Transport Dysfunction in Tubulointerstitial Disease
| Defect | Cause(s) |
|---|---|
| Reduced GFRa | Obliteration of microvasculature and obstruction of tubules |
| Fanconi syndrome | Damage to proximal tubular reabsorption of solutes, primarily glucose, amino acids, and phosphate; may also exhibit hypouricemia, proximal tubular acidosis, low-molecular-weight proteinuria |
| Hyperchloremic acidosisa | 1. Reduced ammonia production (CKD) or excretion (hyperkalemia) |
| 2. Inability to acidify the collecting duct fluid (distal renal tubular acidosis) | |
| 3. Proximal bicarbonate wasting (proximal RTA) | |
| Polyuria, isothenuriaa | Damage to medullary tubules (thick ascending limb and/or collecting duct) and vasculature |
| Hypokalemic alkalosis | Damage or hereditary dysfunction of the thick ascending limb or distal convoluted tubule (Bartter's and Gitelman's syndromes) |
| Magnesium wasting | Damage or hereditary dysfunction of the thick ascending limb or distal convoluted tubules |
| Hyperkalemiaa | Potassium secretory defects including aldosterone resistance |
| Salt wasting | Distal tubular damage with impaired sodium reabsorption |
aCommon.
Abbreviations: CKD, chronic kidney disease; RTA, renal tubular acidosis.