2016 AJKD--Pathophysiology of Renal Tubular Acidosis: Core Curriculum 2016 -- dRTA dx and Mx

Topic: Pathophysiology of Renal Tubular Acidosis: Core  Curriculum 2016 -- dRTA dx and Mx
整理	內容 CD’s intercalated cells failed to reabsorb HCO3 => persistent alkaline urine: impaired acid excretion inability to reduce urinary pH to < 5.3 if spontaneous acidemia or acid loading => decreased NH4 => NAE reduced + titratable acid excreetion + HCO3 wasting => serum HCO3 decreased + hyperchloremic metabolic acidosis        2.   CD’s H secretion abnormality: 1) H-ATPase, cytosolic CA II, or kidney  AE1 defect               => failed to trapping of luminal NH3        3.     Unique feature: 1. very low urinary citrate levels <= proximal tubule increased reabsorption of citrate in response to intracellular acidosis => less stone        4.     hereditary dRTA vs. acquired dRTA => if mutations in CA II impaired HCO3 reabsorption in the proixmal tubule and collecting duct (mixed dRTA and pRTA (type III RTA) => affecting bone osteoclast resulting in osteopetrosis        5. Clinical picture: severe hypokalemia, and associated sx sx related to renal calculi hyperchloremic metabolic acidosis w/ persistent urine pH > 5.3 => dRTA + hypo-K BUT if dRTA + hyper-K <= low urine NH4: UAG>0 + low UOG                             <=>  hyper-Cl metabolic acidosis <= diarrhea: UAG<0 + high UOG             6. Tx of dRTA: daily loss of HCO3: 1~2 mEq/kg/d => required 4~8mEq/kg/d to supply         7. Imcomplete dRTA: normal serum HCO3 while lacking the ability to acidify urien when challenged with an acid loading test         8. More severe hypokalemia in dRTA than pRTA
摘要