Clinical differentiation of acute pyelonephritis from lower urinary tract infection in children

Abstract

Background and purpose: To evaluate clinical variables for diagnosing childhood acute pyelonephritis (APN) when technetium-99m dimercaptosuccinic acid (DMSA) scintigraphy is not available.

Methods: We retrospectively reviewed the records of 590 children with febrile UTI seen from January 1999 to February 2004. On the basis of DMSA scintigraphy performed within 7 days after admission, they were divided into APN (n = 237) or non-APN (n = 353) groups. Gender, age, clinical presentation, absolute neutrophil count, C-reactive protein (CRP), urinalysis, culture, and sonographic findings were recorded from charts.

Results: A CRP level of > or =66.4 mg/L, in patients with >2 days prior to admission had a sensitivity of 71.6% and a specificity of 72.5% for APN. Similarly, a CRP of >27.3 mg/L in patients with < or =2 days prior to admission and a white cell count of >14,990/mm3 had sensitivities of 68.6% and 62.0% and specificities of 66.1% and 63.0%, respectively. Combining two or more variables did not result in better discrimination.

Conclusions: If a DMSA scan is not available, it is reasonable to treat a febrile UTI as APN if the CRP is >66.4 mg/L in a patient with >2 days of fever or if the CRP is >27.3 mg/L in a patient febrile for < or =2 days.