The type Ic morphology of urinary calculi: an alert to primary hyperoxaluria? Experience with 43 Moroccan children

Faïza Meiouet,Michel Daudon,Saâd El Kabbaj

doi:10.5802/crchim.160

Abstract

Primary hyperoxaluria is the most severe stone disease responsible for multiple stone recurrence and impairment of kidney function. It is a rare inherited disease with an autosomal transmission. Due to the high proportion of consanguineous marriages by comparison to other areas in the world, this pathology is more frequent in North Africa. Stones are made of calcium oxalate monohydrate, which is not unique to the disease and cannot help physicians for the diagnosis. By contrast, stone morphology may be a useful marker of the pathology. We report our experience based on 614 stones from Moroccan children analyzed by infrared spectroscopy and examined by stereomicroscopy for the determination of their morphological type. Our results show that 85 stones (13.8%) exhibit a type Ic morphology, strongly suggestive of the disease in children patients. It was confirmed in all subjects of a subgroup of 43 patients who benefited from urinary biochemical explorations revealing whewellite crystalluria and a very high oxalate to creatinine ratio.

Highlights

Primary hyperoxaluria (PH) is one of the most severe hereditary kidney stone diseases and is caused by defects in glyoxylate metabolism, resulting in overproduction of oxalate and eventually end stage renal disease (ESRD)
We report our experience based on 614 stones from Moroccan children analyzed by infrared spectroscopy and examined by stereomicroscopy for the determination of their morphological type
Because type Ic morphology of stones has been described as a strong marker suggesting PH [18,19], we focused our attention on patients who formed calcium oxalate monohydrate (COM) stones with a type Ic morphology

Summary

Introduction

Primary hyperoxaluria (PH) is one of the most severe hereditary kidney stone diseases and is caused by defects in glyoxylate metabolism, resulting in overproduction of oxalate and eventually end stage renal disease (ESRD). Oxalosis characterized by calcium oxalate deposits in all tissues, in particular bones and the cardiovascular system [7,8]. It accounts for 1 to 2% of cases of pediatric ESRD, according to registries from Europe, the United States, and Japan [1,9,10], but it appears to be more prevalent in countries in which consanguineous marriages are common (with a prevalence of 10% or higher in some North African and Middle Eastern nations), but it is certainly underestimated [11]. Data from PH cohorts in industrialized countries show that the diagnosis was only made after progression to ESRD in more than 30% of patients [1,9,12,16]

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Conclusion