Consult the medical resource doctors trust

UpToDate is one of the most respected medical information resources in the world, used by over 360,000 doctors and thousands of patients to find answers to medical questions.

  • Content written by a faculty of over 4,000 physicians from leading medical institutions
  • Unbiased: free of advertising or pharmaceutical funding
  • Evidence-based treatment recommendations
  • Continuously updated to incorporate new medical findings

Overview of renal tubular acidosis

INTRODUCTION

The lungs and the kidneys are responsible for the maintenance of acid-base balance within the body. Alveolar ventilation removes carbon dioxide, while the kidneys reabsorb filtered bicarbonate and excrete a daily quantity of hydrogen ion equal to that produced by the metabolism of dietary protein.

The normal renal response to acidemia is to reabsorb all of the filtered bicarbonate and to increase hydrogen excretion primarily by enhancing the excretion of ammonium ions in the urine (graph 1). Each hydrogen that is secreted results in the regeneration of a bicarbonate ion in the plasma. (See "Chapter 11B: Regulation of renal hydrogen excretion".)

Renal tubular acidosis (RTA) refers to the development of metabolic acidosis because of a defect in the ability of the renal tubules to perform these functions [1]. All forms of RTA are characterized by a normal anion gap (hyperchloremic) metabolic acidosis. This form of metabolic acidosis usually results from either the net retention of hydrogen chloride or its equivalent (such as ammonium chloride) or the net loss of sodium bicarbonate or its equivalent [2]. The major cause of a normal anion gap acidosis in patients without renal failure is diarrhea. (See "Approach to the adult with metabolic acidosis".)

There are three major subgroups of RTA with different clinical characteristics (table 1):

  • Distal or type 1 RTA
  • Proximal or type 2 RTA
  • Hypoaldosteronism or type 4 RTA
To continue reading this article you need to subscribe.

Read the rest of this article and others like it

The content on the UpToDate website is not intended nor recommended as a substitute for medical advice, diagnosis, or treatment. Always seek the advice of your own physician or other qualified health care professional regarding any medical questions or conditions. The use of this website is governed by the UpToDate Terms of Use (click here) ©2009 UpToDate, Inc.
References Top
  1. Rodriguez Soriano, J. Renal tubular acidosis: the clinical entity. J Am Soc Nephrol 2002; 13:2160.
  2. Gluck, SL. Acid-base. Lancet 1998; 352:474.
  3. Sly, WS, Whyte, MP, Sundaram, V, et al. Carbonic anhydrase II deficiency in 12 families with the autosomal recessive syndrome of osteopetrosis with renal tubular acidosis and cerebral calcification. N Engl J Med 1985; 313:139.
  4. Hu, PY, Roth, DE, Skaggs, LA, et al. A splice junction mutation in intron 2 of the carbonic anhydrase II gene of osteopetrosis patients from Arabic countries. Hum Mutat 1992; 1:288.
  5. Maldonado, JE, Velosa, JA, Kyle, RA, et al. Fanconi syndrome in adults. A manifestation of a latent form of myeloma. Am J Med 1975; 58:354.
  6. Izzedine, H, Launay-Vacher, V, Isnard-Bagnis, C, Deray, G. Drug-induced Fanconi's syndrome. Am J Kidney Dis 2003; 41:292.
  7. Igarashi, T, Sekine, T, Inatomi, J, Seki, G. Unraveling the molecular pathogenesis of isolated proximal renal tubular acidosis. J Am Soc Nephrol 2002; 13:2171.
  8. Sebastian, A, McSherry, E, Morris, RC Jr. Renal potassium wasting in renal tubular acidosis (RTA). Its occurrence in types 1 and 2 RTA despite sustained correction of systemic acidosis. J Clin Invest 1971; 50:667.
  9. Brenner, RJ, Spring, DB, Sebastian, A, et al. Incidence of radiographically evident bone disease, nephrocalcinosis, and nephrolithiasis in various types of renal tubular acidosis. N Engl J Med 1982; 307:217.
  10. Batlle, D, Moorthi, KM, Schlueter, W, Kurtzman, N. Distal renal tubular acidosis and the potassium enigma. Semin Nephrol 2006; 26:471.
  11. Batlle, DC, Arruda, JA, Kurtzman, NA. Hyperkalemic distal renal tubular acidosis associated with obstructive uropathy. N Engl J Med 1981; 304:373.
  12. Buckalew, VM Jr, McCurdy, DK, Ludwig, GD, et al. Incomplete renal tubular acidosis. Am J Med 1968; 45:32.
  13. DeFronzo, RA. Hyperkalemia in hyporeninemic hypoaldosteronism. Kidney Int 1980; 17:118.
  14. Widmer, B, Gerhardt, RE, Harrington, JT, Cohen, JJ. Serum electrolyte and acid-base composition: The influence of graded degrees of chronic renal failure. Arch Intern Med 1979; 139:1099.
white circle LOG IN
white circle DEMO