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04- Central nervous system infections Flashcards

1
Q

Meningitis

A

inflammation of the meninges

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2
Q

encephalitis

A

inflammation of the brain

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3
Q

Brain abcess

A

collection of pus anywhere within the brain

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4
Q

blood-brain barrier

A

limits access to CSF in the brain, limit organisms in brain. Also restricts pharmocotherapy

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5
Q

Best drugs for brain infections

A

fat soluble and small, easy time transporting across blood brain barrier

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6
Q

Bony processes with the infection

A

Brain is surrounded by the skull, causing intracranial pressure. Can be a medical emergency

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7
Q

Host Factors

A

Absence of normal flora
less local macrophages, antibodies & complement
Inflammation; Increases permeability of the blood-brain barrier facilitating pathogen entry & increases BBB permeability to antibiotic therapy and immune cells

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8
Q

inflamed blood brain barrier

A

caused by infection, more permeable to drugs and immune cells, but also allows more pathogens to enter the blood brain barrier.

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9
Q

Portals of Infection

A

-Trauma to bones and meninges, medical
procedures
-Peripheral neurons (rapids)

Most common (secondary infections):

  • Respiratory system
  • Gastrointestinal system
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10
Q

Acute Meningitis

A

medical emergency, always caused by an infection, sick for less then 2 weeks, severe and sudden

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11
Q

Chronic or aseptic meningitis

A

Medication or viruses, medication can case inflammation. Varying symptoms, kinda mild and lasts long

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12
Q

Clinical findings in meningitis

A

SYSTEMIC INFECTION
Fever
Myalgia
Rash

MENINGEAL INFLAMMATION
Neck stiffness
Brudzinski's Sign
Kernig's Sign
Jolt Accentuation of headache
CEREBRAL VASCULITIS (inflammation of blood vessels)
Seizures
ELEVATED INTRACRANIAL PRESSURE
Headache, N&V
Change in mental status
Neurologic symptoms
Seizures
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13
Q

Meningitis rash associated with what kind of infections…..

A

Gram negative infections

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14
Q

Meningitis Diagnosis

A

Patient history
Symptoms & Signs

Chills, neck stiffness, headache, altered mental
state, focal neurological deficits, seizure,
photophobia, nausea & vomiting
Fever, nuchal rigidity, Brudzinski & Kernig signs,
jolt accentuation of headache, Glasgow coma
scale (GCS), rash

Physical exam
Laboratory tests; blood, CSF analysis & culture

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15
Q

Classical clinical triad of meningitis

A

Fever, nuchal rigidity, headache
Triad present in only 44% of patients with meningitis
Absence of all three rules out meningitis with 99% certainty

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16
Q

95% of clients with meningitis exhibit 2 of the following:

A

Headache
Fever
Neck stiffness (nuchal rigidity)
Altered mental state

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17
Q

Nucal rigidity

A

Stiff neck, sign of possible meningitis
gently force neck forward, causes pain, which stretches meninges, force heard forward and will resist and state pain. This is a positive sign

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18
Q

Brudzinski’s sign

A

pain with resistance and involuntary flex of hip/knee when neck is flexed to chest when lying supine,

forcing head forward, spine hurts, knee up to relieve pain

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19
Q

Kernigs sign

A

a diagnostic sign for meningitis marked by the person’s inability to extend the leg completely when the thigh is flexed upon the abdomen and the person is sitting or lying down

lift leg, will bend knee

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20
Q

Jolt accentuation of headache

A

worsening of a headache (if they have one) if the head is turned 2 to 3 times per second

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21
Q

Absence of jolt accentuation, and other signs…..

A

Can`t rule out meningitis

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22
Q

Bacterial Meningitis CSF analysis

A

Low CSF glucose levels (< 2.5 mmol/L or < 40% of serum glucose)

High CSF protein levels (> 0.45 g/L)

CSF pleocytosis (500 - 20,000 WBC/mm3); >80% neutrophils (lots)

Gram stain & culture

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23
Q

viral meningitis CSF analysis

A

Normal CSF glucose levels

Normal to mildly increased CSF protein levels

CSF WBC elevated (10 - 1000 WBC/mm3); mainly lymphocytes and monocytes

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24
Q

CSF Pressure

A

Lumbar puncture opening pressure will also be higher in cases of bacterial meningitis

(more inflammation)

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25
Bacteria meningitis pathogens
80% of adult cases -Streptococcus pneumoniae (the leading cause of community aquired pneumonia, gram-positive) -Neisseria meningitidis (gram negative) ``` Haemophilus influenzae (non-immunized) Listeria monocytogenes (specific populations) Group B Streptococcus ```
26
viral meningitis pathogens
Enteroviruses (Coxsackie B) | Herpes Simplex Virus
27
Pneumococcal meningitis
Type of bacterial meningitis Microorganism is in the lungs, resides and changes to cause infection Infectious 1 to 3 days before showing symptoms, contagious 24 hours after antibiotic therapy Case fatality rate of ~26% ~40% of survivors left with permanent neurological deficit (e.g. hearing loss)
28
Pneumococcal meningitis pathogen
Streptococcus pneumoniae
29
Pneumococcal meningitis public health
All cases of pneumococcal meningitis reported to public health No droplet precautions necessary; routine precautions only No chemoprophylaxis for close contacts
30
Pneumococcal meningitis immunizations
Routine infant immunization: Pneumococcal conjugated vaccine (Pneu-C-13; Prevnar13) Pneumococcal polysaccharide vaccine (Pneu-P-23; Pneumovax 23) All Individuals ≥ 65 years of age Individuals at increased risk for invasive pneumococcal disease (pneumonia, bacteremia, meningitis) ≥ 2 years of age
31
Pneumococcal meningitis vulnerable populations
All populations are vunerable
32
Meningococcal meningitis pathogen
Neisseria meningitidis
33
Meningococcal meningitis: how is it aquired
steal iron to grow and produce, produce endotoxins and through blood they cross blood brain barrier and gain access to meninges. Have a capsule as well. Come through nasopharynx
34
Meningococcal meningitis who is vulnerable
Mostly, kids, adolescents and young adults. Only in some of us Behaviour (we are all social)
35
Most common serogroups of Meningococcal meningitis
Serogroups A, B, C, Y and W-135 most common in Canada
36
Meningococcal meningitis: Endotoxin production
Chills, fever, weakness, generalized aches, petechial rash | Endotoxic shock & disseminated intravascular coagulation
37
Meningococcal meningitis Public health implications
All cases of must be reported to public health All suspected or possible cases of meningococcal meningitis should be placed in respiratory isolation for 24 hrs post targeted antibiotic therapy Special attention to "close contacts" Household, child care facility, nursery school contacts Individuals in contact with the patient's oral secretions or who frequently ate/slept in the same dwelling within 7 days of disease onset
38
Meningococcal meningitis Vaccinces
Men-C-C; Serogroup C only (2 months - 11 years of age) Men-C-ACYW; Serogroups A, C, Y, W-135 (Grade 7), more groups (serogroup b most common because not in plan) Bexsero: Serogroup B only (2 months - 17 years of age, cost, not covered) Close contacts should be immunized and also receive chemoprophylaxis Rifampin (all ages) or ciprofloxacin (>18 years of age)
39
Haemophilus Influenza
- gram negative - responsible for cases in Canada in the 80s - After vaccines, dropped 94%
40
Haemophilus Influenza vulnerable populations
people who are immigrants (don`t immunize) or people who don`t immunize
41
Haemophilus Influenza public health
All cases must be reported to public health Transmitted via respiratory droplets Suspected or possible cases of H. influenzae meningitis; respiratory isolation 24hrs post targeted antibiotic therapy Close contacts should receive chemoprophylaxis (rifampin) & immunization
42
Listeriosis pathogen
Listeria monocytogenes
43
Listeriosis transmission
Ingestion of contaminated soft cheeses and deli meats
44
Listeriosis vunerable population
extremes of age (new borns and elders) | -pregnant women
45
Listeriosis public health implications
Routine precautions | Wash foods well, avoid unpasteurized foods and deli meats when pregnant or at extremes of age
46
Group B streptoccocus
Can cause meningitis. Only 1 - 3 % of babies actually get it.
47
Group B streptoccocus risks
If a baby is born premature, we don`t swab so there is a high risk. If the baby is labour for longer there is also a risk
48
Group B streptoccocus protection
- All women should be swabbed for this at week 35 - 37. If they are positive, we can make a plan - blood culture from the baby or assuming and treat with antibiotics can help with protection
49
Group B streptoccocus population
common in neonates, 30 % of women colonized with it in the vagina, transmitted during child
50
Group B streptoccocus antibiotics
give antibiotics at time of labour, 2 hours, 4 hour apart, last dose 2 hours before delivery
51
Group B streptoccocus antibiotics
give antibiotics at time of labour, 2 hours, 4 hour apart, last dose 2 hours before delivery
52
Bacterial Meningitis Treatment
Bactericidal antibiotic therapy: - after lumbar puncture - after blood is drawn - targeted to organism - needs to cross blood brain barrier
53
Bacterial Meningitis General treatment regimen
-corticosteriods -Dexamethasone co-administered with antibiotic therapy (controls inflammation) Decreased risk of death No increase in adverse events Supportive measures Antipyretics, fluids & electrolytes, nutritional support
54
Viral Meningitis
- less acute illness - Enteroviruses (Coxsackie B, Echovirus), Herpes Simplex Virus - supportive therapy, not many anti virals
55
Enteroviruses
Responsible for ~85% of viral meningitis cases in Canada Mode of Transmission: Direct contact & fecal-oral route, most common in summer and fall Self-limited illness in most patients (immunocompetent) Duration of illness typically 7 - 10 days
56
Meningoencephalitis
inflammation of the meninges and brain
57
main cause of encephalitis
viral, somebacterial, fungal and protozoal causes also observed
58
encephalitis manifestations
Hallmarks of brain involvement in infectious processes -Changes in level of consciousness, altered mental status -Neurologic signs (seizures, confusion, behavioral changes, cranial nerve palsies) Classic clinical triad of encephalitis -Fever, headache, altered level of consciousness Neurological symptoms -Disorientation, focal neurologic deficits, seizures CSF lab values (viral): - Increased protein - Increased lymphocytes - Normal glucose - Cultures, CSF analysis, serology
59
How is encephalitis accessed
Viruses most commonly access the brain via bloodstream
60
encephalitis transmission
``` Respiratory tract (e.g. measles, mumps, varicella zoster) Gastrointestinal tract (e.g. poliovirus, enterovirus) Genital tract (e.g. HSV) Subcutaneous tissues (e.g. arbovirus such as West Nile) ```
61
why is viral encephalitis more dangerous then viral meningitis
associated with more intracranial pressure
62
Viral Encephalitis- HSV
Most common cause of non-epidemic encephalitis in Canada Past neonatal period, most infections caused by HSV-1 30% < 20 years of age, 50% > 50 years of age Prognostic factors include age, duration of symptoms and Glasgow Coma Scale measurement at time of treatment
63
Viral Encephalitis- HSV manifestaions
Focal temporal lobe symptoms most common | Visual field cut, hemiparesis, aphasia
64
Viral Encephalitis- HSV Treatment
Acyclovir reduces overall mortality to 28% at 18 months post treatment Patients should be treated presumptively for HSV encephalitis until an alternate pathogen is detected Otherwise, supportive therapy; corticosteroids in some cases
65
Brain abscess clinical manifestations
- varies because depends on the area (memory, vision) | - most people have headache, mental status change or a sensory deficit
66
Brain abscess most involved pathogen
streptococci
67
brain abscess diagnosis
Brain imaging is the cornerstone diagnostic approach Characteristic findings on CT scan Hypo-dense center with an peripherally uniform ring of enhancement following the injection of contrast material CT guided aspiration aids in establishing microbiologic diagnosis
68
Brain Abcess - treatment
Surgical intervention helps to reduce pressure Infection can be treated without surgery, if the origin of the infection is identified, and the diameter of the abscess is less than 2.5 cm -Antimicrobial therapy directed at suspected organisms Empiric therapy should be narrowed in spectrum when culture results are available Aspiration or surgical excision of abscess Corticosteroids are warranted in cases of increased intracranial pressure or significant edema

Microbiology (7 decks)

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