Neonatal Sepsis — SAQ

Stem

A candidate is asked to manage a classic presentation of Neonatal Sepsis in an exam setting. Use precise definitions, scores, doses, and decision thresholds.

Core knowledge (model answer backbone)

Neonatal sepsis is a systemic inflammatory response to a documented or suspected infection in the first 28 days of life. It is the great mimic of neonatology: presentation is non-specific (temperature instability, poor feeding, lethargy, respiratory distress, apnoea). Divided into early-onset sepsis (EOS, within 72 hours or 7 days) — vertically acquired from the maternal genital tract, organisms Group B Streptococcus (GBS), E coli (K1 capsule), Listeria monocytogenes — and late-onset sepsis (LOS, after 72 hours or 7 days) — horizontally/nosocomially acquired, organisms coagulase-negative staphylococci (CoNS, S epidermidis), S aureus (incl MRSA), Klebsiella, E coli, Pseudomonas, Candida. Mortality 10 to 30% overall, higher in premature and LBW infants. Take a blood culture before antibiotics and start empirical IV antibiotics within 1 hour: UK benzylpenicillin + gentamicin (EOS) or flucloxacillin + gentamicin (LOS); US ampicillin + gentamicin (EOS). Lumbar puncture for suspected meningitis. Maternal intrapartum GBS prophylaxis with IV benzylpenicillin reduces early-onset GBS disease by approximately 80%.

Red flags

• Any unwell neonate in first 28 days - sepsis until proven otherwise; ABCDE and empirical IV antibiotics within 1 hour
• Temperature instability (fever in term, hypothermia in preterm), poor feeding, lethargy, respiratory distress or apnoea - neonatal sepsis
• Maternal GBS colonisation, prolonged rupture of membranes over 18 hours, chorioamnionitis, prematurity or LBW - high-risk neonate; investigate and treat early
• Petechiae, bleeding, hypoperfusion, hypotension - DIC/septic shock; urgent fluids, inotropes, antibiotics

High-yield structure examiners expect

Cover: Overview & Definition, Classification, Epidemiology & Risk Factors, Pathophysiology, Clinical Presentation, Differential Diagnosis.

Key doses / thresholds (from topic teaching)

• or serum lactate over 2 mmol/L)
• under 1500 g)
• under 1 mL/kg/h)"
• bedside glucose under 2.6 mmol/L
• CRP over 10 mg/L supportive, two normal CRPs 24 h apar
• over 2 mmol/L suggests tissue hypoperfusion

Questions

a) Define the condition and give the most important classification or severity framework used in exams. (3 marks)

• Clear one-line definition matching standard teaching.
• Named classification / stages / types with discriminating features.
• One sentence on why classification changes management.

b) Outline pathophysiology in a mechanism chain that explains the main clinical features. (3 marks)

• Initiating insult → intermediate pathway → end-organ effect.
• Link at least two symptoms/signs to mechanism.
• Mention one complication pathway (e.g. shock, perforation, herniation, arrhythmia).

c) List discriminating clinical features and bedside assessment. (3 marks)

• Classic presentation plus one atypical group (elderly, pregnancy, child, immunocompromised).
• Named signs/manoeuvres if relevant.
• What must never be missed on exam/bedside (pregnancy test, airway, glucose, etc.).

d) Investigations with thresholds and one named score if applicable. (3 marks)

• First-line tests and what positive findings mean.
• Gold-standard or definitive investigation when needed.
• Score components reproduced exactly if a named score is standard for this topic.

e) Immediate resuscitation and definitive management with doses where standard. (3 marks)

• ABC / time-critical steps first.
• First-line drug(s) with agent + dose + route (or procedure steps).
• Escalation triggers (theatre, ICU, thrombolysis window, antidote, etc.).
• Disposition and safety-netting.

Marking tips

Full marks require specificity (numbers, names, doses) not generic "give antibiotics/fluids." Regional practice (ICMR / NICE / AHA) may be cited as alternative where relevant.