Infecto 1 Flashcards
Meningococcus/Enterovirus
Neisseria meningitidis is a commensal of the human _____
Nasopharynx; 10% of the population are colonized
N. meningitidis is a gram _____; encapsulated; oxidase-_____; aerobic/anaerobic; diplococcus
negative; positive; aerobic
What allows for the definition of the 12 serological capsular groups?
Differences in the chemistry of the polysaccharide capsule
MeningoD; Name the 6 serological types responsible for almost all cases of disease:
A; B; C; W; X; Y
Outbreaks are usually caused by multiple strains (T/F)
False; most outbreaks are clonal; caused by single strains
How is N. meningitidis transmitted?
Aerosol droplets and respiratory secretions; cant survive for long in the enviroment
MeningoD; Carriage peaks during _____ (age period)
adolescence and young adulthood
Highest rate of meningococcal disease occurs in: (age)
Infants <1yr; immunologic inexperience
Most cases of meningococcal d. in <1yr are caused by wich strain?
B strain
After 1yr which strain causes meningo d.?
85% are caused by B and C strains; remainder by Y
MeningoC; Disease occurs ____ after acquisition of the pathogen.
1-14d
How does N. meningitidis circumvents secretory IgA?
Invasive bacteria secretes IgA A1 “protease”
Resistance to complement-mediated lyses and phagocytosis is mediated by
Polysaccharide capsule and “lipopolysaccharide”
Most of the tissue damage in meningo d. is caused by
host immune mechanisms activated by meningo d. components (LPS)
Capillary leak syndrome is explained by:
microvascular injury that leads to increased vasc permeability
Main complication of Capillary leak Sd:
Pulmonary edema
Which cytokine has a negative effect on myocardial contractility?
IL-6
N. meningitidis can penetrate the blood-brain barrier (T/F)
True; this is facilitated by pili and possibly Opc (Opsonization protein C)
Cite the two main mechanisms CNS damage occurs by:
Direct meningeal inflammation and indirectly by circulatory collapse
Main neurological cause of death in meningo d.
increased intracranial pressure > herniation
Levels of Serum Bactericidal Antibody are highest and lowest:
Highest at birth and amog adults; lowest between 6m and 2yr
Nonpathogenic Neisseria can elicit natural antibodies (T/F)
True; N. lactamica and others can estimulate antibodies production
MeningoD; Serum bactericidal antibody is ____ dependent
Complement
Complement deficiencies increase menigo d. risk up to:
1000-fold
Monoclonal antibody against complement prot C5
Eculizumab; increases risk of meningo d.
For paroxysmal nocturnal hemoglobinuria & atypical hemolytic uremic Sd
Most common form of meningococcal infection:
Asymptomatic carriage in the nasopharynx
Main presentation of “invasive” meningo d.
Meningitis; 30-50% of cases
Clinical presentations of invasive meningo d. other than meningitis (5)
Bacteremia; meningo septicemia; pneumonia; chronic meningo; occult bacteremia
Describe initial rash in meningo d.
Maculopapular; indistinguishable from viral rashes; 10% of cases
MeningoD; Rash that develops in 80% of cases:
Nonblanching or petechial rash
Fulminant meningo d. skin lesion:
prominent petechiae and “purpura”; also known as purpura fulminans
Most children <5yrs report headache during meningo meningitis (T/F)
False; most infants do not report headache
Seizures occurs less frequently in meningitis by meningococcus (T/F)
True; seizures more common in pneumococcus and haemophilus b
Serotype that can cause a meningo”encephalitis” like case:
Group A
Simptoms of “chronic” meningococcemia: (6)
fever; nontoxic appearance; arthralgia; headache; splenomegaly; maculopapular petechial rash
Mean duration of chronic meningo:
6-8 wks; cultures may be sterile; sulfonamide therapy is a risk factor
First line of ATB for suspected menigo d.
Third gen Cephalosporin (Ceftriax)
Offers protection against pneumococcus and H. influenzae
Meningo D; When should vancomycin shold be considered as aditional ATB?
Local high rate of B-lactam-resistant pneumococcus
Necrotic skin lesions are less frequent when this ATB is used
Ceftriaxone
Meningococcal disease; Recommended treatment duration
5-7 days
Decreased susceptibility to penicillin in meningo d. is caused by:
Altered penicillin-binding protein 2; doesn’t seem to affect response to therapy
Because of pulmonary edema; ETI is recommended after
40ml/kg with compensated shock; reduces work of breathing
CTC are recommended in meningo meningitis (T/F)
False; alhough used in meningitis by h influenzae; no data supports use in meningo .d
Which viral infection usually reactivates during meningo infection?
Latent herpes simplex
Immune complex vaculitis may occur at wich point of meningo .d
First 10 days
Most commmon complication of severe meningo septicemia
Focal skin infarction; typically lower limbs
Most frequent neurologic sequela of meningo meningitis
Deafness; 5-10%
MeningoD; Profilaxis is indicated for:
Close contacts; contact with oral secretions
MeningoD; Up to ___ occur in the first week after the index case but the risk persists for up to ___
30%; 1yr
Drugs used in profilaxis:
Ceftriaxone; ciprofloxacin; rifampin (doesn’t erradicate colonization in 15%)
Profilaxis is recommended for medical personel (T/F)
False; only if exposure to aerosols (mouth to mouth; intubation; suctioning) before 24h of atb
MeningoD; Type of contact precaution:
Droplet infection control for 24h
Why are Meningo D booster doses recommended during adolescence?
Antibody levels wane after infant immunization
Meningo vaccine for adolescents
Men “ACWY”; single dose
Enteroviruses are ___; ___ stranded; in the picornaviridae family
nonenveloped; single; Picorna = Small RNA
Enteroviruses are part of the picornaviridae along with: (3)
Rhinoviruses; hep A; Paraechoviruses
Enteroviruses have 4 species:
A-B-C-D
Enteroviruses; Although more than 100 types…
Only 10-15 causes most cases
Enterovirus; ___ can cause similar clinical presentations
Paraechoviruses
Enterovirus; responsible for ___ of acute febrile illnesses and ___ of hospitalizations for suspected sepsis
33-65%; 55-65%
Enterovirus; More than ___ occur in children tounguer than __ of age
25%; 1year
Enterovirus; Breastfeeding increases/reduces risk for infection
Reduces; likely via enterovirus-specific antibodies
Enterovirus; Spreading occurs by
fecal-oral and respiratory; hemorrhagic conjunctivitis may spread airborne
Enterovirus; Vertical transmission along with ___ and ___ are possible
peripartum; breastfeeding
Enterovirus; can survive on enviromental surfaces T/F
True; transmission via “fomites”
Enterovirus; Incubation period is tipically ___
3-6 days; except for 1-3 day in acute hemorrhagic conjunctivitis
Enterovirus; respiratory shedding occurs for ___ and fecal continues for ___
<1-3wks; 7-11wks
Enteroviruses; Survival in the GI tract is favored by:
Acid stability
Enterovirus; Primary; transient viremia (minor) results in…
Spread to distant parts of the reticuloendothelial system
Enterovirus; Damage can occur in different organs such as: (8)
CNS; Heart; Liver; Pancreas; Lungs; Muscles; Kidneys; Skin
Enterovirus; CNS infections have ___ in the CSF
Pleocytosis; macrophages and T lymphocytes
Enterovirus; Encephalitis is associated to ___ species
A71; can complicate with pulmonary edema/hemorrhage/pneumonitis
Enterovirus; Mechanism postulated as responsible for neurologic damage in A71 infection
Immunologic cross-reactivity
Enterovirus; Myocarditis is characterizes by…
Perivascular and intesrstitial inflammatory infiltrates and myocyte dmg
Enterovirus; In utero infections are characterized by (2)
Placentitis and infections of multiple fetal organs
Enterovirus; Most important immune defense:
Developmento of type-specific neutralizing antibodies
Enterovirus; Heterotypic antibodies may…
Enhance disease by a different serotype
Enterovirus; Hypo/Agammaglobulinemia predispose to…
severe; chronic infections
Enterovirus; A71 diseas increases after ___ mo of age
6; maternal antibodies level decline
Enterovirus; Symptomatic diseas is more common in…
Young children
Enterovirus; Mot common symptomatic manifestation:
Nonespecific febrile illness
Enterovirus: Illness usually begins ___ with fever of ___; malaise; irritability
abruptly; 38.5-40
Enterovirus; Meningitis may be present but…
Specific clinical features such as meningeal findings or bulging fontanelle are absent
Enterovirus; Fever lasts a mean of __ days
3; can be biphasic
Enterovirus; Ilness lasts a mean of ___ days but can range from ___
4-7; 1 day to >1wk
Enterovirus; WBC count is generally normal but transient ___ can be seen
Neutropenia; concomitant bacterial infection is rare but possible
Enterovirus; Skin manifestations can include: (5)
Macular; maculopapular; urticarial; vesicular; petechiae
Enterovirus; Frequency of cutaneous manifestations is ___ related to age
Inversely
Enterovirus; Serotypes associated with rashes are: 4
Echoviruses; coxsackie A; coxsackie B; A71
Enterovirus; Coxsacke A16 causes
Hand-foot-and-mouth disease; A71; Cox B and some echoviruses are also implicated
Enterovirus; H-F-M disease courses with high fever T/F
False; usually low-grade or without fever and mild illness
Enterovirus; H-F-M disease can also have lesions in __ and ___
Buttocks and groin
Enterovirus; Coxsackie A6 is responsible for relatively severe ___ disease and ___
H-F-M; herpangina; can present desquamation of palms and soles and nails (onychomadesis)
Enterovirus; H-F-M disease can complicate with (5)
Encephalitis; acute flaccid paralysis; myocarditis; pericarditis; shock
Enteroviru; Herpangina is characterized by… (4)
Sudden fever; sore throat; dysphagia; “painful lesions in the posterior pharynx
Enterovirus; Herpangina is associated with __ and ___ viruses
A71; Coxsackie A; others can be implicated
Enterovirus; Related to outbreaks of pneumonia and wheezing
Enterovirus D68
Enterovirus; Bornholn disease consists of:
Pleurodynia; caused mainly by cox B and echoviruses; paroxismal thoracic pain
Enterovirus; Acute hemorrhagic conjunctivitis are caused by…
Enterovirus D70 and cox A24; explosive and highly contagious
Enterovirus; Acute hemorrhagic conjunctivitis clinical features include sudden and severe eye pain and…
Photophobia; blurred vision; lacrimation; conjunctival erythema; lid edema; preauricular adenophaty and subconjuntival hemorrhage
Enterovirus; Acute hemorrhagic conjunctivitis due to D70 hallmark symptom
Subconjunctival hemorrhage; more rare with cox virus
Enterovirus; Acute hemorrhagic conjunctivitis eye discharge is initially serous but…
Can become mucopurulent with secondary bacterial infection
Enterovirus; ___ cases of myocarditis and pericarditis of proven etiology
25-35%; Coxsackie B mostly; Cox A and echo also
Enterovirus; Mio/pericarditis shows ___ on echography (3)
Ventricular dilation; reduced contractility; pericardial effusion
Enterovirus; Myo/pericarditis; Enzimes are often…
elevated
Enterovirus; Associated to orchitis:
Coxsackie B; often biphasic; fever and preurodynia or meningitis may precede orchitis by 2 weeks
Enterovirus; Most common cause of viral meningitis in ___-immunized populations
Mumps; 90% of cases; Cox B; Echo; D70; A71
Enterovirus; CSF in meningitis predominates ___ in the first 48h before becoming mostly ___
Polymorphonuclear; mononuclear
Enterovirus; Normal CSF rules out meningitis T/F
False; can be normal in up to half of cases despite detection of enterovirus in CSF
Enterovirus; __ of cases of encephalitis with an identified cause
10-20%; Echo; Cox A; A71
Enterovirus; Acute flaccid myelitis syndome:
Flaccid limb weakness; MRI abnormal spinal cord gray matter;
Enterovirus; Neonatal infections are tipically caused by…
Cox B; Echoviruses
Enterovirus; Neonatal symptoms can occur as early as __ and severe disease generraly develops within ___
1st day of life; 2wks
Enterovisus; Traditionally; ___ has been used to confirm infection
Cell lines viral culture; Sensitivity ranges from 50-75%
Enterovirus; PCR testing for suspected meningitis decreases diagnostic tests; ___ ; ___ and ___
hospital stay time; ATB use; overall cost
Enterovirus; Paraechovirus __ and __ are the most comon causes of symptomatic infection
1; 3
Enterovirus; Paraechovirus CNS infection has CSF __
Normal celullarity
Enterovirus; Paraechovirus rash is descrived as:
Rash involving extremities with palm and sole erythema
Enterovirus; Antidepressant that interacts with enterovirus 2C protein
Fluoxetine; in vitro activity against enteroviruses B and D
Enterovirus; Hypogammaglonulinemic patiens have reduced incidence of chronic infection with…
Use of high-dose IV immunoglobulin
Enterovirus; Currently there is a vaccine in phase 3 clinical trials for ___
A71
