Fetal uropathies: diagnostic pitfalls and management.

Based on the experience of 63 antenatal diagnoses of fetal uropathic conditions we discuss the diagnostic problems, practical implications of antenatal diagnosis and potential indications of in utero intervention. A correct diagnosis was established in 43 of the 63 cases (70 per cent). Diagnostic problems were encountered in differentiating among multicystic dysplastic kidneys and ureteropelvic junction obstruction, dilatation owing to reflux or obstruction and lack of visualization of small hypoplastic kidneys. Transitory urinary tract dilatation was found in 14 cases (22 per cent) and can be responsible for additional false positive findings. Evaluation of the thoracic development and amniotic fluid must be part of the examination, since they are related to severe obstructive uropathy. Repeat examinations are necessary in these cases. During evaluation of the eventual benefit of an in utero decompression one should consider the diagnostic difficulties, mainly the time of onset of fetal uropathic conditions during morphogenesis and the absence of a clinically reliable method to evaluate fetal renal function. To date there are no real indications for in utero intervention in most detectable cases. The major benefit of prenatal echography is to allow early recognition of major uropathic conditions before postnatal infection worsens the prognosis.