Renal tubular acidosis classification

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] ; Associate Editor(s)-in-Chief: Aditya Ganti M.B.B.S. [2] Syed Ahsan Hussain, M.D.[3] Jogeet Singh Sekhon, M.D. [4]

Overview

Based on underlying defect in concentration of urine process in renal tubule, renal tubular acidosis can be classified into type 1 (distal), type 2 (proximal), type 4 (hypoaldosteronism) and voltage-dependent RTA.

Classification

Renal tubular acidosis can be classified into 4 types. Renal tubular acidosis type 1( distal), renal tubular acidosis type 2 ( proximal), hypoaldosteronism (type 4) and voltage-dependent RTA. Potassium is the most common electrolyte abnormality associated renal tubular acidosis. Hypokalemia is seen in RTA type 1 and type 2 while type 4 and voltage-dependent RTA are hyperkalemic.^[1]^[2]^[3]

Type of RTA	Primary defect	Plasma HCO₃ mEq/L	Urine pH	Plasma potassium	Urine anion gap	Urine calcium/creatinine ratio	Risk for nephrolithiasis
RTA type 1	Impaired distal acidification	< 10	>5.3	Hypokalemic	Positive	↑	↑
RTA type 2	Reduced proximal HCO3 reabsorption.	12 to 20	<5.3	Hypokalemic	Negative	Normal	–
RTA type 3	Mixed (distal+ proximal RTA)	Variable	Variable	Variable	Variable	Variable	Variable
RTA type 4	Decreased aldosterone secretion Aldosterone resistance	>17	Variable	Hyperkalemia	Positive	Normal	–
Voltage-dependent RTA	Reduced sodium reabsorption	>17	Variable	Hyperkalemia	Positive	Normal	–

References

↑ Gil-Peña H, Mejía N, Santos F (April 2014). “Renal tubular acidosis”. J. Pediatr. 164 (4): 691–698.e1. doi:10.1016/j.jpeds.2013.10.085. PMID 24345454.
↑ Rodriguez-Soriano J, Edelmann CM (1969). “Renal tubular acidosis”. Annu. Rev. Med. 20: 363–82. doi:10.1146/annurev.me.20.020169.002051. PMID 4894504.
↑ Morris RC (December 1969). “Renal tubular acidosis. Mechanisms, classification and implications”. N. Engl. J. Med. 281 (25): 1405–13. doi:10.1056/NEJM196912182812508.

[pmid24345454-1] Gil-Peña H, Mejía N, Santos F (April 2014). “Renal tubular acidosis”. J. Pediatr. 164 (4): 691–698.e1. doi:10.1016/j.jpeds.2013.10.085. PMID 24345454.

[pmid4894504-2] Rodriguez-Soriano J, Edelmann CM (1969). “Renal tubular acidosis”. Annu. Rev. Med. 20: 363–82. doi:10.1146/annurev.me.20.020169.002051. PMID 4894504.

[pmid-3] Morris RC (December 1969). “Renal tubular acidosis. Mechanisms, classification and implications”. N. Engl. J. Med. 281 (25): 1405–13. doi:10.1056/NEJM196912182812508.

[1]

[2]

[3]