Urinary tract infection in children

What is a urinary tract infection?

A urinary tract infection is inflammation of the urinary tract caused by bacteria. Most often E. coli, a bacterium that lives in the bowel, travels up the urethra into the bladder and sometimes reaches the kidney.

• Bladder infection (cystitis) usually comes without fever.
• Kidney infection (pyelonephritis) comes with fever and is more serious.

In the first year it is more common in boys, especially uncircumcised boys; after one year of age it is more common in girls.

Signs by age

In infants the signs are often nonspecific:

• fever without a clear cause (often the only sign),
• irritability, poor feeding, vomiting,
• poor weight gain, prolonged jaundice (in a newborn),
• foul-smelling urine.

In older children:

• burning and pain when urinating,
• frequent and urgent urination, new wetting,
• pain in the lower abdomen,
• cloudy, foul-smelling, sometimes bloody urine,
• fever, flank or back pain (in kidney infection).

Diagnosis: a correct urine sample

The diagnosis is made with a urinalysis and urine culture. How reliable the result is depends on how the sample is collected:

• In toilet-trained children: a midstream sample after washing the genitals.
• In infants: the “clean catch” method, and a catheter sample when needed.
• A sample collected with a urine bag is quickly contaminated by skin bacteria, and a positive result is often false.

More: urinalysis and culture.

Treatment

• Cystitis without fever: oral antibiotic, usually for 3–5 days.
• Infection with fever: oral antibiotic or, in severe cases, intravenous antibiotic, usually for 7–10 days. Young infants and children who are very unwell are treated in the hospital.
• The antibiotic is changed according to the culture result when needed.
• Plenty of fluids, and medicines for fever and pain suited to age and weight.

Which children need further tests?

• After the first infection with fever: kidney and bladder ultrasound.
• If the ultrasound is abnormal, febrile infections recur, or the course is atypical: VCUG (voiding cystourethrogram) to check for reflux.
• If kidney scarring is suspected: DMSA 4–6 months after the infection.

Preventing recurrence

• treating constipation,
• enough water through the day and a toilet visit every 2–3 hours,
• in girls, wiping from front to back and avoiding bubble baths,
• in boys, assessing the foreskin in phimosis and recurrent infections,
• if reflux is present, antibiotic prophylaxis at the doctor’s decision.