1. Neisseria meningitidis ( meningococcus) Dr Kamran Afzal

9. Meningitis

11. Etiology Infectious

12. Non-infectious

13. Etiology according to Patient Age Age Common bacteria Birth - 1 month S. agalactiae, E. coli, K. pneumoniae, L. monocytogenes, enterococcus species 1 - 3 months S. agalactiae, E. coli, L. monocytogenes, H. influenzae, S. pneumoniae, N. meningitidis 3 months to over 15 years S. pneumoniae, N. meningitidis, H. influenzae

14. Pathogenesis

15. Bacterial evasion mechanisms Pathogenic Event Host Defense Bacterial Evasion Mechanism Colonization and mucosal invasion 1. Secretory IgA 2. Cellular cilia activity 3. Mucosal epithelium IgA protease secretion Ciliostasis Adhesive pili Survival in the blood stream Activation of Complement Pathways Blockage of Alternative Complement Pathway Crossing the blood-brain barrier Cerebral endothelium Passage through tight junctions between cells Survival within the CSF Poor opsonic activity Rapid bacterial replication

20. CSF evaluation Positive (MTB) Negative Positive Negative Culture Increased +/- Increased Increased 5-40 Protein < 30% Normal <40% 66% CSF : plasma Glucose ratio Decreased Normal Decreased 60-80 Glucose Increased Predominate Late 5 Lymphocytes +/- increased Early Predominate 0 Polymorphs <500 <1000 >1000 0-5 Cells TB Viral Bacterial Normal

29. Complications

30. Meningococcemia Septicemia and fulminant meningococcemia

32. Skin Lesions of Meningococcemia NOTE : Petechiae have coalesced into hemorrhagic bullae