Infecto 1 Flashcards

Meningococcus/Enterovirus

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1
Q

Neisseria meningitidis is a commensal of the human _____

A

Nasopharynx; 10% of the population are colonized

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2
Q

N. meningitidis is a gram _____; encapsulated; oxidase-_____; aerobic/anaerobic; diplococcus

A

negative; positive; aerobic

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3
Q

What allows for the definition of the 12 serological capsular groups?

A

Differences in the chemistry of the polysaccharide capsule

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4
Q

MeningoD; Name the 6 serological types responsible for almost all cases of disease:

A

A; B; C; W; X; Y

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5
Q

Outbreaks are usually caused by multiple strains (T/F)

A

False; most outbreaks are clonal; caused by single strains

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6
Q

How is N. meningitidis transmitted?

A

Aerosol droplets and respiratory secretions; cant survive for long in the enviroment

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7
Q

MeningoD; Carriage peaks during _____ (age period)

A

adolescence and young adulthood

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8
Q

Highest rate of meningococcal disease occurs in: (age)

A

Infants <1yr; immunologic inexperience

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9
Q

Most cases of meningococcal d. in <1yr are caused by wich strain?

A

B strain

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10
Q

After 1yr which strain causes meningo d.?

A

85% are caused by B and C strains; remainder by Y

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11
Q

MeningoC; Disease occurs ____ after acquisition of the pathogen.

A

1-14d

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12
Q

How does N. meningitidis circumvents secretory IgA?

A

Invasive bacteria secretes IgA A1 “protease”

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13
Q

Resistance to complement-mediated lyses and phagocytosis is mediated by

A

Polysaccharide capsule and “lipopolysaccharide”

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14
Q

Most of the tissue damage in meningo d. is caused by

A

host immune mechanisms activated by meningo d. components (LPS)

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15
Q

Capillary leak syndrome is explained by:

A

microvascular injury that leads to increased vasc permeability

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16
Q

Main complication of Capillary leak Sd:

A

Pulmonary edema

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17
Q

Which cytokine has a negative effect on myocardial contractility?

A

IL-6

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18
Q

N. meningitidis can penetrate the blood-brain barrier (T/F)

A

True; this is facilitated by pili and possibly Opc (Opsonization protein C)

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19
Q

Cite the two main mechanisms CNS damage occurs by:

A

Direct meningeal inflammation and indirectly by circulatory collapse

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20
Q

Main neurological cause of death in meningo d.

A

increased intracranial pressure > herniation

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21
Q

Levels of Serum Bactericidal Antibody are highest and lowest:

A

Highest at birth and amog adults; lowest between 6m and 2yr

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22
Q

Nonpathogenic Neisseria can elicit natural antibodies (T/F)

A

True; N. lactamica and others can estimulate antibodies production

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23
Q

MeningoD; Serum bactericidal antibody is ____ dependent

A

Complement

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24
Q

Complement deficiencies increase menigo d. risk up to:

A

1000-fold

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25
Q

Monoclonal antibody against complement prot C5

A

Eculizumab; increases risk of meningo d.

For paroxysmal nocturnal hemoglobinuria & atypical hemolytic uremic Sd

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26
Q

Most common form of meningococcal infection:

A

Asymptomatic carriage in the nasopharynx

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27
Q

Main presentation of “invasive” meningo d.

A

Meningitis; 30-50% of cases

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28
Q

Clinical presentations of invasive meningo d. other than meningitis (5)

A

Bacteremia; meningo septicemia; pneumonia; chronic meningo; occult bacteremia

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29
Q

Describe initial rash in meningo d.

A

Maculopapular; indistinguishable from viral rashes; 10% of cases

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30
Q

MeningoD; Rash that develops in 80% of cases:

A

Nonblanching or petechial rash

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31
Q

Fulminant meningo d. skin lesion:

A

prominent petechiae and “purpura”; also known as purpura fulminans

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32
Q

Most children <5yrs report headache during meningo meningitis (T/F)

A

False; most infants do not report headache

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33
Q

Seizures occurs less frequently in meningitis by meningococcus (T/F)

A

True; seizures more common in pneumococcus and haemophilus b

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34
Q

Serotype that can cause a meningo”encephalitis” like case:

A

Group A

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35
Q

Simptoms of “chronic” meningococcemia: (6)

A

fever; nontoxic appearance; arthralgia; headache; splenomegaly; maculopapular petechial rash

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36
Q

Mean duration of chronic meningo:

A

6-8 wks; cultures may be sterile; sulfonamide therapy is a risk factor

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37
Q

First line of ATB for suspected menigo d.

A

Third gen Cephalosporin (Ceftriax)

Offers protection against pneumococcus and H. influenzae

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38
Q

Meningo D; When should vancomycin shold be considered as aditional ATB?

A

Local high rate of B-lactam-resistant pneumococcus

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39
Q

Necrotic skin lesions are less frequent when this ATB is used

A

Ceftriaxone

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40
Q

Meningococcal disease; Recommended treatment duration

A

5-7 days

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41
Q

Decreased susceptibility to penicillin in meningo d. is caused by:

A

Altered penicillin-binding protein 2; doesn’t seem to affect response to therapy

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42
Q

Because of pulmonary edema; ETI is recommended after

A

40ml/kg with compensated shock; reduces work of breathing

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43
Q

CTC are recommended in meningo meningitis (T/F)

A

False; alhough used in meningitis by h influenzae; no data supports use in meningo .d

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44
Q

Which viral infection usually reactivates during meningo infection?

A

Latent herpes simplex

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45
Q

Immune complex vaculitis may occur at wich point of meningo .d

A

First 10 days

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46
Q

Most commmon complication of severe meningo septicemia

A

Focal skin infarction; typically lower limbs

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47
Q

Most frequent neurologic sequela of meningo meningitis

A

Deafness; 5-10%

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48
Q

MeningoD; Profilaxis is indicated for:

A

Close contacts; contact with oral secretions

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49
Q

MeningoD; Up to ___ occur in the first week after the index case but the risk persists for up to ___

A

30%; 1yr

50
Q

Drugs used in profilaxis:

A

Ceftriaxone; ciprofloxacin; rifampin (doesn’t erradicate colonization in 15%)

51
Q

Profilaxis is recommended for medical personel (T/F)

A

False; only if exposure to aerosols (mouth to mouth; intubation; suctioning) before 24h of atb

52
Q

MeningoD; Type of contact precaution:

A

Droplet infection control for 24h

53
Q

Why are Meningo D booster doses recommended during adolescence?

A

Antibody levels wane after infant immunization

54
Q

Meningo vaccine for adolescents

A

Men “ACWY”; single dose

55
Q

Enteroviruses are ___; ___ stranded; in the picornaviridae family

A

nonenveloped; single; Picorna = Small RNA

56
Q

Enteroviruses are part of the picornaviridae along with: (3)

A

Rhinoviruses; hep A; Paraechoviruses

57
Q

Enteroviruses have 4 species:

A

A-B-C-D

58
Q

Enteroviruses; Although more than 100 types…

A

Only 10-15 causes most cases

59
Q

Enterovirus; ___ can cause similar clinical presentations

A

Paraechoviruses

60
Q

Enterovirus; responsible for ___ of acute febrile illnesses and ___ of hospitalizations for suspected sepsis

A

33-65%; 55-65%

61
Q

Enterovirus; More than ___ occur in children tounguer than __ of age

A

25%; 1year

62
Q

Enterovirus; Breastfeeding increases/reduces risk for infection

A

Reduces; likely via enterovirus-specific antibodies

63
Q

Enterovirus; Spreading occurs by

A

fecal-oral and respiratory; hemorrhagic conjunctivitis may spread airborne

64
Q

Enterovirus; Vertical transmission along with ___ and ___ are possible

A

peripartum; breastfeeding

65
Q

Enterovirus; can survive on enviromental surfaces T/F

A

True; transmission via “fomites”

66
Q

Enterovirus; Incubation period is tipically ___

A

3-6 days; except for 1-3 day in acute hemorrhagic conjunctivitis

67
Q

Enterovirus; respiratory shedding occurs for ___ and fecal continues for ___

A

<1-3wks; 7-11wks

68
Q

Enteroviruses; Survival in the GI tract is favored by:

A

Acid stability

69
Q

Enterovirus; Primary; transient viremia (minor) results in…

A

Spread to distant parts of the reticuloendothelial system

70
Q

Enterovirus; Damage can occur in different organs such as: (8)

A

CNS; Heart; Liver; Pancreas; Lungs; Muscles; Kidneys; Skin

71
Q

Enterovirus; CNS infections have ___ in the CSF

A

Pleocytosis; macrophages and T lymphocytes

72
Q

Enterovirus; Encephalitis is associated to ___ species

A

A71; can complicate with pulmonary edema/hemorrhage/pneumonitis

73
Q

Enterovirus; Mechanism postulated as responsible for neurologic damage in A71 infection

A

Immunologic cross-reactivity

74
Q

Enterovirus; Myocarditis is characterizes by…

A

Perivascular and intesrstitial inflammatory infiltrates and myocyte dmg

75
Q

Enterovirus; In utero infections are characterized by (2)

A

Placentitis and infections of multiple fetal organs

76
Q

Enterovirus; Most important immune defense:

A

Developmento of type-specific neutralizing antibodies

77
Q

Enterovirus; Heterotypic antibodies may…

A

Enhance disease by a different serotype

78
Q

Enterovirus; Hypo/Agammaglobulinemia predispose to…

A

severe; chronic infections

79
Q

Enterovirus; A71 diseas increases after ___ mo of age

A

6; maternal antibodies level decline

80
Q

Enterovirus; Symptomatic diseas is more common in…

A

Young children

81
Q

Enterovirus; Mot common symptomatic manifestation:

A

Nonespecific febrile illness

82
Q

Enterovirus: Illness usually begins ___ with fever of ___; malaise; irritability

A

abruptly; 38.5-40

83
Q

Enterovirus; Meningitis may be present but…

A

Specific clinical features such as meningeal findings or bulging fontanelle are absent

84
Q

Enterovirus; Fever lasts a mean of __ days

A

3; can be biphasic

85
Q

Enterovirus; Ilness lasts a mean of ___ days but can range from ___

A

4-7; 1 day to >1wk

86
Q

Enterovirus; WBC count is generally normal but transient ___ can be seen

A

Neutropenia; concomitant bacterial infection is rare but possible

87
Q

Enterovirus; Skin manifestations can include: (5)

A

Macular; maculopapular; urticarial; vesicular; petechiae

88
Q

Enterovirus; Frequency of cutaneous manifestations is ___ related to age

A

Inversely

89
Q

Enterovirus; Serotypes associated with rashes are: 4

A

Echoviruses; coxsackie A; coxsackie B; A71

90
Q

Enterovirus; Coxsacke A16 causes

A

Hand-foot-and-mouth disease; A71; Cox B and some echoviruses are also implicated

91
Q

Enterovirus; H-F-M disease courses with high fever T/F

A

False; usually low-grade or without fever and mild illness

92
Q

Enterovirus; H-F-M disease can also have lesions in __ and ___

A

Buttocks and groin

93
Q

Enterovirus; Coxsackie A6 is responsible for relatively severe ___ disease and ___

A

H-F-M; herpangina; can present desquamation of palms and soles and nails (onychomadesis)

94
Q

Enterovirus; H-F-M disease can complicate with (5)

A

Encephalitis; acute flaccid paralysis; myocarditis; pericarditis; shock

95
Q

Enteroviru; Herpangina is characterized by… (4)

A

Sudden fever; sore throat; dysphagia; “painful lesions in the posterior pharynx

96
Q

Enterovirus; Herpangina is associated with __ and ___ viruses

A

A71; Coxsackie A; others can be implicated

97
Q

Enterovirus; Related to outbreaks of pneumonia and wheezing

A

Enterovirus D68

98
Q

Enterovirus; Bornholn disease consists of:

A

Pleurodynia; caused mainly by cox B and echoviruses; paroxismal thoracic pain

99
Q

Enterovirus; Acute hemorrhagic conjunctivitis are caused by…

A

Enterovirus D70 and cox A24; explosive and highly contagious

100
Q

Enterovirus; Acute hemorrhagic conjunctivitis clinical features include sudden and severe eye pain and…

A

Photophobia; blurred vision; lacrimation; conjunctival erythema; lid edema; preauricular adenophaty and subconjuntival hemorrhage

101
Q

Enterovirus; Acute hemorrhagic conjunctivitis due to D70 hallmark symptom

A

Subconjunctival hemorrhage; more rare with cox virus

102
Q

Enterovirus; Acute hemorrhagic conjunctivitis eye discharge is initially serous but…

A

Can become mucopurulent with secondary bacterial infection

103
Q

Enterovirus; ___ cases of myocarditis and pericarditis of proven etiology

A

25-35%; Coxsackie B mostly; Cox A and echo also

104
Q

Enterovirus; Mio/pericarditis shows ___ on echography (3)

A

Ventricular dilation; reduced contractility; pericardial effusion

105
Q

Enterovirus; Myo/pericarditis; Enzimes are often…

A

elevated

106
Q

Enterovirus; Associated to orchitis:

A

Coxsackie B; often biphasic; fever and preurodynia or meningitis may precede orchitis by 2 weeks

107
Q

Enterovirus; Most common cause of viral meningitis in ___-immunized populations

A

Mumps; 90% of cases; Cox B; Echo; D70; A71

108
Q

Enterovirus; CSF in meningitis predominates ___ in the first 48h before becoming mostly ___

A

Polymorphonuclear; mononuclear

109
Q

Enterovirus; Normal CSF rules out meningitis T/F

A

False; can be normal in up to half of cases despite detection of enterovirus in CSF

110
Q

Enterovirus; __ of cases of encephalitis with an identified cause

A

10-20%; Echo; Cox A; A71

111
Q

Enterovirus; Acute flaccid myelitis syndome:

A

Flaccid limb weakness; MRI abnormal spinal cord gray matter;

112
Q

Enterovirus; Neonatal infections are tipically caused by…

A

Cox B; Echoviruses

113
Q

Enterovirus; Neonatal symptoms can occur as early as __ and severe disease generraly develops within ___

A

1st day of life; 2wks

114
Q

Enterovisus; Traditionally; ___ has been used to confirm infection

A

Cell lines viral culture; Sensitivity ranges from 50-75%

115
Q

Enterovirus; PCR testing for suspected meningitis decreases diagnostic tests; ___ ; ___ and ___

A

hospital stay time; ATB use; overall cost

116
Q

Enterovirus; Paraechovirus __ and __ are the most comon causes of symptomatic infection

A

1; 3

117
Q

Enterovirus; Paraechovirus CNS infection has CSF __

A

Normal celullarity

118
Q

Enterovirus; Paraechovirus rash is descrived as:

A

Rash involving extremities with palm and sole erythema

119
Q

Enterovirus; Antidepressant that interacts with enterovirus 2C protein

A

Fluoxetine; in vitro activity against enteroviruses B and D

120
Q

Enterovirus; Hypogammaglonulinemic patiens have reduced incidence of chronic infection with…

A

Use of high-dose IV immunoglobulin

121
Q

Enterovirus; Currently there is a vaccine in phase 3 clinical trials for ___

A

A71