CNS Infections
Terms
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- Most common causes of Acute Bacterial Meningitis in: birth-4 weeks
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1. Group B Strep
2. E. coli
3. Listeria - Most common causes of Acute Bacterial Meningitis in: 4 weeks - 15 years
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1. S. pneumoniae
2. N. meningitidis
3. H. influenza Type B - Most common causes of Acute Bacterial Meningitis in: 15 years - 30 years
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1. N. meningitidis
2. S. pneumoniae - Most common causes of Acute Bacterial Meningitis in: 30 years - 50 years
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1. S. pneumoniae
2. N. meningitidis - Most common causes of Acute Bacterial Meningitis in: > 50 years
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1. S. pneumoniae
2. Listeria
3. Enteric GNR - Bacterial causes of meningitis
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pneumococcus
meningococcus
h. influenzae
enteric GNR
Group B Strep
Listeria - Aseptic causes of meningitis
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TB
Syphilis
Viruses
Fungi
Parasites - Clinical Presentation of Meningitis
- fever, headache, nuchal rigidity, nausea/vomiting, drowsiness, confusion, seizures, cranial nerve palsies, papilledema
- Pathogenesis of Meningitis
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1. Upper resp tract colonization --> bacteremia
2. direct inoculation: congenital defects, trauma, surgery, parameningeal focus with rupture
3. retrograde access via neuron: Rabies/Herpes - Dx of Meningitis
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If Acutely Ill:
Blood culture, start abx (dont wait), THEN LP
If Stable:
LP, blood culture, start abx - Lab Tests for Meningitis on CSF
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Gram Stain
Culture
India Ink Stain
Latex Agglutination
Counter Immuno Electrophoresis - What is India Ink Staining?
- use it to visualize the yeast Cryptococcus, gets black outline
- What is Latex Agglutination?
- Agglutination of latex particles coated with specific antibody in presence of polysaccharide antigen in CSF. Use it to detect capsular polysaccharides.
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Meningitis Predisposition:
Meningococcus - outbreaks in close populations (military/college dorm)
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Meningitis Predisposition:
Pneumococcus - recent head trauma (esp w/ nasal CSF leak)
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Meningitis Predisposition:
Group B Strep, E. coli, Listeria - colonize vagina and infect neonate at birth
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Meningitis Predisposition:
S. Epidermis - ventricular/peritoneal shunt
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Meningitis Predisposition:
Cryptococcus and Listeria - Immunosuppression
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Meningitis Predisposition:
Gram Negative Rods - Post-Neurosurgery
- Differential Diagnosis for Meningitis
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aseptic meningitis
brain abscess
subdural/epidural empyema
viral encephalitis - Meningitis Chemoprophylaxis
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Meningococci: Ciproflaxin/Rifampin
H. Influenzae: Rifampin - Meningitis Vaccines:
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meningococcus: vaccine w/ serotypes A, C, Y, W-135
pneumococcus: 23 serotype unconjugated vaccine or 7 serotype conjugated vaccine
h. influenzae: capsular poly B conjugated vaccine - Causes of Brain Abscess
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oral flora: viridans, anerobes (bacteroides, fusobacterium, peptostreptococcus)
Listeria, Nocardia, Actinomyces - Brain Abscess Clinical Picture
- prolonged fever, headache, altered mental status, similar to other space occupying lesions
- Diagnosing Brain Abscess
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MRI (NO LP!)
blood culture
culture/stain pus from abscess - Brain Abscess Therapy
- 3G Cephalosporin plus metronidazole
- Viral Meningitis Causes:
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Enteroviruses (coxasackie, echoviruses)
HSV2 - Viral Meningitis Diagnosis:
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CSF tests for protein, sugar, cells
failure to find bacteria on stain/culture
viral cultures
rise in AB titer (retrospective) - Causes of Viral Encephalitis
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non-neonates: 70% unknown, HSV-1, Arboviruses
neonates: HSV-2 - Diagnosis of Herpes I Encephalitis
- PCR CSF, treat with acyclovir
- Post Infectious/Post-Vaccination Encephalitis
- varicella, MMR, H flu B
- Acute Flaccid Paralysis causes:
- Poliovirus, coxsackie, echo, west nile, guillain barre