Bacterial Meningitis in Children

Background

• Bacterial meningitis is a life-threatening medical, neurologic, and sometimes neurosurgical emergency caused by a bacterial infection of the meninges leading to tissue inflammation.
• Risk factors for meningitis include exposure to pathogens, reduced host immunity, young age, and implanted medical devices in the central nervous system.
• Infection occurs when bacteria breech the host's natural defenses and enter the central nervous system by hematogenous spread or direct extension from a contiguous site.
• Age may determine which pathogens are most likely; the most common include Streptococcus agalactiae (group B Streptococcus), Listeria monocytogenes, Streptococcus pneumoniae, Neisseria meningitidis, Haemophilus influenzae type b and nontypeable H. influenzae, Escherichia coli, and Klebsiella.
• Vaccination is the most effective means of meningitis prevention.

Evaluation

• Clinical presentation of meningitis in infants and children may include:
  • symptoms of fever, lethargy, poor feeding, irritability, vomiting, headache, confusion, seizure, and neck stiffness
  • signs such as bulging fontanelle, petechial or purpuric rash (if meningococcemia present), nuchal rigidity, Kernig and Brudzinski signs, and shock
• Initial testing for suspected meningitis
  • Draw blood for culture, complete blood count with differential, glucose, and C-reactive protein or procalcitonin level (if available).
  • Perform a lumbar puncture (LP) to diagnose meningitis unless it will delay antibiotic therapy or is contraindicated due to increased intracranial pressure from an alternate cause.
    • Check opening pressure and perform Gram stain, culture and sensitivities, cell count and differential, protein, and glucose.
    • Consider polymerase chain reaction (PCR) testing on cerebrospinal fluid (CSF).
    • Consider herpes simplex virus (especially in neonates) and enteroviral PCR testing.
• Suspect meningitis in children with suspicious clinical presentation and abnormal CSF findings, including:
  • positive Gram stain
  • elevated opening pressure based on age
  • elevated white blood cell count with neutrophil predominance (may vary from < 100 cells/mm³ to > 10,000 cells/mm³)
  • glucose < 40 mg/dL (0.56 mmol/L)
  • protein > 58 mg/dL (may not be accurate in neonates)
• Diagnosis is confirmed with positive CSF cultures or CSF polymerase chain reaction for specific pathogen.

Management

• Start antimicrobial therapy once cerebrospinal fluid (CSF) analysis or the clinical presentation (when lumbar puncture is delayed or contraindicated) suggests the diagnosis of bacterial meningitis.
• Empiric antibiotic choice depends on the likely pathogens, which are based on age and Gram stain results.
  • Dosing and interval will vary by age.
  • Adjust antibiotics based on culture and antimicrobial sensitivities of any isolated pathogen.
  • Duration of therapy varies by organism.
  • Consider using IV antibiotics for the entire duration of therapy.
• For suspected of confirmed Haemophilus influenza type B meningitis, give dexamethasone 0.15 mg/kg IV, if possible, 10-20 minutes before and no later than with the first antibiotic dose; repeat every 6 hours for 2-4 days (Strong recommendation). It may not be recommended for use in neonates (Weak recommendation). Use in pneumococcal meningitis is controversial.
• Fluid and electrolyte management is determined by the clinical situation, as children are prone to shock as well as dehydration, elevated intracranial pressure, and hyponatremia from the syndrome of inappropriate antidiuretic hormone.
• Give rifampin 20 mg/kg (maximum 600 mg) orally once daily for 4 days prior to discharge for children ≥ 1 month old with H. influenza type B meningitis that did not receive cefotaxime or ceftriaxone during treatment (dose for infants < 1 month old is not established, but some experts recommend lowering the dose to 5 mg/kg every 12 hours).
• Follow-up of children with meningitis includes:
  • audiologic evaluation preferably prior to discharge then followed by regular hearing evaluations
  • developmental, behavioral, and neurologic evaluations for the first year following infection
• Chemoprophylaxis for contacts of children with H. influenza and meningococcal meningitis should be done in conjunction with the local health department, ideally within 24 hours, but no later than 14 days after diagnosis of index patient.