Enteric hyperoxaluria, recurrent urolithiasis, and systemic oxalosis in patients with Crohn's disease

Prevalence of recurrent calcium-oxalate (CaOx) urolithiasis (UL) is up to fivefold higher in Crohn's disease than in the general population. Treatment options are scarce and the risk of recurrent UL or progressive renal CaOx deposition, (oxalosis) based early end-stage renal failure (ESRF), subsequent systemic oxalosis, and recurrence in the kidney graft is pronounced. We aimed to find proof that secondary hyperoxaluria is the main risk factor for the devastating course and correlates with intestinal oxalate absorption. 24-h urines were collected and analyzed for urinary oxalate (Uox) in 27 pediatric (6-18 years) and 19 adult patients (20-62 years). In the 21 patients (8 adults and 13 children) with hyperoxaluria a [C-13(2)]oxalate absorption test was performed under standardized dietary conditions. Mean Uox was significantly higher in patients with UL or oxalosis (0.92 +/- A 0.57) compared with those without (0.53 +/- A 0.13 mmol/1.73 m(2)/24 h, p < 0.05, normal < 0.5). Hyperoxaluria then significantly correlated with intestinal oxalate absorption (p < 0.05). As UL/oxalosis has major implications for the general health in patients with Crohn's disease (ESRF and systemic oxalosis), new medication, e.g. to reduce intestinal oxalate absorption, is definitely needed.