Diagnosis and treatment of a child with the syndrome of apparent mineralocorticoid excess type 1

We report the case of a 16-month-old boy who presented with chronic vomiting, failure to thrive, arterial hypertension and medullary nephrocalcinosis. Laboratory results revealed hypokalaemia, metabolic alkalosis, increased urinary potassium excretion and a hyporeninaemic hypoaldosteronism. Chromatographic determination of urinary steroid metabolites showed an abnormal elevation of tetrahydrocortisol and allo-tetrahydrocortisol compared to tetrahydrocortisone; this pattern of urinary steroid excretion is essential for the diagnosis of the syndrome of apparent mineralocorticoid excess type 1 and believed to be a result of the underlying metabolic defect, a decreased activity of the 11 beta-hydroxysteroid dehydrogenase. A second variant, called syndrome of apparent mineralocorticoid excess type 2, has similiar clinical features but lacks the typical urinary steroid profile. Therapy with spironolactone resulted in growth, weight gain and blood pressure control.