A 4-month-old girl is brought to the urgent care clinic by her father due to fussiness and persistent fever. She developed fever 2 days ago and has been receiving acetaminophen a few times a day. She had 1 episode of vomiting yesterday. Today, the patient is less interested in feeding and is not finishing her bottles of breast milk. The girl is still making wet diapers, and the urine has no foul odor or blood. She has no diarrhea, rhinorrhea, cough, or congestion. The patient has no chronic medical conditions and immunizations are up to date. Temperature is 39.4 C (102.9 F), and pulse is 160/min. Examination shows a tired-appearing girl. The fontanelle is open and flat. Tympanic membranes are clear with normal bony landmarks. There are no exudates or lesions in the posterior oropharynx. The lungs are clear to auscultation bilaterally. The abdomen is soft and nontender. She has no rashes, including on the palms or soles. Which of the following is the best next step in management of this patient?
Urinary tract infection (UTI) in children | |
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RBUS = renal & bladder ultrasound; VCUG = voiding cystourethrogram; WBCs = white blood cells. | |
This child has high fever (≥39 C [102.2 F]) without a source (eg, acute otitis media, bronchiolitis). Most children with fever have a viral illness, but occult bacterial infection (eg, urinary tract infection [UTI], bacteremia, pneumonia) must be considered in infants or unimmunized children due to an increased risk in these groups. The most common occult infection is a UTI; female children, uncircumcised male infants, and those with urologic abnormalities (eg, vesicoureteral reflux) are at highest risk.
In contrast to UTI symptoms in older children (eg, dysuria, suprapubic pain), the presentation of UTI in infants is nonspecific and can include fever, fussiness, and poor feeding. Gastrointestinal symptoms (eg, vomiting) may also occur.
Evaluation for an occult UTI is with urinalysis and urine culture; straight catheterization is preferred for obtaining a sterile sample in patients who are not toilet trained. Pyuria (white blood cells) on urinalysis and bacteriuria (≥50,000 colony-forming units/mL from a catheterized sample) on urine culture confirm the diagnosis. Treatment is with antibiotics (eg, cephalosporin) to prevent pyelonephritis and renal scarring.
(Choice A) Abdominal ultrasound can evaluate for appendicitis, which can cause fever, fussiness, and vomiting. However, this diagnosis is rare in infants and an abnormal abdominal examination (eg, tenderness, distension) is typical.
(Choice B) Empiric oral antibiotics should be started when urine dipstick is suggestive of a UTI (eg, leukocyte esterase, nitrites). However, antibiotic administration before obtaining urine studies is not recommended due to the risk of antibiotic resistance and the potential for unnecessary therapy.
(Choice C) Lumbar puncture is performed in all neonates age ≤21 days with fever alone, because of the increased risk for meningitis due to an immature immune system and lack of immunization. In contrast, the risk for CNS infection is low in this older child (age 4 months) who is immunized (eg, pneumococcus, Haemophilus influenzae type b vaccines given at age 2 months) and lacks other classic features of meningitis (eg, bulging fontanelle).
(Choice D) Reassurance and close follow-up can be considered in a febrile infant with a source of infection on examination, such as wheezing from bronchiolitis or rash consistent with hand-foot-and-mouth disease; those who are well appearing with a low-grade fever can also be observed closely. This infant with a high fever and no identifiable source requires evaluation for occult UTI.
Educational objective:
Urinary tract infection should be considered in an infant with fever ≥39 C (102.2 F) with no identifiable source because occult infection is common in this age group and presentation is nonspecific (eg, fussiness, poor feeding). Evaluation is with urinalysis and urine culture.