- Acidosis causes urine ↑Ca, ↑PO4 (bone demineralization), ↓citrate (using up buffer)
- Hypocitraturia < 100 mg/d: think of Type I RTA
- Impaired distal acidification = cannot excrete hydrogen ions → acidemia
- acidemia → bone resorption → hypercalcemia/hypercalciuria → proximal reabsorption of citrate to solubilize calcium → hypocitraturia
- Citrate is important for chelating urinary calcium/preventing crystallization
- High urine pH favors precipitation of calcium phosphate stones
- Urine pH > 5.5
- Urine sodium > 25 mEq/L
- Urine anion gap c/w low urine ammonium
- Acid load test
- Give PO acid load (eg ammonium chloride 0.1 g/kg)
- measure urine pH and serum bicarb at 2h, 4h, and 6h after
- Bicarb should fall by > 3 mEq/L, and urine pH < 5.3
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last edited: Sept. 24, 2020, 8:31 p.m. | pk: 181
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