Failure to thrive, hyponatremia, and hyperkalemia in a neonate.

CME EDUCATIONAL OBJECTIVES: 1.Describe the varying clinical presentations of pseudohypoaldosteronism in the neonatal period.2.Review the physiology of aldosterone production and pathophysiology of pseudohypoaldosteronism.3.Identify treatment options for pseudohypoaldosteronism when identified in the neonatal period. Pseudohypoaldosteronism type I (PHA1) is a rare disease of mineralocorticoid resistance caused by defects in sodium transport in the distal tubule of the kidney. It presents in the neonate with life-threatening dehydration due to salt wasting, accompanied by hyperkalemia, acidosis, and, frequently, failure to thrive. Patients with PHA1 are often initially diagnosed with congenital adrenal hyperplasia, but their electrolyte abnormalities are resistant to treatment with glucocorticoids and mineralocorticoids. In these patients, an astute clinician will broaden his or her differential, resulting in life-saving treatment.