Nephrogenic Diabetes Insipidus or Bartter Syndrome? A Dilemma of Refractory Hypokalemia in Pregnancy: A Case Report from Soedono Regional Public Hospital in Madiun

Hypokalemia is a rare condition in pregnant women. Muscle weakness and life-threatening heart damage can occur if the baseline condition is not treated, especially if it recurs and persists. The differential diagnosis in recurrent hypokalemia includes nephrogenic diabetes insipidus, characterized by the kidneys' inability to respond to vasopressin to concentrate urine, or Bartter syndrome, a tubulopathy resulting from a rare genetic mutation affecting the loop of Henle, leading to potassium wasting. A 24-year-old primigravida at 35/36 weeks gestation presented with refractory hypokalemia, indicative of diabetes insipidus or a differential diagnosis of Bartter syndrome. The patient complained of limb weakness combined with polydipsia, polyuria, and a history of periodic paralysis due to severe hypokalemia since 2016. She consistently took potassium supplements and monitored her potassium levels. Since becoming pregnant in November 2021, the patient has been hospitalized three times due to limb weakness, with the lowest serum potassium level recorded at 1.6. Throughout her pregnancy, fetal growth and development remained within normal limits, and her blood pressure ranged from 100-120/60-80. In patients with limb weakness, evaluating serum potassium levels is crucial. In this case, the suspicion of nephrogenic diabetes insipidus could not be confirmed due to the unavailability of antidiuretic hormone (ADH) tests. Bartter syndrome, although rarely encountered, should be considered in patients with recurrent hypokalemia. The challenge in Indonesia lies in the lack of specific gene examinations for diagnosis, making diagnostics relatively difficult. Our recommendation for cases like this is to conduct ADH examinations and thoroughly investigate refractory hypokalemia.