In this entity the primary event is an increased loss of calcium into the urine. Note, however, that the elevation in PTH level may be extremely modest and often difficult to detect. These events are depicted in Fig. 7. Note that the primary event in this cascade of events is an enhanced renal leak of calcium, with all subsequent pertubations being secondary. Patients with a primary renal leak, when placed on low calcium diet continue to leak large amounts of calcium in the urine, which distinguishes them from the hyperabsorptive variety.
Much controversy exists regarding the optimal modality of therapy.
Hypercalciuria is decreased by decreasing the filtered load of calcium and Hunting calcium secretion. Hyperuricosuria Hyperuricosuria will be dealt with in a subsequent paragraph. However, the point to be made is that if uric acid crystals are present in the urine they may form a nidus for heterologous nucleation. It is not uncommon to find calcium oxalate stones in the setting of hyperuricosuria. Alternately, in patients with calcium oxalate stones, elevated levels of uric acid in the urine is not an uncommon event.