 Cystitis is a UTI limited to the bladder. Cystitis typically presents with localized symptoms of frequency, urgency, fever, and dysuria. Cystitis in the absence of pyelonephritis is usually not associated with long-term sequelae [4]. Acute pyelonephritis is infection of one or both kidneys. Pyelonephritis typically presents with systemic symptoms such as high fever, malaise, vomiting, abdominal or flank pain, and tenderness [2-5]. Pyelonephritis is diagnosed in children on the basis of the presence of pyuria and/or bacteriuria, fever, flank pain, or tenderness. Between 50% and 64% of children who have a febrile UTI are found to have defects on renal cortical scintigraphy indicating acute pyelonephritis [7]. Pyelonephritis can cause renal scarring, which is the most severe long-term sequela of UTI and can lead to accelerated nephrosclerosis, leading to hypertension and chronic renal failure [2-5]. The reported incidence of scarring in children after pyelonephritis varies widely in the literature. A systematic review showed that 15% (95% confidence interval, 11%-18%) of children had evidence of renal scarring after the first episode of UTI [7]. With the increased use of prenatal ultrasound (US), it was determined that many of the scars that had been attributed to pyelonephritis actually occur in utero and represent renal dysplasia [2-5]. Contrary to earlier studies suggesting that renal scarring secondary to pyelonephritis is the most common cause of chronic renal disease in children, it is now evident that the long-term risk is low [2-5]. The role of imaging is to guide treatment by identifying patients who are at high risk to develop recurrent UTIs or renal scarring. However, identification of children at risk is relevant only if there is effective treatment. Current management strategy to prevent UTIs and renal scarring is based on prophylactic antibiotics and selective surgical correction of vesicoureteral reflux (VUR).
Urinary Tract Infection Child.  Cystitis is a UTI limited to the bladder. Cystitis typically presents with localized symptoms of frequency, urgency, fever, and dysuria. Cystitis in the absence of pyelonephritis is usually not associated with long-term sequelae [4]. Acute pyelonephritis is infection of one or both kidneys. Pyelonephritis typically presents with systemic symptoms such as high fever, malaise, vomiting, abdominal or flank pain, and tenderness [2-5]. Pyelonephritis is diagnosed in children on the basis of the presence of pyuria and/or bacteriuria, fever, flank pain, or tenderness. Between 50% and 64% of children who have a febrile UTI are found to have defects on renal cortical scintigraphy indicating acute pyelonephritis [7]. Pyelonephritis can cause renal scarring, which is the most severe long-term sequela of UTI and can lead to accelerated nephrosclerosis, leading to hypertension and chronic renal failure [2-5]. The reported incidence of scarring in children after pyelonephritis varies widely in the literature. A systematic review showed that 15% (95% confidence interval, 11%-18%) of children had evidence of renal scarring after the first episode of UTI [7]. With the increased use of prenatal ultrasound (US), it was determined that many of the scars that had been attributed to pyelonephritis actually occur in utero and represent renal dysplasia [2-5]. Contrary to earlier studies suggesting that renal scarring secondary to pyelonephritis is the most common cause of chronic renal disease in children, it is now evident that the long-term risk is low [2-5]. The role of imaging is to guide treatment by identifying patients who are at high risk to develop recurrent UTIs or renal scarring. However, identification of children at risk is relevant only if there is effective treatment. Current management strategy to prevent UTIs and renal scarring is based on prophylactic antibiotics and selective surgical correction of vesicoureteral reflux (VUR).