What is the treatment of a hospitalized child with complicated pyelonephritis in pediatric urinary tract infection (UTI)?

Updated: Mar 19, 2019
  • Author: Donna J Fisher, MD; Chief Editor: Russell W Steele, MD  more...
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Provide appropriate IV fluids, usually at 1-1.5 times the usual maintenance rate. Parenteral treatment with a third-generation cephalosporin (eg, ceftriaxone, cefotaxime) is appropriate initial empiric coverage for a complicated UTI and pyelonephritis to cover for ampicillin-resistant, gram-negative pathogens (see Table 3). Add ampicillin if gram-positive cocci are present in the urinary sediment or if no organisms are observed.

Gentamicin is an alternative empiric choice and may be considered in patients with cephalosporin allergy. Monitor renal function and blood aminoglycoside levels if this medication is required for more than 48 hours.

Results of urine culture and sensitivity studies are usually available within 48 hours. If the pathogen is sensitive to the antibiotic used and the child is improving, continue treatment via the parenteral route until the child has been afebrile for 24-36 hours, has improved clinically, and is able to retain oral medications. An oral antibiotic that is effective against the infecting organism may then be substituted for parenteral therapy (see Table 4).

The hospitalized patient is usually ready to go home after 48-72 hours. Continue therapeutic doses of antibiotics for a total of 10-14 days of antibiotic therapy. Antibiotic prophylaxis can be considered (see Table 5); if chosen, it should continue until a VCUG is obtained, if one is to be performed.

Table 3. Antibiotic Agents for Parenteral Treatment of a Urinary Tract Infection (Open Table in a new window)


Dosage and Route



50-75 mg/kg/day IV/IM as a single dose or divided q12h

Do not use in infants < 6 wk of age; parenteral antibiotic with long half-life; may displace bilirubin from albumin


150 mg/kg/day IV/IM divided q6-8h

Safe to use in infants < 6 wk of age; used with ampicillin in infants aged 2-8 wk


100 mg/kg/day IV/IM divided q8h

Used with gentamicin in neonates < 2 wk of age; for enterococci and patients allergic to cephalosporins


Term neonates < 7 days: 3.5-5 mg/kg/dose IV q24h

Infants and children < 5 years: 2.5 mg/kg/dose IV q8h or single daily dosing with normal renal function of 5-7.5 mg/kg/dose IV q24h

Children ≥5 y: 2-2.5 mg/kg/dose IV q8h or single daily dosing with normal renal function of 5-7.5 mg/kg/dose IV q24h

Monitor blood levels and kidney function if therapy extends >48 h

Note: IM = intramuscular; IV = intravenous; q = every.

Table 4. Antibiotic Agents for the Oral Treatment of Urinary Tract Infection (Open Table in a new window)


Daily Dosage

Sulfamethoxazole and trimethoprim (SMZ-TMP)

30-60 mg/kg SMZ, 6-12 mg/kg TMP divided q12h

Amoxicillin and clavulanic acid

20-40 mg/kg divided q8h


50-100 mg/kg divided q6h


8 mg/kg q24h


10 mg/kg divided q12h


5-7 mg/kg divided q6h

*Nitrofurantoin may be used to treat cystitis. It is not suitable for the treatment of pyelonephritis, because of its limited tissue penetration.

Table 5. Antibiotic Agents to Prevent Reinfection (Open Table in a new window)


Single Daily Dose

Nitrofurantoin *

1-2 mg/kg PO

Sulfamethoxazole and trimethoprim (SMZ-TMP) *

5-10 mg/kg SMZ, 1-2 mg/kg TMP PO


1-2 mg/kg PO

*Do not use nitrofurantoin or sulfa drugs in infants younger than 6 weeks. Reduced doses of an oral first-generation cephalosporin, such as cephalexin at 10 mg/kg, may be used until the child reaches age 6 weeks. Ampicillin or amoxicillin are not recommended because of the high incidence of resistant E coli.

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