10-14 L1-2 CNS infections

Question 1

What are some cardial mainfestations suggesting CNS infection?

Answer 1

• Fever
• HEadache
• Aleration of mental status
• Focal neurological signs

Question 2

Discribe the difference between

Acute vs Chronic infections

Answer 2

• Acute: rapid or sudden (a couple of hours)
  
  • clinical presentation maybe be quite dramatic or fulminate
• Chronic: slower (several days or months)
  
  • clinical presentation may not be as dramatic or fulminate.

Question 3

Encephalitis

vs

Meningitis

Answer 3

• Encephalitis: inflammation of the brain (‘brain fever’)
• **Meningitis: **inflammation of any or all o fhte meninges of the brain & spinal cord, usually caused by a bacterial infection.

Question 4

Postinfectious syndromes

Answer 4

• Usually begins as another infeciton (many times sub-clinical or not soncidered to be noteworthy)
• Infection maybe in CNS
• Presumed to be immunologically-mediated
  
  • GBS (guillain barre syndrome)
  • Post-infection encephalomyelities

Question 5

Prions

Answer 5

• Unconventional infection
• chronic (years to decades)
• usually no fevers
• high mortality
  
  • Kuru, CJD, PML, nvCJD

Question 6

What CSF values are different in adults than infants (or premature infants)

Answer 6

• Neutrophils
  
  • adults: 0
  • infants: 60
• Proteins
  
  • adults: 30
  • infants: 90

Question 7

What is the CNS infection entity that causes the most sensation?

What is at risk for involvement with the disease mentioned above?

Answer 7

• Meningitis (especially acute, bacterial meningitis)
• When meninges inflamed, anything passing thorugh them is at risk for involvement
  
  • blood vessels feeding the cerebral cortex
  • Nerves exiting the brain (cranial nerves, especially those at the base of the brainstem)

Question 8

Meningitis epidemiology

• <1 month old
• Toddler
• Teenagers
• >19 yrs old

Answer 8

• <1 month old: Group B strep
• Toddler: Streptococcus pneumoniae
• Teenagers: meningitis
• >19: streptococcus pneumonia

Question 9

The vaccination that dramatically changed the survival rate of 1-23 month old, b/t 1986 adn 1995 was against what virus?

Answer 9

Hib

(haemophilus influenzae b)

Question 10

Streptococcus pneumoniae

• morphology
• blood culture
• aviasion of immune system
• transmission

Answer 10

• morphology: G+, diplococcus (typically found in lancet-shaped pairs)
• blood culture: Alpha-hemolytic
• **aviasion of immune system: **
  
  • polysaccharide capsule (avoid phagocytosis)
  • Pneumolysin (cytoctoxic for phagocytic cells)
  • IgA protease
• transmission: spread by airborn droplet and direct contact with secretions

Question 11

Streptococcus agalactiae

Group B Streptococcus

• morphology
• blood culture
• aviasion of immune system
• transmission

Answer 11

• morphology: FAcultative G+ coccus
• blood culture: Beta-hemolytic
• aviasion of immune system:
  
  • adherence to vaginal and intestinal epithelium, placental membranes, BBB
  • Pili
  • Polysaccharide encapsulated (not major): inhibits complement deposition
• transmission: puerperal sepsis in newbrons (spread by direct contact)
  
  • Preventable process: vaccinate the mom!

Question 12

Haemophilus influenzae (Hib)

• morphology
• aviasion of immune system
• specious found in:
• transmission

Answer 12

• morphology: Facultative, G- coccobacillary organism, noo-motile (encapsulated(sm polysaccharide capsule)
• aviasion of immune system: pili, epithelial adherence, IgA protease
• specious found in: exlusively humans
• transmission: sread via airbone droplets and direct conteat with csecretions

Question 13

Neisseria Meningititdis

• morphology
• aviasion of immune system
• Seortype production

Answer 13

• morphology: G-, diplococcus, polysaccharide capsule, fastidious growth
• aviasion of immune system: Pili, IgA protease, terminal complement deficiences pre-dispose
• serotype production: A, B, C, W-135, and Y

Question 14

Escherichia coli

• Morphology:
• aviason from immune system
• member of what

Answer 14

• Morphology: G-, Facultative bacillus, rapidly growing and ferment lgucose
• Aviason from immune system: Pili, LPS, Exotoxins
• Member of the Enterobacteriaceae

Question 15

Listeria monocytogenes

• Morphology
• Hemolysis
• Aviasion from immune system
• Transmission

Answer 15

• Morphology: Facultative anerobic, G+, non-spore-forming bacillus, Motile with tumbling motilitys
• Hemolysis: Beta-hemolytic
• Aviasion from immune system: intracellular invasion, use listerolysin O to escape the phagosome and the cellular movement using acting polymerization
• Transmision: cold enrichment, via food

Question 16

Mycobacterium tuberculosis

• Morphology
• Cell composition

Answer 16

• Morphology: acid fast bacillus (tubercle bacillus) Slow growing
• Meningitis is a form of extrapulmonary TB, typically chronic, may or may not occur in face of immunocompromise
• Cell composition: cell wall characteristics with mycoloic acids and lipoarabinomannas (LAMs)

Question 17

What are common antitubercular treatment?

Answer 17

• INH (Isonizaid) and PZA (pyrizinamide) reach CSF concentraitons equal to blood concentrations
• Rifampin penetrates BBB also to a lesser degree (in also increases cYP450)

Question 18

INH (isoniazid)

MOA

Answer 18

inhibition of mycolic acid synthesis (cell wall)

Question 19

Riampin

MOA

Answer 19

DNA dependent RNA polymerase

Question 20

PZA (pyrizinamide)

MOA

Answer 20

Mechanism of action is unknown

Question 21

Cryptococcus neoformans

• Morphology
• Aviasion of immune system
• Transmission
• Population most effected

Answer 21

• Morphology: not dimorphic fungus (always in yeast phase),
  
  • polysaccharide capsule (antiphagocytic): Glucoronoxy lomannan (aslo immunomodulateory suppressive)
• Aviasion of immune system: Intracellular phagocyte survival (melanin)
• Transmission: aerosolized/inhaled fungi from environmental source (breating it in)
• Population most effected: Immunocompromised (AIDS!)

Question 22

How do you treat pt with fungal infection?

Answer 22

• Antifungal therapies amide at fungal cell membrane componenets (erostersols) not found in mammalian cells
• Azole antifungals target sterol synthesis
• Amphtericin B binds to ergosterol and likely through steric hindrance causes membrane permeability to increase.
• Fluocytosin: cnoncompetitive inhibitor of thymidilate sythetase

Question 23

How do you treate an AIDS pt vs a non-AIDS pt?

Answer 23

• AIDS: induction w/a_mphotericin B+/- fluocytosine for 4 weeks,_
  
  • followed by a consolidation phase of fluconazole (which may be life-long depending upon underlying immune compromise)
• Non-AIDS cases: Amphotericin B+ flyocytosine for 2 weeks

Question 24

Whats the most commonc cause of aseptic meningitis ‘virus meningitis’?

• Transmission
• Treament

Answer 24

Enteroviruses

• sm ss + sense RNA viruses (picornaviruses) in a naked icosahenral capsid
• spread by the fecal oral route and have a summer-Fall seasonality in temperate climates
• Include polioviruses, coxsackieviruses, echoviruses, parechoviruses, and others simply designated enteroviruses
• Treatment: supportive care

Question 25

How is **lymphocytic choriomeningitis virus** transmited what disease does it cause?

Answer 25

* Arenea virus family * singlestranded RNA * _Predilection for rodents_ * parasites of rodents with high species specificity _Mus domesticus and Mus musculus_ * Worldwide * human infection only demonstrated in Europe and Americas * Autumn occurrenece (due to rodent seasonlaiyt) * _Aseptic meningitis._

Question 26

What virus causes the highest morbidity and mortality? Is this virus treatable? (MOA)

Answer 26

Herpes simplex yes, high dose IV acyclovir MOA: activated by viral thymidine kinase to become a competitve inhibitor of viral DNA polymerase by blocking deoxyguanosine uptake.

Question 27

What is the most common US mosquito borne encephalitidies? Treatment?

Answer 27

West nile and St. Louis are the most common treatment: supportive care

Question 28

How is rabies spread?

Answer 28

* Rhabdovirus * NEg sense, single stranded RNA virus * Rod or bullet shaped * helical nucleocapsid * liporotein envelope * Affects all mammals * **Retrograde axonal spread** * **spread via bites and infected oral secretions and organ transplant**

Question 29

What is the cause of Meningo-encephalitis?

Answer 29

Listeriosis

Question 30

How are Toxoplasmosis acquired? How is it diagnosed?

Answer 30

* consumption of raw meat (beef, pork, lamb) * Diagnosis * serologic testing IgG and IgM (though IgM less reliabel methodology) * Direct tissue bipsy (for definitive diagnosis) * PCR

Question 31

How do you treat toxoplasmosis: Chorioretinitis & encephalitis?

Answer 31

* Chorioretinitis (3-4 weeks) * Pyrimethamine, sulfadiazine, leukovorine and corticosteroids * Encephalitis (4-6 weeks) * Pyrimethamine, sulfadiazine, leukovorine and corticosteroids (steroids are controversial)