Review Question - QID 104792

This 12-day-old boy is presenting with a fever and lethargy, which should raise suspicion for a bacterial infection in this age group. Ill-appearing febrile neonates should receive a thorough evaluation to include blood counts, inflammatory markers, a chest radiograph, and cultures of CSF, blood, and urine.

Neonatal fever is defined as a rectal temperature above 100.4°F (38.0°C) in a patient under 28 days of age. Neonates do not have a fully developed immune system and rely upon a waning supply of maternal humoral immunity. In addition, they are not yet vaccinated against a variety of potential pathogens. For these reasons, the risk of serious invasive bacterial infections such as bacteremia or meningitis, or herpes simplex infection, is particularly high in this age group. More recent data suggest that the risk of invasive bacterial infection is most pronounced in those under 21 days of age. All ill-appearing febrile infants under 28 days of age should be assumed to have an invasive bacterial infection. These patients should be evaluated for a source of focal infection with a chest radiograph to screen for pneumonia, as well as cultures of the blood, urine, and CSF. Complete blood count and inflammatory markers such as ESR, CRP, and procalcitonin are also an important part of evaluation. Patients are typically covered empirically with broad-spectrum antibiotics. Vancomycin is added if MRSA is suspected or patients are particularly ill. Acyclovir is added for patients in whom herpes simplex virus infection is suspected or those with risk factors for herpes simplex virus infection. Ceftriaxone is avoided in patients under 2 months of age due to the risk of biliary sludging and kernicterus.

Moerschel et al. discuss management of jaundice, which can be a benign physiologic process or can be a sign of a more serious underlying condition, including sepsis. They note that frequent feeding (8-12 times in 24 hours) is important for primary prevention while regular monitoring, risk stratification (including nomogram use), and prompt outpatient follow-up are important for secondary prevention.

Incorrect Answers:
Answer 1: CBC alone would be an inadequate evaluation of this patient with a high likelihood of critical illness.

Answer 2: CBC and inflammatory markers would likely reveal abnormality, but would be an inadequate evaluation of this patient with a high likelihood of critical illness.

Answer 3: CBC, chest radiograph, and urine culture would all be indicated for this patient, but would be an inadequate evaluation due to the high likelihood of serious bacterial infection.

Answer 4: CBC, chest radiograph, and viral testing would be an inadequate evaluation of this patient with a high likelihood of critical illness.

Bullet Summary:
Ill-appearing, febrile neonates should receive a thorough evaluation to include blood counts, inflammatory markers, a chest radiograph, and cultures of CSF, blood, and urine.