Infectious Disease Committee Flashcards
What factors influence the transmission of HSV infection to newborns?
- Nature of maternal infection 2. Mode of delivery 3. Duration of ROM 4. Use of intrapartum instrumentation
How is maternal genital HSV classified? (Two classifications)
- Newly acquired - Either a first episode PRIMARY infection (mother has no serum antibodies to HSV-1 or -2 at onset) or a first episode NONPRIMARY infection (mother has a new infection with one HSV type in the presence of antibodies of another type) 2. Recurrent Mother has pre-existing antibodies to the HSV type that is isolated from the genital tract
What is the most common route of Neonatal HSV acquisition?
Intrapartum (Although In Utero and Postnatal infections can occur, it is not the most common)
What category of maternal genital HSV (Primary or Recurrent) have the highest risk of HSV transmission? Why?
Categorizing the maternal genital HSV infection as either primary or recurrent is important! Mom who have had an HSV infection transmit HSV-neutralizing antibodies to their infant across the placenta, provided that their infant is not born before 32 weeks Therefore, infants born to moms with a first-episode primary infection at time of delivery are at the highest risk of acquiring HSV, with transmission rates up to 60% because the mom has no pre-existing neutralizing antibodies to transmit Second highest risk = First episode non-primary infection Lowest risk = Recurrent infections
What is the role of elective C/S for NHSV transmission?
Elective C/S markedly reduces but does not eliminate the risk for newborn infection
How are pregnant women with recurrent genital HSV treated during pregnancy?
They are given prophylaxis with acyclovir or valcyclovir from 36 weeks until delivery. This helps lower the recurrence of genital HSV and shedding at delivery BUT we are not sure if this translates to a reduced risk for NHSV infection
Why are infant serologies (HSV IgG and IgM) not useful in diagnosing neonatal HSV infections? (Three reasons)
- Transplancental IgG antibodies cannot be differentiated from IgG produced by the infant 2. Severely affected infants can not make antibodies (it is impaired) 3. HSV IgM antibody assays are variable and limited reliability
What is the duration of therapy for NHSV infections?
Depends on the category of disease. SEM disease - 14 day course of IV acyclovir Disseminated/CNS disease - minimum 21 days of IV acyclovir
What are the side effects of using IV acyclovir for the treatment of NHSV?
Neutropenia, Nephrotoxicity
What is the additional medication you give for an infant with ocular HSV manifestations?
1% Trifluridine with the IV acyclovir
What swabs need to be done for an HSV exposed asymptomatic neonate?
When evaluating NHSV infection in exposed asymptomatic infants, mucous membrane swabs should be obtained from the mouth, nasopharynx and conjunctivae AT LEAST 24 h after delivery. Additional swabs may be obtained (eg, from sites of scalp electrodes, if present).
How do you manage an asymptomatic neonate who was delivered via C/S before ROM by a mom with active HSV lesions that is presumed first-episode primary or first-epsiode non-primary HSV infection?
Risk for NHSV is very low If child is asymptomatic, take mucosal swabs (mucous membranes, NP swab) at 24 hours of life. Do HSV PCR by blood if available. Neonate can be discharged pending results If results are positive, then need to be managed as an HSV case
How do you manage an asymptomatic neonate who was delivered vaginally or C/S after ROM by a mom with active HSV lesions that is presumed first-episode primary or first-episode non-primary HSV infection?
Do type-specific antibodies for HSV on mom. Infant’s mucous membrane swabs be obtained and should be started on IV acyclovir. Do blood HSV PCR if available. If positive results - Do LP to determine acyclovir duration If negative results - check mom’s serologies. If mom’s results are more in keeping with recurrent HSV - stop ACV If mom’s results are not available or in keeping with a first HSV infection, baby needs 10 days of ACV despite negative swabs
How do you manage an asymptomatic neonate who was delivered by C/S by a mom with active HSV lesions, thought to be recurrent HSV?
If child is asymptomatic, take mucosal swabs (mucous membranes, NP swab) at 24 hours of life. Do HSV PCR by blood if available. Neonate can be discharged pending results If results are positive, then need to be managed as an HSV case
How do you manage an asymptomatic neonate who was delivered vaginally by a mom with active HSV lesions, thought to be recurrent HSV?
If child is asymptomatic, take mucosal swabs (mucous membranes, NP swab) at 24 hours of life. Do HSV PCR by blood if available. Neonate can be discharged pending results If results are positive, then need to be managed as an HSV case
How do you manage a neonate born to a mom who does not have active HSV lesions at delivery?
Observe for signs for NHSV and educate parents, but no swabs necessary. Consider swabs if active lesions were seen during the third trimester or near delivery
Historically, what are the three top causes of meningitis prior to the introduction of vaccines?
- Strep pneumo 2. Hemophilus Influenza Type B 3. Neisseria Meningitidis
In which circumstances do you consider listeria meningitis beyond the neonatal period? What antibiotic would you add if you suspected listeria?
- Specific host risk factors (i.e. immunosuppression) 2. Brainstem infection as the initial presentation You would add ampicillin to cover for listeria
What are 4 contraindications in performing an LP on a child you suspect meningitis in?
- Coagulopathy 2. Cutaneous lesions at the proposed puncture site 3. Signs of herniation 4. Unstable clinical status such as shock
Based on one adult study, what are the three factors associated with poor prognosis with meningitis?
- Delay in starting antibiotics 2. Severity of clinical state at presentation 3. Isolation of nonpenicillin-susceptible strep pneumoniae
What is the empiric therapy when meningitis is suspected in a child >1 month old?
Ceftriaxone/Cefotaxime + Vancomycin
What antibiotic do we use to treat the close contacts of a child who had meningococcal or HiB meningitis?
Rifampin
In which clinical situation does research support the use of steroids in acute bacterial meningitis?
HiB meningitis where evidence shows that steroids decrease hearing loss in children if they are administered just before or with the initial antimicrobial therapy
What should the CSF gram stain show before you consider starting IV dexamethasone? How long should you continue IV dexamethasone for?
If there are no contraindications to steroid use for a particular infant or child, when a bacterial meningitis is suspected (especially if CSF gram stain shows gram positive diplococci or gram negative coccobacili), some experts recommend starting IV steroids immediately before, concomitant with, or within 30 minutes after the first dose of antimicrobials. If Strep pneumo or HiB is cultured or identified by molecular testing, steroids should be continued for 2 days but if another etiology is found within 48 hours, then steroids should be discontinued
In which situations do you require repeat CSF sampling for a child with meningitis?
GBS meningitis - some experts recommend documentation of CSF sterilization 24-48 hours after initiation of therapy Gram negative enteric pathogens causing meningitis - require repeat LP at 24-48 hours
When should a formal audiology assessment be done on a child with confirmed bacterial meningitis?
Before discharge or within 1 month of discharge
What is the recommended duration of treatment for: a) Strep pneumo meningitis b) HiB meningitis c) N Meningitidis d) GBS meningitis
Strep pneumo meningitis = 10-14 days HiB meningitis = 7-10 days N Meningitidis = 5-7 days GBS meningitis = 14-21 days, and depends on whether cerebritis is present
In disseminated HSV infections, what organs are most commonly affected?
Liver = Consider NHSV particularly in neonates with sepsis accompanied by liver dysfunction Lung
What are the most common clinical presentations of invasive Group A Strep infections?
- Necrotizing Fasciitis or myositis 2. Bacteremia with no septic focus / Toxic shock syndrome 3. Pneumonia
What is a prominent risk factor for the development of invasive Group A Strep infection in children?
Varicella infections
How do you diagnose streptococcal TSS (toxic shock syndrome)?
Hypotension with at least 2 of the following signs: 1. Renal impairment 2. Coagulopathy 3. Liver function abnormality 4. ARDS 5. Generalized erythematous rash that may desquamate
What’s the difference between a confirmed invasive GAS case versus probable invasive GAS case?
A probable case means that the isolation of GAS was from a nonsterile site; as opposed to a confirmed invasive GAS case which is from a sterile site
Who should be offered chemoprophylaxis if you have a patient with invasive GAS disease?
- Household contacts who have spent at least 4 h per day on average in the previous seven days or 20 h per week with the case. - Nonhousehold persons who share the same bed with the case or had sexual relations with the case. - Persons who have had direct mucous membrane contact with the oral or nasal secretions of a case (eg, mouth-to-mouth resuscitation, open mouth kissing) or unprotected direct contact with an open skin lesion of the case. - Injection drug users who have shared needles with the case. - Selected contacts of long-term care facilities. - Selected contacts in child care settings. - Selected hospital contacts.
When should chemoprophylaxis be offered for close contacts of a patient with invasive GAS disease?
- Should only be offered to close contacts of a confirmed case of severe GAS during the period from 7 days before the onset of symptoms in the case to 24 hours after initiation of antibiotics in the case 2. Chemoprophylaxis of close contacts should be administered as soon as possible and preferably within 24 h of case identification, but chemoprophylaxis is still recommended for up to seven days after the last contact with an infectious case.
What antibiotic is the preferred choice for chemoprophylaxis of close contacts of a patient with invasive GAS disease?
First generation cephalosporin (Cephalexin)
What antibiotics do you use to treat invasive GAS disease?
Penicillin + Clindamycin
In addition to antibiotics, what other treatment do you consider in a patient with streptococcal TSS or severe toxin-mediated disease in the absence of shock?
IVIG
What are three potential risk factors for transmission of blood-borne viruses in child care centres?
- Aggressive behaviour with frequent biting 2. Oozing skin lesions 3. Bleeding disorders
Which kind of bites in the child care setting can potentially transmit HBV?
A bite that breaks the skin has the potential to transmit the virus (the virus is not transmitted by simple contact of saliva or blood with intact skin)
What is the transmission likelihood of HIV by a bite in the child care setting?
Extremely unlikely. There has been no report of HIV transmission in child care. Only rare reports of HIV by severe bites by adults where considerable blood exchange has occurred.
Of HBV, HIV, and HCV; rank the three viruses based on the risk of transmission by a bite in a child care setting
All of these are of low likelihood in general. Risk of transmission is higher with HBV, followed by HCV, and then HIV (lowest likelihood)
Do bites in the child care setting lead to bacterial infections?
Bites from young children rarely lead to bacterial infections. Routine wound care should decrease the risk of infection to almost zero
In the case of a bite that breaks the skin, if either the biter or the one bitten is known to be a HBV carrier, what needs to be done?
If the child is known to be non immune or incompletely immunized, then hepatitis B immunoglobulin and HBV vaccine should be administered
In the case of a bite that breaks the skin, if one child is non immune or incompletely immunized and the status of the other child is unknown, what needs to be done?
Because of the low risk of infection, HBV testing is not justified. The nonimmune child should be given the HBV vaccine
In the case of a bite that breaks the skin, and both children’s HBV status is unknown, what needs to be done?
Because of the low risk of infection, HBV testing is not justified. Both children should be given HBV vaccine, unless already fully immunized
Why is PO erythromycin not used in babies to treat gonorrhea/chlamydia?
Association with pyloric stenosis
What is the CPS stance on neonatal ocular prophylaxis with erythromycin?
May no longer be useful and should not be routinely recommended
What is the management of infants exposed to N gonorrhoeae who appear to be healthy at birth?
They should have a conjunctival culture for gonorrhea and receive a single dose of Ceftriaxone
What is the management of infants exposed to N gonorrhoeae who appear to be unwell at birth?
Take blood and CSF cultures. Consult peds ID
In what situation will a patient have IgG varicella antibodies?
Only when they were naturally exposed. Patients who received the varicella vaccination do not demonstrate an IgG to VZV
Why do we currently give the second varicella vaccine at 4-6 years of age?
To prevent secondary vaccine failure (waxing and waning)
What is the minimum space (duration of time) that is needed before a child can receive the second varicella vaccine?
The two doses must be given a minimum 3 months apart for children less than 12 years old, and 4 weeks apart for older children
What period of time is the highest risk for sepsis in a patient who is asplenic?
The first 3 years post-splenectomy or the first 3 years of life if patient has congenital asplenia
What is the most common bacteria that causes fulminant sepsis in asplenic patients?
Streptococcus Pneumoniae (at least 50% of cases)
What vaccine should asplenic patients receive to protect them from pneumococcus?
All asplenic patients should receive both the conjugated 13-valent pneumococcal vaccine (part of the normal immunization schedule) and the 23-valent polysaccharide vaccine (supplemental protection).
What vaccine do we give to protect asplenic patients from meningococcus?
All asplenic patients should receive conjugate quadrivalent meningococcal vaccine (MCV4) and the new meningococcal vaccine to protect against serotype B
Why is the influenza vaccine recommended in asplenic patients?
To lower the risk of secondary bacterial infections
When should vaccines be given in a patient going for an elective splenectomy?
When a patient is undergoing an elective or semielective splenectomy, there is some evidence that the best responses occur when vaccines are administered at least two weeks before the surgery is performed.
Before what age should all asplenic patients receive antibiotic prophylaxis?
Because S pneumoniae is the most common cause of severe infections in children with asplenia or hyposplenia, with significant associated mortality, patients younger than five years of age should all receive antibiotic prophylaxis.
What other organisms are we concerned about in asplenic patients less than 3 months of age?
Escherichia coli, Klebsiella are of concern in this age group
What are the CPS recommendations on antibiotic prophylaxis to patients with asplenia?
CPS recommends antibiotic prophylaxis for a minimum of 2 years postsplenectomy and for all children under 5 years of age
What is the initial treatment for a patient with asplenia who comes in with fever and you are worried about sepsis?
IV Ceftriaxone Where intermediate or high penicillin-resistant pneumococci are prevalent, administer both ceftriaxone and vancomycin (60 mg/kg/day in divided doses every 6 h)
What are the primary features of an atypical bacterial pneumonia?
subacute onset, prominent cough, minimal leukocytosis and a nonlobar infiltrate, usually in a school-aged child
What are nosodes?
Homeopathic biologic preparations Derived from an element of disease or diseased tissue and serially diluted
What are the 5 meningococcal serotypes that cause invasive meningococcal disease?
A, B, C, Y, W
What is the known side effect of the 4CMenB vaccine?
Fever Fever persisted >24 hours in 2/3 of the cases
Name 5 groups of patients at highest risk for invasive meningococcal disease and should receive the 4CMenB?
- Asplenia or hyposplenism 2. Congenital complement, properdin, factor D or primary antibody deficiencies 3. Individuals prescribed the terminal complement inhibitor eculizumab 4. Individuals who have had more than 1 episode of IMD 5. Laboratory personnel who work with the organism
What is now the most prevalent serogroup of N Meningitidis causing invasive meningococcal disease?
Serogroup B (MenB) is now the most prevalent serogroup in Canada, accounting for >50% of cases between 2002 and 2011
What is different about meningococcal B versus the other meningococcal serogroups?
Unlike other meningococcal serogroups, group B does not elicit a response to the polysaccharide capsule The MenB capsule cross-reacts with human fetal neural tissue and renders the capsule nonimmunogenic
For how long can HBV be detected in discarded needles?
HBV is the most stable of the blood-borne viruses and can survive up to 1 week under optimal conditions
Which immunization records should be obtained in a child who had a community needle stick injury?
Tetanus and HBV status
What bloodwork should be obtained in a child who had a community needle stick injury?
Baseline HBV, HIV, HCV status
What bloodwork do you do for a child who has sustained a community needle stick injury and antiretrovirals are considered?
CBC diff AST, ALT, ALP BUN, Cr
What is the ideal timeframe to give HBIG following a needle stick injury for a child that has not been fully vaccinated against HBV or has been fully vaccinated and anti-HBs antibody positive and HBsAg negative?
Ideally within 48 h of injury; efficacy unknown if >7 days after injury
When should we treat for HIV in a child who has sustained a community needle stick injury?
Only high risk cases - source is considered to have HIV, incident involved a needle and syringe with visible blood and blood may have been injected
If the decision is to treat a child who has sustained a community needle stick injury for HIV with antiretrovirals, when should antiretrovirals be started?
As soon as possible, ideally within 1 to 4 hours of the injury. Prophylaxis is not recommended if it cannot be initiated within 72 h of the injury
What antiretrovirals should be used in children for HIV treatment in low-risk situations?
zidovudine plus lamivudine
What antiretrovirals should be used in children for HIV treatment in high-risk situations?
zidovudine plus lamivudine plus lopinavir/ritonavir
When doing a risk assessment for HIV transmission following a needle stick injury, what are high risk conditions when considering the source (2 reasons), device (1 reason), and injury (2 reasons)
Source: Known or presumed high prevalence of HIV, source known to have HIV
Device: Large lumen devices with visible blood
Injury: Actual blood injection, splashes involving large volume of blood in contact with extensive areas of nonintact skin
For a child who sustained a needle stick injury, what do you do for HBV prophylaxis when a child is known to be HBV antibody- or HBsAg-positive
No action required
For a child who sustained a needle stick injury, what do you do for HBV prophylaxis when a child has not been fully vaccinated against HBV?
For a child who sustained a needle stick injury, what do you do for HBV prophylaxis when a child has been fully vaccinated against HBV?
What is the most frequently reported STI in Canada?
Chalmydia
What should you suspect in a prepubertal child with vaginal, urethral or rectal chlamydia infection?
Sexual Abuse
What are the two sexually transmitted infections that are more likely to be transmitted through the birth process?
Gonorrhea and Syphillis
(Chlamydia is rare)
If an adolescent has a gonorrheal STI, what other STI is often concurrently found?
Chlamydia
What is the indication for STI screening in the female adolescent population?
All who are sexually active or are victims of sexual assault or abuse
What is the best method of testing for a Chlamydia infection?
NAAT. Specimen may be first-catch void urine, vaginal, endocervical, or urethral specimens
When is chlamydial culture of cervical or urethral specimens the test of choice?
Although less sensitive than the NAAT, remains the test of choice for medico-legal purposes
In which situations should you perform a test of cure when you are treating a patient with a chalmydial STI?
In prepubertal individuals by NAAT 3-4 weeks after completion of therapy
In postpubertal patients TOC, when compliance is uncertain, an alternative treatment was used, re-exposure is likely or an adolescent is pregnant
Name 6 indications for obtaining a gonorrhea culture with susceptibility testing to determine the resistance pattern of the isolate?
- When sexual abuse of children (rectal, pharyngeal, vaginal) is suspected
- Sexual assault cases
- When treatment failure is presumed
- Evaluating PID
- Symptomatic MSM
- If infection is believed to have been acquired overseas or in an area of recognized antimicrobial resistance
What bug causes lyme disease?
Borrelia burgdorferi
What animal carries the ticks in lyme disease?
mice, other small rodents, small mammals, birds and white-tailed deer
What is the peak incidence of lyme disease in children?
5 to 9 years old
What is the optimal time to remove a tick to prevent lyme disease?
Removing a tick within 24-46 hours of its starting to feed is likely to prevent LD
During which seasons is the risk for lyme disease greatest?
Late spring and summer
Is lyme disease a nationally reportable disease?
Yes
What are the 3 phases of lyme clinical manifestations called?
Early localized disease
Early disseminated disease
Late disease
What is the most common clinical manifestation seen in early localized lyme disease?
Erythema Migrans (develops 7-14 days after a tick bite)
What are the 2 most common clinical manifestations seen during the early disseminated disease phase of lyme disease?
- Secondary annular erythematous lesions (reflects spirochetemia with cutaneous dissemination)
- Acute neurologic signs (i.e. facial nerve palsy, papilledema, lymphocytic meningitis))
What is the most common clinical manifestations seen during the late disease phase of lyme disease?
Pauciarticular arthritis
If you detect erythema migrans on your exam and you suspect your patient has lyme disease, should you do serodiagnostic testing?
No because antibodies against B burgdorferi are often not detectable by serodiagnostic testing within the first four weeks after infection
Under which situations do you require laboratory confirmation of lyme disease?
When your patient demonstrates symptoms of possible LD, except EM, require laboratory confirmation
How do you make the diagnosis of early disseminated and late lyme disease?
Two tiered serological testing, first by ELISA screening followed by confirmatory western blot test
What is the antibiotic of choice to treat lyme disease in a child less than 8 years old?
Amoxicillin
What is the antibiotic of choice to treat lyme disease in a child more than or equal to 8 years old?
Doxycycline
What is the Jarisch-Herxheimer reaction?
Can be seen in the context of lyme disease treatment.
Fever, headache, myalgia, and an aggravated clinical picture lasting <24 hours
What do you do if you feel like your patient has Jarisch-Herxheimer reaction following lyme treatment?
Continue antibiotics. Start NSAIDs
Which serogroup of meningitis is known to be associated with higher mortality rates, particularly in adolescents?
Serogroup C
The quadrivalent conjugated vaccine appears to induce protective antibodies in which population?
Adults and children two years of age or older
Why is it that the anamnestic response cannot be relied upon to prevent meningococcal disease?
Meningococcal disease has a very short incubation period, so circulating antibodies are needed at all times for protection
When is the MCV-C vaccine given for healthy Canadian children?
12 months of age
When should the MCV-C vaccine be given for infants at risk for invasive meningococcal infection?
2 months of age
At what age should MCV-4 be given in a child who is at increased risk for meningococcal infection?
2 years of age and older
When is the booster dose for meningococcal vaccine given? Which meningococcal vaccine is given?
Booster dose is given at 12 years of age. Can be either MCV-4 or MCV-C
What groups are at increased risk for invasive meningococcal disease (6)?
- Anatomical or functional asplenia
- Primary antibody deficiency disorders
- Complement, properdin, factor D deficiency
- Travellers to area where meningococcal risk is high
- Lab personnel exposed to meningococcus
- Military
Why does rotavirus infection generally cause milder symptoms for children who are less than 3 months old?
Because of transplacental maternal antibodies
How is rotavirus transmitted?
Fecal-oral route and through fomites
Rotavirus hospitalization is common in which age group?
6 month to 24 month age group
What are the 2 major risk factors for severe rotavirus disease?
- Prematurity (lack of transplacental maternal antibodies)
- Immunocompromised children
What is the most frequently used laboratory test to confirm a rotavirus diagnosis?
Antigen detection in stool by enzyme immunoassay
What was the biggest complication associated with the old rotavirus vaccine?
Intussusception
What are the 3 contraindications for rotavirus vaccination?
- Hypersensitivity to the vaccine components
- History of intussuception
- Infants that are suspected or known to be immunocompromised, especially those with SCID
When should the rotavirus vaccination be started and finished by?
Between six and 14 weeks plus six days of age, with the series completed by eight months of age
Children of which age range are at the highest risk of adverse outcomes from influenza illness?
Children younger than 2 years of age; but children younger than 5 years of age are at a higher risk in general
If the decision is made to start an antiviral drug for Influenza, when should treatment ideally be started?
As soon as possible after illness onset. The benefit is much greater at less than 12 hours compared to 48 hours
What is the typical treatment duration of antiviral agents for influenza infection?
Routinely for five days, but may be longer if clinically indicated
Would you treat infants younger than 1 year of age with a NAI (e.g. Tamiflu) for a mild or uncomplicated influenza illness?
No. It is currently not approved for routine treatment.
Would you treat children 1 to 5 years of age with a NAI (e.g. Tamiflu) for a mild or uncomplicated influenza illness and no other risk factors for severe disease?
Depends. Those who are otherwise healthy and have mild disease not requiring hospitalization do not routinely require antiviral therapy
Would you treat children 1 to 5 years of age with a NAI (e.g. Tamiflu) for a mild or uncomplicated influenza illness as well as additional risk factors for severe disease?
Yes. If less than 48 hours, treat with Tamiflu. If more than 48 hours, treatment is considered on a case-by-case basis
What is the CPS recommendation for the use of influenza vaccine in children with severe egg allergy?
Recommended (Inactivated vaccine). Live vaccine has not been studied and can’t be recommended at this time
