ปีที่ 2 ฉบับที่ 4 ตุลาคม - ธันวาคม พ.ศ. 2559
Transient diabetes insipidus (DI) or gestational DI should be recognized in the pregnant women who present with polyuria and polydipsia. Transient DI is characterized by loss of anti-diuretic hormone (ADH) effect which regulates water balance. The main pathogenesis is increased metabolic clearance of ADH mediated by vassopressinase that is synthesized from syncytiotrophoblast in placenta. This condition commonly occurs in 2nd and 3rd trimester of pregnancy. Psychogenic primary polydipsia and pre-existing DI are essential for the differential diagnosis. Therefore, water deprivation test should be done.
The important characters to differentiate gestational and central DI are ability of kidney to increase urine osmolarity after administration of vasopressin and DDAVP during water deprivation test. Central DI typically responds to vasopressin and DDAVP. However, gestational DI is only responsive to DDAVP, but is resistant to vasopressin. Thus, treatment of choice in transient DI is DDAVP. The clinical courses are terminated in approximately 4-6 weeks after delivery.