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• Meningitis


  Inflammation of the membranes covering the brain and spinal cord (meninges)
• Meningitis is one of the most potentially serious infections occurring in infants and children, with a high rate of acute life-threatening complications and risk of long-term morbidity
• The incidence of bacterial meningitis is sufficiently high in febrile infants
• Etiologies of meningitis


  • Bacterial infection
  • Viral infection
  • Fungal infection
  • Inflammatory disease
  • Malignancy
  • Trauma to the head and spinal cord
• Bacterial causes of meningitis by age group

  • 0-2 months: Group B streptococcus, Escherichia coli, Listeria monocytogenes, S. Aureus
  • Infants and children: Streptococcus pneumoniae, Neisseria meningitidis, Haemophilus influenzae type b
  • Adolescents and adults: Streptococcus pneumoniae, Neisseria meningitidis, Haemophilus influenzae type b
• Other bacteria that may cause meningitis include Syphilis and Tuberculosis (TB)
• Viral meningitis


  In most instances, the infections are self-limited, but in some cases, substantial morbidity and mortality occur
• Viral agents for aseptic meningitis


  • Enterovirus (e.g. poliovirus, Echovirus, coxsackievirus)
  • Herpes viruses
  • Paramyxovirus (mumps, measles)
  • Arboviruses
  • Rabies
  • Toga virus (mumps)
  • Retrovirus (HIV)
• Fungal meningitis


  It is rare in healthy people, but is a higher risk in those who have AIDS or other forms of immunosuppression
• Common fungal agents for meningitis

  • Cryptococcus neoformans
  • Candida
  • Histoplasma capsulatum
• Transmission of meningitis


  The mode of transmission is probably person-to-person contact through respiratory tract secretions or droplets
• Pathophysiology of bacterial meningitis

  1. Hematogenous dissemination of microorganisms from a distant site of infection

  2. Bacterial invasion from a contiguous focus of infection such as paranasal sinusitis, otitis media, mastoiditis, orbital cellulitis, or cranial or vertebral osteomyelitis

  3. Introduction of bacteria via penetrating cranial trauma, dermal sinus tracts, or meningomyeloceles
• Risk factors for meningitis

  • Age
  • Community setting (large groups like college dorms, military, childcare facilities)
  • Ear infection
  • Alterations of host defense (anatomic defect, CSF leak, immune deficit, altered immunoglobulin production, defects of the complement system, splenic dysfunction, T-lymphocyte defects)
• Clinical manifestations of meningitis

  • Systemic manifestations (fever, hypothermia, lethargy, respiratory distress, jaundice, poor feeding, vomiting, diarrhea, seizures, restlessness, irritability, bulging fontanel)
  • Headache
  • Profound hypotension and shock
  • DIC
  • Photophobia
  • Petechial, purpura and erythematous skin rash
  • Altered consciousness
  • Increased ICP
  • Seizures
  • Focal neurologic findings (hemiparesis, quadriparesis, facial palsy, visual field defects)
• Contraindications for lumbar puncture

  • Evidence of increased ICP (other than a bulging fontanel)
  • Severe cardiopulmonary compromise requiring prompt resuscitative measures
  • Infection of the skin overlying the site of the LP
  • Thrombocytopenia (relative contraindication)
• CSF findings in CNS infections

  The diagnosis is confirmed by the isolation of bacteria from the gram stain and culture of CSF
• Blood tests for meningitis diagnosis

  • Complete blood count
  • Blood cultures
  • Serum electrolytes and glucose
  • Blood urea nitrogen and creatinine
  • Elevations of C-reactive protein, erythrocyte sedimentation rate, and procalcitonin
• Indications for imaging before lumbar puncture in children with suspected bacterial meningitis

  • Coma
  • Presence of a cerebrospinal fluid (CSF) shunt
  • History of hydrocephalus
  • Recent history of CNS trauma or neurosurgery
  • Papilledema
  • Focal neurologic deficit (except palsy of cranial nerve VI or VII)
• Treatment of meningitis


  1. Antibiotics as soon as possible after LP if no signs of increased ICP

  2. Antibiotics without LP and before CT scan if signs of increased ICP or focal neurologic findings

  3. Supportive therapy (fluid/electrolyte balance, temperature control, oxygen, seizure management)

  4. Selected antibiotics to achieve bactericidal levels in CSF

  5. Corticosteroids (dexamethasone) 1-2 hrs before or with first antibiotics
• Duration of antimicrobial therapy for meningitis

  • Neisseria meningitidis: 7 days
  • Haemophilus influenzae: 7 days
  • Streptococcus pneumoniae: 10-14 days
  • Streptococcus agalactiae: 14-21 days
  • Aerobic gram-negative bacilli: 21 days
  • Listeria monocytogenes: 21 days
  • Neonatal HSV: 21 days
• Complications of meningitis


  • Acute: seizures, increased ICP, cranial nerve palsies, stroke, cerebral/cerebellar herniation, dural venous sinus thrombosis
  • Chronic: hearing loss, cognitive impairment, recurrent seizures, delayed language acquisition, visual impairment, behavioral problems
• Prognosis of meningitis


  Prognostic factors include level of consciousness, etiologic agent, prolonged/complicated seizures, low CSF glucose, delayed CSF sterilization, nutritional status

  Overall mortality is ~5% in developed countries and ~8% in developing countries
• Meningitis prevention


  • Isolation
  • Vaccination
  • Antibiotic prophylaxis
  • Chemoprophylaxis for contacts of meningococcal and Hib meningitis