Familial, dexamethasone-suppressible, normokalemic hyperaldosteronism

An 8-year-old boy was found to be hypertensive on routine exam (144/88). His brother (age 6) and father (age 31) were also found to have elevated blood pressure. Detailed investigations first revealed a low renin level without hypokalemia. Further study revealed that all three patients had low plasma renin activity and nonsuppresible plasma aldosterone levels after saline infusion. Serum potassium was almost always normal. A trial of dexamethasone therapy normalized blood pressure, and plasma and urinary aldosterone decreased to low levels and renin levels increased. Therapy with spironolactone and prednisone also normalized blood pressure. However, the amount of prednisone required to maintain normotension resulted in Cushingoid features and has been discontinued. Studies in the father suggest that the aldosterone production by his adrenals is hyperresponsive to adrenocorticotropic hormone (ACTH). Renin levels should be determined in all hypertensive children and their hypertensive parents. If renin is low and plasma aldosterone fails to be suppressed by saline infusion, a trial of dexamethasone would seem indicated before other investigations are carried out.