Abstract: SA-PO1001

An Atypical Presentation of Gitelman’s Syndrome: Unmasking with Vomiting and Diarrhea

Session Information

Category: Nephrology Education

  • 1302 Fellows and Residents Case Reports

Authors

  • Chang, Eric, Yale University, New Haven, Connecticut, United States
  • Turner, Jeffrey M., Yale University, New Haven, Connecticut, United States
Background

Hypokalemia is frequently encountered in the daily practice of nephrology. There are a variety of reasons for hypokalemia, commonly hypomagnesemia, diarrhea or diuretics. Genetic entities such as a salt-wasting tubulopathy like Gitelman syndrome, are rarer etiologies. We report a case of Gitelman syndrome unmasked by vomiting and diarrhea from small bowel overgrowth syndrome.

Methods

A 22-year-old male was referred for persistent severe hypokalemia and hypomagnesemia. He presented with the following electrolyte levels: potassium 2.4-3.4 mmol/L, magnesium 1.2-1.4 mmol/L, and calcium 10.5-10.7 mmol/L. His hypokalemia was noted to occur after acute onset of nausea, vomiting, and diarrhea. His electrolyte abnormalities persisted despite oral potassium and magnesium repletion as well as treatment of small bowel overgrowth syndrome with improved gastrointestinal symptoms. After obtaining additional historical labs, it was noted that he had mild to moderate hypokalemia dating back years prior to his onset of nausea, vomiting, and diarrhea. Our workup revealed a potassium fractional excretion of 11%, magnesium fractional excretion of 7%, aldosterone level of 4, plasma renin activity level of 11.9 (aldo/PRA 0.33). Genetics panel demonstrated compound heterozygous mutations in the SLC12A3 gene. He is now maintained on high dose oral potassium and magnesium supplementation daily with weekly intravenous infusions as well. Adjunctive therapy has been intermittently tolerated due to perceived worsening of his gastrointestinal symptoms. This has included a potassium sparing diuretic, angiotensin receptor blocker, mineralocorticoid receptor antagonist, and NSAIDs.

Conclusion

Gitelman syndrome is a rare autosomal recessive disorder afflicting 1:40,000 people. Specifically, mutations in the SLC12A3 lead to defective NCC channels in the distal tubules, creating a thiazide-like effect leading to hypokalemia and hypomagnesemia. This case presented a diagnostic challenge as his electrolyte abnormalities initially presented in the setting of severe gastrointestinal illness, which were thought to be the source of his potassium and magnesium losses. This case highlights the critical role of routinely screening for renal wasting of electrolytes even when alternative causes are present.