Objective: Idiopathic hypercalciuria (IH) is a metabolic risk factor in patients with urinary calcium stones and implicated in 30%-50% of all urinary stone diseases. Clinical manifestations and distribution of types of IH are reviewed, as well as current treatment methods and long-term outcomes.
Patients: A total of 131 patients (70 boys and 61 girls), aged 1-15 years (mean 7.9+/-3.19 years), were studied. Follow up was between 6 months and 16 years (mean 4.1+/-6.8 years).
Results: Fifty-three patients (40%) were diagnosed following calcium challenge as renal type, and 51 (39%) as absorptive type of hypercalciuria. Whereas 72 patients (54.9%) had a family history of nephrolithiasis, 59 patients did not. Nephrolithiasis was found in 27 patients (20%) on admission (absorptive=9.9%, renal=4.5%, undetermined=6.1%), but developed in eight other patients (6.1%) (absorptive=2.2%, renal=0.7%, undetermined=3.8%). Urinary calcium excretion reversed in 65 patients with the suggested diet therapy; it recurred in 30 patients (22.9%) (absorptive=9.1%, renal=11.4%, undetermined=2.2%) but 35 returned to normal definitively (26.7%) (absorptive=11.4%, renal=12.9%, undetermined=2.2%). No change was seen in the status of 50 patients (38.1%) (absorptive=18.3%, renal=16%, undetermined=3.8%).
Conclusion: IH may be accompanied by nephrolithiasis; type must be determined and those patients with absorptive type should be followed for nephrolithiasis. Our results suggest that formation of new stones could be prevented with diet and thiazide therapies in IH.