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pathophysiology and csf analysis in simpler form

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  1. 1. Meningitis Group- 5 Tutor:Dr.Rajiv Shrestha
  2. 2. Group Members • Sagun Baral • Ashkal Basi • Ashutosh Ghimire • Kamal Ghimire • Anup Subedi • Samir Raut • Prasesh Dhakal • Prastuti Shrestha • Saugat Lamichhane • Kriti Pandey • Shravya Rayilla
  3. 3. What is meningitis?? • Meningitis refers to an inflammatory process of leptomeninges and CSF within the sub-arachnoid space. • Meningitis is generally caused by an infection, but chemical meningitis may also occur in response to a bacterial irritant injected into the sub-arachnoid space.
  4. 4. CLASSIFICATION • Infectious meningitis is broadly classified into three groups : - Acute Pyogenic (Bacterial) Meningitis - Aseptic (usually acute viral) Meningitis - Chronic (usually tuberculous / fungal) Meningitis
  6. 6. - BACTERIAL AGENTS: Neonatal: E. coli Group B Streptococci Infants: Hemophilus influenzae Adolescents and young adults: Niesseria meningitidis(most common) Streptococcus pneumoniae Elderly: Listeria monocytogens Streptococcus pneumoniae - VIRAL AGENTS: Enterovirus(most common), Mumps virus, Coxsackie virus, HSVII, EBV - FUNGAL AGENTS: Candida albicans, Cryptococcus neoformans, Blastomyces dermatidis, Coccidiodesimitis - PARASITES: Protozoa, Nematodes, Cestodes
  7. 7. Routes of Infection : There are 4 methods by which microbes enter the nervous system 1. Hematogenous route : through arterial and venous spread; is the most common route of entry 2. Direct implantation : it may be traumatic or rarely iatrogenic i.e. through a lumbar puncture needle 3. Local extension : through air sinuses, infected tooth or a surgical site. 4. Through peripheral nervous system : as occurs with certain viruses.
  8. 8. Pathogenesis of bacterial meningitis: Nasopharynx Nasopharyngeal colonisation (in epithelial cells) Local invasion into intravascular space bacteria transported across epithelial cells in membrane bound vacuoles OR by creating separations in apical tight junctions Bacteremia (avoid phagocytosis due to presence of polysaccharide capsule) Reach choroid plexus / Adhere to cerebral capillary endothelium Bacteria gain access to CSF Rapid multiplication in CSF Lysis of bacteria …contd
  9. 9. Release of bacterial component Cytotoxic edema (lipopolysaccharide, endotoxin, peptidoglycan, teichoic acid) Cerebral microvascular endothelium Macrophages activated and release cytokines IL-1,TNF Increase BBB permeability; Vasculitis Subarachnoid space inflammation Vasogenic edema and ↑CSF outflow Exudates leakage of serum proteins resistance; ↑ICP into the sub arachnoid space CSF flow obstruction & Hydrocephalus ↓CSF reabsorption ↓cerebral blood flow Interstital edema
  10. 10. Morphology of Bacterial Meningitis GROSS: • Exudates in the leptomeninges and the surface of brain. • Engorged meningeal vessels. • In H. influenzae exudates are localized to the base. • In Pneumococcal meningitis the exudate is seen over cerebral convexities near the sagittal sinus. • When the meningitis is fulminant, the inflammation may extend to the ventricles producing ventriculitis. MICROSCOPY: • Neutrophils fill the entire subarachnoid space. • In severe cases they infilterate the vessel wall and even the brain. • Untreated cases can follow leptomeningeal fibrosis and hydrocephalus.
  11. 11. Acute pyogenic meningitis showing purulent exudates
  12. 12. Clinical Features • Fever, chills and rigor • Headache, nausea, vomiting • Seizures, cranial nerve palsies • Signs of meningeal irritation – Neck rigidity – Photophobia
  13. 13. Signs
  14. 14. Complications: • Bacterial : - Waterhouse-Friderichsen syndrome - obstructive hydrocephalus - chronic adhesive arachnoiditis - focal cerebritis - phlebitis leading to venous occlusion and hemorrage of underlying brain.
  15. 15. Cerobrospinal Fluid (CSF) in Normal individuals and in different types of meningitis Characteristics Normal CSF Acute pyogenic meningitis Tuberculous meningitis Viral meningitis Pressure Normal (<20cm H20) Highly increased Moderately increased Slightly increased Direct examination A. Cell count/cumm and predominant cell 1-3 Lymphocytes 1,000-20,000 Neutrophils (90-95%) 50-500 Lymphocytes (90%) 10-500 Lymphocytes B. Biochemical analysis 1. Protein (mg%) 2. Sugars (mg%) 30-45 40-80 Highly increased (100-600) Diminished (10-20) Moderately increased (80-120) Diminished (10-20) Slightly increased (60-80) Normal Bacteriological examination A. Microscopy Gram stain ZN-staining Nil Nil GPC,GNC,GN B,GPB etc Nil - Acid fast bacilli - B. Culture Nil Specific medium In LJ medium Cell cultures
  16. 16. References Harrison’s Principles Of Internal Medicine Pathologic Basis Of Disease Robbins and Cotran
  17. 17. K YOU  THANK YOU