Fever Without a Source - neonate

Authors: Hemal Kanzaria, MD, Christine Cho, MD, Andi Marmor, MD, Ellen Laves, MD
Updated: 2/2/2012

Pediatric Fever Without a Source: Birth - 28 Days Old

  • Age ≤ 28 days (be more conservative for premature infants)
  • Fever defined as temperature ≥ 38°C / 100.4°F (rectal)
  • Viral URI symptoms do NOT count as a fever source in this age group.
  • Disposition: ADMIT all of these patients to the hospital.


History and physical are not reliable to rule-out serious bacterial infection (SBI)

Common causes for SBI

  • UTIs 20%
  • Bacteremia 3%
  • Meningitis 1%

Other causes for SBI’s

  • Bacterial gastroenteritis
  • Gonococcal keratoconjunctivitis
  • Omphalitis
  • Osteomyelitis
  • Peritonitis
  • Pneumonia
  • Septic joint


  • More common:
    • E. coli
    • Group B Strep
    • HSV
  • Less common:
    • Listeria
    • Salmonella
    • Staph aureus


  1. CBC with differential
  2. Blood cultures
  3. Catheterized urinalysis and urine culture (or via suprapubic tap)
  4. CSF studies (cell count, glucose, protein, gram stain, culture, extra tube to hold for potential other studies)
  5. Consider: Stool culture (if diarrhea)
  6. Consider: CXR and rapid viral testing (if respiratory sx or increased work of breathing, although viral testing should not change sepsis workup)


Timely administration of IV antibiotics (ampicillin + cefotaxime, or ampicillin + gentamicin).

  • May give IM, if IV not possible
  • Cefotaxime more consistently absorbed IM than gentamicin.

Add acyclovir, if any 1 of following:

  • Ill-appearing
  • Skin or mucosal lesions consistent with HSV (i.e. vesicles)
  • CSF pleocytosis
  • Seizure
  • Focal neurologic signs
  • Abnormal neuroimaging
  • Respiratory distress, apnea, or progressive pneumonitis
  • Thrombocytopenia
  • Elevated liver transaminases, viral hepatitis, or acute liver failure
  • Conjunctivitis, excessive tearing, or painful eye symptoms

Note: Disseminated HSV and HSV encephalitis may not present with rash


  • Ishimine P, The evolving approach to the young child who has fever and no obvious source. Emerg Med Clin North Am. 2007 Nov;25(4):1087-115, vii. [PubMed]