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Urinary tract infection is common in children. Before the age of 6 months; boys are more susceptible to UTI than girls thereafter, the incidence is substantially higher in girls than in boys .Up to 11.3% of girls and 3.6% of boys studied in UK will have had an UTI by age 16years .UTI is usually caused by gram-negative organisms, especially Escherichia coli which accounts for about 80% of all pathogens. Proteus is more common in boys. (1, 2) In childhood, upper UTI with 5.3% prevalence rate, are one of the most important causes of hospitalization. Although acute pyelonephritis might presents with fever, lethargy, anorexia, and vomiting but there are no certain specific diagnostic laboratory tests and clinical symptoms for diagnosis of UTI (1, 2) Untreated upper UTI can produce severe renal damages. Delay in treatment of acute pyelonephritis increases the risk of kidney damage. Complications of acute pyelonephritis include intra renal and peri renal abscess. Early diagnosis and treatment of urinary tract infection in children is important (3, 4) Recurrent UTI is defined as a further infection by a new organism. Relapsing UTI is defined as a further infection with the same organism. (1-5) Uncomplicated UTI infection requires no imaging and often shows no imaging abnormalities. Children who fail to respond to treatment or are severely ill need imaging evaluation (11) Obstructive anomalies are found in up to 4%, and vesico ureteral reflux in 8% to 40% of those with first urinary tract infection. Acute pyelonephritis and reflux are two synergistic factors in the destruction of kidneys of children (1-5) In children, vesico ureteral reflux of infected urine is the most common cause of chronic pyelonephritis and chronic interstitial nephritis. Intra renal reflux induces reflux nephropathy, progressive renal injury and cortical scarring. Reflux nephropathy usually observed as a focal cortical scar that overlies a blunted calyx in the upper pole of kidney (11) Imaging findings in children with reflux nephropathy is similar to chronic pyelonephritis in adults. Both type of nephropathy are best demonstrated on IVP or US and CT as classically lobar, with normal lobes with normal calyces interposed between diseased lobes. (11-17) CT is more sensitive than Ultrasound in demonstrating subtle changes in the renal parenchyma associated with uncomplicated pyelonephritis. CT is normal in some patients with mild uncomplicated pyelonephritis. Complications such as renal or peri renal abscess are well demonstrated by CT or US (17) Although imaging studies have been considered after the diagnosis of a first urinary tract infection, the effect of such studies on outcome has been unclear. Recently, low radiation procedures recommended for diagnosis of VUR (18) |
