Diagnosing apparent mineralocorticoid excess in a child with hypertension and nephrocalcinosis: from symptoms to genetics.

Apparent mineralocorticoid excess (AME) is a rare genetic disorder caused by reduced activity of the 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2) enzyme. It is characterized by hypertension, hypokalemia, and low levels of renin and aldosterone. This study presents the case of a 2-year-old female patient who exhibited abdominal distension, hypertension, recurrent hypokalemia with metabolic alkalosis, failure to thrive, polyuria, and features of rickets. Furthermore, the patient presented with nephrocalcinosis and enlarged kidneys with a normal renal Doppler study. The genetic analysis revealed a homozygous mutation in the HSD11B2 gene, confirming the diagnosis of AME. The treatment with amiloride and spironolactone resulted in normalized urine output, stabilized blood pressure, and balanced electrolyte levels. This case emphasizes the importance of considering AME in pediatric patients presenting with unexplained refractory hypertension associated with hypokalemia and nephrocalcinosis, and it underscores the crucial role of genetic testing in diagnosis and management.