CD - iGAS, HiB, Var Flashcards
what is the agent for invasive group A streptococcus (iGAS) (1)
1- streptococcus pyogenes
which age groups are most commonly affected by iGAS (2) - think extremes of age
1- young children less than 5yo
2- adults 65+
what is the seasonal pattern for iGAS? (2)
1- peak during the winter and early spring
2- decrease over the summer
what are risk factors for acquiring iGAS
(‘host factor’- 1 - A
‘medical condition’- 5 - CIWIC
‘SDoH’- 2; - CS
‘close contact’- 1)
(9)
1- age: children <5 yo & adults 65+
2- chronic diseases (e.g. pulm, cardiac, liver, DM )
3- immunocompromise (e.g. HIV, cancer)
4- 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
what is the reservoir for iGAS (1)
1- humans
what is the mode of transmission for iGAS (2)
1- direct/indirect contact (with infectious resp secretions, or wound/lesion exudates)
2- sharing of contaminated needles
what is the incubation period for iGAS (varies by site of disease) (3)
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)
what is the communicable period for iGAS (2)
1- 7 days prior to the onset of symptoms, until 24 hours after the start of antibiotics
2- 10-21 days for untreated impetigo
where is GAS colonized in asymptomatic carriers? (4) - NSVP
1- nasopharynx
2- skin
3- vagina
4- perianal area
what are examples of non-invasive GAS disease? (4) - ESIS
1- erysipelas
2- strep throat
3- impetigo
4- scarlet fever
what is the clinical presentation of strep throat - M-CENTOR (7) - and then rare complications (RRS) (3)
1- M- must be older than 3yo
2- C- cough absent
3- E- exudative tonsillitis/swollen
4- N- nodes - lymphadenopathy in anterior cervical chain
5- T- temperature >38C (febrile)
6- O- often young, <15yo
7- R- rarely older than 45yo
8- rare complications: rheumatic fever, rheumatic heart disease, scarlet fever (sandpaper rash)
what is the clinical presentation of impetigo (1)
1- vesicles –> pustules –> honey-coloured crusted lesions
what makes a disease presentation of GAS invasive (1)
What are examples of iGAS presentations (6) - BM-PANT
1- when the infection is in deep tissues or organs that are otherwise sterile
2- iGAS presentations:
Bacteremia
Meningitis
Pneumonia
Arthritis, septic
Necrosis, soft tissue (e.g. gangrene, necrotising fasciitis)
Toxic Shock Syndrome (TSS)
what makes a case of iGAS severe? (6) - M-PNT + 2
1- meningitis
2- pneumonia
3- necrosis, soft tissue including necrotizing fasciitis, myositis, gangrene
4- toxic shock syndrome
+
5- iGAS resulting in death
6- other life-threatening conditions
what are some examples of iGAS disease that are not severe (2) - B-A
1- septic arthritis
2- bacteremia
what are the criteria for having STSS - (1) - H + two of (2-6) - R-CLAG
1- hypotension (SBP <90 for adults; <5th %ile for children)
AND AT LEAST 2 OF:
2- renal impairment (creatinine level ≥ 177 for adults)
3- coagulopathy (platelet count ≤ 100,000 or disseminated intravascular coagulation)
4- liver function abnormality (AST, ALT or total bilirubin ≥ 2x upper limit of normal)
5- adult respiratory distress syndrome
6- generalized erythematous macular rash that may desquamate
iGAS case mgmt: what information would you require on history from a case, assessing potential source and potential to spread (3)
1- history of varicella
2- occupation
3- attendance at daycare/institution
iGAS case mgmt: how long should iGAS cases self-isolate in the community (1)
1- those with strep pharyngitis (especially kids) should isolate until 24h post-antibiotic initiation
iGAS contact mgmt: what is the definition of a ‘contact’ (1 + one of 2-5 - SHIN)
1- exposure from 7d prior to case’s symptom onset to 24h after initiation of antibiotics
AND MEET ANY OF THESE CRITERIA:
SHIN - secretions, HH contacts >20h/wk, IVDU, Non-HH share bed/sex
2- household contact (spent 4h/d in the last 7 days, or 20h/wk with the case)
3- non-household contact who share same bed or have sexual relations with case
4- contact with direct exposure to case’s oral/nasal secretions (e.g. kissing)
5- IVDU who have shared needles with a case
who are usually not considered contacts of iGAS case unless they meet the previously-described criteria (3) - CCS
Classmates, colleagues, social contacts
1- School classmates (kindergarten and older)
2- work colleagues
3- social or sports contacts
iGAS contact mgmt: who is chemoprophylaxis given to (generally) (1)
1- only to close contacts of a confirmed severe case
iGAS contact mgmt: what is chemoprophylaxis for close contacts of a severe iGAS case (1) and what is its purpose (1)
1- first gen cephalosporin (cephalexin)
2- purpose is to eradicate nasopharyngeal colonization of GAS and prevent disease
iGAS contact mgmt: what general education would you give to close contacts (2)
1- monitor for signs/symptoms of iGAS
2- seek immediate medical attention should they develop
what is the agent for HiB (1)
1- haemophilus influenzae serotype B (encapsulated)
what’s the difference between encapsulated vs. non-encapsulated Haemophilus influenzae (Hi) (2)
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
what serotype of Hi is the most pathogenic (1)
1- Hib is the most pathogenic strain, which caused 95% of the disease before vaccine programs were introduced in 1988
in which age groups is Hib incidence the highest (2)
1- infants <1yo
2- children <5yo
how does knowing the most impacted age groups affect vaccination programming for Hib? (1)
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
what are risk factors for acquiring Hib -
(‘medical conditions- 2
‘SDoH’- 5)
(7)
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
what is the reservoir for Hib (1)
1- humans
what is the mode of transmission for Hib (1)
1- direct or indirect contact (with respiratory droplets)
what is the incubation period for Hib (1)
1- 2-4 days
what is the communicable period for Hib (2)
1- unknown duration
2- risk of infection persists as long as organisms are present in nasal discharge until 24-48h after starting antibiotics
can people be colonized with Hib, i.e. be asymptomatic carriers (1)
1- yes, asymptomatic colonization is common
what is an example of a disease presentation of non-invasive Hib (1)
1- acute otitis media
what are examples of disease presentations of invasive Hib (6)
1- bacterial meningitis
2- epiglottitis
3- pneumonia
4- cellulitis
5- septic arthritis
6- bacteremia
what is the case fatality rate for Hib meningitis (1)
1- 5% case fatality rate
what are some complications of Hib infection (5)
1- permanent hearing loss
2- paralysis
3- seizures
4- permanent neurological impairment
5- death
what is the efficacy of Hib vaccine (1)
1- childhood series is 95-100% effective
what is the primary series schedule for Hib vaccine (1)
1- 2, 4, 6 months and 18 months
what is the schedule for Hib vaccine for high risk individuals, specifically children (2)
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
Hib case mgmt: what are 3 general steps to take as part of case mgmt (3)
1- history: symptom onset, immunization status, serotype of Hi
2- contact history, specifically childcare attendance or work
3- treatment
Hib case mgmt: what is the treatment for Hib (3)
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
Hib contact mgmt: what is the definition of a contact (1)
1- spending 4+ hours/day with case, for at least 5 out of 7 days preceding the day of case’s hospital admission
Hib contact mgmt: what is chemoprophylaxis for contacts (1)
1- give rifampin ASAP
Hib contact mgmt: why does Hib chemoproph need to be given ASAP (2)
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
Hib contact mgmt: in what circumstances can secondary transmission of Hib from a contact to others around them occur -
(‘household’- 3)
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
Hib contact mgmt: in what circumstances can secondary transmission of Hib from a contact to others around them occur -
(‘childcare’- 2)
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
Hib contact mgmt: who should be offered immunoprophylaxis (1)
1- all susceptible contacts who are under/unimmunized against Hib should be offered Hib primary series completion
