Week 2 - A. Prunuske

Question 1

What are the “Big Three” symptoms that CNS infections share in common?

Answer 1

1. Fever
2. Headache
3. Altered Mental State

Question 2

What are the noninfectious causes of fever, headache, and altered mental state?

Answer 2

• Subarachnoid hemorrhage
• Inflammatory disease (e.g. lupus)
• Neoplasm
• Metabolic disorder
• Drug (e.g. NSAIDs)

Question 3

What are the infectious causes of fever, headache, and altered mental status?

Answer 3

• Meningitis
• Encephalitis
• Abscess

Question 4

What part of the brain does meningitis occur?

Answer 4

Subarachnoid space

Question 5

What part of the brain does encephalitis occur?

Answer 5

diffuse parenchyma

Question 6

What part of the CNS does myelitis occur?

Answer 6

spinal cord

Question 7

What type of meningitis is most common?

Answer 7

Viral

Question 8

What type of meningitis is most life-threatening?

Answer 8

Bacterial

Question 9

When do fungi or protozoa cause meningitis?

Answer 9

patient is immunocompromised

Question 10

What virulence factor allows pathogens to evade immune system and cause meningitis?

Answer 10

Capsules

Question 11

What additional symptom is common in meningitis?

Answer 11

Nuchal rigidity (stiff neck)

Question 12

What additional symptoms are seen in Encephalitis that are not seen in Meningitis?

Answer 12

• Motor and sensory deficits
  
  • Seizures
  • Speech disturbances
  • Lethargy
  • Coma

Question 13

What are common viral causes of Encephalitis?

Answer 13

• Enterovirus
• Arbovirus
• Herpes
• Rabies

Question 14

What are common non-viral causes of Encephalitis?

Answer 14

• Rickettsia
• Mycoplasma
• Acute disseminated encephalomyelitis (ADEM)

Question 15

What is a brain abscess?

Answer 15

Focal infection of parenchyma

Question 16

What is the typical problem leading to brain abscess?

Answer 16

• Pre-existing ischemia
• Necrosis begins as cerebritis
• Area becomes encapsulated

Question 17

What are common conditions that can lead to brain abscess?

Answer 17

• Otitis media –> temporal lobe/cerebellum
• Dental/sinus infection –> frontal lobe
• Hematogenous –> multiple, territory of middle cerebral artery
• Trauma

Question 18

What happens if a brain abscess ruptures?

Answer 18

Meningitis! (scary)

Question 19

What five clinical features are common in Encephalitis but not Encephalopathy?

Answer 19

Common in Encephalitis (not Encephalopathy):

1. Fever
2. Headache
3. Seizures
4. Leukocytosis in CBC
5. Pleocytosis in CSF (increased WBC’s)

Question 20

Why are infections of the CNS uncommon?

Answer 20

1. Scalp/skull protects
2. Three meningeal layers surround brain/spinal cord
3. Tight-jxns in BBB prevent organisms from entering
4. Vaccination

Question 21

What two cells are innate immune cells in the CNS?

Answer 21

• Microglia (macrophages in the brain)
• Astrocytes

Question 22

What are the basic pathways of introducing pathogens to the CNS?

Answer 22

• Placental-fetal (milk)
• Respiratory
• Sexual
• Oral
• Zoonotic
• Blood transfusion
• Trauma

Question 23

What components of a patient’s history are important for diagnosing pathogen/CNS infection?

Answer 23

1. Travel history
2. Recent trauma
3. Living conditions
4. Season
5. Immunosuppressants (Prednisone)

Question 24

What is the clinical course if CNS infection is speculated?

Answer 24

• H & P
• Blood culture then start antibiotic Tx
• Neuroimaging
• LP/biopsy
• Identify organism - Gram stain, PCR, RT-PCR
• Switch to definitive Tx based on antibiotic susceptibility tests and/or supportive therapy

Question 25

Are most CNS infections acute or chronic?

Answer 25

ACUTE!!!

Question 26

What should you do if you suspect bacterial meningitis?

Answer 26

\*\*\*Start IMMEDIATE treatment!

Question 27

What antibiotic properties would be important to consider for a CNS infection?

Answer 27

* Can cross BBB * Small * Lipophilic * Not effluxed * low affinity for plasma binding proteins * Bactericidal * Broad spectrum

Question 28

What drug, besides antibiotics, is also important to give when treating a CNS infection?

Answer 28

Dexamethasone (decreases inflammation in subarachnoid space)

Question 29

If a focal mass lesion is found on neuroimaging (CT/MRI), what test should not be done? Why?

Answer 29

LP! Because of risk of brain herniation occuring.

Question 30

In the case of meningitis, what would a head CT show? MRI?

Answer 30

CT: nothing, NORMAL! MRI: leptomeningeal enhancements, but no focal lesions.

Question 31

What immune function does the subarachnoid space lack when fighting meningitis?

Answer 31

**Antibody** and **Complement** production required for phagocytosis.

Question 32

What are 11 possible clinical symptoms a patient with meningitis could present with?

Answer 32

1. Fever (older individuals less likely) 2. Headache 3. Altered mental status 4. Nuchal rigidity (30% cases) 5. Photophobia 6. Rash 7. Nausea 8. Vomiting 9. Diarrhea 10. Anorexia 11. Upper respiratory symptoms

Question 33

What type of meningitis usually shows high presence of PMN's on CSF from LP?

Answer 33

Bacterial meningitis

Question 34

What three symptoms are common in Aseptic Meningitis Syndrome?

Answer 34

1. Fever 2. Headache 3. Photophobia (less neck stiffness/altered mental status)

Question 35

What are the typical CSF findings in the case of Aseptic Meningitis Syndrome?

Answer 35

* Increase in lymphocytes and monocytes * Slight increase in protein * Normal glucose

Question 36

What are the typical CSF findings in bacterial meningitis?

Answer 36

* High opening pressure * High WBC count * \>80% PMN's on WBC differential * High protein * Low glucose

Question 37

What is the treatment for Aseptic Meningitis Syndrome?

Answer 37

Supportive therapy & recover on their own (unless neonatal)

Question 38

What age has the highest incidence of Aseptic Meningitis Syndrome?

Answer 38

0-1 yoa | (first year of life)

Question 39

85% of viral meningitis cases are associated with what type of virus?

Answer 39

Enteroviruses | (RNA viruses)

Question 40

How do you treat bacterial meningitis?

Answer 40

* **Immediate** empiric treatment with **Ceftriaxone** (3rd generation cephalosporin) * 3 hr delay leads to increase in 3 month fatality

Question 41

If you suspect a patient with bacterial meningitis to have a risk of other pathogen agents, how do you treat them?

Answer 41

* Risk of other agents, then add: * MRSA - Vancomycin * HSV-2 - Acyclovir * *Pseudomonas* - Cefepime (4th generation cephalosporin) * *Listeria* - Ampicillin

Question 42

Which bacterial pathogen most commonly causes bacterial meningitis in adults?

Answer 42

Streptococcus pneumonia

Question 43

What pathogen most commonly causes bacterial meningitis in 11-17 year olds?

Answer 43

Neisseria meningiditis

Question 44

Because their risk is 10x higher than other adults, what should all adults over age 65 receive?

Answer 44

13-valent pneumococcal conjugate vaccine

Question 45

What are the 9 steps in the development of bacterial meningitis by H. influenza type b, and N. meningiditis, Strept. pneumonia?

Answer 45

1. Mucosal colonization at nasopharynx 2. Invasion and multiplication in bloodstream 3. Cross BBB 4. Egress into CSF 5. Astrocytes and microglia release inflammatory cytokines in CSF 6. Increased permeability of BBB 7. Diapedesis of leukocytes into CSF 8. Edema and increased intracranial pressure 9. Neuronal injury including hearing loss (CN VIII)