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Microbiology > 04- Central nervous system infections > Flashcards

04- Central nervous system infections Flashcards

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Biology 101 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
Q

Bacteria meningitis pathogens

A

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
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26
Q

viral meningitis pathogens

A

Enteroviruses (Coxsackie B)

Herpes Simplex Virus

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27
Q

Pneumococcal meningitis

A

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)

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28
Q

Pneumococcal meningitis pathogen

A

Streptococcus pneumoniae

29
Q

Pneumococcal meningitis public health

A

All cases of pneumococcal meningitis reported to public health
No droplet precautions necessary; routine precautions only
No chemoprophylaxis for close contacts

30
Q

Pneumococcal meningitis immunizations

A

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
Q

Pneumococcal meningitis vulnerable populations

A

All populations are vunerable

32
Q

Meningococcal meningitis pathogen

A

Neisseria meningitidis

33
Q

Meningococcal meningitis: how is it aquired

A

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
Q

Meningococcal meningitis who is vulnerable

A

Mostly, kids, adolescents and young adults. Only in some of us

Behaviour (we are all social)

35
Q

Most common serogroups of Meningococcal meningitis

A

Serogroups A, B, C, Y and W-135 most common in Canada

36
Q

Meningococcal meningitis: Endotoxin production

A

Chills, fever, weakness, generalized aches, petechial rash

Endotoxic shock & disseminated intravascular coagulation

37
Q

Meningococcal meningitis Public health implications

A

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
Q

Meningococcal meningitis Vaccinces

A

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
Q

Haemophilus Influenza

A
  • gram negative
  • responsible for cases in Canada in the 80s
  • After vaccines, dropped 94%
40
Q

Haemophilus Influenza vulnerable populations

A

people who are immigrants (dont immunize) or people who dont immunize

41
Q

Haemophilus Influenza public health

A

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
Q

Listeriosis pathogen

A

Listeria monocytogenes

43
Q

Listeriosis transmission

A

Ingestion of contaminated soft cheeses and deli meats

44
Q

Listeriosis vunerable population

A

extremes of age (new borns and elders)

-pregnant women

45
Q

Listeriosis public health implications

A

Routine precautions

Wash foods well, avoid unpasteurized foods and deli meats when pregnant or at extremes of age

46
Q

Group B streptoccocus

A

Can cause meningitis. Only 1 - 3 % of babies actually get it.

47
Q

Group B streptoccocus risks

A

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
Q

Group B streptoccocus protection

A
  • 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
Q

Group B streptoccocus population

A

common in neonates, 30 % of women colonized with it in the vagina, transmitted during child

50
Q

Group B streptoccocus antibiotics

A

give antibiotics at time of labour, 2 hours, 4 hour apart, last dose 2 hours before delivery

51
Q

Group B streptoccocus antibiotics

A

give antibiotics at time of labour, 2 hours, 4 hour apart, last dose 2 hours before delivery

52
Q

Bacterial Meningitis Treatment

A

Bactericidal antibiotic therapy:

  • after lumbar puncture
  • after blood is drawn
  • targeted to organism
  • needs to cross blood brain barrier
53
Q

Bacterial Meningitis General treatment regimen

A

-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
Q

Viral Meningitis

A
  • less acute illness
  • Enteroviruses (Coxsackie B, Echovirus), Herpes Simplex Virus
  • supportive therapy, not many anti virals
55
Q

Enteroviruses

A

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
Q

Meningoencephalitis

A

inflammation of the meninges and brain

57
Q

main cause of encephalitis

A

viral, somebacterial, fungal and protozoal causes also observed

58
Q

encephalitis manifestations

A

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
Q

How is encephalitis accessed

A

Viruses most commonly access the brain via bloodstream

60
Q

encephalitis transmission

A 
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
Q

why is viral encephalitis more dangerous then viral meningitis

A

associated with more intracranial pressure

62
Q

Viral Encephalitis- HSV

A

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
Q

Viral Encephalitis- HSV manifestaions

A

Focal temporal lobe symptoms most common

Visual field cut, hemiparesis, aphasia

64
Q

Viral Encephalitis- HSV Treatment

A

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
Q

Brain abscess clinical manifestations

A
  • varies because depends on the area (memory, vision)

- most people have headache, mental status change or a sensory deficit

66
Q

Brain abscess most involved pathogen

A

streptococci

67
Q

brain abscess diagnosis

A

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
Q

Brain Abcess - treatment

A

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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