How are urinary tract infections treated?

Late initiation of adequate antimicrobial therapy in children with urinary tract infection leads to serious consequences: damage to the renal parenchyma (with possible formation of areas of shrinkage) and sepsis. Analysis of the results of scintigraphy performed within 120 hours from the start of treatment showed that antimicrobial therapy prescribed to children with fever and suspected urinary tract infection in the first 24 hours of illness allows to completely avoid focal defects in the renal parenchyma. Starting treatment at a later date (2-5 days) leads to the appearance of parenchymal defects in 30-40% of children.

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Indications for use

Parenteral (intravenous or intramuscular) administration of antimicrobial agents is indicated for children with fever, toxicosis, inability to administer oral therapy, as well as to ensure optimal antimicrobial concentration in the blood, eliminate acute infection, prevent urosepsis and reduce the likelihood of renal damage. When administering medications intravenously to children with urinary tract infection, a single daily dose of ceftriaxone is recommended, and when administered intramuscularly, in accordance with official recommendations. After clinical improvement (usually 24-48 hours after the start of treatment) and in the absence of vomiting, the child can be transferred to taking the drug orally (step therapy).

Choice of antimicrobial therapy

The initial choice of therapy for urinary tract infection is always empirical. It is based on knowledge of the predominant uropathogens in children of this age group, the expected antibacterial sensitivity of the microflora, and the clinical status of the child. In the vast majority of cases, the empirical choice of protected penicillins, third-generation cephalosporins (e.g., cefixime), or aminoglycosides is justified. According to Allen UD et al. (1999), the sensitivity of E. coli to aminoglycosides can reach 98%. The drugs of choice include amoxiclav or augmentin. The main problem in choosing antimicrobial therapy for urinary tract infection is associated with the development of resistance of the urinary microflora. Resistance most often develops in case of urinary tract anomalies; therefore, when changing antibacterial therapy, it is necessary to be guided by the proven sensitivity of the urinary microflora to the antimicrobial agent.

Antimicrobial agents recommended for the treatment of urinary tract infections in children

Preparation	Sensitivity of microflora	Route of administration and dosage
Amoxicillin	E. coli, Klebsiella	Orally: children under 2 years old - 20 mg/kg three times; 2-5 years old - 125 mg three times; 5-10 years old - 250 mg three times; over 10 years old - 250-500 mg three times IM: 50 mg/kg per day in 2 administrations
Augmentin (amoxiclav)	E. coli, Proteus mirabilis, Proteus vulgaris, Klebsiella, Salmonella	Intravenously: children during the first 3 months of life 30 mg/kg per administration at intervals of 12 hours; aged 3 months to 12 years - 30 mg/kg per administration every 6-8 hours; over 12 years, a single dose of 1.2 g every 6-8 hours. Orally: children under 9 months are not prescribed; children under 12 years are given in the form of syrup; children aged 9 months to 2 years - 2.5 ml (0.156 g/5 ml) per dose; from 2 to 7 years - 5 ml (0.156 g/5 ml) per dose; from 7 to 12 years - 10 ml (0.156 g/5 ml) per dose; over 12 years - 0.375 g per dose (in the form of syrup or tablets)
Cephalexin	E. coli	Orally: for children weighing up to 40 kg - 25-50 mg/kg per day in 4 doses; over 40 kg - 250-500 mg every 6-12 hours
Cefotaxime	E. coli, Citrobacter, Proteus mirabilis, Klebsiella, Providencia, Serratia, Haemophilus influenzae, Pseudomonas aeruginosa	I/m and I/v: 50-180 mg/kg per day
Ceftriaxone	E. coli, Citrobacter, Proteus, Klebsiella, Pseudomonas aeruginosa, Enterobacter	Intramuscularly and intravenously: newborns up to 2 weeks old - 20-50 mg/kg per day once; older than 2 weeks of age, 50-100 mg/kg per day once
Cefixime	E. coli, Proteus mirabilis, Moraxella (Branhamella) catarrhalis, N. gonorrhoeae, Haemophilus influenzae, Streptococcus pneumoniae, Streptococcus pyogenes	By mouth: children from 6 months to 12 years - 4 mg/kg every 12 hours; children over 12 years and weighing more than 50 kg - 400 mg 1 time per day or 2 mg 2 times per day
Cefaclor	E. coli, Haemophilus influenzae, Proteus mirabilis, Klebsiella	Orally: 20 mg/kg per day in 3 doses. When conducting anti-relapse treatment: 5-10 mg/kg per day in 1-3 doses
Gentamicin	E. coli, Proteus, Klebsiella, Pseudomonas aeruginosa, Enterobacter	Intramuscularly and intravenously: newborns and premature infants - 2-5 mg/kg per day in 2 administrations; children under 2 years old - 2-5 mg/kg per day in 2 administrations, children over 2 years old - 3-5 mg/kg per day in 2 administrations (a single intravenous administration of the daily dose of gentamicin is allowed)
Amikacin	E. coli, Klebsiella, Pseudomonas aeruginosa, Enterobacter	I/m and I/v: first injection - 10 mg/kg, subsequent - 7.5 mg/kg (administration interval 12 hours); a single intravenous administration of a daily dose of amikacin is allowed
Netilmicin	E. coli, Proteus, Klebsiella, Pseudomonas aeruginosa, Enterobacter	Intramuscularly and intravenously: premature infants and newborns under 7 days old - 6 mg/kg per day in 2 doses; newborns over 7 days old, children under 2 years old - 7.5-9 mg/kg per day in 2 doses; children over 2 years old - 6-7.5 mg/kg per day in 2 doses; a single intravenous administration of the daily dose of netilmicin is allowed.
Nalidixic acid	E. coli, Proteus, Klebsiella	Orally: 15-20 mg/kg per day once at night (to prevent recurrence of UTI)
Trimethoprim	E. coli, Proteus, Klebsiella	Orally: 2-3 mg/kg per day once at night (to prevent recurrence of urinary tract infections)
Furagin	E. coli, Proteus, Klebsiella, Enterobacter	Orally: 2-3 mg/kg per day once at night (to prevent recurrence of urinary tract infections); 6-8 mg/kg per day (therapeutic dose)

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Duration of the course of antimicrobial therapy

Numerous studies have shown that the duration of antimicrobial therapy in children with urinary tract infection should not be less than 7 days. The optimal duration of antibacterial therapy for pyelonephritis is 10-14 days.

Evaluation of the effectiveness of antibacterial therapy

Clinical improvement within 24-48 hours from the start of treatment. With the right treatment, urine becomes sterile within 24-48 hours. Reduction or disappearance of leukocyturia on the 2nd-3rd day from the start of treatment.

Efficacy and safety of some antibacterial drugs in children with urinary tract infection

Preparation	Efficiency, %	Safety (frequency of side effects and complications), %
Ethymycin (Zhao C. et al., 2000)	85.3	8.6
Netilmicin (Zhao C. et al., 2000)	83.9	9.4
Sulbactam (Li JT et al., 1997)	85	5
Cefotaxime (Li JT et al., 1997)	81	10
Norfloxacin (Goettsch W. et al., 2000)	97.6	-
Trimethoprim (Goettsch W. et al., 2000)	74.7	-
Nitrofurantoin (Goettsch W. et al., 2000)	94.8	-
Amoxicillin (Goettsch W. et al., 2000)	65.2	-

Lack of remission after the 14th day of treatment is possible in patients with anomalies in the development of the urinary tract. The question of the need to continue antibacterial therapy should be decided after a repeated examination of the child, determination of the urine culture and its sensitivity to antimicrobial drugs, and urine microscopy. Consultation with a pediatric nephrologist and urologist is indicated.

Necessary studies during antibacterial therapy.

• On the 2nd to 3rd day of treatment, it is necessary to conduct urine microscopy. The indication for repeated determination of the degree of bacteriuria and sensitivity of urine microflora to antimicrobial drugs is the absence of clinical improvement during the first 48 hours of therapy.
• After completion of antibacterial therapy, conduct a urine test and a general blood test.

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Prevention of recurrence of urinary tract infections

The main indication for prescribing anti-relapse therapy is abnormalities of the genitourinary system, metabolic disorders that determine the development of relapses. Currently, the following medications are recommended for anti-relapse treatment of urinary tract infections.

• Furagin 2-3 mg/kg per day once at night in the absence of bacteriuria.
• Co-trimoxazole 2 mg trimethoprim + 10 mg sulfamethoxazole per kg/day once at night.
• Nalidixic acid 15-20 mg/kg per day once at night.

The duration of anti-relapse therapy is at least 3 months.

As part of complex therapy for exacerbations and as a preventive measure for relapses, it is advisable to prescribe the herbal medicine Canephron N. The drug has a complex effect: anti-inflammatory, mild diuretic, antimicrobial, antispasmodic, increases the effectiveness of antibacterial therapy and reduces the number of repeated exacerbations of the disease. It is used for a long time: for infants - 10 drops 3 times a day; for preschoolers - 15 drops 3 times a day; for school-age children - 25 drops or 1 dragee 3 times a day.

Outpatient observation of patients with pyelonephritis is carried out for 5 years. Vaccination of children is carried out during the period of clinical and laboratory remission.