Infectious Diseases- Practice Points Flashcards
how do most cases of polio present?
Most cases of polio are asymptomatic or present as a short, self-limiting illness.
what percentage of polio presents with paralysis
1%
Paralytic poliomyelitis is characterized by an acute onset of ASYMMETRIC flaccid paralysis
How do you test for polio
stool and throat swab
what are the symptoms associated with measles
Cough Coryza Conjunctivitis followed after a few days by a descending maculopapular rash endemic in Germany
what disease is associated with koplik spots?
measles
bluish-white spots on red buccal mucosa
what are 4 complications of measles
otitis media
pneumonia
meningitis
death
how do you test for measles (3)
serology, NP swab and urine sample
how does a patient with diphtheria present? how is it diagnosed?
Sore throat, weakness, fever, and a rapidly progressive swelling of the neck
“bull neck”
clinical diagnosis
is there herd immunity for tetanus?
No! Herd immunity plays no role in protection
How does a patient present with tetanus
rigidity and spasms
what is the classic presentation for mumps
unilateral or bilateral parotitis
Vaccine failure is common with mumps. Therefore, testing should be considered in all cases of parotitis unless the infection is confirmed to be bacterial in origin
what strains are in the quadrivalent influenza vaccine
2 strains of influenza A
2 strains of influenza B
what influenza vaccine should be given to children
quadrivalent vaccine is recommended
influenza B causes more mortality and morbidity in children than in adults.
what are contraindications to LAIV (3)
- age <2 yo
- pregnancy
- immunocompromised
- severe asthma (defined as current active wheezing or currently on oral or high-dose inhaled glucocorticosteroids, or medically attended wheezing within the previous 7 days)
- who are receiving chronic acetylsalicylic acid-containing therapy, because of the association of Reye’s syndrome with acetylsalicylic acid given during influenza infection.
when should you receive influenza vaccine?
influenza vaccine should be given as soon as it is available, before the onset of the influenza season.
what are 2 contraindication to influenza vaccine
- An anaphylactic reaction to a previous dose of influenza vaccine or to any of the components of the vaccine with the exception of egg
- onset of Guillain-Barré syndrome within 6 weeks of influenza vaccination without other known cause
is egg allergy a contraindication to influenza vaccine?
No! egg allergy is no longer a contraindication to the use of IIV
what is the dose of the inactivated influenza vaccine
0.5mL IM
The dose of LAIV4 is 0.2 mL (0.1 mL administered in each nostril as an intranasal spray)
who needs two doses of influenza vaccine
The first year that a child younger than 9 years of age receives influenza vaccine (either IIV or LAIV), two doses at least 4 weeks apart are required. If a child less than 9 years of age has received at least one dose of any influenza vaccine in the past, only one dose is required this season. Children 9 years of age or older and adults require only one dose each year.
What are two ways that we can build a protective environment for immunocompromised ppl
- immunization- especially MMRV and influenza vaccine
family and health care providers - hand hygiene
Preventive measures to reduce risk for respiratory infections include the following:
Avoid contact with individuals known to have a respiratory illness, especially if symptomatic
Notify physician at the first signs of respiratory illness during influenza season.
Inform the child’s medical team when there is influenza illness within the household.
Minimize exposure to crowded environments, such as shopping malls, during influenza/respiratory virus season.
Avoid primary or secondary exposure to tobacco smoke.
Avoid risk of exposure to fungal pathogens by:
Minimizing exposures to construction, excavation and renovations sites, where fungal spores (e.g., Aspergillus) can thrive,
Minimizing inhalation of fungal spores from plants and animals (i.e. in farms, barns or pigeon coops, or from mulching, turning compost piles or cave exploration),
Not smoking marijuana.
Preventive measures to reduce risk of contracting a waterborne illness include the following
Not drinking tap water in Canada when ‘boil water’ advisories are in effect.
Drinking only bottled or boiled water when travelling to regions with suboptimal sanitation.
Not drinking well water unless the source is properly screened and monitored by health authorities.
Not drinking water directly from rivers, streams, lakes and ponds.
Not using hot tubs, which have been associated with infections such as Pseudomonas folliculitis [18], Legionella pneumophila infections [19], and mycobacterial infections [20].
Cleaning abrasions with water from a safe source and avoid swimming in water that may be contaminated. Waterborne pathogens can enter through skin abrasions, or the respiratory tract if aspirated.
how can you prevent foodbourne illness
All milk, fruit and vegetable juices should be pasteurized.
Avoid cheeses produced from raw or unpasteurized milk, especially soft and semi-soft varieties (e.g., Brie, Camembert, and blue-veined cheeses).
Avoid raw meats, seafood and eggs.
Lettuce and all other raw vegetables should be washed thoroughly, even when they are labelled as prewashed.
Avoid cross-contamination when preparing foods. Keep cooked and raw foods separate and use different cutting boards or surfaces for raw and cooked foods
what are some preventative strategies for safer sexual practices for immunocompromised ppl (4)
Using latex condoms
immunization with hepatitis B and HPV vaccines
having fewer sexual partners
educating the immunocompromised adolescent are essential preventive strategies.
who should get chemoprophylaxis for invasive group A strep
Chemoprophylaxis should only be offered to close contacts of a confirmed case of severe IGAS who have been exposed during the period from 7 days before the onset of symptoms in the index case to 24 h after initiating antimicrobial therapy in the case.
close contacts:
(>4h/day or total of 20h)
shared a bed with the index case
sexual relations with the index case
Persons who have had direct contact with the mucous membranes or oral or nasal secretions of the index case
IV drug users who shared a needle
all children and staff in family or home child care settings
NOT recommended in group or institutional child care centres and preschools.
when should a person get chemoprophylaxis for invasive group A strep?
Chemoprophylaxis should be started as soon as possible, preferably within 24 h of identifying the case, but is still recommended up to 7 days after the last contact with the case.
Recommended chemoprophylaxis regimens for close contacts of invasive group A streptococcal disease? first line? second line?
First line:
- cephalexin
- cefadroxil
second line:
- clindamycin
- clarithromycin
what is empiric treatment for TSS
cloxacillin + clindamycin
what is considered SEVERE invasive group a strep
a. Streptococcal TSS
b. Soft-tissue necrosis (including NF, myositis or gangrene);
c. Meningitis
d. Pneumonia (with isolation of GAS from a sterile site such as pleural fluid). Note that bronchoalveolar lavage (BAL) is not considered to be from a sterile site.
e. A combination of the above.
f. Any other life-threatening condition or infection resulting in death
how can you confirm invasive GAS
Isolation of group A streptococcus (GAS) from a normally sterile site, with or without clinical evidence of severe invasive disease).
what is seen on CXR for TB
ground glass opacities
hilar, mediastinal or subcarinal lymphadenopathy
disseminated disease: miliary nodules
what is seen on LP for TB meningitis
CSF typically shows pleocytosis with lymphocytic predominance
what testing is done to diagnose TB
sputum cultures
children who cannot expectorate sputum: fasting gastric aspirates 3x morning samples
send for acid fast bacilli stain and culture
all need testing for HIV
children less than 2 should they have TST or IGRA
TST
what is the treatment for latent TB (2)
Rifampin, Isoniazid
what is the treatment for TB (4)
Rifampin, Isoniazid, Ethambutol, Pyrazinamide
what is the treatment for a child who has contact with TB
child <5 with TST <5mm
child >5 with TST <5
child >5 and TST >5
< 5 years with TST < 5mm= prevention prophylaxis (window prophylaxis with 1 TB drug)
Repeat TST 8-10 weeks after initial contact
If repeat test <5mm then dc window prophylaxis
Child ≥ 5 and initial TST <5mm repeat BOC TST 8-10 weeks (no prophylaxis required)
Child ≥ 5 and ≥ 5mm but no symptoms on initial or BOC TST= treat for latent infection
BOC= break of contact
When a child or youth is identified as a contact of an index case of TB what should you do? (4)
conducting a history and physical exam
requesting chest radiographs
perform an initial TST are essential steps
Obtaining the index case’s drug sensitivities is also required
what are the two types of salmonella
typhoid- salmonella typhi, salmonella paratyphi
non-typhoid
how can you get salmonella
contaminated food/water
direct contact with reptiles/amphibians
what is the treatment for typhoid fever
Azithromycin x 7 days
Fever typically persist 6-8 days from start of antibiotics. Fever is not a contraindication to switch to oral antibiotics or to hospital discharge
how should you manage a child that has a positive BLOOD culture for s. typhi
- send blood culture
- start ceftriaxone
- look for signs of disseminated disease
- admit to hospital
- repeat blood cultures every 24-48h until negative
how should you manage a child that has a positive STOOL culture for s. typhi
if no travel to resource poor country and afebrile then observe, do blood culture if febrile
if febrile, unwell, immunocompromised- do blood culture, start ceftriaxone, look for signs of disseminated disease
when should you start treatment for influenza if you are going to treat? how long is the treatment
as soon as possible, start within 48 hours
duration is typically 5 days
what are the 2 antivirals that are used in Canada for influenza
Oseltamivir
Zanamivir (for children ≥ 7)- administered via disk inhaler, not recommended for those with chronic respiratory illnesses such as asthma
what is the dose for zanamivir
10mg BID vis disk inhaler (two 5mg inhalations)
what is the dose for oseltamivir
≤15 kg 30 mg twice daily
>15 kg to 23 kg: 45 mg twice daily
>23 kg to 40 kg: 60 mg twice daily
>40 kg: 75 mg twice daily
Children 3-12 months = 3mg/kg/dose BID (or daily)
who is considered high risk for influenza complications and hospitalizations
All children <59 months of age*
All children ≥6 months of age; adolescents and adults with chronic health conditions (severe enough to require regular medical follow-up or hospital care), specifically:
Cardiac or pulmonary disorders, including bronchopulmonary dysplasia, cystic fibrosis, asthma or conditions associated with an increased risk for aspiration
Diabetes mellitus and other metabolic diseases
Renal disease
Anemia or hemoglobinopathy
Cancer or other immune-compromising conditions (due to disease or therapy)
Obesity, with a body mass index (BMI)≥40 kg/m2 OR a BMI z-scores >3 SD above the mean for age and gender
Neurological or neurodevelopmental conditions
Children and adolescents (<18 years of age) currently undergoing prolonged treatment with acetylsalicylic acid for a chronic condition
All Indigenous persons
All residents of chronic care facilities
All pregnant women, including adolescents, in all trimesters
All adults ≥65 years of age
when should you consider treating for influenza
if they are >1yo?
> 1 yo and have a risk factor for influenza complication apart from age and within 48 hours of symptoms
if beyond 48 hours- consider on a case by case basis
start oseltamivir
if your patient is not responding to Oseltamivir what should you do
switch them to Zanamivir
test for oseltamivir resistance
what are some physician approaches to vaccine hesitancy (5)
- Understand the key role that vaccine advice can play in parent decision-making, and do not dismiss vaccine refusers from your practice
- Use presumptive and motivational interviewing techniques to understand vaccine concerns
- Use simple clear language to present evidence of disease risks and vaccine benefits
- Address pain
- Community protection (herd immunity) does not guarantee personal protection
what are 5 steps to address hesitancy and improve vaccine uptake rates?
1) Detecting under-immunized subgroups, diagnosis and targeted interventions
2) Educating all health care workers on best practices
3) Employ evidence-based strategies to increase uptake
4) Educating children, youth and adults on the importance of immunization for health
5) Working collaboratively with government, nongovernmental organizations, community leaders and health services
what infectious diseases do you worry about in a returning traveller
Malaria
Typhoid fever
Meningococcemia
Viral hemorrhagic fevers
what are the initial investigations for a returning traveller with a fever
CBC with differential electrolytes LFTs BUN/CRE blood culture malaria smears (thick and thin) urinalysis +/- culture
Other tests, to be done more selectively:
Serology (EBV, CMV, hepatitis viruses, HIV, dengue, chikungunya, Zika, brucellosis, strongyloidiasis…)
CXR
Stools for C/S, O/P
Ddx for fever in a returning traveller
Malaria Typhoid Fever Dengue Fever Traveller's diarrhea infectious hepatitis Chikungunya virus Zika virus viral hemorrhagic fever (Ebola)
how long before immunosuppression do you give live vaccines? inactivated vaccines?
Inactivated vaccines should be given at least two weeks before
live vaccines must be given at least four weeks before
when can you give live vaccines following high dose steroids?
High dose Steroids (>2mg/kg/day): live vaccines 1 month post-discontinuation
High dose steroid therapy is defined as systemic treatment with the equivalent of prednisone ≥2 mg/kg/day or ≥20 mg/day if weight >10 kg for ≥14 days
when can you have live vaccines following chemotherapy
live vaccines 3 months after chemo
