Kidney abscess as a rare complication of the urinary tract infections in children - 20 years of single-center observations

Kidney abscess is one of the complications of the urinary tract infection. Gram (-) intestinal flora is considered the most common etiological factor in development of kidney abscess. The spreading of bacteria usually occurs via an ascending route. Currently, in the era of antibiotic therapies, the kidney abscess is a relatively rare complication.The study aimed to analyse the prevalence, risk factors, clinical course of the disease, results of treatment, and the long-term consequences in pediatric patients with kidney abscess diagnosis.The renal abscess was diagnosed in 8 out of 32,000 hospitalized children (0.00025%) (5 girls, 3 boys, average age 6 years). In 7 cases, the association with urinary tract infection was confirmed (87.5%). In all patients, the abscess was limited to the renal parenchyma and its diameter was below 50 mm; two patients had multiple abscesses. Three children (37.5%) had a history of urinary tract disease. All patients had increased levels of the inflammation markers but the renal function parameters were within the reference values. Five children (62.5%) presented clinical symptoms (fever, pain, dysuria); in 2 children (25%) the clinical course was chronic and oligosymptomatic. The sensitivity and specificity of ultrasound examinations (US) were 100% accurate in the diagnosis and monitoring of treatment. In all cases, antibiotic therapy was effective. Post-antibiotic treatment renoscintigraphy showed persistent post-inflammatory scars in 62.5% of cases.During 20 years of observations, kidney abscess was a rare complication of urinary tract infection. Most patients did not have any underlying risk factors. Ultrasound examination had high sensitivity and specificity in the diagnosis and monitoring of the treatment. Broad-spectrum, prolonged antibiotic therapy proved to be an effective treatment in all patients. However, after the abscess has been successfully healed, most patients required permanent nephrology care due to the presence of the post-inflammatory scars.