Immunization and Infectious Disease volume 3 Flashcards
Which of the following is true?
a) rapid HIV testing is the standard of care to diagnose HIV in Canada
b) The window period for HIV seroconversion is 4-6 weeks
c) If EIA is negative then the patient is confirmed HIV negative
d) Western blot is licensed in Canada for HIV 2 detection only
b) true 4-6 weeks between infection and detectable antibodies by enzyme immunoassay, fourth generation enzyme immunoassay will shorten the window period
the rest are false
a) false - The standard approach to diagnosing HIV in Canada is multistep enzyme immunoassay (EIA). rapid HIV tests must give a result in 30 minutes but need to be confirmed by traditional serology tests, acceptable sensitivity and specificity, good for high risk women in pregnancy
c) if EIA is negative then a confirmatory test such as western blot or line immunoassay should be done
d) false - for HIV1 only, if WB indeterminate then either early infection, infection with HIV2, waning maternal antibodies in an infant, or false positive result
Which of the following is false?
a) routine prenatal testing for HIV is recommended in all Canadian provinces and territories
b) zidovudine (AZT)was shown to reduce HIV transmission from 25% to 8% in a RCT
c) most perinatal transmission happens in utero
d) women with undetectable viral loads rarely transmit HIV
e) the rate of perinatal HIV transmission in Canada is only 1.2% in women with recognition of HIV in pregnancy
c) false - most happens at delivery, transmission rate 25% without treatment
the rest true
a) true but compliance varies
most successful programs test women unless they actively opt out, since most women don’t report traditional risk factors
Which of the following is not an optimal management strategy to reduce HIV transmission
a) treatment of all pregnant women in Canada with zidovudine mono therapy
b) AZT (zidovudine) for 6 weeks for most neonates born to HIV positive women
c) HIV +ve women in Canada should not breastfeed
d) elective C section prior to ROM for women with HIV who are not receiving antiretroviral drugs or AZT alone
a) FALSE need to tailor the treatment to the woman’s case, based on viral load, how long she has had HIV, last treatment she was on, side effects, antiviral susceptibility of the strain, etc. talk to ID when possible.
- international studies/some US observational studies do show some reduction in perinatal HIV transmission with shorter courses of maternal AZT, but less than with longer multi medication regimens
- according to bit nun - triple therapy in 2nd trimester, and zidovudine while delivery
the rest true
b) most will be AZT mono therapy, some cases where may need combo therapy based on high risk situations or perinatal events (should talk to ID for those)
c) true - since formula feeding is safe and available here, should not breastfeed, 9% transmission risk per year of breastfeeding, same strategy regardless of viral load or antiretroviral treatment
d) true, not great consensus on what to do for women on treatment with incompletely suppressed viral loads
american college -
Which of the following is false?
a) significant short term side effects from antiretroviral in utero is rare
b) 25% of Canadians who are HIV positive are women
c) HIV testing should be repeated later in pregnancy (after the initial early test) if thought to be continued exposure
d) lots of long term data exists on the side effects of treatment with antiretroviral treatment in utero
d) false- not lots of data on this but pretty clear that benefits of treatment outweigh the risks
the rest are true
other recommendations
-make sure HIV result available at time of labour and delivery
- if women not tested or risk factors, should try very hard to do expedited HIV serology during labour and delivery or even after the baby is born
- if mom refuses testing, document, should re ask again, and do counselling, consider referring to counsellor, newborn should be considered unknown HIV status, consider treatment (with HIV specialist) if high risk)
see us guidelines for more details
http://www.aidsinfo.nih.gov/
guidelines/html/3/perinatal-guidelines/0/
Which of the following is not recommended in Canada?
a) testing of infants 1000, treat the infant with zidovudine for 6 weeks plus 3 weeks of nevirapine in 1st week
d) testing of infants exposed to HIV with 2 HIV PCR tests, with the 2nd after 4 months of age
a) preferred method of testing for
Which of the following is not appropriate?
a) treat close contacts of patients with invasive meningococcal, Hib and GAS disease with prophylactic antibiotics
b) treat UTI if symptoms present and presence of significant E. coli in catheter sample
c) treat MRSA in nasopharyngeal samples to eliminate carriage
d) patients with IgE mediated penicillin allergy should avoid penicillins in the future and get allergy testing
c) false - MRSA from nasal or rectal specimens (without symptoms) should not trigger treatment, same as getting GAS from throat of asymptomatic person (likely only represents carriage)
the rest true
meningococcal- rifampin for close contacts
Hib- rifampin
GAS- controversial, different choices, in Canada penicillin or cephalosporin most common
IgE mediated is anaphylaxis within 1 hour of administration, low cross reactivity with cephalosporin (2%), if have reaction should get allergy testing so that label can be removed if not true. allergy in parent not a grounds for not giving penicillin to the kid
serious non IgE reactions - i.e. SJS or TEN - don’t use penicillin OR any related antibiotics in the future (i.e. cephalosporin)
use local antibiograms can use narrower spectrum
narrow when you know - i.e. staph if sensitive switch to clox or cephalexin
Which of the following is not an acceptable optimal dosing interval for the infection at hand?
a) twice daily amoxicillin for otitis media
b) twice daily amoxicillin for cellulitis treatment
c) once daily gentamicin for 2 month old with UTI
b) should be tid-4x/day for severe infections, can get away with bid for mild OM
gentamycin - dose dependant killing, kill when initial dose is high with less frequent dosing
amino glycosides should be dosed q24 hours in all children beyond the neonatal period with normal kidney function (some centres use for neonates also)
other abx - i.e. amoxicillin and cephalosporins- time dependant killing, so maximum action for 1 hour after giving, need to have dose that can kill for at least half of the day (otherwise the bacteria will multiply in the trough levels)
Which of the following is not an appropriate course of antibiotics?
a) streptococcus pharyngitis 10 days amoxicillin
b) UTI in 1 year old - 7-14 days
c) otitis media in 6 months old 5days amoxicillin
d) pneumonia in 6 year old - 7 days amoxicillin
c) false, only 5 days if > 2 years and uncomplicated
use the shortest course possible
vaccines lower abx use
- ie) conjugated pneumococcal vaccine - lowers OM and pneumonia, reduces antimicrobial use significantly
influenza vaccine - reduces febrile illnesses and antibiotic use
dx UTI - need to send urinalysis, urine microscopy and culture from clean catch or catheter sample
wheezing is rarely bacterial
GAS - should respond to cephalexin (narrow spectrum, 1st generation cephalosporin)
any draining wounds should be cultured
shorter courses - less side effects and resistance
penicillin for streptococcal pharyngitis is still 10 days. he in >2 year old with uncomplicated AOM - 5 days (not 7-10) uncomplicated pneumonia in heathy kid - can do 7 days treatment
UTI - 7-14 days
Which is the first line treatment for thrush in Canada?
a) gentian violet
b) nystatin 200 000 units 4x /day
c) oral clotrimazole
d) fluconazole
b) nystatin is the most common treatment - well tolerated, usually cures 50% after one week and 80% after 2 weeks of treatment; should administer AFTER feeds
the others:
- gentian violet - moderately effective but can cause irritation/ ulceration after prolonged use, can also stain clothing and interfere with clinical assessment
- oral clotrimazole, and miconazole gel not available in Canada - these are 1st generation imidazoles; these work better than nystatin,
anecdotal - chronic, can use clotrimazole troches (lozenges?) , clotrimazole on pacifier reported to be effective, but not evidence based so can’t recommend
2nd generation - ie fluconazole, itraconazole - consider if fails conventional treatments especially in immunocompromised; not first line data because limited studies in kids, potential adverse effects and high costs
only a few good studies (RCTs) exist
thrush can start as early as 7 days of life, with incidence of 5-10%, usually good response in neonates with underlying condition, harder to treat if also using soother, unless soother is carefully washed. colonized by candida albicans in first week of life, systemic candidiasis a risk factor for prems; candiasis risk after systemic antibiotics, can happen anytime after
Which of the following is true of candidal diaper dermatitis?
a) anti-inflammatory preparations with high concentrations of steroids in combination with anti fungal agents should be avoided
b) the best treatment is zinc oxide cream
c) most commonly affects neonates in 1st month of life
d) best treated by concomitant oral and topical anti fungal agents
a) true- no well designed studies to look at the role of anti-inflammatory agent - high anti-inflammatory agents such as high potency steroids (1%) may impair the response to anti fungal, unclear the role of lower dose steroids with anti-fungal treatments (some people against, some are for it)
the rest false
b) study comparing miconazole with zinc oxide- miconazole worked better, safe and more effective in moderate to severe cases
c) most commonly age 2-4 months, present in feces of 90% of babies in this group, need to treat by changing diaper frequently, leaving diaper off plus treatments
d) not clear - one study, no effect of doing both, another relapses decreased efficiently
miconazole dose 2% once or twice daily
Which of the following is not a commonly used treatment for tinea versicolor (aka pityriasis versicolour)?
a) ketoconazole 2% applied once daily
b) selenium sulfide 2% lotion once daily
c) selenium sulfide 1%shampoo once daily
d) nystatin cream
e) clotrimazole
d) not commonly used
caused by malassezia, which invades the stratum corneum, adolescents, hypo/hyperpigmented, often have recurrences
the other three shampoos are common, apply 15-30 minutes nightly for 1-2 weeks, then once/month for 3 months to avoid recurrences
clotrimazole (aka canesten) dose is 1% 2 daily for 7-14 days
Which of the following ways is not a way to get ringworm?
a) aerosols
b) human - human
c) animals
d) fomites
a) not a way
the others are ways
direct contact with infected humans, animals (usually cats and dogs) or rarely fomites
can be treated by clotrimazole, ketoconazole, miconazole, terbinafine (all give a good response, apply bid for 14-21 days)
Which of the following is not an appropriate treatment for ringworm?
a) topical ketoconazole 2% once daily
b) topical terbinafine (Lamisil) 1% applied 1-2 x daily
c) topical miconazole (Monistat) 2% twice daily
d) topical clotrimazole 1% mixed with beclomethasone
d)should avoid topical agents that are mixed with topical steroids
ringworm tinea corporis - occur at any age, causes in Canada Trichophyton rubrum, Trichophyton mentagrophytes and Microsporum species (especially Microsporum canis and Epidermophyton floccosum).
can be treated by clotrimazole, ketoconazole, miconazole, terbinafine (all give a good response, apply bid for 14-21 days)
Which of the following is the not a reasonable treatment for tinea capitis?
a) terbinafine 62.5mg/kg/day to 250 mg/kg/day based on weight
b) itraconazole 3-5 mg/kg/day (max 400 mg daily)
c) fluconazole 3-5 mg/kg/day
d) ketoconazole 5-10 mg/kg/day
c) fluconazole - not great for superficial tinea infections because hydrophilic - present in mainly body fluids rather than keratin or lipids, not useful for treatment for most topical fungal infection
the rest:
griseofulvin - not available in Canada
itraconazole - azole, affinity for lipids and keratin, good for dermatophytes, Candida and moulds, shown to be 90% effective for trichyphyton or microsporum species; secreted in sebum one month after stopping, may become new 1st line but more studies needed
ketoconazole - 1st agent studied for resistant superficial tinea infections (such as tinea capitis), equivalent to griseofulvin
terbinafine - fungicidal, lipophilic, keratinophilic agent, diffuses to keratinocytes from bloodstream to reach stratum corneum and follicles. no liquid formulation available in Canada, 250 mg tablet available
one study suggested that it might become the drug of choice. less drug interaction since not metabolized through cut P450 (which AZOLES are) , GI and skin reactions in only 2-7%
tinea capitis - dermatophyte infection species - M capitis - Europe; Trichophytan tonsurans - N/A, doesn’t respond well to topical therapy alone
cradle cap - seborrheic dermatitis cause by Malassezia species - soap best , selenium sulphide or azole shampoo in severe forms
tinea pedis - not common in kids, treat with drying agent, if involves toenails need oral treatment
Which of the following medications is associated with loss of taste?
a) fluconazole
b) terbinafine
c) itraconazole
d) ketoconazole
b) terbinafine (aka lamisil) - loss of taste is reported, but resolves after therapy has ended
good for treatment of rinfections including tinea unguium (onychomycosis), tinea pedis and tinea corporis or tinea cruris, achieving mycological cure in over 80% of adult patients; in peds, 4 week treatment for tinea capitis dose is 62.5 mg/kg/day for 250 mg/kg/day for >40 kg
these drugs are all rather pricey, itraconazole is the most expensive
Which of the following drugs is not likely to interact with ketoconazole?
a) cortisol
b) cyclosporine
c) antiarrythmics
d) penicillin
d)
azoles inhibit the excretion of certain drugs that are metabolized by cytochrome P450 (aka CYP 3A)
antiarrhytmics, cortisol, cyclosporine, tacrolimus, estradiol
terbinafine has very few drug interactions *, doesn’t interact with CYP 3A
Which of the following is not associated with otitis externa?
a) swimming
b) using soft malleable plug to keep water out of ears
c) trauma
d) using a hearing aid
b) not associated, this helps to prevent otitis externs
associated with:
- swimming, immunocompromised- ie insulin dependant diabetes, immunodeficient, trauma, foreign body, using hearing aid, wearing tight head scarves, chronic otorrhea, certain derm conditions
Which of the following is not a common symptom of otitis externa ?
a) high persistent fever
b) itching
c) otalgia
d) hearing loss
e) ear canal pain while chewing
a)more likely with otitis media or malignant OE
the others are common
otalgia - 70%, itching - 60%, fullness - 22%, hearing loss (32%) with or without, otorrhea
distinguising factor with OM is significant pain out of proportion when the tragus is pushed and the pinna is pulled, pain at TMJ when chewing also possible
canal - local inflammation, may have cellulitis or chondritis of the surrounding area
otorrhea, regional lymphadenitis, tympanic membrane erythema, or cellulitis of the pinna and adjacent skin
rapid onset of symptoms within 48 hours within last 3 weeks
Which of the following is not a likely cause of acute otitis externa?
a) streptococcus pneumoniae
b) pseudomonas aeruginosa
c) staphylococcus aureus
d) aspergillus
a) not a common cause
pseudomonas aeruginosa and staphylococcus aureus are the most common, often polymicrobial, other gram negative infections are less common
rare fungal infections with aspergilosis are possible
shouldn’t take swabs from external canal too seriously, may be normal flora or colonizing organisms, only take swabs if severe or refractory infections
Which of the following is true ?
a) topical antimicrobials are less effective than effective than oral antimicrobials for the treatment of mild-moderate otitis externa
b) topical steroids with topical antimicrobials improve the clinical and anti microbial cure of otitis externa compared to topical antimicrobials on their own
c) topical neomycin can be used to treat OE with tympanostomy tubes
d) topical acidifying solutions are as effective at clinical cure of OE at one week
d)true, but inferior at bacteriological cure at 2 weeks
a) false - no RCT comparing systemic to topical antimicrobials topical antimicrobials increased absolute clinical cure rates of AOE by 46% and bacteriological cure rates by 61% compared with placebo
b) false - does not seem to be any discernible benefit to adding the steroids, although quality of the studies is poor
c) false - ototoxic agents such as gentamycin or neomycin, as well as low ph agents (most acidifying and antiseptic agents) , or cortisporin should not be used for treatment when there is perforated TM or tympanostomy tubes, more and more evidence that they are ototoxic. should not use them if the TM can’t be seen.
topical acidifying solutions good at clinical cure in one week but inferior in clinical and microbiological cure at 2 weeks
1st line - topical antimicrobial with or without topical steroids x 7-10 days
more severe cases need IV Abx that cover pseudomonas, S aureus
if can’t see the ear canal, can put in wick to deliver topical medications, ear candling has no effect
tx with antibiotics should respond in 48-72 hours, may take up to 6 days. if not respond then consider - foreign body, obstruction, non adherence or alternate diagnosis - (dermatitis with nickel contact, viral/fungal infection or resistant infection)
A 16 year old insulin dependent type 1 diabetic with poor control presents with fever, right sided facial nerve palsy, and pain. What is the appropriate management?
a) ciprodex drops and discharge
b) oral amoxicillin treatment
c) CT scan, admission to hospital, debridement and IV antibiotics that cover pseudomonas and aspergillus
c) is the management
also need to control the underlying immunocompromised state
prevention of acute otitis externa - keep ears dry, some experts - soft water plugs, remove water from ears after swimming, avoid hard earplugs (may cause trauma), controversial tight swim caps and ear canal molds
Which of the following ear drops can be used in a child with acute otitis externa with perforated tympanic membrane?
a) Buro-sol
b) Ciprodex
c) Neosporin
d) Polysporin eye drops
b) can be used, off label use
see the chart, the following cannot be used in this case, worry about ototoxicity, also if can’t see the tympanic membrane or if tympanostomy tubes
the others:
- polysporin (has polymyxin which is ototoxic), neosporin (has neomycin), cortisporin (has neomycin), sofracort (antiseptic agent), curo-sol (antiseptic agent),garamycin (gentamycin), garasone (gentamicin-betamethasone), see table
Which of the following patients should be treated with 7 day course of TMP/SMX following drainage of a skin abscess?
a) 4 month old with skin abscess with surrounding cellulitis
b) 2 month old with skin abscess, temperature of 37.6 (R), and looks well
c)
b) 1-3 months who has no fever and no other systemic signs of illness: TMP/SMX only pending culture , (TMP/SMX) in infants younger than two months of age remains controversial. Most experts believe there is no risk of kernicterus in well infants older than four weeks of age, and many would also use in infants two to four weeks of age with no visible jaundice
a) should be treated with TMP/SMX AND cephalexin (to cover GAS)pending cultures since > 3 months of age and has the surrounding cellulitis
c) 3 months with low grade or no fever and no systemic signs of illness - can observe after drainage, only consider antibiotics if child doesn’t improve or culture grows organism other than staph aureus
**ALL ABSCESSES need to be drained, antibiotics usually 7 day course
also consider abx if kid has other significant illnesses or systemic signs or significant cellulitis
Which of the following is an appropriate management of a skin abscess?
a) start empiric antibiotics without taking a culture
b) consider doxycycline for treatment of a 9 year old with a skin abscess that is not improving post drainage
c) treat with TMP/SMX if culture grows Group A strep
d) decolonization of family members of a child treated for CA-MRSA
b) TRUE doxy or >8 year old who can swallow pills, increasing resistant to clindamycin, also higher risk of C. Diff, and it tastes bad so not a great choice
the rest are false
a) is false can’t tell clinically MRSA vs other so absolutely must take a culture when doing I and D, however many abscess do occur on the lower limbs and buttocks with MRSA
**ALL ABSCESSES need to be drained
consider Abx in these cases if systemic signs of illness, fever, or significant surrounding cellulit
antibiotics usually 7 day course
c) TMP/SMX is not good for group A strep, therefore if significant risk of GAS (i.e. big cellultitis) then should add a second antibiotic that covers it (i.e. cephalexin); increased resistance to fluoroquinolones TMP/SMX is a covers almost 100% of MSSA and CA-MRSA
d) decolonization is not helpful, failure is common
if significant systemic signs of illness other than low grade fever or cellulitis, then should treat with IV Abx
see table for details
this is management pending culture, once culture results are available should target
populations with overcrowding/close contacts reported to have more CA-MRSA, but many kids no risk factors
CA-MRSA can progress to septic arthritis, osteomyelitis, NEC fasc, sepsis and pneumonia
Which of the following is the most common cause of pneumonia in a school age child?
a) Strep pneumo
b) Group A strep
c) Mycoplasma pneumoniae
d) Chlamydophila pneumoniae
e) Influenza
a)
strep pneumo - most significant pathogen in all ages
GAS pneumonia - much less common
Staph aureus - not common but is increasing in areas where MRSA is prevalent
Hib almost disappeared due to vaccination
viruses as a sole cause (other than influenzae)are not a common cause of pneumonia in older children
Mycoplasma and Chlamydophila are common causes in school age children
Which of the following children is tachypnic?
a) 2 month old with resp rate of 50
b) 4 month old with resp rate of 40
c) 4 year old with resp rate of 40
d) 4 year old with resp rate of 25
c) tachypnic
< 2 months - normal (34-50), tachypnea - 60
2-12 months- normal 25-40, tachypnea - 50
1-5 years - normal 20-30, tachypnea - 40
>5 years - normal 15-25, tachypnea - 30
symptoms - remember abdo pain as a symptom; abrupt rigours favour bacterial
persistent cough - think mycoplasma
influenza season - consider both primary and secondary pneumonia caused by this
fever and tachypnea; normal O2 sat DOES NOT exclude pneumonia
Which of the following is not a physical sign of pneumonia?
a) dullness to percussion
b) increased tactile fremitus
c) increased bronchial breath sounds
d) increased vesicular breath sounds
d) in fact these normal vesicular breath sounds are decreased, the rest are present
wheezing should suggest that it is from atelectasis/mucous plugging (i.e. asthma or bronchiolitis) rather than pneumonia
Which of the following tests is not particularly helpful in most children with moderate pneumonia?
a) sputum culture
b) Chest X ray
c) CBC
d) nasopharyngeal swab for viruses
d)don’t need routine viral testing for mild-moderate illness, helpful in hospital to cohortneed to do an X ray
atypical - more patchy disease on X ray , more than clinical findings
if you can get sputum, do it (it’s certainly helpful) just hard to get and therefore to determine aetiology
for Gram Staining and subsequent culture
CBC - typical has more WBC than atypical
Which of the following is the best outpatient treatment option for a school age child with pneumonia after influenza infection?
a) amoxicillin 80 mg/kg/day x 7 days
b) amoxicillin clavulanate 80 mg/kg/day amox component x 7 days
c) cefotaxime 200 mg/kg/day x 7 days
d) azithromycin 10 mg/kg/day x 5 days
b) is the answer
non severe - amox/clav PO or cefuroxime IV
severe - ceftriaxone or cefotaxime, plus azithro/clarithro; some advice also cloxacillin
see the table
for infection after/during influenza, need good coverage for pneumococcus, MSSA, and Group A strep. some experts suggest adding cloxacillin for MSSA.
table suggests
LOW threshold to admit
Which of the following is the best antibiotic option for a 5 year old girl hospitalized with pneumonia and requiring 40% oxygen?
a) IV ampicillin
b) IV ceftriaxone
c) IV ceftriaxone and azithromycin PO/IV
d) IV cloxacillin
c)
severe pneumonia is defined as:
- needing supplemental O2 (FiO2 >30%) , moderate resp distress or ICU
atypicals don’t always cover pneumococcus so should be reserved for children with atypical suspected
Which of the following features is not suggestive of an exudative pleural effusion?
a) glucose >2.2
b) pH 1000 u/L
d) increased WBC
e) cloudy appearance or bacteria growth
a) false - the opposite, glucose 1000 u/L, increased WBC, cloudy appearance or bacteria growth)
if the criteria met, should drain with/without fibrinolytics and then treat with antibiotics
antibiotics should cover pneumococcus, GAS, and MSSA
controversy regarding routing clinda for this use
separate practice point on this
if the fluid is exudative (pH lower than 7.20, glucose level lower than 2.2 mmol/L, lactose dehydrogenase level greater than 1000 U/L, significant white blood cell count, cloudy appearance or bacteria growth), the child likely has an empyema and ongoing drainage should be arranged, usually initially with a chest tube with or without fibrinolytics. Antibiotics should cover pneumococcus, group A streptococcus and MSSA. The need to routinely add additional anaerobic coverage with clindamycin is controversial.
