Background: Urinary tract infection is a common infectious disease in children and associated with the risk for renal scarring and long-term complications, usually consists of pyelonephritis and may cause complications such as scars in kidney, hypertension and renal failure. Some studies demonstrated association between urinary tract infection and electrolyte disturbances such as hyponatremia. The present study has been designed for assessment of association between urinary tract infection and hyponatremia in children.

Methods: This is a descriptive, cross-sectional study has been conducted on 120 children have referred to the Golestan Hospital, Ahvaz Jundishapur University of Medical Science from 21 March 2011 until 20 March 2013. A total of 120 children who were aged 6 months to 12 years and had febrile urinary tract infection. The study population and were classified into two group of sixty children: hyponatremic and nonhyponatremic. We compared the laboratory findings in two groups with each other. The data included serum sodiom level, white blood cell (WBC) count, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) and ddimercaptosuccinic acid (DMSA) scan results collected from children with febrile urinary tract infections admitted in pediatric ward. Data analysis was performed using descriptive statistics, chi-square and independent T-test with SPSS software, ver. 20 (IBM, Armonk, NY, USA).