Concurrent Gitelman Syndrome and Hyperthyroidism: Diagnostic Challenges in a 51-Year-Old Patient

Area of Science:

• Nephrology
• Genetics
• Endocrinology

Background:

• Gitelman syndrome (GS) is an uncommon autosomal recessive inherited disorder affecting the distal tubules, caused by SLC12A3 gene mutations.
• It often presents in adulthood with hypokalemia and alkalosis, requiring differentiation from other hypokalemic conditions like hyperthyroidism.

Observation:

• A 51-year-old woman presented with hypokalemia, fatigue, and palpitations, initially treated for hypokalemia without improvement.
• Concurrent hyperthyroidism was diagnosed and treated, but hypokalemia persisted, alongside hypomagnesemia and metabolic alkalosis.

Findings:

• Genetic testing revealed compound heterozygous mutations in the SLC12A3 gene, confirming a diagnosis of Gitelman syndrome.
• Treatment with potassium, magnesium, and spironolactone normalized serum potassium levels, and hyperthyroid medication dosage was reduced.

Implications:

• Simultaneous Gitelman syndrome and hyperthyroidism can lead to misdiagnosis due to overlapping symptoms.
• Early genetic diagnosis and comprehensive management are crucial for Gitelman syndrome, a condition that presents therapeutic challenges.