Infectious Diseases in Pediatrics
Bacterial meningitis is a serious infection of the protective membranes (meninges) covering the brain and spinal cord. In children, it's a medical emergency that requires immediate recognition and treatment.
📋 Definition and Etiology
Understanding Bacterial Meningitis
Definition
Bacterial meningitis is an acute inflammation of the meninges caused by bacterial infection of the cerebrospinal fluid (CSF). It represents a neurological emergency with high morbidity and mortality.
Common Pathogens by Age
- Neonates (0-28 days): Group B Streptococcus, E. coli, Listeria
- Infants & Children (1 month–5 years): S. pneumoniae, N. meningitidis, H. influenzae type b
- Older Children & Adolescents: N. meningitidis, S. pneumoniae
Note: Routine vaccination against Hib, pneumococcus, and meningococcus has dramatically reduced incidence in vaccinated populations.
🩺 Clinical Presentation
Signs and Symptoms by Age
Neonates & Young Infants
Often non-specific and subtle
- Fever or hypothermia
- Poor feeding, irritability
- Lethargy, decreased activity
- High-pitched cry
- Bulging fontanelle
- Seizures, apnea
Older Infants & Children
Classic symptoms become apparent
- High fever, severe headache
- Neck stiffness (nuchal rigidity)
- Photophobia, vomiting
- Altered mental status
- Seizures
- Petechial/purpuric rash
🚨 Important Clinical Note
The classic triad of fever, neck stiffness, and altered mental status is present in only ~50% of cases. Maintain a high index of suspicion.
🔍 Investigations
Diagnostic Approach
Lumbar Puncture (LP) & CSF Analysis – Gold Standard
- Cell count: Elevated WBCs (neutrophils predominant)
- Protein: Elevated (>100 mg/dL)
- Glucose: Decreased (<40 mg/dL or CSF:blood ratio <0.4)
- Gram stain: Positive in 60–90%
- Culture & PCR: For organism identification
Additional Investigations
- Blood tests: Cultures, CBC, CRP, procalcitonin, electrolytes
- Imaging: CT head before LP if ↑ICP suspected; MRI for complications
📊 Contraindications to Immediate LP
Delay LP if signs of increased intracranial pressure, focal neurological deficits, or cardiovascular instability. Start antibiotics immediately after blood cultures.
💊 Management
Emergency Treatment Principles
⏱️ Immediate Empiric Antibiotics
- Neonates: Ampicillin + Gentamicin/Cefotaxime
- Infants/Children (1 mo–18 yr): Vancomycin + Ceftriaxone/Cefotaxime
- Immunocompromised: Add ampicillin for Listeria coverage
Adjunctive Therapy
- Dexamethasone: Given before/with first antibiotic dose (except neonates). Reduces hearing loss & neurological sequelae in pneumococcal meningitis.
Supportive Care
- ICU monitoring
- Judicious fluid management (risk of SIADH & cerebral edema)
- Seizure control
- Management of ↑ICP
- Respiratory support if needed
Critical Timing: "Time is brain" – every hour of delay worsens outcomes. Never delay antibiotics for diagnostic tests if clinical suspicion is high.
📈 Complications
Acute and Long-term Sequelae
Acute Complications
- Seizures (20–30%)
- Cerebral edema & ↑ICP
- Hydrocephalus, brain abscess
- Cerebral infarction (stroke)
- Septic shock, DIC
- Death (5–10% mortality)
Long-term Complications
- Hearing loss (10–30%) – routine post-recovery testing required
- Cognitive impairment & learning disabilities
- Developmental delays, epilepsy
- Motor deficits, cerebral palsy
- Vision & behavioral issues
⚠️ Risk Factors for Poor Outcome
- Delayed treatment
- Very young age
- Pneumococcal infection
- Low CSF glucose, high CSF protein
- Seizures at presentation
🛡️ Prevention
Vaccination and Prophylaxis
Vaccination Schedule
- Hib: 2, 4, 6, 12–15 months
- PCV13: 2, 4, 6, 12–15 months
- MenACWY: 11–12 years, booster at 16
- MenB: For high-risk individuals/adolescents
Other Measures
- Chemoprophylaxis for close contacts (meningococcal/Hib)
- Good hygiene, handwashing
- Avoid sharing drinks/utensils
- Prompt treatment of ear/sinus infections
- Breastfeeding for passive immunity
Public Health Impact: Vaccination has reduced Hib meningitis by >99% and remains the most effective preventive strategy.
🎯 Key Takeaways
- Bacterial meningitis is a medical emergency requiring immediate recognition and treatment.
- Presentation varies by age: neonates show non-specific signs; older children may have fever, headache, neck stiffness.
- Lumbar puncture with CSF analysis is diagnostic, but never delay antibiotics for testing if clinical suspicion is high.
- Empiric antibiotic choice is age-dependent: neonates (ampicillin + aminoglycoside/3rd-gen cephalosporin); older children (vancomycin + ceftriaxone).
- Adjunctive dexamethasone improves outcomes in pneumococcal meningitis (except neonates).
- Complications are common: hearing loss, neurological impairment, seizures, death.
- Prevention relies on routine vaccination (Hib, PCV, MenACWY) and chemoprophylaxis for contacts.