Meningitis Flashcards
(8 cards)
What’s meningitis and meningoencephalitis?
Meningitis = Inflammation of leptomeninges + CSF in subarachnoid space.
➡️ These structures are exposed to infections from blood or nearby tissue.
- Meningoencephalitis = Inflammation extends into brain tissue itself.
➡️ Indicates a more severe infection affecting neurons directly.
What are the types of meningitis?
Chemical meningitis = Inflammatory response to noninfectious irritants (e.g., contrast agents, drugs).
➡️ Body reacts as if it’s infected, even though no pathogen is present.
Acute pyogenic (bacterial) ➡️ Rapid onset, severe.
➡️ Bacteria trigger a strong neutrophilic response.
- Aseptic (usually viral) ➡️ Less severe, often self-limited.
➡️ Viruses don’t trigger pus formation.
- Chronic (TB, syphilis, cryptococcus) ➡️ Slow onset, persistent.
➡️ Pathogens with slower growth and chronic inflammation.
Age-Related Pathogens ,neonate,adolescent, elderly/immunocompromised (Explain Why Different Germs?)
- Neonates ➡️ E. coli, Group B Streptococcus, Listeria.
⏩ Immature immune systems allow these gut/vaginal flora to invade.
- Adolescents/Young Adults ➡️ Neisseria meningitidis, Streptococcus pneumoniae.
⏩ These colonize the nasopharynx and spread during close contact.
- Elderly/Immunocompromised ➡️Same as neonates, esp. Listeria.
⏩ Weakened immunity increases susceptibility.
- ** reduced H. influenzae due to vaccination.**
➡️ Vaccines removed this once common pediatric cause
What are the Clinical Signs of meningitis(Why These Symptoms?)
- Fever + meningeal signs (headache, photophobia, neck stiffness)
⏩ Inflammation irritates meninges and increases intracranial pressure.
- Altered consciousness and irritability
⏩ Pressure and cytokines affect cortical and subcortical function.
What are CSF Findings in Bacterial Meningitis (Classic Triad)
Also a typical and chem (Check VN).
- Cloudy/purulent CSF + increased pressure
⏩ Neutrophils and protein create turbidity and raise intracranial pressure.
- ⬆️ Neutrophils (up to 90,000/mm³)
⏩ Bacteria stimulate massive neutrophilic response.
- ⬆️ Protein
⏩ Due to inflammation and breakdown of blood-brain barrier.
- ⬇️ Glucose
⏩ Bacteria consume glucose; neutrophils may also impair transport.
- Gram stain or culture may show bacteria
⏩ Confirms etiology and guides antibiotic therapy.
What pathogens cause brain abscesses?
A: Mostly Streptococcus and Staphylococcus species.
Localized CNS Infections
- Abscess: Often caused by Streptococcus and Staphylococcus.
➡️ These enter through sinus, ear, or blood and form pus-filled masses.
- Subdural Empyema: Usually polymicrobial (includes anaerobes).
➡️ Often arises from adjacent infection like sinusitis or trauma.
Why is protein high in bacterial meningitis CSF?
A: Inflammation increases blood-brain barrier permeability.
