Transient diabetes insipidus in pregnancy

[摘要] Gestational diabetes insipidus (DI) is a rare complication of pregnancy, usually developing in the third trimester and remittingspontaneously 4–6 weeks post-partum. It is mainly caused by excessive vasopressinase activity, an enzyme expressed byplacental trophoblasts which metabolises arginine vasopressin (AVP). Its diagnosis is challenging, and the treatment requiresdesmopressin. A 38-year-old Chinese woman was referred in the 37th week of her first single-gestation due to polyuria,nocturia and polydipsia. She was known to have gestational diabetes mellitus diagnosed in the second trimester, wellcontrolled with diet. Her medical history was unremarkable. Physical examination demonstrated decreased skin turgor; herblood pressure was 102/63 mmHg, heart rate 78 beats/min and weight 53 kg (BMI 22.6 kg/m2). Laboratory data revealed lowurine osmolality 89 mOsmol/kg (350–1000), serum osmolality 293 mOsmol/kg (278–295), serum sodium 144 mmol/l (135–145),potassium 4.1 mmol/l (3.5–5.0), urea 2.2 mmol/l (2.5–6.7), glucose 3.5 mmol/l and HbA1c 5.3%. Bilirubin, alaninetransaminase, alkaline phosphatase and full blood count were normal. The patient was started on desmopressin withimprovement in her symptoms, and normalisation of serum and urine osmolality (280 and 310 mOsmol/kg respectively).A fetus was delivered at the 39th week without major problems. After delivery, desmopressin was stopped and she had nofurther evidence of polyuria, polydipsia or nocturia. Her sodium, serum/urine osmolality at 12-weeks post-partum werenormal. A pituitary magnetic resonance imaging (MRI) revealed the neurohypophyseal T1-bright spot situated ectopically,with a normal adenohypophysis and infundibulum. She remains clinically well, currently breastfeeding, and off allmedication. This case illustrates some challenges in the diagnosis and management of transient gestational DI.

[学科分类] 血液学

[关键词] Pregnant adult;Female;Asian - Chinese;United Kingdom;Placenta;Neuroendocrinology;AVP;Diabetes insipidus – gestational;Gestational diabetes mellitus;Nocturia;Polyuria;Polydipsia;MRI;Serum osmolality;Sodium;Potassium;Urine osmolality;Urea and electrolytes;Haemoglobin A1c;Glucose (blood);Urine 24-hour volume;Desmopressin;Levothyroxine;Obstetrics;Insight into disease pathogenesis or mechanism of therapy;October;2015