How would you distinguish among the various forms of Idiopathic Hypercalciuria
Forms of Idiopathic Hypercalciuria
| LABORATORY VALUE | AH-I | AH-II | AH-III | RH |
|---|---|---|---|---|
| Serum calcium | Normal | Normal | Normal | Normal |
| Serum phosphorus | Normal | Normal | ↓ | Normal |
| Serum intact PTH | Normal | Normal | Normal | ↑ |
| 24-hour urinary calcium (1-g calcium diet) | ↑ | ↑ | ↑ | ↑ |
| Urine Ca/Cr ratio (1-g calcium load) | ↑ | ↑ | ↑ | ↑ |
| 24-hour urinary calcium (400-mg calcium diet) | ↑ | Normal | ↑ | ↑ |
| Fasting urinary calcium (mg/dL GFR) | Normal | Normal | ↑ | ↑ |
↑, Increased; ↓, decreased; AH, absorptive hypercalciuria; Ca/Cr, calcium/creatinine; GFR, glomerular filtration rate; IH, idiopathic hypercalciuria; PTH, parathyroid hormone; RH, renal hypercalciuria. See questions 17–20.
