CD - iGAS, HiB, Var

Question 1

what is the agent for invasive group A streptococcus (iGAS) (1)

Answer 1

1- streptococcus pyogenes

Question 2

which age groups are most commonly affected by iGAS (2)

Answer 2

1- young children less than 5yo
2- adults 65+

Question 3

what is the seasonal pattern for iGAS? (2)

Answer 3

1- peak during the winter and early spring
2- decrease over the summer

Question 4

what are risk factors for acquiring iGAS
(‘host factor’- 1
‘medical condition’- 5;
‘SDoH’- 2;
‘close contact’- 1)

(9)

Answer 4

1- age: children <5 yo & adults 65+
2- chronic diseases (e.g. pulm, cardiac, liver, DM )
3- immunocompromise (e.g. HIV, cancer)
4- open wounds or breaks in the skin (e.g. cuts, burns, varicella/shingles)
5- recent infection with chickenpox or resp viruses
6- during childbirth, post-partum post-surgical
7- living in a crowded environment (e.g. dorms, shelters, barracks)
8- substance use, including IV drugs, alcohol use
9- recent close contact GAS or iGAS case

Question 5

what is the reservoir for iGAS (1)

Answer 5

1- humans

Question 6

what is the mode of transmission for iGAS (2)

Answer 6

1- direct/indirect contact (with infectious resp secretions, or wound/lesion exudates)
2- sharing of contaminated needles

Question 7

what is the incubation period for iGAS (varies by site of entry) (3)

Answer 7

From shortest to longest:
1- 24-48 hours for STSS (strep toxic shock syndrome)
2- 1-3 days for pharyngitis (non-invasive)
3- 7-10 days for impetigo (non-invasive)

Question 8

what is the communicable period for iGAS (2)

Answer 8

1- 7 days prior to the onset of symptoms, until 24 hours after the start of antibiotics
2- 10-21 days for untreated impetigo

Question 9

where is GAS colonized in asymptomatic carriers? (4)

Answer 9

1- nasopharynx
2- skin
3- vagina
4- perianal area

Question 10

what are 2 examples of non-invasive GAS disease? (2)

Answer 10

1- strep throat
2- impetigo

Question 11

what is the clinical presentation of strep throat (4)

Answer 11

1- fever
2- exudative tonsilitis
3- lymphadenopathy
4- rare complications: rheumatic fever, rheumatic heart disease, scarlet fever (sandpaper rash)

Question 12

what is the clinical presentation of impetigo (1)

Answer 12

1- vesicles –> pustules –> honey-coloured crusted lesions

Question 13

what makes a disease presentation of GAS invasive (1)

Answer 13

1- when the infection is in deep tissues or organs that are otherwise sterile

Question 14

what makes a case of iGAS severe? (5)

Answer 14

1- cases of STSS (streptococcal toxic shock syndrome)
2- soft-tissue necrosis including necrotizing fasciitis, myositis, or gangrene
3- meningitis
4- GAS pneumonia
5- confirmed case resulting in death

Question 15

what are some examples of iGAS disease that are not severe (2)

Answer 15

1- septic arthritis
2- bacteremia

Question 16

what are the criteria for having STSS (1, 2abcde)

Answer 16

1- hypotension (SBP <90 for adults; <5th %ile for children)

AND AT LEAST 2 OF:
2a- renal impairment (creatinine level ≥ 177 for adults)
2b- coagulopathy (platelet count ≤ 100,000 or disseminated intravascular coagulation)
2c- liver function abnormality (AST, ALT or total bilirubin ≥ 2x upper limit of normal)
2d- adult respiratory distress syndrome
2e- generalized erythematous macular rash that may desquamate

Question 17

iGAS case mgmt: what does hospital mgmt entail, briefly (3)

Answer 17

1- culture of affected site
2- treatment (e.g. penicillin)
3- contact/droplet precautions until 24h post-antibiotic initiation

Question 18

iGAS case mgmt: what information would you require on history from a case, assessing potential source and potential to spread (3)

Answer 18

1- history of varicella
2- occupation
3- attendance at daycare/institution

Question 19

iGAS case mgmt: how long should iGAS cases self-isolate in the community (1)

Answer 19

1- those with strep pharyngitis (especially kids) should isolate until 24h post-antibiotic initiation

Question 20

iGAS contact mgmt: what is the definition of a ‘contact’ (1, 2abcd)

Answer 20

1- exposure from 7d prior to case’s symptom onset to 24h after initiation of antibiotics
AND MEET ANY OF THESE CRITERIA:

2a- household contact (spent 4h/d in the last 7 days, or 20h/wk with the case)
2b- non-household contact who share same bed or have sexual relations with case
2c- contact with direct exposure to case’s oral/nasal secretions (e.g. kissing)
2d- IVDU who have shared needles with a case

Question 21

who are usually not considered contacts of iGAS case unless they meet the previously-described criteria

Answer 21

1- School classmates (kindergarten and older)
2- work colleagues
3- social or sports contacts

Question 22

iGAS contact mgmt: who is chemoprophylaxis given to (generally) (1)

Answer 22

1- only to close contacts of a confirmed severe case

Question 23

iGAS contact mgmt: what is chemoprophylaxis for close contacts of a severe iGAS case (1) and what is its purpose (1)

Answer 23

1- first gen cephalosporin (cephalexin)
2- purpose is to eradicate nasopharyngeal colonization of GAS and prevent disease

Question 24

iGAS contact mgmt: what general education would you give to close contacts (2)

Answer 24

1- monitor for signs/symptoms of iGAS
2- seek immediate medical attention should they develop

Question 25

what is the agent for HiB (1)

Answer 25

1- haemophilus influenzae serotype B (encapsulated)

Question 26

what’s the difference between encapsulated vs. non-encapsulated Haemophilus influenzae (Hi) (2)

Answer 26

1- Encapsulated strains (a to f) are more likely to invade normally sterile sites, causing invasive disease
2- non-encapsulated strains generally cause milder infections

Question 27

what serotype of Hi is the most pathogenic (1)

Answer 27

1- Hib is the most pathogenic strain, which caused 95% of the disease before vaccine programs were introduced in 1988

Question 28

in which age groups is Hib incidence the highest (2)

Answer 28

1- infants <1yo
2- children <5yo

Question 29

how does knowing the most impacted age groups affect vaccination programming for Hib? (1)

Answer 29

1- this is why Hib vaccination is given at 2, 4, 6 months and again around 18mo so that the protection is gained around/before time of increase infection risk

Question 30

what are risk factors for acquiring Hib -
(‘medical conditions- 2
‘SDoH’- 5)

(7)

Answer 30

1- all transplant/cochlear implant recipients
2- medical conditions/immunosuppressed status increase risk of invasive disease (asplenia, primary immunodeficiency, HIV, malignant hematologic disorders)
3- Large household size/crowding
4- Child care attendance
5- Low socioeconomic status
6- School-aged siblings
7- from Inuit community

Question 31

what is the reservoir for Hib (1)

Answer 31

1- humans

Question 32

what is the mode of transmission for Hib (1)

Answer 32

1- direct or indirect contact (with respiratory droplets)

Question 33

what is the incubation period for Hib (1)

Answer 33

1- 2-4 days

Question 34

what is the communicable period for Hib (2)

Answer 34

1- unknown duration
2- risk of infection persists as long as organisms are present in nasal discharge until 24-48h after starting antibiotics

Question 35

can people be colonized with Hib, i.e. be asymptomatic carriers (1)

Answer 35

1- yes, asymptomatic colonization is common

Question 36

what is an example of a disease presentation of non-invasive Hib (1)

Answer 36

1- acute otitis media

Question 37

what are examples of disease presentations of invasive Hib (6)

Answer 37

1- bacterial meningitis
2- epiglottitis
3- pneumonia
4- cellulitis
5- septic arthritis
6- bacteremia

Question 38

what is the case fatality rate for Hib meningitis (1)

Answer 38

1- 5% case fatality rate

Question 39

what are some complications of Hib infection (5)

Answer 39

1- permanent hearing loss
2- paralysis
3- seizures
4- permanent neurological impairment
5- death

Question 40

what is the efficacy of Hib vaccine (1)

Answer 40

1- childhood series is 95-100% effective

Question 41

what is the primary series schedule for Hib vaccine (1)

Answer 41

1- 2, 4, 6 months and 18 months

Question 42

what is the schedule for Hib vaccine for high risk individuals, specifically children (2)

Answer 42

1- children age 5-17 can get a single dose of Hib vaccine regardless of prior vaccination history
2- this single dose should be at least 1 year apart from any previous Hib dose

Question 43

Hib case mgmt: what are 3 general steps to take as part of case mgmt (3)

Answer 43

1- history: symptom onset, immunization status, serotype of Hi
2- contact history, specifically childcare attendance or work
3- treatment

Question 44

Hib case mgmt: what is the treatment for Hib (3)

Answer 44

1- cefotaxime or ceftriaxone
2- cases <2yo or who are a member of a household with a susceptible contact should get rifampin prior to hospital d/c as well, if cefotax/ceftriax were not used for treatment
3- initiate antibiotics immediately to eliminate Hib colonization

Question 45

Hib contact mgmt: what is the definition of a contact (1)

Answer 45

1- spending 4+ hours/day with case, for at least 5 out of 7 days preceding the day of case’s hospital admission

Question 46

Hib contact mgmt: what is chemoprophylaxis for contacts (1)

Answer 46

1- give rifampin ASAP

Question 47

Hib contact mgmt: why does Hib chemoproph need to be given ASAP (2)

Answer 47

1- this is because most cases in households occur in the first week after hospitalization of the index case
2- chemoproph is recommended to eliminate NP carriage of Hib bacteria and prevent secondary transmission

Question 48

Hib contact mgmt: in what circumstances can secondary transmission of Hib from a contact to others around them occur -
(‘household’- 3)

Answer 48

1- all households (HH) with at least one susceptible contact under 4yo who is under/unimmunized
2- all HH with a child <12mo old who has not received the primary vaccine series
3- all HH with an immunocompromised child, regardless of child’s Hib immunization status

Question 49

Hib contact mgmt: in what circumstances can secondary transmission of Hib from a contact to others around them occur -
(‘childcare’- 2)

Answer 49

1- childcare settings (CC) if one case of invasive Hib disease has occurred - give chemoproph to under/unimmunized kids <4yo
2- in CC if 2+ cases have occurred within 60 days and under/unimmunized kids attend the facility, all attendees/providers should get chemoproph

Question 50

Hib contact mgmt: who should be offered immunoprophylaxis (1)

Answer 50

1- all susceptible contacts who are under/unimmunized against Hib should be offered Hib primary series completion