Infectious Disease Flashcards
Tx of echinococcus
albendazole
Tx of strongyloides
ivermectin
___ is associated with increased risk of invasive pneumococcal PNA
opioid use
___ (behavior) is associated with increased CAP
high alcohol consumption
risk factors for pseudomonas pna
- prior pseudomonas infection
- bronchiectasis
- tracheostomy
- COPD
WHich imaging has highest sensitivity of PNA
POCUS
CT Chest
Most common pathogens in lower respiratory infection
VIRUSES - more common than bacterial
#1 rhinovirus
Influenza A & B
HMP
RSV
Parainfluenza
Coronavirus
Adenovirus
and #1 strep pneumoniae
MRSA nares has what components of the following (high or low)
Sensitivity
Specificity
PPV
NPV
85% sensitivity
92% specificity
POOR PPV (57%)
great NPV (98%)
If the test is negative, very unlikely that MRSA is present in the lungs
Parente, Clin ID 2018
Does having MRSA in the past 12 mo show colonization?
no
In non-severe outpatient CAP, what testing is indicated
Influenza
Covid
In severe and non-severe admitted patients with CAP, what testing is indicated
What about immunocompromised patients
(Based on ATS/IDSA 2019 guidelines)
Influenza
Blood & resp culture (only if risk of MRSA or pseudomonas in non-severe)
Legionella U Ag only if local outbreak
MRSA PCR
In severe CAP and immunocompromised, additionally should include legionella UAg no matter what, Strep urinary Ag
PNA PCR (NAAT)
RVP
What is the effect of using procalcitonin in treatment of CAP
reduce the # of days the patient will be on Abx
CURB 65
Confusion
Urea
Resp
Blood pressure <90/60
> 65 yo
3 or more requires hospitalization
Severe CAP criteria (whether or not to admit to ICU)
Either 1 major or 3+ minor
Major criteria:
1. Septic Shock with need of vasopressors
2. Respiratory failure requiring mechanical ventilation
Minor:
- RR >30bpm
- P:F ratio <250
- Multilobar infiltrates
- Confusion
- Uremia BUN >20
- Leukopenia <4000
- Thombocytopenia <100
- Hypothermia core <36C
- Hypotension requiring aggressive fluid resus
Minor: RPM CULTHH
CAP outpatient tx
No comorbidities:
the usuals (amox, doxy, or macrolides)
+ comorbidities:
Augmentin
Cefuroxime
PLUS macrolide or doxy
or resp fluoroquinolone
ATS/IDSA 2019
CAP inpatient tx
Non-severe:
beta-lactam + macrolide
OR
resp fluoroquinolone
+ antipseudomonal if prior pseudomonas in 12 mo
Severe:
betalactam + macrolide
OR
betalactam + resp fluoroquinolone
for either above:
+ Anti-MRSA to be added if prior MRSA infection in 12 mo
+ anti-pseudomonal if prior pseudomonas in 12 mo
Covid tx outpatient
paxlovid
can get remdesivir
Indication for starting remdesivir for covid 19
hospitalization
O2 requirement (but not if its so severe you need HFNC, can consider in those who are at high risk of dz progression)
Indication for starting dexamethasone in covid 19
requiring O2 supplement
If with HFNC, should be given with remdesivir
If still very hypoxic, add baricitinib or IV tocilizumab
Indication for giving IV tocilizumab in covid-19 infection
(or IV sarilumab)
Hospitalized, requiring mechanical ventilation or ECMO
within 24h of MICU admission
When is remdesivir NOT indicated for covid-19 infection
hospitalized without O2 requirement OR mechanically ventilated OR ECMO
(so the mild-moderate people can get it, not the severe)
Duration of abx for CAP coverage in the hospital
3-5-7days if clinically stable
When should you cover for anaerobes in PNA
severe CAP (even this is controversial)
Parapneumonic effusion
WHen is corticosteroids indicated in CAP
severe CAP with high CRP
Covid-19 with O2 requirement
Contraindicated in influenza
Vaccinations indicated for respiratory protection (6)
Influenza
Covid-19
RSV
PCV20
Herpes Zoster
TdaPertussis
Definition of HAP
> 48h in the hospital
Ventilator associated pneumonia definition
ventilated for >48h
AND
2 or more of:
fever
abnormal WBC
sputum purulence
New infiltrate
VAP after vomiting in a patient who had abd surgery, patient likely has which pathogen
pseudomonas aeruginosa!
Gram negative bacteria
Rate of anaerobes in VAP and aspiration pneumonia
pretty much none
Superinfections in the ICU associated with covid-19 include which pathogens?
(4 bacteria, 2 fungi)
acinetobacter
e. coli
kleb
pseudomonas
candida
aspergillus
MDR risk factors (3)
- IV abx in the past 90 days
- Unit rate >20% of MRSA
- positive screening or prior infection or colonization with MDR
Most relevant risk factor for suspecting MDR pathogens in patients with HAP
prior IV Abx use within 90 days
HAP tx (no MDR risk factors with low risk of death)
zosyn
cefepime
levoflox
imipenem or meropenem
consider coverage for MSSA
If CF or NonCF bronchiectasis, consider pseudomonal coverage
VAP tx
MRSA coverage
Pseudomonal coverage (consider double)
Risk factor for MRSA
Prior 90d abx therapy
Unit rate 10-20% prevalence or unknown
Need for vent support or septic shock
When to add double pseudomonal coverage in HAP
High mortality risk
VAP
prior risk of pseudomonas
What abx should you not use alone for HAP
aminoglycoside
Duration of tx for HAP or VAP
7d
unless non-lactose fermenting GNR (pseudomonas, acinetobacter, steno) and not getting better, consider longer duration
Tx for acinetobacter HAP/VAP sensitive only to polymyxins
IV polymyxin (colistin or polymyxin B)
AND
adjunctive inhaled colistin
No effect on mortality or nephrotoxicity but with clinical improvement
For GNR/acinetobacter VAP/HAP with sensitivity to aminoglycosides or polymyxins OR carbapenem resistant, must use ____
both inhaled and systemic abx
Should you treat ventilator associated tracheitis?
NO
Tx of acinetobacter and pseudomonas (at the same time)
cefiderecol
Treatment of acinetobacter
unasyn (beta lactams)
or carbapenems and fluoroquinolones
aminoglycoside or bactrim for UTI
Resistant disease: polymyxin B, colistin
Carbapenemase producing genes (Enterobacterales)
KPC
OXA-48
MBL
Most common resistance mechanism in pseudomonas (intrinsic)
DNA gyrase and topoisomerase IV (fluoroquinolone resistance)
AmpC (b-lactams)
Most common resistance mechanism in pseudomonas (imported)
class A, B, D ….
b-lactam (ESBL) and carbapenem resistance and abx inactivation
Important VAP prevention
Oral care- toothbrushing WITHOUT chlorhexedine
Minimize sedation
Maintain and improve physical conditioning
Avoid intubation/prevent reintubation
What ICU interventions have no impact on VAP rates
stress ulcer ppx
monitoring residual gastric volumes
closed endotracheal suctioning systems
percent of household contact that will become infected with TB
~35%
Percent of LTBI that progresses to TB disease
how about if you’re on HIV or TNF alpha-blockers?
~10% per lifetime
HIV and TNF alpha blocker = 10% PER YEAR
MDR TB definition
Resistant to INH AND Rifampin
XDR TB definition
MDR TB (INH, Rif) +
Fluoroquinolone
AND
at least one of the injectables or bedaquiline/linezolid
infecting dose of MTB = __#___ organisms
10
smear negative TB but culture positive, how infectious is the patient?
15-17%
Most common location of pulmonary TB in immunocompetent patient
RUL posterior segment
Sensitivity of 3x AFB and 2x MTB PCR for TB disease
85%
Pregnant patients and TB tx
IRE (no PZA - in US lack of safety data, though WHO recommends it)
for 2 mo, then 7 mo of IR (total 9 mo)
MDR TB tx
BPaL
Bedaquiline, Pretomanid
Linezolid
Timing of highest risk of TB reactivation after exposure
within 1-2 years
You can have + TST or IGRA with what other diseases other than MTB
M. bovis, NTM
IGRA and TST PPV and NPV (in non-immunocompromised patients)
both >90% NPV
Better specificity of IGRA
Dose of prednisone that increases TB reactivation risk
> 15 mg prednisone
“Dimorphic” definition
can live in either shape as a yeast or mold depending on temp
septated acute branching hyphae at 45 degree angle
aspergillus
Biggest risk factor for invasive pulmonary aspergillosis
prolonged neutropenia
CGD
Pauci-septated 90degree angle branching hyphae, ribbon like
mucor
What can give you false positive galactomannan
histoplasma
high rice/pasta diet (What?)
plasma-lyte
some beta-lactams (older ones)
Does TBBx increase sensitivity for diagnosing invasive pulmonary aspergillosis?
not much
WHich are more likely to have pleural effusion, mucor or invasive aspergillosis?
mucor
Other than vori, what other meds can you use for invasive aspergillosis
isavuconazonium
posaconazole (for ppx)
can be paired with echinocandin
which type of aspergillus would aspergillus IgG ab be present?
chronic necrotizing pulmonary aspergillosis
AND
ABPA
Tx of ABPA
steroids +/- itraconazole
+/- omalizumab
BDG and Galactomannan for mucor
would be negative
Mucor tx
- surgical resection
- antifungals (ampho, posaconazole, isovuconazole)
- immune reconstitution
stop iron chelating agent if they are on it
candida in urinary or respiratory tract, do you treat?
more likely colonization
spaghetti and meatballs, yeast and pseudohyphae on path
candida
Treatment of toxoplasmosis
pyrimethamine and sulfadiazine
Treatment of paragonimiasis
praziquantel (two long Ps!)
fungal infection most likely to have peripheral eosinophilia
coccidiodomycosis
treatment of mpox
tecovirimat
2nd line cidofovir
Someone works with animal skinning, pleural effusion with lymphocytic predominance
Tuleremia
Treatment for tuleremia
mild: doxy or cipro
mod to severe: aminoglycoside (classically genta)
Pt with nocardiosis, aspergillosis and noncaseating granulomas on path, what does this patient likely have
chronic granulomatous disease CGD
How do you test for CGD
test for dihydrorhodamine with indirect flow cytometry
path showing “pseudohyphae, budding yeasts”
candida
branching, beaded, anaerobe on path
actino
branching beaded, will grow on agar (aerobe). weakly acid fast. Gram positive
nocardia
which can you use with carbapenem-resistant enterobacterales?
ceftaz/avibactam or ceftolozane/tasobactam
ceftaz/avibactam
Treatment of candidemia (antifungal and duration)
echinocandins –> later can transition to azoles if susceptible
Candidemia only: Continue two weeks after neg blood cultures
Endophthalmitis 4-6 weeks
Consider prophylaxis for 1 week with fluconazole if colonization of 2 or more sites (inconsistent literature)
broad based dimorphic fungus like a bowling pin
+ skin lesion
blasto
Mississippi/Arkansas/Michigan, dog is also sick, bony erosion, ulcerative, verrucous derm findings, pneumonia (or even ARDS) think ___
blasto
Dx of blasto
serum and urine Ag, BAL
Ab to anti-BAD-1 Ag
fruiting heads on path
aspergillosis
Infection that is an absolute contraindication for lung transplant
Bukholderia cenocepacia, M. abscessus
Owl’s eyes on path
CMV
Blasto tx
no tx if sx are mild (like mild cough)
Mild-moderate: itraconazole 6-12 mo
Severe ampho B 1-2wk then itraconazole
CNS: ampho
Pregnancy: ampho (avoid azoles)
Skin manifestation of coccidioidomycosis
erythema nodosum
Dx of coccidio
Ab testing
Urine and serum Ag
Spherules on culture or path
coccidiomycosis
Treatment of coccidio
immunocompetent: observation
If sx persist >6 weeks:
fluconazole or itra
or amphotericin in severe cases
Narrow based fungus
histo
spelunking and bats, chicken coops pneumonia with pulm nodules
histo
infection related to broncholithiasis and fibrosing mediastinitis
histo
Dx of histo
serum Ag (sens 81%, spec 98%)
Urine Ag, BAL, CSF
culture may take 6 weeks to grow
Tx of histo
mild or chronic - observation
moderate disease: itraconazole
severe: ampho
Round, oval, helmet, crushed ping-pong ball or crescent shaped, dot-like foci with enhanced staining
PJP
Tx for influenza that is contraindicated in asthma
zanamivir
halo, narrow based budding, mucicarnine stain +
crypto
Alternative to TMP-SMX for PJP
Add steroids if a-a gradient >35mmHg
Severe disease
clinda + primaquine
IV pentamidine
Mild disease:
TMP + dapsone
Atovaquone
Difference between malaria and lepto (serum lab findings) (2)
- lepto has isolated elevated bilirubin
- hypoglycemia is more typical in malaria
Tx for c. neoformans
Fluconazole (lung)
Ampho + flucytosine (CNS) - induction (minimal 2 weeks, or more if severe and cryp Ag still high), consolidation with fluconazole for 2 mo, then 1 year of maintenance therapy with fluc or other azoles (except itra) if not tolerating fluc
Where is Cryptococcus gattii endemic
tropical and subtropical regions plus pacific coast of N america
Azoles that need monitoring (levels)
itraconazole
posaconazole
voriconazole
(IPV)
MOA of azoles
inhibit cell wall function/growth
What is echinocandins fungicidal to
CANDIDA
echinoCANDins
Which test should we use for influenza that is recommended by the CDC
RT-PCR (4-6h turn around time)
Rapid influenza Ag detection (neuroaminidase assay) has low/mod sensitivity but high specificity
What viruses (aside from Sars-cov-2) can cause really bad ARDS
adenovirus
Human metapneumo
who should be treated for influenza
pregnant ppl
immunocompromised
within 48h of sx
If hospitalized, lab confirmed, can prob treat >48h of sx
Start early, don’t wait for viral test to come back if influenza is suspected
CMV timing post LT
1-6 mo (not in the acute post-transplant time)
Which is more typical for actinomyces rather than nocardia
can extend fascial planes
Tx of nocardia
bactrim
CNS involvement: bactrim, meropenem, amikacin (6 weeks IV), then ORAL bactrim, minocycline, augmentin
6-12 mo therapy
Definition of “refractory MAC”
ongoing positive sputum after 6 mo
add amikacin (for pan-sensitive)
Tx for patients exposed to MDR-TB
levofloxacin for 6-12 mo
difference between crypto neoformans and c. gattii
c. neoformans: immunocompromised
c. gatti: immunocompetent ppl (eucalyptus tree)
risk for actinomycosis
ETOH
Poor dentition
actino on path
sulphur granules
actino treatment
PENICILLINS
or
ceftriaxone
avoid aminoglycoside
How is nocardia spread throughout the body
hematogenously
How is actinomycosis spread throughout the body
direct invasion
SE Asia, raw crab & crayfish ingestion, consolidation, eosinophilic pleural effusion, chocolate-colored sputum. Dx/Tx?
Paragonimus westermani
eggs in BAL + Elisa
Tx: praziquantel, triclabendazole
SE asia, nocturnal cough, migratory GGOs, refractory asthma, peripheral eos, mosquito bite, elevated IgE. Dx?
Wuchereria bancrofti
Tx diethylcarbamzine
Tx histoplasmosis
Mild: itraconazole
Severe: ampho
Blasto tx
Mild: itraconazole
Severe ampho
Cocci tx
Mild fluconazole or itraconazole
Severe ampho
Sporothricosis tx
Mild itra
Severe ampho
Paracoccidiomycosis tx
Mild itra +/- bactrim
Severe ampho
Bipolar gram negative stain, safety pin looking; pathogen and tx
Yersinia
Tx aminoglycoside
What disease look like malaria but can be transmitted through blood transfucion
Babesia
What disease can cause mulch pneumonitis and cause eosinophilia
CGD
Maltese cross
babesia
though can be in in the trophozite circular form too
Difference between baloxavir and oseltamivir in influenza tx
Baloxavir has greater reduction in viral load by day 1 of treatment
Procal lvl to discontinue abx
<0.5
OR
decrease by 80% from peak
How do you get M. Bovis and what is it usually resistant to
unpasteurized cheese
PZA resistant
