Febrile neonates represent a challenge to clinicians as the risk for serious bacterial infections is highest at this age, the presence of discriminating clinical signs are often absent, and outcomes can be poor in the absence of early treatment. For this reason, most experts recommend that all neonates with a rectal temperature 38°C or higher have blood, urine, and cerebrospinal fluid cultures regardless of clinical appearance (Ann. Emerg. Med. 1993;22:1198-1210). Such neonates should be admitted to the hospital and treated with empiric antibiotics.
In a study of 41,890 neonates (up to 28 days of age) evaluated in 36 pediatric emergency departments, 2,253 (5.4%) were febrile. Three hundred sixty-nine (16%) infants were seen, then discharged from the ED; the remaining 1,884 (84%) were seen and admitted.
As with prior studies, a high rate of serious infection (12%) was documented; urinary tract infection (27%), meningitis (19%), bacteremia and sepsis (14%), cellulitis and soft tissue infections (6%), and pneumonia (3%) were most common. Of the 369 infants discharged, 3 (1%) had serious infection; of the 1,884 admitted, 266 (14%) did.
The study demonstrated significant variability in the approach used to evaluate and treat febrile neonates, with 16% of infants being discharged from the emergency department, the majority of whom (97%) did not get antimicrobial therapy. Sixty-four (3%) of all febrile infants were discharged without any laboratory evaluation or treatment. Eighty-four percent of febrile infants were admitted to the hospital, and 96% of those admitted received antimicrobial treatment (Pediatrics 2014;133:187).
Prior studies reported that serious bacterial infection was uncommon in febrile neonates who met the following six low-risk criteria: 1. an unremarkable medical history, 2. a healthy, nontoxic appearance, 3. no focal signs of infection, 4. an erythrocyte sedimentation rate less than 30 mm at the end of the first hour, 5. a white blood cell count of 5,000-15,000/mcL, and 6. a normal urine analysis (Arch. Dis. Child Fetal Neonatal Ed. 2007;92:F15-8).
Although it is unclear what criteria were used to discharge febrile neonates from the pediatric ED in the current study, only 1 of the 369 neonates discharged from the pediatric ED subsequently returned to the same pediatric ED and was diagnosed with serious infection; however, only 10 in total returned for evaluation. How many subsequently were diagnosed with serious infection at a different facility is unknown. These results were consistent with the initial studies of the "low-risk criteria," which indicates these criteria are not sufficiently reliable to exclude the presence of serious infection.
The study demonstrates that there remains disagreement about how febrile neonates should be evaluated and managed in the ED setting, and how much reliance should be placed on clinical and laboratory parameters. Unlike children older than 3 months of age, in whom immunization with Haemophilus influenzae type b and 13-valent pneumococcal conjugate vaccines has dramatically reduced the incidence of invasive disease, serious infection in febrile neonates up to 28 days of age remains common.
The current spectrum of pathogens and disease – gram-negative uropathogens, staphylococcal and streptococcal skin and soft tissue infections, group B Streptococcus and Staphylococcus aureus bacteremia, and CNS infection – have not been significantly impacted by efforts to prevent "early-onset" neonatal sepsis and by vaccine strategies that target primarily older children. Age remains a risk, with a decreasing incidence of serious bacterial infection as each week of life passes. However, in another study, the rate of serious bacterial infection in febrile neonates 15-21 days of age was found to be sufficiently high to warrant comparable management to that given younger neonates (Pediatr. Inf. Dis. J. 2012;31:455-8).
Thus, currently there seem to be few strategies that would protect febrile neonates from delays in therapy and preventable outcomes, other than the traditional practice of thorough medical evaluation, laboratory testing to include blood, urine, and cerebrospinal fluid cultures, chest x-ray when respiratory tract signs/symptoms are present, and presumptive treatment with parenteral antibiotic therapy.
Office-based studies report greater reliance on clinical judgment with the belief that reliance on clinical guidelines would have only a small benefit, if any, but would result in greater hospitalization and laboratory testing (JAMA 2004;291:1203-12). Still the high rate of disease (14%) in those admitted to the hospital underscore the vulnerability of this age group, the significance of fever, and the potential for a poor outcome without thorough evaluation of each child and presumptive treatment for serious bacterial infection.
Dr. Pelton is chief of pediatric infectious disease and coordinator of the maternal-child HIV program at Boston Medical Center. Dr. Pelton said he had no relevant financial disclosures. E-mail him at pdnews@frontlinemedcom.com.