History

Symptoms in infants are almost impossible to ascertain. However, fever, vomiting, diarrhea, weight loss, failure to thrive, colic, unexplained jaundice, and CNS abnormalities may be present.

Older children can complain of dysuria, increased frequency, or lower abdominal or flank pain.

• voiding history in toilet-trained children
• prolonged baths
• family history for vesicoureteral reflux/recurrent UTIs

Physical Exam

Vital signs, especially temperature and blood pressure, are important to assess how sick the child is. Dehydration and sepsis, with their attending findings, should be considered.

Other areas of physical exam include:

• dribbling
• abdominal examination for large kidneys
• bowel distension and evidence of constipation
• meatal stenosis
• vulvovaginitis or labila adhesions in females

Lab Investigations

Urine specimens should be analyzed as they would be in an adult.

Bacteuria is considered significant when culture shows over 50,000-100,000 colonies of a single species per ml. Most UTIs show >1,000,000 colonies, while contamination typically shows less than 10,000.

Collected urine needs to be sterile, which can be quite challenging in children.

• A clean-catch mid-stream collection can be done with older children, or with toddlers whose parents are patient!
• Catheterization is most commonly done for infants.
• Suprapubic aspiration is frequently used for neonates. It allows specimens to be obtained directly from the bladder, yielding a lower cutoff, but is quite invasive.
• Bag collection is non-invasive, but has very low specificity. It can be done in situations of low acuity or as a screen, but is not routine. Ai negative result can be helpful to rule out UTI, but if positive, it must be followed with a catheter.

Specimens must be transported as quickly as possible and refrigerated if not going to be received within 1-2 hours. They should include as much information as possible, such as the method and time of collection and the patient's antibiotics.

Diagnostic Imaging

After first febrile UTI in infants, the American Academy of Pediatrics recommend imaging to rule out obstruction or vesicoureteric reflux. This, however, is not agreed upon by everyone. Newer UK guidelines recommend imaging after two UTIs, in infants under six months of age, or with other risk factors.

Imaging includes ultrasound, voiding cystourethrogram (VCUG - catheterized dye into the bladder with X-ray series), or dimercaptosuccinic acid (DMSA).