RESUMEN
Upper urinary tract infection is a serious bacterial illness among febrile infants and young children. Significant renal scarring may occur after a single episode especially with delayed diagnosis and treatment. In this study, we evaluated the value of measurement of urinary beta 2 microglobulin [B2-MG] in the differentiation between upper and lower urinary tract infections. Fifty children with urinary tract infections [UTis] aged between 1-12 years were studied: 15 children with acute pyelonephritis documented by positive DMSA scan, 15 children with acute cystitis documented by negative DMSA scan and 20 normal children as control. In all children, total leukocytic count [TLC], erythrocyte sedimentation rate [ESR], serum C reactive protein [CRP], blood urea and serum creatinine were measured. Also, B2-MG in 24 hours collected urine was measured using ELISA technique. It was found that TLc, ESR and RP were significantly higher in cases of acute pyelonephritis compared with those of cystitis. However, there was no statistically difference between the three studied groups as regards blood urea and serum creatinine. Urinary B2-MG was significantly higher in children with acute pyelonephritis compared with the other two groups [P= 0.01]. The sensitivity, specificity, and positive predictive value of urinary B2-MG in the diagnosis of acute pyelonephritis were 94.3%, 100% and 91.6% respectively. This study showed the importance of measuring of urinary B2-MG in children with urinary tract infection and the possibility of using this non invasive test in the differentiation between upper and lower UTIs