Equis ISSN 2398-2977

Kidney: renal tubular acidosis

Synonym(s): RTA

Contributor(s): Han van der Kolk

Introduction

  • Renal tubular acidosis (RTA) is rare in horses and its diagnosis usually is a challenge.
  • Renal tubular acidosis refers to those conditions in which metabolic acidosis results from a diminished net tubular secretion of hydrogen ions.
  • There are three major types:
    • Type 1: distal.
    • Type 2: proximal.
    • Type 4.
  • What was called type 3 has proved to be a variant of type 1.
  • Type 4 has not so far been described in horses.
  • Cause: the disorder is part of the differential diagnosis of hyperchloremic metabolic acidosis. As a result, in the absence of other signs of renal failure (normal concentrations of creatinine and urea nitrogen) and diarrhea and with severe metabolic acidosis and hyposthenuria, a renal tubular disorder is considered likely.
  • Signs: include anorexia and depression.
  • Treatment: has to be geared towards the replacement of alkali and potassium.
  • Prognosis: good.

Pathogenesis

Etiology

  • The exact cause of the disorder usually remains unknown.

Pathophysiology

  • The disorder results from a diminished net tubular secretion of hydrogen ions.
  • Type 1: the condition is characterized by a decrease in the net secretion of hydrogen ions in the collecting tubules usually associated with an alkaline urine   Urine: pH  .
  • Type 2: proximal re-absorption of bicarbonate is reduced associated with a variable urine pH   Urine: pH  .

Timecourse

  • Usually development of the disorder over several days.

Diagnosis

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Treatment

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Prevention

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Aleman M R, Kuesis B, Schott H C & Carlson G (2001)Renal tubular acidosis in horses.J Vet Intern Med15, 136-43 PubMed.
  • Davidman M & Schmitz P (1988)Renal tubular acidosis - a pathophysiologic approach.Hospital Pract23, 77-96 PubMed.
  • MacLeay J M & Wilson J H (1998)Type-2 renal tubular acidosis and ventricular tachycardia in a horse.JAVMA212, 1597-1599 PubMed.
  • Van der Kolk J H & Kalsbeek H C (1993)Renal tubular acidosis in a mare.Vet Rec133, 43-44 PubMed.


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