LRTI Flashcards
pathophysiology of pneumonia
inhale aerosolised droplets + susceptible host -> pneumonia
risk factors for pneumonia
1) smoking
2) COPD, lung cancer, asthma
3) immune suppression
clinical presentation of pneumonia - systemic
fever, chill, malaise, change in mental status (elderly), tachycardia, hypotension
clinical presentation of pneumoniae - locaslied
cough, chest pain (pruritic chest pain: pain from coughing), SOB, tachypnoea, hypoxia, increased sputum production
pneumonia diagnosis - physical examination
- diminished chest sound over affected area
- inspiratory cackles during lung expansion
pneumonia diagnosis - radiographic finding
- require evidence of new infiltrates/dense consolidations (unilateral white patches)
pneumoniae diagnosis - lab findings
1) general (WBC, CRP, procalcitonin)
- X specific to pneumonia
2) urinary antigen test
- test for strep pneumoniae, legionella pneumophilla
- can remain positive for days-wks despite treatment
- recommend for severe CAP or hopistalised pt
- X for outpatient
where to obtain culture for gram stain for pneumonia
1) sputum
- hypotonic saline to induce pt to cough out sputum
- low yield cuz prone to contamination by oropharyngeal secretion
2) LRTI samples
- invasive sampling, less contamination
why take blood culture for diagnosis of pneumonia?
rule out bacteriaemia
ISDP guidelines for who needs pre-treatment culture & gramstain
1) Severe CAP
2) risk factors for drug resistant pathogens (MRSA, pseudo)
- empirically treated for either
- either infection in last 1 yr
- hospitalised/IV Abx within last 90 days
definition of community acquired pneumonia
onset in community or < 48 hr after hospital admission
risk factors for community acquired pneumonia
- history of pneumonia
- normal pneumonia risk factors (Recite them.)
prevention of community acquired pneumonia
1) smoking cessation
2) immunisation (influenza, pneumococcal)
CAP: CURB-65: criteria
(each criteria 1 point)
1) new onset confusion
2) urea > 7 mmol/L
3) RR ≥ 30 breaths/min
4) BP (SBP > 90 or DBP ≤ 60)
5) age ≥ 65 yo
CAP: CURB-65: total score vs location of treatment
- 0/1: outpatient
- 2: inpatient
- ≥ 3: inpatient (ICU)
classification of severe CAP
(≥ 1 major or ≥ 3 minor criterion)
major:
1) mechanical ventilation
2) septic shock requiring vasoactive medications to keep BP going
minor
1) RR ≥ 30 breaths/min
2) PaO2/FiO2 ≤ 250
3) multilobar infiltrates
4) confusion/disorientation
5) uraemia (urea > 7 mmol/L)
6) leukopenia (WBC < 4 x 10^9 /L)
7) hypothermia (< 36)
8) hypotension requiring aggressive fluid resuscitation -> vasopressors
types of pathogen causing outpatient CAP wo comorbidities
strep pneumoniae
empiric therapy for outpatient CAP wo comorbidities
1) beta lactam (amoxicillin)
2) respiratory fluoroquinolone
pathogen for outpatient CAP w comorbidities
1) Strep pneumoniae
2) haemophilus influenzae
3) atypical (mycoplasma, legionella, chlamydia)
empiric for outpatient CAP w comorbidities
1) beta lactam (augmentin) + macrolide (clarithro)
2) respi fluroquinolone
what are considered comorbidities for outpatient CAP
chronic heart/lung/liver/renal disease, DM, alcoholism, malignancy, asplenia
type of pathogens for non severe inpatient CAP
1) strep pneumoniae
2) haemophilus influenzae
3) atypicals
empiric therapy for non severe inpatient CAP
1) beta lactam (augmentin) + macrolide (clarithro)
2) respi fluroquinolone
what are some MRSA risk factors CAP
1) respiratory isolation in MRSA in last 1 year
2) hospitalisation/parenteral Abx in past 90 days + MRSA PCR screen +ve (need to swab to see if colonised by MRSA)
empiric therapy for non severe inpatient CAP w MRSA risk factor
add MRSA coverage to normal empiric
- IV vanco/linezolid
pseudomonas risk factors for non severe inpatient CAP
respiratory isolation of pseudomonas in last 1 year
empiric therapy for non severe inpatient CAP w pseudomonas risk
modify for pseudomonas coverage
- beta lactam: piperacillin/tazo or ceftazidime
- macrolide: levofloxacin
for non severe inpatient CAP
- start IV then step down to PO
- test for influenza during season
possible pathogen for severe inpatient CAP
- all non severe
- staph aureus
- other gram -ve (klebsiella pneumoniae, burkholderia pseudomallei)
burkholderia pseudomallei (severe inpatient CAP)
- tropical countries
- gram -ve rod found in soil (moist)
empiric therapy for severe inpatient CAP
1) beta lactam (augmentin) + ceftazidime + macrolide (clarithromycin)
2) respiratory fluoroquinolone + ceftazidime
empiric therapy for severe inpatient CAP w MRSA risk factors
normal empiric + MRSA coverage (IV vanco)
pseudomonas risk factor for severe inpatient CAP
- respiratory isolation of pseudomonas in last 1 year
- hospitalisation/IV Abx use in last 90 days
empiric therapy for severe inpatient CAP w pseudomonas risk
same as normal empiric for wo pseudomonas risk but already covered (ceftazidime, levoflox)
anaerobic cover for CAP
- if radiology report lung abscess/emphysema
- add IV/PO metronidazole
influenza management for CAP
- add empiric oseltamivir to Abx regimen ASAP if suspected
- +ve influenza PCR
**5 day course
** discontinue Abx at 48-72 hr if X evidence of bacterial pathogen
why respiratory fluoroquinolone X used as first line for CAP
1) increase AE
- tendonitis, tendon rupture, neuropathy, QTc prolongation, CNS disturbances, hypoglycaemia
2) development of resistance w overuse
3) preserve activity for other gram -ve infection
4) delay diagnosis of tb
5) undesirable monotherapy if tb
adjunctive corticosteroid therapy for CAP
- reduce inflammation in lung
- only if septic shock refractory to fluid resuscitation & vasopressor support
when to de-escalate from IV to PO treatment for CAP
1) haemodynamically stable
2) improve clinically
3) can tolerate oral meds
how to de-escalate from IV to PO
1) +ve culture
- use AST to guide narrow spectrum
2) -ve culture
- stop empiric for MRSA/pseudomonas/burkholderia pseudomallei after 48 hrs if pathogen X isolated & improving
- same Abx from IV to PO or from same class
what is nosocomial pneumonia
hospital acquired + ventilator associated
definition for hospital acquired pneumonia (HAP)
onset ≥ 48 hrs after hospital admission
definition for ventilator associated pneumonia (VAP)
onset ≥ 48 hrs after mechanical ventilation
risk factors for nosocomial pneumonia
1) pt related
- elderly
- smoking, COPD, cancer, immunosuppresion
- prolonged hospi, coma, impaired consciousness
- malnutrition
2) infection control
- X hand hygiene
- contaminated respi care devices
3) healthcare related
- prior Abx use (normal flora alr affected)
- impaired deep breath & exhale (sedative, opioid analgesics, mechanical ventilation, supine position)
prevention of nosocomial pneumonia
- consistent hand hygiene
- judicious Abx use & meds w sedative effect
- VAP specific
** limit duration of mechanical ventilation
** minimise duration & deep levels of sedation
** elevate head of bed by 30%
types of pathogen for nosocomial pneumonia
1) non-fermenting gram neg: pseudomonas, acinetobacter
2) enteric gram neg: enterbacter spp, klebsiella spp, e.coli
3) staph aureus
when to cover MRSA for nosocomial pneumonia
- prior IV Abx use within 90 days
- hospitalisation in unit where > 90% staph aureus MRSA
how many antipseudomonals for pseudomonas & GNR for nosocomial pnuemonia
- normally 1 antipseudomonal (X aminoglycoside)
when to use double pseudomonal for nosocomial pneumonia
1) Risk factor for antimicrobial resistance
- prior IV Abx use within 90 days
- acute renal replacement therapy prior to VAP onset
- isolation of pseudomonas in last 1 year
2) hospitalisation in unit where > 10% pseudomonas isolate resistant to agent considered for monotherapy
3) prevalence of pseudomonas X known
nosocomial pneumonia pathogen vs empiric
1) pseudomonas, other GNR (enterobacter spp, klebsiella spp, e coli)
- antipseudomonal beta lactam (pip/tazo)
- +/- antipseudomonal fluoroquinolone (levo, avoid if X MRSA cover)
2) MRSA
- IV vanco
nosocomial when to de-escalate/change from IV to oral
1) haemodynamic stability
2) improve clinically
3) able to ingest oral
nosocomial how to de-escalate/change from IV to oral
1) +ve culture
- use AST to guide culture-directed narrow spectrum
- double to single antipseudomonal
2) -ve culture
- maintain coverage according to local antibiogram
- X possible if significant for MDRO
- PO if tolerate.
