CSF Analysis

Lumbar Puncture (LP) is performed to examine the cerebrospinal fluid

Meningitis

• Infective
  • Bacterial
  • Aseptic - Viral, TB, Fungi, Parasites
• Non-infective
  • Malignancy
  • Auto-immune

Age-related Causes of Meningitis

• Bacterial:
  • Neonatal (<3/12)
    • Gram negative (E coli)(Pseudomonas), Listeria, Group B strep, Coag –ve staphylococcus
  • 3/12 to 15 years
    • Neiserria meningitidis, Pneumococcus (strep pneumonia), Haemophilus pneumonia
  • Adult > 15 years
    • N meningitidis, s. pneumonia, listeria, klebsiella, s. aureus
  • Elderly
    • Gram negatives predominate
  • Immunocompromised
    • Complement deficiency – Neiserria
    • Humoral or asplenic - Neiserria, enterovirus
    • Sickle cell disease - Capsulated organisms
• Aseptic meningitis (Generally accepted as mainly viral meningitis)
  • Lymphocytosis, variable protein elevation and normal glucose
  • Viral
    • Echovirus, Enterovirus, Mumps
    • HSV 1 + 2, CMV, VZV, EBV
  • Other
    • TB, Nocardia, Leptospira, Treponema
    • Fungi, rickettsia, parasites
    • Malignancy, auto-immune

Specific Risk Factors

• Pneumococcus: (40%) – Otitis media, head injury, pneumonia, immunocompromised
• N meningitidis: (30%) – Children and adolescents
• Staphylococcus: Penetrating skull injury, ear or neuro operations
• Fungal: HIV and organ transplant
• Listeria: Extremes of age
• H Influenzae: (3%)  - Head trauma with CSF leak, otitis, sinusitis, anatomical defects such as dermal sinus tracts
• Anaerobes: Consider brain abscess, elderly