Uric acid stones

The construction of guidelines for management of renal stone disease is complicated by several issues. First, diagnosis is critical to good management, but levels of evidence have not been described for diagnostic tests particularly when there is no comparative test of 100% sensitivity and specificity. Second, the disease is managed by a variety of specialties, mainly urology, and hence nephrologists cannot claim to have overarching expertise. Finally, stone disease is one of the oldest diseases known to man. Many therapies were imbedded in practice before randomized prospective trials were cornerstones of clinical research. Some therapies are so much part of the routine that controlled trials involving no such therapy (e.g. allopurinol vs placebo in uric acid stone disease) are unlikely to ever be performed. In the few randomized trials that have been performed, a fall in stone frequency is often seen in the control patients (‘stone disease effect’), making interpretation of the uncontrolled trials difficult. The epidemiology of childhood stones is less clear. Children are more affected by genetic and anatomical disorders, and require very specific expertise. Accordingly childhood stones will not be covered in these guidelines.