Evaluación de la función renal pre y post operatoria de pacientes pediátricos con obstrucción de la unión pieloureteral . Importancia de l'estudi metabòlic mineral y de los antecedentes familiares de urolitiasis

Abstract

The association between urolithiasis and congenital malformations of the urinary tract has been known for a long time. Urinary stasis has been assumed to play an important part in the pathogenesis of nephrolithiasis, associated with distortion of the renal anatomy, delayed clearing of crystalluria and the risk of urinary infection caused by Proteus, which is a very common bacterium in these cases. The frequency of morphological abnormalities of the underlying urinary tract in children with urolithiasis is between 19.1% and 29.8%. However, the exact pathogenetic relationship between the two entities remains unknown, because the explanation mentioned above does not occur in most cases. In 2003, García Nieto et al. published that the prevalence of hypercalciuria in pediatric patients with vesicoureteral reflux is higher than in the general population and that the stones formed in patients with this malformation could have a metabolic origin; Furthermore, we observed that hypercalciuria appeared to be inherited with an autosomal dominant character and with a greater probability of being inherited from the mother. Recently, Madani et al. confirmed that the frequency of hypercalciuria and hyperuricosuria was higher in children with vesicoureteral reflux than in controls, although their relatives were not studied. The incidence of urolithiasis in patients with pyeloureteral stenosis (UPE) is of the order of 16-44.7%. The risk of stone formation in these patients has been reported to increase up to 70 times. In 1995, Husmann et al. reported that 70% of UPE patients who had removed stones other than struvite were carriers of an identifiable metabolic abnormality that could cause the stones. In subsequent work, hypercalciuria was cited as the most frequently observed metabolic abnormality in children with this malformation (Husmann, 1996), although the presence of other metabolic abnormalities was also feasible (Matin and Streem 2000; Tekin et al. 2001) . None of these studies wrote about the possible origin of the hypercalciuria observed in these patients. García Nieto et al. studied 27 children who had undergone UPE surgery and their families. Hypercalciuria was detected in 17 of the 27 children (63%) and in 15 of them (88%), the existence of a family history of urolithiasis was confirmed. In addition, in seven of the ten children without hypercalciuria, there was also a family history of kidney stones. Subsequently, the same group described similar results in pediatric patients with simple renal cysts, pyelic ectasia and renal agenesis. Based on these data, the hypothesis has been formulated that in children who have a family history of urolithiasis in their families, there may be an increased susceptibility to being carriers of morphological abnormalities of kidney development. These children would also inherit hypercalciuria that can also promote the formation of kidney stones in the future, as in their predecessors. On the other hand, it is widely accepted that pyeloplasty is the treatment of choice for pyeloureteral stenosis (UPE). However, recovery of kidney function after treatment is a matter of debate. Different parameters have been used to predict the recovery of kidney function after surgical correction with conflicting results. Not surprisingly, this must be caused by the existence of congenital dysplastic anomalies in children with unrecognized UPE until a few years ago. As a pediatric surgeon, I think it is interesting and necessary to know the evolution of my patients with respect to their renal function and with respect to knowing if they are carriers of a genetic predisposition to form kidney stones.