Neonatal sepsis: investigations and onset patterns
THE CONTEXT
Evaluation of suspected neonatal sepsis combines clinical assessment, blood culture, a screening panel, and assessment for meningitis.
Clinical assessment and treatment initiation
•
Late metabolic acidosis, congestive heart failure, and even nasal obstruction can mimic neonatal sepsis. Clinical examination and relevant investigations help distinguish these conditions and avoid unnecessary antibiotic therapy.
•
Clinically stable neonates may be observed without admission while receiving good supportive care.
•
A sick neonate with a high probability of sepsis does not require an investigation result before treatment is started.
Blood culture and sepsis screen
•
Blood culture provides a definitive diagnosis and should be obtained before antimicrobial therapy.
•
The described collection method uses skin cleaning with alcohol, povidone-iodine, and alcohol again, followed by collection of 0.5–1.0 mL of blood into a bottle containing 5–10 mL of liquid broth.
•
For clinically doubtful cases, the sepsis screen includes total leukocyte count, absolute neutrophil count, immature-to-total neutrophil ratio, CRP, and micro-ESR.
•
The sepsis screen is considered positive when two parameters are positive.
Lumbar puncture
•
Lumbar puncture should be performed in all suspected cases of neonatal sepsis except asymptomatic neonates investigated for maternal risk factors.
•
Interpretation of cerebrospinal fluid parameters uses gestation-specific cut-offs.
Early-onset and late-onset patterns
•
Early-onset sepsis occurs up to 72 hours of age. Listed risks include spontaneous preterm labor, rupture of membranes for more than 18 hours, foul-smelling liquor, multiple vaginal examinations, maternal fever, and difficult or prolonged labor.
•
Early-onset sepsis presents as pneumonia and less commonly as septicemia or meningitis.
•
Late-onset sepsis occurs after 72 hours. Risks include poor hand hygiene, low birth weight, lack of breastfeeding, poor cord care, superficial infections, aspiration of feeds, needle-related disruption of skin integrity, and intravenous fluids.
•
Late-onset sepsis may present as generalized sepsis, pneumonia, or meningitis.