Point-of-Care Guides

Young Febrile Infants: Step-by-Step Evaluation

 

Am Fam Physician. 2018 Jan 1;97(1):45-46.

Author disclosure: No relevant financial affiliations.

Clinical Question

Can signs, symptoms, and laboratory findings distinguish young febrile infants who need a full septic workup, hospital admission, and antibiotics from those who warrant less intensive management?

Evidence Summary

A fever without an obvious source in an infant younger than three months is highly concerning. Although some infants have a potentially life-threatening invasive bacterial infection, such as meningitis, bacteremia, or sepsis, most have less serious conditions, such as a viral syndrome. Ordering hospital admission, a full septic workup (i.e., blood, urine, and cerebrospinal fluid cultures), and empiric intravenous antibiotics for all of these patients would expose many young infants and their parents to unnecessary, invasive, stressful, and resource-intensive medical care. The goal of clinical decision rules is to identify low-risk infants who can be spared intensive management, while not missing infants who have a serious infection.

A recent study 1 prospectively evaluated the Rochester criteria,2 the Lab-score,3 and the Step-by-Step approach4  (Table 11) for their ability to distinguish low-risk infants from higher-risk infants, comparing the prediction from each clinical decision rule to the actual outcome. The study included previously healthy infants 90 days or younger presenting to 11 European pediatric emergency departments between 2012 and 2014 with a fever (body temperature of 100.4°F [38.0°C] or higher documented at home or in the emergency department) of unknown etiology. [corrected] All of the infants had the testing necessary to use the three clinical decision rules (in centers where the absolute band count was not available, a white blood cell count of 5,000 to 15,000 per mm3 [5.0 to 15.0 × 109 per L] was used as a proxy for an absolute band count of less than 1,500 per mm3 [1.5 × 109 per L]). This was a pragmatic trial, so any further testing (e.g., spinal fluid studies, influenza testing) and treatment were at the discretion of the treating physician.1

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TABLE 1.

The Step-by-Step Approach for Determining Risk in Infants with Fever of Unknown Etiology

Criteria*Setting

Ill-appearing†

Initial examination by the physician

Age ≤ 21 days

Initial history by the physician

Dipstick urinalysis positive for leukocyte esterase

Point-of-care test

Procalcitonin ≥ 0.5 ng per mL

Laboratory test

C-reactive protein > 20 mg per L (190.5 nmol per L) or absolute neutrophil count > 10,000 per mm3 (10 × 109 per L)

Laboratory test


*—Infants are considered low risk for invasive bacterial infection when they meet none of these criteria.

†—Abnormal ABC (appearance, breathing, circulation to the skin) assessment.

Information from reference 1.

TABLE 1.

The Step-by-Step Approach for Determining Risk in Infants with Fever of Unknown Etiology

Criteria*Setting

Ill-appearing†

Initial examination by the physician

Age ≤ 21 days

Initial history by the physician

Dipstick urinalysis positive for leukocyte esterase

Point-of-care test

Procalcitonin ≥ 0.5 ng per mL

Laboratory test

C-reactive protein > 20 mg per L (190.5 nmol per L) or absolute neutrophil count > 10,000 per mm3 (10 × 109 per L)

Laboratory test


*—Infants are considered low risk for invasive bacterial infection when they meet none of these criteria.

†—Abnormal ABC (appearance, breathing, circulation to the skin) assessment.

Information from reference 1.

Of the 2,185 infants in the study, 87 (4%) had a final diagnosis of invasive bacterial infection (i.e., bacteremia or meningitis), and 417 (19.1%) had a serious but noninvasive bacterial infection, such as a urinary tract infection, bacterial gastroenteritis, or cellulitis. Patients with invasive or noninvasive bacterial infections were classified as having serious bacterial illness. The classification by each score is shown in Table 2.1 The Lab-score classified nearly twice as many infants as low risk, but also misclassified the most patients with an invasive bacterial infection as low risk, failing to detect 35 invasive bacterial infections in 1,798 infants classified as low risk (1.9%). The Rochester criteria and Step-by-Step approach classified a similar number of infants as low risk, but the Step-by-Step approach missed invasive bacterial infections in only 0.7% of the low-risk group, compared with 1.7% with the Rochester criteria. The Step-by-Step approach also missed fewer serious bacterial illnesses than the other scores.1 An editorial accompanying this study expresses the performance of the clinical decision rules as a ratio. Using the Rochester criteria, 933 infants avoided unnecessary interventions, whereas invasive bacterial infection was missed in 16 infants classified as low risk—a 933-to-16 ratio or roughly 58:1. The Lab-score performed at 50:1, and the Step-by-Step approach performed best at 140:1.5

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Address correspondence to Joshua Steinberg, MD, at jds91md@gmail.com. Reprints are not available from the author.

Author disclosure: No relevant financial affiliations.

References

show all references

1. Gomez B, Mintegi S, Bressan S, et al. Validation of the “Step-by-Step” approach in the management of young febrile infants. Pediatrics. 2016;138(2):e20154381....

2. Jaskiewicz JA, McCarthy CA, Richardson AC, et al.; Febrile Infant Collaborative Study Group. Febrile infants at low risk for serious bacterial infection—an appraisal of the Rochester criteria and implications for management. Pediatrics. 1994;94(3):390–396.

3. Galetto-Lacour A, Zamora SA, Andreola B, et al. Validation of a laboratory risk index score for the identification of severe bacterial infection in children with fever without source. Arch Dis Child. 2010;95(12):968–973.

4. Mintegi S, Bressan S, Gomez B, et al. Accuracy of a sequential approach to identify young febrile infants at low risk for invasive bacterial infection. Emerg Med J. 2014;31(e1):e19–e24.

5. Aronson PL, Neuman MI. Should we evaluate febrile young infants Step-by-Step in the emergency department? Pediatrics. 2016;138(2):e20161579.

This guide is one in a series that offers evidence-based tools to assist family physicians in improving their decision-making at the point of care.

This series is coordinated by Mark H. Ebell, MD, MS, Deputy Editor for Evidence-Based Medicine.

A collection of Point-of-Care Guides published in AFP is available at http://www.aafp.org/afp/poc.

 

 

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