Abstract: SA-PO992

Hypokalemia in Pregnancy: A Case of Maternal Bartter Syndrome

Session Information

Category: Nephrology Education

  • 1302 Fellows and Residents Case Reports

Authors

  • Vogel, Savannah, University of Wisconsin - Madison, Madison, Wisconsin, United States
  • Guerra Rodas, Daniel, University of Wisconsin Hospital and Clinics, Middleton, Wisconsin, United States
  • Waheed, Sana, University of Wisconsin - Madison, Madison, Wisconsin, United States
Background

Bartter Syndrome (BS) type 3, a rare autosomal recessive renal tubular disorder caused by a mutation in the CIC-Kb chloride channel in the ascending loop of Henle, is characterized by a post-natal presentation of hypokalemia, metabolic alkalosis, hypomagnesemia and failure to thrive. Here, we report a case of the management of BS during pregnancy.

Methods

A 22-year-old G1P0 female presented to us at 19w0d gestation for management of BS diagnosed at 6 months of age. Prior to her pregnancy, she was managed with indomethacin 50mg QD, spironolactone 25mg BID and potassium chloride (KCl) 30mEq BID. Due to the risk of fetal complications, these medications were discontinued, amiloride was added at 10mg QD and KCl supplementation was increased. Potassium levels stabilized after an eight-week titration period up to 10mg BID amiloride and 400mEq QD potassium. Her potassium levels remained stable between 3.2-3.7 mEq/L for the remainder of the pregnancy. The patient delivered a healthy male infant with Apgar scores of 9 at 1 and 5 minutes by spontaneous vaginal delivery at 38w5d. Amiloride was discontinued at the start of labor and the patient was given potassium and magnesium supplementation throughout labor, delivery and her postpartum hospital stay. Following delivery, as patient was breastfeeding, indomethacin was restarted at 50 mg QD and potassium supplementation was titrated down to 30mEq BID. Postpartum potassium levels stabilized in the range of 3.4-3.6 mEq/L.

Conclusion

Patients with Bartter Syndrome often experience severe metabolic disturbances without treatment. NSAIDs, aldosterone antagonists and ACE inhibitors are considered the mainstay of treatment, however, these drugs have documented fetal side effects and thus cannot be safely used during pregnancy. Management of BS in pregnancy is further complicated by increased potassium needs due to increased volume of distribution. In our patient, we successfully used amiloride, a class B drug during pregnancy, along with increased KCl supplementation to maintain serum potassium levels. She was able to tolerate the high dose of KCl 400mEq QD without any complications. Due to concerns for its safety in breastfeeding, amiloride was discontinued at the initiation of labor and replaced with indomethacin and patient’s post-partum potassium levels were again stabilized.