GESTATIONAL DIABETES MELLITUS WITH TRANSIENT DIABETES INSIPIDUS LATER IN AGE OF GESTATION

INTRODUCTION:Gestational diabetes insipidus is a rare endocrine problem which can complicate up to 1 in 30,000 pregnancies.  The gravid women can experience diabetes insipidus through the effects of placental vasopressinase which causes accelerated degradation of vasopressin. 

CLINICAL CASE:A 31 y.o, multiparous woman, known with gestational diabetes mellitus with good glycemic control with insulin was admitted on her 38-39 weeks’ gestation because of recurrent myalgia and weakness of the lower extremities and polyuria amounting to 4 to 5 liters per day.  Work-ups revealed hypokalemia (K=2.97 (n.v.3.8-5 mmol/L), normal creatinine (0.58 mg/dL; <1.2), normal magnesium (1.78mg/dL), normal urinalysis with specific gravity of 1.010, no pyuria, glucosuria, nor albuminuria. Twenty four hour urine creatinine (0.6g/24hrs), sodium (168mmol/24hrs), and potassium (42mmol/24hrs) were normal.  Thyroid function test was also normal.  Ultrasound of the kidneys showed bilateral medullary nephrocalcinosis.  Her urine osmolality was low at 151 mosm/kg H20 (n.v. 300-900mOsm/kg). Impression was gestational diabetes insipidus hence she was given desmopressin (DDAVP) 0.1mg tablet.  After one dose of desmopressin there was correction of hypokalemia but her copious urination persisted.  The obstetrician terminated the pregnancy; she delivered via a caesarian section to a live, healthy boy infant.  Post-operatively, she had marked decrease in the amount of urine volume averaging 1-1.5 liters per day and her serum potassium remained normal.       

CONCLUSION: Transient diabetes insipidus may develop in later age of gestation and may remit post-partum.