Descrição de parâmetros bioquímicos e ultrassonográficos de avaliação pré-natal de função renal em fetos portadores de uropatias obstrutivas

Abstract

Fetal urinary tract malformations account for 20% of all diagnosable prenatal structural anomalies. Among them, obstructive uropathies are the most common ones and the main cause of renal failure in childhood and adolescence. The posterior urethral valve is the main site of urinary tract obstruction in male neonates, and the most responsible cause of obstructive renal disease in children. OBJECTIVES: To compare the relationship between biochemical and echographic markers of prenatal renal function and the occurrence of perinatal death. METHODS: In the period between January 2008 and January 2013 we selected 18pregnant women whose fetuses had been diagnosed with low obstructive uropathy and met criteria for renal function evaluation and possible indication for intrauterine treatment. We studied ultrasonographic parameters (amniotic fluid volume, renalparenchyma aspect, presence of fetal hydronephrosis, dilatation of ureter and bladder), as well as biochemical ones (fetal urinary creatinine, 2-microglobulin, uromodulin, osmolarity and fetal urinary calcium), comparing them to mortality and postnatal renal function. RESULTS: Death occurred in 11 of the 18 selected cases and the renal function of the seven surviving ones was assessed according to theneonatology an pediatric nephrology services protocol. Gestational age median at obstructive lesions diagnosis was 21 weeks (minimum 16, maximum 28). Among the seven survivors, osmolarity and B2-microglobulin were normal in all cases. However, creatinine was altered in six cases (85,71%) and uromodulin in four cases (57,14%). Amniotic fluid was altered in five cases (71,43%) and enlarged bladderswere found in six cases (85,71%). Catheter insertion was performed in four cases (57,14%). Gestational age median in the 11 fatal cases was 20 weeks (minimum 16, maximum 20). Creatinine was altered in all 11 cases (100%). Alterations in uromodulin concentrations were found in eight cases (72,73%) and in osmolarity in five cases (45,45%). In nine cases (81,82%) fetal kidneys presented hyperechogenicity and alterations in amniotic fluid were found in 10 cases (90.91%).Hydronephrosis was present in 100% of the cases, being five severe ones (45,45%), five moderate cases (45,45%) and one case of mild hydronephrosis (9,09%). All 11 cases (100%) had enlarged bladders and 10 of them (90,91%) had dilated ureters. CONCLUSION: None of the analyzed parameters has been shown to be accurate in predicting postnatal renal function and mortality.