was present and rendered clinically overt during pregnancy.

Diabetes Insipidus: Pathogenesis, Diagnosis, and Clinical Management

Diabetes insipidus (DI) is an endocrine condition involving the posterior pituitary peptide hormone, antidiuretic hormone (ADH). ADH exerts its effects on the distal convoluted tubule and collecting duct of the nephron by upregulating aquaporin-2 channels (AQP2) on the cellular apical membrane surface. DI is marked by expelling excessive quantities of highly dilute urine, extreme thirst, and craving for cold water. The two main classifications of DI are central diabetes insipidus (CDI), characterized by a deficiency of the posterior pituitary gland to release ADH, and nephrogenic diabetes insipidus (NDI), characterized by the terminal distal convoluted tubule and collecting duct resistance to ADH. The two less common classifications include dipsogenic DI, characterized by excessive thirst due to a low osmotic threshold, and gestational DI, characterized by increased concentration of placental vasopressinase during pregnancy. Treatment of DI is dependent on the disease classification, but severe complications may arise if not tended to appropriately. The most important step in symptom management is maintaining fluid intake ahead of fluid loss with emphasis placed on preserving the quality of life. The most common treatment of CDI and gestational DI is the administration of synthetic ADH, desmopressin (DDAVP). Nephrogenic treatment, although more challenging, requires discontinuation of medications as well as maintaining a renal-friendly diet to prevent hypernatremia. Treatment of dipsogenic DI is mainly focused on behavioral therapy aimed at regulating water intake and/or administration of antipsychotic pharmaceutical therapy. Central and nephrogenic subtypes of DI share a paradoxical treatment in thiazide diuretics.