Development of kidney scars after acute uncomplicated pyelonephritis: relationship with clinical, laboratory and imaging data at diagnosis

Abstract

The type of lesion at diagnosis of acute uncomplicated pyelonephritis is highly correlated with the development of kidney scars. Further studies are needed to test the therapeutic schedules tailored according to the imaging data.

Dynamic magnetic resonance imaging in acute pyelonephritis

“…In effect, serial follow-up studies demonstrated a decrease in the number and extension of foci and a change from bilateral to unilateral involvement and ultimately the disappearance of the areas of nonenhancement, all of which are considered predictors of positive outcome and indicators of treatment effectiveness [14]. Although a posteriori, and in the absence of histological confirmation, these findings validate the accuracy of the MRI signs of APN seen in the diagnostic phase.…”

“…Follow-up with dynamic MRI allowed differentiation between active foci of APN and scar tissue, seen in 16.5% of positive cases, predominantly in subjects with more extensive and severe infection at diagnosis due to the presence of abscesses. Renal scars are characterised by parenchymal retraction, more-or-less marked deformation of the renal contour and constant signal hypointensity both at baseline and on delayed postcontrast scans [6,9,14]. This finding, while not unexpected [1], provided additional confirmation that imaging is instrumental in assessing the real severity of renal damage.…”

“…In the delayed phase (l) the abscess lesion is no longer visible. been reported by several studies [4,14,15]. In particular, Piccoli et al [4] emphasised that imaging is indispensable not only for identifying cases of severe disease but also for confirming treatment effectiveness during the follow-up.…”

“…In consideration of these data, we used MRI in the study of APN both as an initial diagnostic investigation -in place of ultrasound followed by CT, as was done in the past -and as a follow-up investigation to monitor the evolution of inflammatory foci and the effects of therapy. The reasons that led us to use dynamic MRI, especially in the follow-up [4,14,15]. In particolare Piccoli et al [4] [17,18].…”

“…I controlli seriati hanno infatti consentito di evidenziare la riduzione del numero, dell'estensione delle localizzazioni e del coinvolgimento da bi-a monolaterale dei focolai fino alla scomparsa delle lacune di enhancement, considerati fattori prognostici positivi ed indici di efficacia terapeutica [14], avvalorando, seppure a posteriori, in assenza di riscontri istologici, l'accuratezza dei segni RM di pielonefrite acuta evidenziati in fase diagnostica. Nondimeno il follow-up con RM dinamica ha consentito di differenziare focolai di pielonefrite attiva da esiti evolutivi cicatriziali, riscontrati nel 16,5% dei casi positivi, prevalentemente nei soggetti che alla diagnosi presentavano una maggior estensione e gravità del processo flogistico per la presenza di lesioni ascessuali.…”