type 4 (hyperkalemic distal) RTA typically present with hyperkalemia, a normal anion gap metabolic acidosis, and impaired urine acidification, but with the ability to maintain the urine pH to <5.5. The specific cause can be differentiated by measurement of plasma renin activity, serum aldosterone, and serum cortisol. Initial treatment includes correction of the underlying cause if possible, with discontinuation of offending medications. Replacement of mineralocorticoids with fludrocortisone is indicated for patients with documented deficiency and should be considered for those with hyporeninemic hypoaldosteronism unless hypertension or heart failure is present.