Abstract
BACKGROUND: Gitelman syndrome (GS) is a rare autosomal recessive inherited salt-losing tubulopathy, typically devoid of hypercalcemia. Herein, we described one patient of GS presenting with hypercalcemia concomitant with primary hyperparathyroidism (PHPT). METHODS: On September 28, 2020, a middle-aged female patient was admitted to our hospital with a 12-year history of hypokalemia and hypomagnesemia. Laboratory examinations unveiled hypokalemia with renal potassium wasting, hypomagnesemia, metabolic alkalosis, hypocalciuria, and gene sequencing revealed a homozygous mutation in SLC12A3 (c.179C > T [p.T60M]). Subsequently, the diagnosis of GS was confirmed. In addition, the patient exhibited hypercalcemia and elevated levels of parathyroid hormone. Parathyroid ultrasound revealed left parathyroid hyperplasia, consistent with PHPT. Following aggressive treatment with potassium chloride and magnesium oxide, her serum potassium rose to 3.23 mmol/L, serum magnesium was 0.29 mmol/L, and her joint pain was relieved. RESULTS: Based on the patient's medical history, laboratory findings, and gene sequencing results, the definitive diagnosis was GS concomitant with PHPT. CONCLUSION: PHPT should be taken into consideration when patients diagnosed with GS exhibit hypercalcemia. While the serum potassium level readily exceeded the target threshold, correcting hypomagnesemia proved challenging, primarily because PHPT augments urinary magnesium excretion.