Neonatal bacterial infection and sepsis: SAQ

This infant presents at 18 hours of life with temperature instability, respiratory distress (grunting, retractions, tachypnoea), and neurological signs (lethargy, poor feeding). He was born at 36 weeks to a mother with chorioamnionitis and prolonged rupture of membranes, placing him at high risk for early-onset sepsis. [1]

Question 1 (10 marks)

Outline your initial assessment and investigation plan for this infant. [1]

Begin with an ABC assessment and overall gestalt of whether the infant appears sick or well. This infant is unwell: he has grunting respirations, tachypnoea, temperature instability, and lethargy. Obtain a full set of vital signs including heart rate, blood pressure, capillary refill, and oxygen saturation. Examine the anterior fontanelle, chest, abdomen, and skin for focal signs of infection. [1]

The investigation plan is a full septic workup. Obtain a blood culture with at least 1 mL before starting antibiotics. Send a complete blood count with differential and immature-to-total neutrophil ratio, and a baseline CRP. Perform a lumbar puncture for CSF analysis (cell count, protein, glucose, Gram stain, and culture) if the infant is stable enough. Send a chest X-ray for the respiratory distress. Check a bedside blood glucose immediately. Recheck the CRP at 24 hours. [2]

Question 2 (10 marks)

Describe your initial management including empiric antibiotics and the criteria for stopping antibiotics at 48 hours. [1]

Start empiric antibiotics immediately after obtaining cultures. The standard first-line regimen for suspected early-onset sepsis is benzylpenicillin 25 mg/kg intravenously combined with gentamicin 5 mg/kg intravenously, with dosing intervals adjusted for gestational and postnatal age. If meningitis is suspected, add cefotaxime 50 mg/kg intravenously for cerebrospinal fluid penetration. Provide respiratory support as needed and give a 10 mL/kg fluid bolus of 0.9 per cent sodium chloride if there are signs of poor perfusion or shock. [1]

At 36 to 48 hours, apply antibiotic stewardship principles. If blood and CSF cultures are negative, the CRP has normalised, and the infant is clinically well with normal vital signs, feeding, and examination, stop antibiotics. This approach reduces unnecessary antibiotic exposure and its associated harms — including necrotising enterocolitis, fungal colonisation, and selection of resistant organisms — without increasing the rate of missed infections. [3]