Infectious Diseases Flashcards
H influenza b is now relatively uncommon in Canada, except in which groups of children?
- unimmunized
- partially immunized
- child new to Canada
- immunocompromised
How do the symptoms of meningitis differ between infants and children/adolescents?
- Infants: more non-specific findings, absence of nuchal rigidity
- Children/Adolescents: more likely to have specific symptoms (headache, nuchal pain/rigidity, impaired LOC)
List 4 contraindications to lumpar puncture
- Coagulopathy
- Cutaneous lesions at the proposed puncture site
- Signs of herniation
- Clinical instability (ie. shock)
- Focal neurological defects (unless head imaging normal)
List two potential complications of acute meningitis
- SIADH
2. Increased ICP
What are the bacterial organisms most likely to cause meningitis in patients older than 1 month?
- Strep pneumoniae
- N meningitidis
- GBS/E coli (only in infants
When should steroids be used in the management of acute meningitis?
- when there are no other contraindications to steroid use, for patient suspected to have meningitis of bacterial aetiology
- to be given before, concomitant with or within 30 minutes after the administration of the first dose of antibiotics.
What are the minimum durations of therapy for meningitis caused by S. pneumo, H influenza b, N meningitidis, GBS, respectively
- S. pneumo = 10-14 days
- H influenza b = 7-10 days
- N meningitidis = 5-7 days
- GBS = 14-21 days
What are the types of maternal genital HSV cases?
- First episode primary infection (mother has no serum antibodies to HSV 1 or 2), newly acquired
- First episode non primary infection (mother has serum antibodies to the opposite type of HSV than she is infected with), newly acquired
- Recurrent infection (mother has pre-existing antibodies to the HSV type with which she is infected.
Which type of maternal genital HSV infection holds the highest risk of transmission to infant?
- First episode primary infection (followed by First episode non primary infection, followed by low risk from Recurrent)
What are ways in which risk of transmission of HSV can be decreased when mother is known to have genital HSV infection?
- elective C/S
- prophylaxis with acyclovir/valacyclovir from 36 weeks onwards until delivery
- avoidance of using scalp sampling/monitoring, forceps/vaccums
- avoidance of PROM
How are perinatal/natal/postnatal HSV infections in the infant classified?
- Skin, eyes, mucous membrane (SEM) infection
- Localized CNS HSV
- Disseminated HSV
What clinical features would raise suspicion of neonatal HSV infection?
- unwell infant
List the different types of tests used to detect HSV
- Viral cultures (oropharynx, nasopharynx, skin lesions, mucous membranes swabs, rectal swabs, blood buffy coat and CSF)
- PCR testing (CSF, skin lesions, mucous membranes, blood)
- Direct immunofluorescent antibody staining of skin lesions
- Enzyme immunoassays for HSV antigens in skin lesions
What is the gold standard diagnostic method for HSV outside the CNS?
- viral culture
What is the gold standard diagnostic method for HSV in the CNS?
- PCR
What are the durations of therapy for treating SEM disease, CNS disease and disseminated disease with HSV, respectively?
- SEM disease = 14 days
- CNS disease = minimum 21 days
- Disseminated disease = minimum 21 days
Follow-up for infants infected with HSV should include what?
- neurodevelopment
- vision/opthalmologic complications
- hearing/audiologic complications
How is an infant born to a mother with suspected first-episode genital HSV via C/S with no rupture of membranes managed?
- mucous membrane swabs
- +/- PCR of blood
How is an infant born to a mother with suspected first-episode genital HSV via C/S with membranes ruptured pre-delivery managed?
- mucous membrane swabs
- IV acyclovir x 10 days
How is an infant born to a mother with suspected first-episode genital HSV via vaginal delivery managed?
- mucous membrane swabs
- IV acyclovir x 10 days
How is an infant with positive HSV mucous membrane swabs managed?
- Admit
- Obtain CSF and blood for HSV PCR
- Obtain liver enzyme levels
- Treatment duration of 14 days for SEM, 21 days for disseminated or CNS infection
How is an infant born to a mother with recurrent genital HSV via vaginal delivery managed?
- Mucous membrane swabs at 24 hours
- Treat only if positive
How is an infant born to a mother with recurrent genital HSV via C/S managed?
- Mucous membrane swabs at 24 hours
- Treat only if positive
Which infants with neonatal HSV infection should receive suppressive therapy with oral acyclovir?
- infants with localized CNS HSV (not as effective for SEM or disseminated disease, but could still be offered)
- duration 6 months
- monitor CBC, BUN, Cr monthly while on acyclovir
What causes a child to have absent or defective splenic function?
- congenital anatomical absence of spleen
- surgical removal of spleen (or part of spleen)
- medical conditions that result in poor or absent splenic function (ie. SCD, thalassemia major, hereditary spherocytosis)
List the types of infectious agents that asplenic/hyposplenic patients are at most risk of?
- encapsulated bacteria*
- S. pneumoniae
- N. meningitidis
- H. influenzae
- Salmonella species
- E. coli
- Pseudomonas, Klebsiella, streptococci, staphylococci (less common)
- Capnocytophaga species (dog/cat bites)
- malaria
- Babesia
In addition to the regular childhood and adolescent immunizations, what additional immunizations should asplenic/hyposplenic patients receive?
- 23-valent pneumococcal vaccine
- quadrivalent meningococcal vaccine (serotypes ACWY), + coverage for serotype B
- H influenzae b
- Seasonal influenza vaccine
What type of prophylaxis is recommended for asplenic/hyposplenic patients age 0-3 months?
- Amoxicillin/clavulanate BID + Pen VK BID
or - Amoxicillin BID
What type of prophylaxis is recommended for asplenic/hyposplenic patients age 3 months to 5 years?
- Penicillin VK BID
or - Amoxicillin BID
What type of prophylaxis is recommended for asplenic/hyposplenic patients older than 5 years old?
- Penicillin VK BID
or - Amoxicillin BID
What is the recommended duration of antibiotic prophylaxis for children with asplenia/hyposplenia?
- minimum 2 years post-splenectomy
- minimum 5 first years of life
- ideally recommended as lifelong prophylaxis
What antibiotic should be administered to a febrile child with asplenia/hyposplenia?
- Ceftriaxone (after blood cultures)
What ophthalmologic complications occur in gonococcal ophtalmia?
- corneal ulceration
- perforation of the clone
- permanent visual impairment
For an asymptomatic infant exposed to gonorrhoea during delivery, what is the recommended management?
- culture eyes
- give Ceftriaxone x1 dose
For a symptomatic infant exposed to gonorrhoea during delivery, what is the recommended management?
- FSWU, start Ceftriaxone
For an asymptomatic infant who is suspected to have been exposed to gonorrhoea during delivery, what is the recommended management?
- good education and follow-up instructions
- if in doubt of adequate follow-up, can administer Ceftriaxone x1 prophylactically
For an asymptomatic infant exposed to chlamydia during delivery, what is the recommended management?
- monitor and treat only if symptomatic and eye culture positive
- no regular eye cultures recommended
- no prophylactic antibiotics recommended
What is antimicrobial stewardship defined by?
- interventions geared toward: 1) optimizing prescribing of antimicrobials, 2) appropriate selection/dosing/route/duration of antimicrobial therapy, 3) optimizing patient outcomes, 4) decreasing adverse events related to antimicrobial therapy
What are the benefits of antimicrobial stewardship?
1) decreased risk of antimicrobial-resistant bacteria
2) decreased incidence of C diff gastrointestinal infections
3) decreased adverse events related to antimicrobial use
4) decreased super infections related to antimicrobial use
5) cost savings associated with lowering antimicrobial use
The principles of antimicrobial stewardship (ie. watchful waiting, narrow spectrum antimicrobials) may not apply to which groups of patients?
- immunosuppressed patients
- asplenic/hyposplenic patients
- patients with congenital immunodeficiency syndromes
- newborns with suspected infection
What are non-pharmacological methods of preventing RSV infections?
- avoiding direct contact with other children with URTIs, especially during RSV season
- good hand hygiene at home
- breastfeeding (inconsistent data)
- avoidance of cigarette smoke (inconsistent data)
In Canada, most RSV programs offer palivizumab to which groups of children?
- infants with chronic lung disease
- infants with hemodynamically significant congenital heart disease who are
Which is the most common bacterial agent causing pneumonia?
Strep pneumoniae
What are the two most common clinical signs of pneumonia?
- Fever
- Tachypnea
What is the prominent radiographic pattern in bacterial pneumonia? Viral? Atypical?
Bacterial: lobar consolidations with air bronchograms
Viral: poorly defined patches of infiltrates or atelectasis
Atypical: bilateral focal or interstitial infiltrates that appear more extensive than the clinical symptoms
When should NP swabs be sent in patients with pneumonia?
In all patients admitted to hospital with pneumonia during influenza season, as antiviral are likely to be of benefit for influenza pneumonia
List investigations for an uncomplicated bacterial pneumonia
- CXR
- CBC w/ diff
- Blood culture
List the indications for hospitalization of a patient with pneumonia
- Inadequate oral intake
- Intolerance of oral therapy
- Severe illness
- Respiratory compromise
- Complicated pneumonia
- Higher threshold for infants
What is the outpatient and inpatient antibiotic choice for uncomplicated bacterial pneumonia?
- Outpatient: Amoxicillin po
- Inpatient: Ampicillin IV
In a toxic patient presenting with pneumonia, what is the empiric choice of antibiotics?
- Ceftriaxone/Cefotaxime
- +/- Vancomycin (add if rapidly progressing multi lobar disease or pneumatoceles)
In a patient with atypical pneumonia, what is the treatment regime?
- Most children actually resolve on their own
- If not, Azithromycin x 5 days
What is the prognosis for uncomplicated bacterial pneumonia?
- Should improve within 48 hours of starting antibiotics
- CXR changes may persist for 4-6 weeks
- No repeat CXR required to confirm clearance
List reasons for lack of clinical resolution in a bacterial pneumonia
- Foreign body aspiration
- Reactive airways disease with atelectasis
- Congenital pulmonary anomaly
- Tuberculosis
- Unrecognized immunodeficiency with an opportunistic infection
List the modes of acquiring various infectious diseases for a patient undergoing an organ transplantation
- the endogenous reactivation of latent pathogens
- transmission from donated organ/tissue
- transmission from within the community or health care setting
What is the time interval between administering an inactivated vaccine and transplantation?
- more than 2 weeks
What is the minimal interval between the last dose of a live vaccine and onset of immune suppression
- 4 weeks
What types of infections occur in the first month post-transplant
- 95% similar to infections incurred by nonimmunosuppressed patient swho have undergone a comparable surgical procedure
- remaining: infection that was present in recipient before transplantation, or infection transmitted by allograft
What types of infections occur in the 1-6months post transplant period?
- Opportunistic infections
- Viral pathogens (CMV, EBV, HHV6, HepB, HepC)
- Listeria, aspergillus, pneumocystis jirovecii
What types of infections occur >6 months post-transplant
- Well-maintained immunosuppression: same community-acquired infections as health children
- Poorer post-transplant outcomes: high risk for recurrent infections, opportunistic infections
When is it safe to vaccinate a patient post-transplant
- None for 6-12months (except annual influenza vaccine - vaccinate no earlier than 1 months post-transplant)
List vaccines that are contraindicated in post-transplant, immunosuppressed patients
measles mumps rubella varicella rotavirus BCG
Which vaccines are indicated in post-transplant patients
- pneumococcal vaccines
- meningococcal vaccines (conjugate MCV should be used instead of polysaccharide vaccine)
- HPV vaccine
- HepA/HepB
- Inactivated polio, Hib, diphtheria, tetanus, acellular pertussis
Who should receive the annual influenza vaccination?
- All children and youth >6 months of age
Which individuals are at high risk for influenza infection?
- Children 65yo
- All aboriginal peoples
- All residents of chronic care facilities
What are the contraindications to influenza vaccine?
- Guillain Barre within 6 weeks of influenza vaccination in past
- Anaphylaxis to inflenza vaccination in past
- Live attenuated influenza vaccine (LAIV) is contraindicated in those with egg-allergies, immunocompromised, severe asthmatics, pregnant women and those on ASA (aged 2-17yo)
Which strains of HPV in the HPV vaccine protect against cervical cancer? against genital warts?
- Cervical cancer: 16 & 18
- Genital Warts: 6 & 11
List risk factors for HPV infection
- increased number of sexual partners
- early age of first intercourse
- never being married
- never being pregnant
- immunosuppression
- STIs
What is the schedule for the HPV vaccine?
Administer to all girls 9-13yo
0, 2, 6 months
Contraindicated in pregnant women
What are the most common pathogens in the setting of complicated pediatric pneumonia in an immunocompetent host?
- S. pneumonia
- S. aureus
- S. pyogenes (GAS)
- MRSA
When should drainage of empyema be considered?
- in a patient with moderate to severe respiratory distress
What empiric regimen of antibiotics should be considered for a patient with complicated pneumonia?
- Cefotaxime/Ceftriaxone +/- Clinda (anaerobe coverage) or Vanco (MRSA coverage)
- Duration 3-4 weeks
When should a patient with complicated pneumonia be transitioned to oral antibiotics?
- when no further drainage of empyema
- when afebrile
- when off O2
- When clinical improving
When should a CXR be repeated following a complicated pneumonia?
- 2-3 months after to ensure resolution
By what age do most boys have retractile foreskin?
17yo
List potential benefits of neonatal circumcision
- decreasing risk of UTI in high risk infants (ie. those with recurrent UTI, high grade VUR, obstructive uropathy)
- decreased risk of HIV, HPV, HSV
- small decrease risk of squamous cell carcinoma of penis
List potential risks of circumcision
- Acute complications: minor bleeding, local infection, pain, unsatisfactory cosmetic result
- Severe complications: partial amputation of penis, death from hemorrhage, death from sepsis
- Most common late complication: metal stenosis, which may require surgical dilatation (prevent with vaseline x6 months to glans)
List the contraindications to neonatal circumcision
- hypospadias
- bleeding diathesis
When should gloves be worn in office settings?
- If anticipating direct hand contact with blood, body fluids, secretions or excretions, or items contaminated with these.
- Direct hand contact with mucous membranes or non intact skin
- Direct hand contact with the patient when the health care worker has open lesions on the hands
All office personnel should be immune to which viruses>
- measles
- mumps
- rubella
- varicella
- HepB
- Polio
- Acellular pertussis (at least one adult booster)
What is the work restriction for health care providers with the following illnesses:
- Hep A
- Measles
- Mumps
- Pertussis
- Rubella
- one week after onset of jaundice
- four days after onset of rash
- nine days after onset of parotitis
- five days of appropriate antibiotics
- seven days after onset of rash
What types of infections are asplenic and hyposplenic patients at risk for?
- Encapsulated bacteria: Strep pneumoniae, H influenzae, N. meningitides
- Also at risk of other infections: Salmonella, E. coli, Pseudomonas, Klebsiella, Streptococci, Staphylococci
- More at risk of severe or fatal malaria, protozoan Babesia (tick bites)
What are the special vaccine schedules for asplenic/hyposplenic patients?
- Pneumococcus: 13-valent (= Prevnar, 4 doses) and 23-valent (=Pneumovax, at 24mo and booster at 5yo)
- Meningococcus: MCV4 (4 doses, 2/4/6/12-15mo, revaccinated q5 years), 4CMenB should also be given (? schedule)
- Hib: 4 doses (2,4,6,18mo), repeat vaccine if they get Hib invasive infection
- Influenza annually
- Household contacts should be fully immunized
When should vaccines be given with relation to elective splenectomy?
- best responses occur when vaccines administered at least 2 weeks before surgery is performed
In which populations is Hepatitis C infection higher?
- IVDUs
- Hemophiliacs
- Those receiving blood transfusions before 1990s
How are Hepatitis C infections defined as chronic?
- Active viral replication persisting for >6 months
- Test indicated by presence of HCV RNA in blood on most or all blood specimens
- 75% of acute cases become chronic
What is the rate of vertical transmission of HCV?
- 5%
What are the factors that increase vertical transmission of HCV?
- higher maternal viral titre
- elevated ALT in year before pregnancy
- Presence of maternal cirrhosis
- mothers with HIV
What are the precautions to be taken during labour of a woman with HCV
- no need for C/S
- inconsistent evidence that PROM is risk factor
- avoid scalp electrodes or amniocentesis
- no contraindication to breastfeeding (unless flared with cracked nipples)
Which women are at high risk of HCV and should be screened antenatally for HCV?
- Past or present IVDUs
- Recipients of blood products before 1990
- Recipients of blood products in developing countries
- Patients with unexplained elevated aminotransferases
- Patients who have undergone organ or tissue transplantation from unscreened donors
Mother with known HCV delivers a healthy infant. What is the recommended management?
- Serologies at 12-18 months (if positive before 18mo, repeat at 18mo)
- HCV RNA after 2months can be performed if significant parental anxiety or fear of loss to follow-up
How many infants will clear HCV?
- Approximately 25% of infants with HCV vertical transmission will clear the virus
How to manage a woman with no documentation of previous rubella immunization?
- screen during pregnancy
- one dose of rubella vaccine postpartum if seronegative
- breastfeeding not contraindication to giving mother rubella vaccine
- immunizing all nonpregnant immigrant and refugee women at their first encounter with Canadian health care system unless have documentation of effective vaccination or natural immunity