Pseudo Gitelman syndrome: a rare case of hypokalemia in pregnancy

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Z. Brkic, R.A. Carels, F.E. de Jongh

Woensdag 20 april 2016

15:40 - 15:50u in Zaal 0.5

Categorieën: Parallelsessie

Parallel sessie: Parallelsessie 4: Case reports/research

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Introduction: Next to hyperemesis gravidarum there are other causes of hypokalemia in pregnancy. Pseudo Gitelman syndrome presents with same clinical and laboratory findings as Gitelman syndrome, but is differentiated from classic Gitelman by absence of genetic mutations in SLC12A3 and by reversibility of electrolyte imbalances after delivery.

Case: 32-year old woman was admitted at our hospital at 34 weeks of gestation due to hypokalemia 2.5 mmol/L. She was symptom free with unremarkable medical history and no medication use. Physical examination did not show abnormal findings with blood pressure 115/75mmHg and regular pulse 68/min. ECG was normal and lab results showed bicarbonate 43mmol/L, normal calcium and magnesium. Urine analysis revealed high potassium excretion 59 mmol/L, high chloride excretion and low calcium excretion. Surreptitious vomiting was excluded by high urine chloride and diuretic abuse was excluded by negative assessment of diuretics in urine. Potassium was daily supplemented and patient delivered a healthy boy at 35 weeks of gestation after which potassium levels remarkably improved. Since genomic analysis excluded SLC12A3 mutations, pseudo Gitelman syndrome was diagnosed.

Discussion: Instead of genetic mutations, pseudo Gitelman is caused by physiological changes during pregnancy. To preserve circulating volume during pregnancy, estrogens have been shown to upregulate Na-Cl cotransporter in apical membrane of the distal tubule. In pregnant women with malfunction of this estrogen dependent upregulation, hyperaldosteronism occurs enhancing potassium and hydrogen secretion leading to pseudo Gitelman syndrome.

Conclusion: Pseudo Gitelman syndrome should be considered in pregnant women with hypokalemia, metabolic alkalosis and high potassium and chloride excretion.