Overview
Definition:
Early-onset sepsis (EOS) is defined as sepsis occurring in the first 72 hours of life in a newborn
It is a serious, life-threatening infection
Risk calculators are tools designed to assess the probability of EOS based on maternal and neonatal risk factors.
Epidemiology:
The incidence of EOS varies globally, with estimates ranging from 1 to 10 per 1,000 live births, depending on the population and diagnostic criteria
Prematurity, low birth weight, and maternal infections are significant risk factors
Prompt recognition and management are crucial due to high morbidity and mortality.
Clinical Significance:
Accurate risk assessment for EOS is vital for guiding clinical decisions, including the need for empirical antibiotic therapy and the duration of treatment
Over-treatment can lead to antibiotic resistance and adverse drug effects, while under-treatment can result in severe outcomes
Risk calculators aim to optimize this balance.
Clinical Presentation
Symptoms:
Vague and nonspecific signs are common
Difficulty feeding
Lethargy or irritability
Vomiting
Tachypnea or apnea
Temperature instability (hypothermia or fever)
Poor perfusion or hypotension
Jaundice
Seizures.
Signs:
Generalized signs of illness: decreased muscle tone, poor cry
Respiratory distress: grunting, retractions, nasal flaring
Cardiovascular compromise: tachycardia, bradycardia, weak pulses
Neurological signs: hyporeflexia, altered consciousness
Skin findings: petechiae, purpura, pallor.
Diagnostic Criteria:
No single definitive criterion for EOS
Diagnosis is based on clinical suspicion supported by laboratory findings suggestive of infection (e.g., elevated inflammatory markers, positive blood cultures)
The presence of risk factors is also considered in the initial assessment.
Diagnostic Approach
History Taking:
Maternal history: GBS colonization status, prolonged rupture of membranes (>18 hours), maternal fever, chorioamnionitis
Neonatal history: gestational age, birth weight, mode of delivery, signs of distress at birth, Apgar scores, any prenatal complications.
Physical Examination:
Comprehensive neonatal examination focusing on vital signs (temperature, heart rate, respiratory rate, blood pressure, oxygen saturation)
Assessment for signs of systemic illness, respiratory compromise, cardiovascular instability, and neurological deficits
Detailed examination of skin, abdomen, and fontanelles.
Investigations:
Complete blood count (CBC) with differential: elevated WBC count (>30,000/mm³), elevated absolute neutrophil count (ANC) (>20,000/mm³), decreased platelet count (<150,000/mm³), elevated immature to total neutrophil ratio (I:T ratio) (>0.2)
Inflammatory markers: C-reactive protein (CRP) and procalcitonin are useful but have limitations
Blood culture: gold standard for diagnosis, requires at least 48-72 hours for results
Urine culture: less sensitive in neonates
Lumbar puncture: for CSF analysis (cell count, protein, glucose, Gram stain, culture) if meningitis is suspected
Chest X-ray: for pneumonia
Other imaging may be indicated based on clinical suspicion.
Differential Diagnosis:
Transient tachypnea of the newborn (TTN)
Meconium aspiration syndrome
Birth asphyxia
Neonatal hypoglycemia
Neonatal hypocalcemia
Congenital anomalies
Intrauterine infections not leading to sepsis.
Risk Calculator Implementation
Purpose:
To quantify the probability of EOS based on maternal and neonatal risk factors, thereby guiding empirical antibiotic use and hospital management protocols.
Common Calculators:
Various calculators exist, often based on proprietary algorithms or research data
A commonly referenced approach involves factors like GBS status, duration of ROM, maternal fever, and gestational age
Specific calculators may include maternal antibiotic use and neonatal clinical signs.
Input Parameters:
Typically include: Group B Streptococcus (GBS) colonization status of the mother
Rupture of membranes (ROM) duration
Maternal fever during labor
Gestational age at birth
Presence of neonatal clinical signs suggestive of infection
Maternal antibiotic treatment for GBS.
Output Interpretation:
The calculator provides a numerical probability score or risk category (e.g., low, intermediate, high)
This score is then used to inform decisions about initiating antibiotic therapy, the need for further investigations, and the duration of observation.
Limits Of Risk Calculators
Inherent Limitations:
Risk calculators are predictive tools, not diagnostic tests
They do not replace clinical judgment
Their accuracy can vary depending on the population studied and the specific algorithm used.
Population Variability:
Algorithms developed in one geographic region or healthcare setting may not be directly applicable to others due to differences in local epidemiology, pathogen prevalence, and antibiotic resistance patterns.
Diagnostic Accuracy:
Sensitivity and specificity can vary, leading to potential for false positives (unnecessary antibiotics) and false negatives (missed sepsis)
The performance characteristics of a specific calculator should be known and understood.
Clinical Scenario Complexity:
Calculators may not adequately account for all clinical nuances or the presence of atypical presentations
A clinician's overall assessment remains paramount.
Lack Of Real Time Data:
Some calculators rely on historical data or data not available at the time of initial decision-making, potentially delaying their utility.
Management Principles Guided By Risk
Initial Assessment:
Immediately assess the newborn for clinical signs of sepsis, regardless of risk calculator score
Obtain vital signs and perform a thorough physical examination.
Antibiotic Decision Making:
Use the risk calculator score in conjunction with clinical presentation and local guidelines
High-risk scores often warrant empirical antibiotic treatment, while low-risk scores may allow for close observation
Intermediate scores require careful clinical judgment.
Empirical Antibiotic Therapy:
Commonly used regimens include ampicillin and gentamicin, tailored to local resistance patterns
Duration of therapy is guided by blood culture results and clinical response, typically 5-7 days for confirmed sepsis.
Diagnostic Workup:
In patients with suspected sepsis (either clinically or based on a high-risk score), perform blood cultures, CBC, CRP/procalcitonin, and consider urine culture and lumbar puncture based on clinical condition
Chest X-ray if respiratory symptoms are present.
Supportive Care:
Aggressive supportive care is critical: fluid resuscitation for hypotension, oxygen therapy for respiratory distress, glucose monitoring, thermoregulation, and treatment of seizures if present.
Key Points
Exam Focus:
Understand the definition of EOS
Know the common risk factors and typical clinical presentations
Be familiar with the principle behind risk calculators and their role in guiding antibiotic therapy decisions
Recognize the limitations of these tools.
Clinical Pearls:
Always trust your clinical acumen
calculators are adjuncts, not replacements for judgment
Consider local epidemiological data for GBS and other pathogens when interpreting risk scores
Be aware of the turnaround time for blood cultures and their importance in de-escalating therapy.
Common Mistakes:
Over-reliance on a low-risk calculator score without considering subtle clinical signs
Delaying antibiotics in a critically ill infant due to waiting for calculator output
Inadequate workup for suspected sepsis
Failure to adjust antibiotic choice based on culture results or local resistance patterns.