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renal tubular acidosis (RTA)
Classification:
1) Type 1 RTA (distal RTA)
a) serum HCO3- 5-15 meq/L
b) urine pH > 6.0
c) low serum K+
2) Type II RTA (proximal RTA)
a) serum HCO3- 14-20 meq/L
b) urine pH < 5.0
c) normal or mildly decreased serum K+
d) increased HCO3- in urine
3) Type III RTA (rare)
4) Type IV RTA (distal RTA)
a) serum HCO3- 14-20 meq/L
b) urine pH < 5.5, but may be > 6.0 with urinary obstruction
c) high serum K+
d) high serum chloride
e) associated with diabetes
Etiology:
1) diabetes mellitus
2) hypercalcemia
3) pharmacologic causes:
- acetazolamide
- amphotericin B
- tetracycline (degraded)
Laboratory:
1) arterial blood gas
2) chem7:
a) serum Na+, serum K+. serum choride, serum bicarbonate
b) calculate anion gap
- normal anion gap in all types
Differential diagnosis:
- Fanconi's syndrome:
- glucosuria, aminoaciduria, hyperphosphaturia, hyperuricosuria
- normal serum glucose
Management:
1) see specific type
2) distal RTA:
a) bicarbonate
b) loop diuretic for hyperkalemia
3) proximal RTA: thiazide diuretic to reduce bicarbonate loss
Specific
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)
General
metabolic acidosis
renal tubular disease
References
- Harrison's Principles of Internal Medicine, 13th ed.
Companion Handbook, Isselbacher et al (eds), McGraw-Hill
Inc. NY, 1995, pg 829-39
- Rodriguez Soriano J.
Renal tubular acidosis: the clinical entity.
J Am Soc Nephrol. 2002 Aug;13(8):2160-70. Review.
PMID: 12138150 Free Article
- Yaxley J, Pirrone C.
Review of the Diagnostic Evaluation of Renal Tubular Acidosis.
Ochsner J. 2016 Winter;16(4):525-530. Review.
PMID: 27999512 Free PMC Article
- Medical Knowledge Self Assessment Program (MKSAP) 19
Board Basics. An Enhancement to MKSAP19.
American College of Physicians, Philadelphia 2022