Role of Dimercaptosuccinic Acid Renal Scintigraphy in the Diagnosis of Urine Culture Negative Urinary Tract Infection

Abstract

Background: Acute pyelonephritis with negative urine culture has been reported in previous studies. Dimercaptosuccinic acid (DMSA) renal scintigraphy can help diagnose pyelonephritis. The present study aimed at determining the role of DMSA renal scintigraphy in the diagnosis of urine culture negative urinary tract infection (UTI). Methods: This cross- sectional study was conducted on 193 children (one month to 12 years) with UTI, who referred to children hospital in Qazvin, Iran, from October 2010 to October 2013. UTI was defined as signs and symptoms compatible with UTI and pyuria. Negative urine culture was defined as colony count < 102 CFU/mL for one microorganism or more than one microorganism (mixed) growth. The gold standard for the diagnosis of pyelonephritis was DMSA renal scan. Results: Mean age was 35.7 ± 31.3 months (32.6% of patients were younger than one year old). Of 193 patients, 90.7% were female. Urine culture was negative in 68 (35.2%) patients. Of 80 (41.5%) patients with suspected pyelonephritis, 39 had negative urine culture. DMSA was abnormal in 59 (30.6%) patients. Of 59 patients, 24 (40.7%) had negative urine culture. Considering the DMSA renal scan as the gold standard, the sensitivity, specificity, PPV, and NPV of the urine culture for the diagnosis of pyelonephritis were 59.32%, 32.83%, 28%, and 64.70%, respectively. Conclusions: About 41% of patients with pyelonephritis could have been missed based on negative urine cultures. DMSA renal scan should be considered for the diagnosis of pyelonephritis in children with a negative urine culture and abnormal urinalysis.