We conclude that mortality rate for acute renal failure in cardiac patients under ECMO continues to be high. Our data suggest that acute renal failure is generally a part of multiorgan failure. This unique form of acute renal failure, causes generalized edema and fluid overload despite still low serum creatinine and azotemia, and deteriorates rapidly to death. From this study shows, advanced cardiac failure may need more aggressive and early initiation of ECMO support before acute renal failure develops. Acute renal failure in advanced heart failure under ECMO support means a grave sign, need aggressive heart transplantation therapy as soon as possible. Combination of CRRT and ECMO might serve an alternative therapy bridging the temporary replacement treatment and heart transplantation in advanced cardiac patients.

Renal infection, including acute and chronic pyelonephritis, focal bacterial nephritis, renal and perinephric abscess, pyonephrosis and others, represents a spectrum of interrelated conditions. In recent years, computed tomography, ultrasound, nuclear scintigraphy, excretory urography (IVP) and magnetic resonance imaging have offered varying degrees of utility in evaluating renal infection. Although imaging in acute pyelonephritis has been extensively studied, this condition is a rare initial presentation as a renal cystic feature. This investigation presents a case of acute pyelonephritis, with an atypical initial imaging manifestation in renal cystic feature, which became a heterogeneous mass during follow up, and disappeared after treatment. Two conclusions can be drawn: first, a renal cystic lesion may be an initial presentation of acute pyelonephritis; secondly, the abnormalities of the ultrasonography imaging study of renal pyelonephritis persisted and progressed despite the improvement in clinical symptoms and laboratory findings, and displayed complete resolution of imaging abnormalities several months later.