Proximal Renal Tubular Acidosis

摘要: Proximal renal tubular acidosis (pRTA) is a disease of defective proximal tubule function resulting in metabolic acidosis. This chapter will review the transport processes for acid-base equivalents tubule, clinical features pRTA, and specific molecular defects that can give rise to pRTA. Two mechanisms contribute bicarbonate exit across basolateral membrane cells, namely Na + -HCO 3 ¯ cotransport Cl exchange. predominant mechanism through most length (S1 S2), whereas -CO important S3 segment. A :HCO stoichiometry 1:3 required transporter mediate net HCO efflux cells. Therefore, regulatory change from 1:2 would be expected direction outward inward thereby impede reabsorption. The pRTA defined as hyperchloremic due defect capacity nephron In patient with there greatly reduced threshold plasma at which appears urine, maximal rate reabsorption markedly depressed. principal cause isolated base predicted lead relative alkalinization intracellular pH Such tend mitigate effects systemic maintain citrate excretion higher level than observed distal RTA (dRTA).