renal tubular acidosis (RTA)

Classification

• Type 1 RTA (distal RTA)
  • serum HCO3- 5-15 meq/L
  • urine pH > 6.0
  • low serum K+
• Type II RTA (proximal RTA)
  • serum HCO3- 14-20 meq/L
  • urine pH < 5.0
  • normal or mildly decreased serum K+
  • increased HCO3- in urine
• Type III RTA (rare)
• Type IV RTA (distal RTA)
  • serum HCO3- 14-20 meq/L
  • urine pH < 5.5, but may be > 6.0 with urinary obstruction
  • high serum K+
  • high serum chloride
  • associated with diabetes

Etiology

• diabetes mellitus
• hypercalcemia
• pharmacologic causes:
  • acetazolamide
  • amphotericin B
  • tetracycline (degraded)

Laboratory

• arterial blood gas
• chem7:
  • serum Na+, serum K+. serum choride, serum bicarbonate
  • calculate anion gap
    • normal anion gap in all types

Differential diagnosis

• Fanconi's syndrome:
  • glucosuria, aminoaciduria, hyperphosphaturia, hyperuricosuria
  • normal serum glucose

Management

• see specific type
• distal RTA:
  • bicarbonate
  • loop diuretic for hyperkalemia
• proximal RTA: thiazide diuretic to reduce bicarbonate loss

More general terms

• metabolic acidosis
• renal tubular disease

More specific terms

• autosomal dominant distal renal tubular acidosis
• autosomal recessive distal renal tubular acidosis
• renal tubular acidosis (RTA) type I (hyperchloremic acidosis, distal RTA)
• renal tubular acidosis (RTA) type II (proximal RTA)
• renal tubular acidosis (RTA) type III
• renal tubular acidosis (RTA) type IV (distal RTA)

Patient information

renal tubular acidosis (RTA) patient information