renal tubular acidosis type IV

Last reviewed 06/2022

Type 4 renal tubular acidosis occurs in diseases and conditions associated with a failure of aldosterone action or hypoaldosteronism.

In this type of renal tubular acidosis, the acidosis is a result of loss of pH regulation secondary to hyperkalaemia.

The pH of the urine is usually below 5.4, and there is hyperkalaemia, secondary to hypoaldosteronism - mineralocorticoid deficiency causes a reduction in secretion of H+ in the distal nephron and a reduction in NH4+ sectretion. Other features include hyperchloraemic metabolic acidosis.

Treatment is with modest doses of bicarbonate and mineralocorticoid replacement.