Overview
Definition:
Fever in infants less than 60 days of age is defined as a rectal temperature of 38°C (100.4°F) or higher
This age group is particularly vulnerable due to an immature immune system, increasing the risk of serious bacterial infections (SBIs).
Epidemiology:
Fever is a common presentation in neonates, with approximately 5-10% of febrile infants under 60 days having an SBI
Common SBIs include urinary tract infections, bacteremia, meningitis, and pneumonia
Group B Streptococcus (GBS) and Escherichia coli are the most frequent pathogens
Prematurity, prolonged rupture of membranes (>18 hours), maternal fever, and chorioamnionitis are risk factors.
Clinical Significance:
Prompt and accurate triage of febrile infants under 60 days is critical as SBIs can rapidly progress to severe illness, sepsis, or death
Early identification and appropriate management of these infants are paramount for preventing morbidity and mortality, a key focus in pediatric residency and DNB/NEET SS examinations.
Clinical Presentation
Symptoms:
Fever (rectal temp ≥38°C)
Lethargy or irritability
Poor feeding or vomiting
Apnea or respiratory distress
Hypotonia or unusual cry
Seizures
Jaundice
Petechial or purpuric rash (less common but highly concerning).
Signs:
Vital sign abnormalities: Tachycardia, tachypnea, hypothermia, or shock
Signs of dehydration: Sunken fontanelle, decreased skin turgor, dry mucous membranes
Signs of localized infection: Umbilical redness, pustules, pneumonia findings on auscultation, meningeal signs (irritability with neck stiffness, bulging fontanelle).
Diagnostic Criteria:
There are no specific diagnostic criteria for fever itself, but the diagnostic approach is guided by the age and clinical suspicion of serious bacterial infection
Current guidelines from organizations like the American Academy of Pediatrics (AAP) and Indian Academy of Pediatrics (IAP) emphasize a systematic approach focusing on risk stratification and empirical management.
Diagnostic Approach
History Taking:
Detailed birth history: Gestational age, maternal fever, chorioamnionitis, prolonged rupture of membranes
History of current illness: Onset and duration of fever, feeding pattern, presence of vomiting or diarrhea, changes in activity, recent sick contacts
Pre-existing medical conditions or congenital anomalies
Immunization status (though less relevant in this age group for acute infection)
Red flags: Neonatal jaundice, poor feeding, lethargy, any signs of respiratory distress, recurrent fevers, or known immunodeficiency.
Physical Examination:
Comprehensive physical examination focusing on the infant's general appearance, vital signs (including axillary, rectal temperature if safe and feasible, and peripheral perfusion)
Perform a thorough assessment of all body systems: Skin (rashes, pustules, umbilical stump), HEENT (fontanelle, ears, throat), Cardiopulmonary (auscultation, perfusion), Abdomen (tenderness, hepatosplenomegaly), Neurological (activity, tone, reflexes, irritability), and Genitourinary (meatus).
Investigations:
Complete Blood Count (CBC) with differential: Elevated WBC count (>15,000/µL) or neutropenia (<1,500/µL) may suggest infection
C-reactive protein (CRP): Elevated CRP (>0.5 mg/dL) is a sensitive marker for inflammation
Blood culture: Essential for identifying bacterial pathogens
requires adequate volume (1-2 mL) and proper technique
Urine analysis and culture: Urinalysis may show pyuria or bacteriuria
urine culture is definitive
Lumbar puncture for cerebrospinal fluid (CSF) analysis and culture: Indicated in infants with suspicion of meningitis (pleocytosis, low glucose, high protein)
requires adequate CSF volume
Chest X-ray: If respiratory symptoms are present to rule out pneumonia
Other investigations based on clinical suspicion: e.g., stool culture for diarrhea, viral respiratory panel.
Differential Diagnosis:
Serious Bacterial Infections (SBIs): Sepsis, meningitis, UTI, pneumonia, osteomyelitis, omphalitis
Viral infections: Common viral illnesses can present with fever, but SBIs must be ruled out
Non-infectious causes: Post-vaccination fever (rare in this age group due to few vaccines given), heat stroke, drug fever (rare)
Neonatal Abstinence Syndrome (NAS) can mimic fever and irritability.
Management
Initial Management:
Immediate assessment and stabilization
For infants <60 days with fever, a low threshold for hospital admission and full sepsis workup is recommended, especially if risk factors are present or clinical suspicion is high
Empirical antibiotic therapy should be initiated promptly after obtaining necessary cultures
Fluid resuscitation if signs of shock or dehydration are present.
Medical Management:
Empirical antibiotic therapy is guided by likely pathogens and local resistance patterns
Common regimens include: Ampicillin (50-100 mg/kg/dose IV q6-8h) plus a third-generation cephalosporin (e.g., Cefotaxime 50 mg/kg/dose IV q8-12h or Ceftriaxone 50 mg/kg/dose IV q12-24h for infants >7 days)
Vancomycin may be added if MRSA is suspected or prevalent
Duration of therapy depends on the identified pathogen and clinical response, typically 7-14 days for bacteremia/pneumonia, 10-21 days for meningitis, and 7-10 days for UTI
Antipyretics (e.g., Paracetamol 10-15 mg/kg/dose PO/PR q4-6h) can be used cautiously for comfort, but are not a substitute for antimicrobial therapy.
Surgical Management:
Surgical intervention is rarely required for initial fever workup, but may be indicated if a localized collection develops, such as an abscess secondary to osteomyelitis or omphalitis requiring drainage
Definitive surgical management is dependent on the underlying cause if identified as a surgical emergency.
Supportive Care:
Close monitoring of vital signs, cardiorespiratory status, hydration, and neurological status
Maintain adequate fluid balance
Provide adequate nutrition
Administer antipyretics for comfort
Manage any complications such as respiratory distress or seizures
Strict adherence to infection control protocols.
Complications
Early Complications:
Sepsis-induced hypotension and shock
Disseminated intravascular coagulation (DIC)
Respiratory failure
Seizures
Neurological sequelae (e.g., developmental delay, hearing impairment) from meningitis
Necrotizing enterocolitis (NEC)
Renal failure
Death.
Late Complications:
Long-term neurological deficits from meningitis or hypoxic-ischemic injury
Developmental delay
Hearing loss
Visual impairment
Recurrent infections due to damaged immune system.
Prevention Strategies:
Maternal health and hygiene during pregnancy
Prompt diagnosis and treatment of maternal infections
Aseptic delivery techniques
Postnatal care emphasizing hygiene and avoiding unnecessary exposure to sick individuals
Timely and appropriate vaccination of older siblings and caregivers to reduce transmission risks.
Prognosis
Factors Affecting Prognosis:
The most critical factor is the presence and extent of serious bacterial infection
Early diagnosis and prompt, appropriate antibiotic treatment significantly improve outcomes
Gestational age at birth (preterm infants have poorer prognosis), host immune status, and specific pathogen virulence also play a role.
Outcomes:
With prompt diagnosis and treatment, the prognosis for most febrile infants without SBIs is excellent
For infants with SBIs, outcomes vary widely
Neonatal sepsis and meningitis carry significant risks of mortality and long-term morbidity
Early identification and aggressive management improve survival rates and reduce sequelae.
Follow Up:
Infants treated for SBIs require close follow-up to monitor for resolution of infection and assess for potential long-term complications
This may include serial developmental assessments, hearing and vision screening, and neurological examinations
Infants discharged after a sepsis workup without identified infection also require vigilant parental education on recognizing worsening symptoms.
Key Points
Exam Focus:
Fever in infants <60 days is a medical emergency
Assume SBI until proven otherwise
ALWAYS obtain blood, urine, and consider CSF cultures
Empirical antibiotics are crucial after cultures are drawn
Differentiate between low-risk and high-risk infants based on clinical status and risk factors
Common pathogens: GBS, E
coli, Listeria monocytogenes
Management of meningitis and sepsis is a frequent high-yield topic.
Clinical Pearls:
Always use rectal temperature for definitive fever assessment in neonates if possible and safe
A seemingly minor rash can be petechial/purpuric and highly concerning for meningococcemia
Do not delay antibiotics while awaiting all culture results
start empirically
A thorough neurological exam is vital in febrile neonates
Understand the rationale behind combination antibiotic therapy (e.g., ampicillin + cephalosporin).
Common Mistakes:
Underestimating the severity of fever in neonates
Delaying empirical antibiotic treatment
Inadequate blood or CSF volume for cultures
Failing to consider meningitis in the differential diagnosis
Relying solely on clinical signs without a systematic workup
Discharging a febrile infant without a thorough evaluation and risk stratification.