Neonatal Sepsis
Why is this topic important?
Neonatal sepsis is a major cause of neonatal morbidity and mortality worldwide and is one of the highest-yield neonatal topics in MRCPCH examinations.
Candidates should be able to:
Recognise risk factors
Identify early clinical signs
Differentiate early-onset and late-onset sepsis
Interpret investigations
Understand antibiotic management
Recognise complications
Neonatal sepsis commonly appears in FOP, TAS and AKP examinations.
Definition
Neonatal sepsis is a systemic infection occurring during the first 28 days of life.
It may present with:
Bacteraemia
Meningitis
Pneumonia
Urinary tract infection
Septic shock
Classification
Early-Onset Sepsis (EOS)
Occurs within:
First 72 hours of life
Usually acquired from the mother before or during delivery.
Late-Onset Sepsis (LOS)
Occurs after:
72 hours of life
Usually acquired from the environment or healthcare setting.
Key MRCPCH Facts
Neonatal sepsis often presents with non-specific symptoms.
Group B Streptococcus is a common cause of EOS.
Escherichia coli is another important EOS pathogen.
Coagulase-negative Staphylococci commonly cause LOS.
Blood culture remains the gold standard investigation.
Delayed treatment increases mortality.
Neonatal sepsis may present without fever.
Pathophysiology
Infection enters the bloodstream
↓
Systemic inflammatory response
↓
Cytokine release
↓
Capillary leak
↓
Poor tissue perfusion
↓
Organ dysfunction
↓
Shock (severe cases)
Risk Factors
Maternal Risk Factors
Prolonged Rupture of Membranes
18 hours
Maternal Pyrexia
During labour.
Chorioamnionitis
Major risk factor.
Maternal GBS Colonisation
Increases risk of EOS.
Neonatal Risk Factors
Prematurity
Immature immune system.
Low Birth Weight
Invasive Procedures
Examples:
UVC
UAC
Endotracheal tubes
Long lines
Prolonged NICU Stay
Increases LOS risk.
Common Organisms
Early-Onset Sepsis
Group B Streptococcus
Most important MRCPCH organism.
Escherichia coli
Listeria monocytogenes
Less common but classically tested.
Late-Onset Sepsis
Coagulase-negative Staphylococci
Most common NICU pathogen.
Staphylococcus aureus
Gram-negative organisms
Examples:
Klebsiella
E. coli
Pseudomonas
Clinical Features
Neonatal sepsis often presents subtly.
Temperature Instability
May be:
Fever
Hypothermia
Poor Feeding
Common presentation.
Lethargy
Irritability
Apnoea
Especially in preterm infants.
Respiratory Distress
May mimic RDS.
Tachycardia
Hypotension
Late sign.
Seizures
Suggest CNS involvement.
Examination Findings
Poor Perfusion
Prolonged Capillary Refill Time
Mottled Skin
Respiratory Distress
Reduced Consciousness
Severe disease.
Differential Diagnosis
Respiratory Distress Syndrome
Hypoglycaemia
HIE
Congenital Heart Disease
Metabolic Disorders
Investigations
Blood Culture
Gold Standard
Most important investigation.
Important MRCPCH fact.
Full Blood Count
May show:
Neutropenia
Neutrophilia
Thrombocytopenia
C-Reactive Protein (CRP)
Helpful but non-specific.
Blood Gas
May show:
Metabolic acidosis
Raised lactate
Lumbar Puncture
Consider if:
Meningitis suspected
Positive blood culture
Clinical deterioration
Urine Culture
Usually more relevant in LOS.
Management
Immediate Antibiotics
Do not delay treatment.
Important MRCPCH principle.
Empirical Therapy
Common UK regimen:
Benzylpenicillin + Gentamicin
For EOS.
Local guidelines should always be followed.
Supportive Care
Oxygen
Fluids
Glucose Monitoring
Temperature Control
Intensive Care Support
For severe disease:
Ventilation
Inotropes
Intensive monitoring
Complications
Meningitis
Most important complication.
Septic Shock
Life-threatening.
Multi-Organ Failure
Neurodevelopmental Impairment
Particularly following meningitis.
Death
Risk increases with delayed diagnosis.
Prevention
Maternal GBS Screening Policies
Depending on local practice.
Intrapartum Antibiotics
For high-risk mothers.
Hand Hygiene
Critical in NICU.
Care of Central Lines
Reduces LOS.
Common Exam Traps
Trap 1
Neonatal sepsis often presents without fever.
Trap 2
Poor feeding may be the only symptom.
Trap 3
Blood culture is the gold standard investigation.
Trap 4
Group B Streptococcus is a major EOS pathogen.
Trap 5
Coagulase-negative Staphylococci commonly cause LOS.
Trap 6
Do not wait for culture results before starting treatment.
One Minute Revision
Sepsis may present subtly.
EOS <72 hours.
LOS >72 hours.
GBS and E. coli = important EOS organisms.
CONS = common LOS pathogen.
Blood culture = gold standard.
Start antibiotics early.
Watch for meningitis and shock.
Related Question of the Day
A 2-day-old infant becomes lethargic, feeds poorly and develops temperature instability. What is the most important investigation?
A. Cranial ultrasound
B. Blood culture
C. Echocardiography
D. Sweat test
E. MRI brain
Answer
B. Blood culture
Explanation
Blood culture remains the gold standard investigation for confirming neonatal sepsis.
Related Topics
Respiratory Distress Syndrome
Necrotising Enterocolitis
Apnoea of Prematurity
Hypoglycaemia
Meningitis
Suggested References
NICE Neonatal Infection Guideline
Rennie & Roberton's Textbook of Neonatology
Nelson Textbook of Pediatrics
BNF for Children
Neonatal Life Support (NLS) Manual
British Association of Perinatal Medicine (BAPM)
Disclaimer
These notes are intended for MRCPCH revision and educational purposes only. They do not replace local, national or institutional guidelines. Clinical decisions should always be based on current guidance, senior advice and individual patient circumstances.
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