Chapter 75. Pediatric Urinary Tract Infections

Urinary tract infections (UTIs) are relatively common from infancy through adolescence. The incidence and clinical presentation of pediatric UTIs change with age and sex.

There are 3 age-based clinical presentations for pediatric UTIs. Neonates present with a clinical presentation indistinguishable from that of sepsis, and they may have symptoms that include fever, jaundice, poor feeding, irritability, and lethargy. Older infants and young children typically present with gastrointestinal complaints that may include fever, abdominal pain, vomiting, and a change in appetite. School-age children and adolescents typically present with adult-type complaints such as dysuria, urinary frequency, urgency, and hesitancy. Although the majority of infants and young children with fever and UTI have upper-track disease and require long-course antibiotic treatment, older children and adolescents without fever, flank pain, and flank tenderness are likely to have simple cystitis and can be treated with shorter course therapy similar to adults.

The gold standard for confirming the diagnosis of pediatric UTI is the growth of a single urinary pathogen from a properly obtained urine culture. For infants and children in diapers, catheterization or, rarely, ultrasound guided suprapubic aspiration is required. For children who are toilet trained, urine may be collected as a supervised clean catch specimen. Bagged urine specimens have essentially no role in diagnosis of pediatric UTI.

Because younger children void frequently and do not store urine in the bladder long enough to accumulate leukocytes or nitrites, urinalysis is insensitive in this age group and culture should be sent regardless of dipstick results. Microscopic urinalysis is more specific and is typically considered positive for infection if more than 5 white blood cells per high power field and bacteria are seen. A positive microscopic urinalysis has a sensitivity of 65% for identifying culture-proven UTI. Neither urinary test strips nor microscopic urinalysis can be used to definitively rule out pediatric UTI, though evidence is mounting that delaying treatment until culture results return does not alter the long-term outcome and antibiotics can be safely withheld in the setting of a negative urinalysis and microscopy.

Adolescents may have urinary symptoms as a manifestation of a sexually transmitted disease such as Chlamydia trachomatis. An appropriate sexual history and pelvic examination may be indicated and helpful in making this diagnosis (for a discussion of sexually transmitted diseases, see Chapter 86).

The treatment and disposition of infants and children with UTI depend on age and are based on the severity of concurrent symptoms. In general, antibiotics should not be given until after urine culture has been obtained.

1. Treat neonates for sepsis and obtain cultures of blood and CSF in addition to urine. Administer parenteral antibiotics and admit to the hospital: ampicillin (50 milligrams/kilogram/dose) plus gentamicin (3-5 milligrams/kilogram/dose) or ampicillin (50 milligrams/kilogram/dose) plus cefotaxime (50 milligrams/kilogram/dose) are appropriate empiric choices.

2. Treat infants from 1 month to 2 years of age who are dehydrated, have persistent vomiting, appear ill or septic, or are medically complicated typically with intravenous antibiotics such as ceftriaxone, cefotaxime, or cefepime (all are dosed at 50 milligrams/kilogram/dose).

   Well appearing infants in this age group may be treated with oral antibiotics, which are as effective as parenteral treatment. A third generation cephalosporin such as cefpodoxime (5 milligrams/kilogram/dose given twice daily) or cefdinir (7 milligrams/kilogram/dose given twice daily), is recommended. Treat for 10 to 14 days, as short-course therapy is less effective in young children. High rates of resistance to cephalexin, amoxicillin, and trimethoprim-sulfamethoxasole are now widespread, though these may be appropriate based on local sensitivities.

3. Children older than 2 years who are otherwise doing well and tolerating oral fluids are treated as outpatients with oral antibiotics for at least 7 days with close follow-up with their primary doctors. Emergency physicians should be familiar with the antibiotic-resistance patterns in their geographic area. Appropriate oral antibiotic choices to treat pediatric UTIs include cefixime (8 milligrams/kilogram/d, divided twice daily), cefpodoxime (5 milligrams/kilogram/day divided twice daily) or cefdinir (7 milligrams/kilogram/dose given twice daily). Depending on local sensitivities, trimethoprim/sulfamethoxazole (3 to 6 milligrams/kilogram/dose TMP, 15 to 30 milligrams/kilogram/dose SMX, given twice daily), or cephalexin (10 to 25 milligrams/kilogram/dose, given 4 times a day), may be used.

4. Adolescent females with cystitis or acute pyelonephritis are treated similarly to adults (see Chapter 53).