ICU · Renal / acid-base

Renal Tubular Acidoses (Types I, II, IV) — The Hyperchloraemic Acidoses

Also known as Renal tubular acidosis · RTA · Type 1 RTA · Distal RTA · Type 2 RTA · Proximal RTA · Type 4 RTA · Hypoaldosteronism · Fanconi syndrome · Non-anion-gap metabolic acidosis · Hyperchloraemic acidosis · Nephrocalcinosis · Fludrocortisone

The renal tubular acidoses (RTA) are a group of disorders of the renal acid-base handling that produce a non-anion-gap (the hyperchloraemic) metabolic acidosis from the impaired renal acid excretion (the bicarbonate reabsorption or the acid secretion). The three types: the Type 1 (the distal) — the impaired distal H-plus secretion; the urine pH stays HIGH (over 5.5) despite the acidosis; the HYPOkalaemia; the causes the autoimmune (the Sjogren), the amphotericin B, the lithium; the nephrocalcinosis and the stones; the treatment the bicarbonate plus the potassium. The Type 2 (the proximal) — the impaired proximal bicarbonate reabsorption; the urine pH high then low; the HYPOkalaemia; the Fanconi syndrome, the myeloma, the ifosfamide, the tenofovir, the acetazolamide; the treatment the bicarbonate plus the potassium. The Type 4 — the hypoaldosteronism (or the aldosterone resistance); the urine pH LOW (under 5.5); the HYPERkalaemia (the key discriminator); the diabetes, the Addison, the ACEi, the ARB, the K-sparing diuretics; typically in mild-to-moderate CKD; the treatment the low-dose fludrocortisone and the treat the hyperkalaemia.