IC16 LRTI Flashcards
S/S of acute bronchitis
acute cough (less than 3 weeks) due to inflammation of trachea and lower airways
diagnosis of acute bronchitis is …
clinical, exclude differential diagnosis (no pneumonia, acute asthma, COPD exacerbation)
is diagnostic testing needed for acute bronchitis?
no
unless presence of S/S of bacterial infection
how does acute bronchitis starts
starts from viral upper respiratory tract infection
any tx for acute bronchitis?
it is self limiting
(no abx, regardless of the duration of cough)
when is abx considered for acute bronchitis
when there is complication of bacterial infection
need further diagnosis to confirm
abx for the bacterial infection not acute bronchitis
advice for pt with acute bronchitits
cough may last for 3 weeks, abx will not hasten the resolution of cough
return to clinic if:
- develop fever, SOB, chest pain
- cough increases in extent or frequency
- significant cough persists beyond 3 weeks
Pneumonia definition
infection of lung parenchyma (alveoli, alveolar duct, bronchioles) -> proliferation of microbial pathogens in alveolar level
common: bacterial pneumonia
less common: fungal. viral (influenza)
Pathogenesis of pneumonia: mechanism of infection (exposure)
- aspiration of bacteria in oropharyngeal secretions
- inhalation of aerosols
- hematogenous spread (through bloodstream) eg bacteremia
Pneumonia: RF
- smoking
- chronic lung disease (COPD, asthma, lung cancer)
- immunosuppressed (HIV, GC use, chemo)
Pneumonia: clinical presentations
(pneumonia usually presents with systemic sx)
Systemic: Fever, chills, malaise, change in mental status (elderly), tachycardia, hypotension
Localised: Cough, chest pains, SOB, tachypnoea, hypoxia, increased sputum production
Physical examination: diminished breath sounds, inspiratory crackles on lung expansion
Pneumonia: radiographic finings (chest X-rays, lung CT, lung ultrasonogrpahy)
dx of pneumonia: requires evidence of a new infiltrate or dense consolidation (usually unilateral)
bilateral: fluid overload
Pneumonia: lab findings and urinary antigen tests (and their limitations)
signs of systemic infection (WBC, CRP, procalcitonin) - not specific for pneumonia
urinary antigen tests
- streptococcus pneumonia
- legionella pneumophilia
-> only indicate exposure to respective pathogens (may not be new), remain positive for days-weeks despite abx tx
-> recommended for severe CAP or hospitalised pt only (not for outpatient)
Pnenumonia: what are the possible cultures taken
- sputum: low yield, highly contaminated
- lower respiratory tract samples: invasive, less contamination, need trained HCP to do
- blood cultures: to rule out bacteremia (esp for hospitalised pt)
(outpatient - no need culture, give empiric)
who needs to take pre treatment culture for pneumonia
- severe CAP
- RF for drug resistant pathogens (MRSA, pseudomonas)
- empirically treated for MRSA/ pseudomonas
- previously infected with MRSA/ pseudomonas in last 1 year
- hospitalised or received parenteral abx in last 90 days
classification of pneumonia
CAP: <48hrs after hospital admission
HAP: >= 48hr after hospital admission
VAP: >= 48hr after mechanical ventilation
is CAP serious?
yes, may be admitted to ICU
RF for CAP
history of pneumonia
RF of pneumonia (smoking, chronic lung disease, immunosuppressed)
prevention of CAP
smoking cessation
vaccination (influenza, pneumococcal)
- against influenza and strep pneumoniae
CAP: pathogens (outpatient, inpt non severe, inpt severe)
(outpt, inpt non severe)
- Strep pneumoniae
- Haemophilus influenzae
- Atypicals (Mycoplasma, Chlamydophila, Legionella pneumonia)
(for inpt based on RF) MRSA, pseudomonas
(inpt severe)
- all above +
- Staph aureus
- Gram negative bacilli (Klebsiella pneumonia, Burkholderia psudomallei)
(for inpt based on RF) MRSA, pseudomonas
what other pathogens should be considered (CAP)
influenza for all inpt during circulating season
Burkholderia pseudomallei usually from soil/ rain
what are the risk stratification methods for CAP?
pneumonia severity index (PSI)
CURB 65
IDSA/ATS criteria
class in PSI
class I and II: outpatient
class III: short hospitalisation or observation
class IV and V: inpatient
- complex, limited use in clinical setting
what are the factors in CURB 65
Confusion (1 point)
Urea >7 mmol/L (1 point)
RR >= 30 (1 point)
SBP <90 OR DBP <=60 (1 point)
age >=65 (1 point)
0/1 point: outpatient
2 point: inpatient
>=3 point: inpatient, maybe ICU
IDSA/ATS criteria
major criteria:
- mechanical ventilation
- septic shock requiring vasoactive medication
minor criteria:
- RR> 30bpm
- PaO2/FiO2 <= 250
- multilobar infiltrates
- confusion/ disorientation
- uremia (>7)
- leukopenia (WBC <4)
- hypothermia (<36)
- hypotension requiring fluid resuscitation
severe CAP >= 1 major OR >= 3 minor
CAP: abx for outpatient
Outpatient, no comorbidities
Pathogen: strep pneumoniae
- PO amoxicillin 1g q8h
- PO levofloxacin (pen allergy)
- PO moxifloxacin (pen allergy)
Outpatient, comorbidities (CHD, lung, liver, CKD, DM)
Pathogen: Strep pneumoniae, haemophilus influenzae, Atypicals
Choice 1:
- PO amoxicillin-clavulanate/ cefuroxime
PLUS (to cover atypicals)
- (macrolide) PO clarithromycin, azithromycin
- PO doxycycline
Choice 2:
- PO levofloxacin
- PO moxifloxacin
CAP: abx for inpatient, non-severe
Pathogens: Strep pneumoniae, Haemophilus influenzae, Atypicals
Choice 1:
- IV amoxicillin-clavulanate/ cefuroxime/ ceftriaxone
PLUS (to cover atypicals)
- (macrolide) IV clarithromycin, azithromycin
- PO doxycycline
Choice 2:
- IV levofloxacin
- IV moxifloxacin
(MRSA RF) PLUS
- IV vancomycin, linezolid
(Pseudomonas RF) MODIFY tx:
- IV piperacillin-tazobactam (add atypicals)
- IV ceftazidime (add strep pneumoniae, atypicals)
- IV cefepime (add atypicals)
- IV meropenem (add atypicals)
- IV levofloxacin (moxi does not cover pseudomonas)
initial IV then step down to PO, can start PO if pt is well
MRSA & pseudomonas RF for inpatient non severe
- respiratory isolation of MRSA in last 1 year
- hospitalisation or parenteral abx in last 90 days AND MRSA PCR screen positive
- respiratory isolation of pseudomonas in last 1 year
CAP: abx for inpatient, severe
Pathogens: Strep penumoniae, Haemophilus influenzae, atypicals,
Staph aureus,
gram negative (Klebs, Burkolderia pseudomallei)
Choice 1:
- IV pen G/ amoxicillin-clavulanate
PLUS (to cover Burkholderia)
- ceftazidime
PLUS (to cover atypicals)
- (macrolide) IV clarithromycin, azithromycin
Choice 2:
- IV levofloxacin
- IV moxifloxacin
PLUS (to cover Burkholderia)
- ceftazidime
(MRSA RF) PLUS
- IV vancomycin, linezolid
(Pseudomonas RF) MODIFY tx: ceftazidime/ levofloxacin (cefta already in tx plan)
MRSA, pseudomonas RF for inpt severe
- resp isolation of MRSA/ pseudomonas in last 1 yr
- hospitalisation or parenteral antibiotic use in last 90 days
add anaerobic cover when:
what abx? For pneumonia
(shown by CT scan)
lung abscess
empyema - collection of pus in pleural cavity
add IV/PO metronidazole, clindamycin
if not using:
amoxicillin-clavulanate,
piptazo,
meropenem,
moxifloxacin
influenza management
add empiric oseltamivir x5d
- initiate within 48hrs, up to 5 days
- discontinue at 48-72hrs if no evidence of bacterial pathogen (negative culture, low procalcitonin level <0.25, early clinical stability)
why is respiratory FQ not first line for CAP
(levo and moxi)
- increased AE (tendonitis, tendon rupture, neuropathy, QTc prolongation, CNS disturbances, hypoglycemia)
- cross resistance to 3rd gen cephalosporins
- preserve for gram negative infections (the only PO pseudomonas agent)
- delay diagnosis of TB
- undesirable monotherapy if TB
adjunctive corticosteroid therapy
- for?
- when is it used?
- decrease inflammation in lungs
- not routinely added
- add if shock refractory to fluid resuscitation and vasopressor support (in ICU)
- no benefit in non severe CAP
- conflicting data in severe CAP
CAP de-escalation (when and how)
when:
- pt is hemodynamically stable (good BP, RR, vitals)
- improving clinically
- able to digest oral
how:
- positive cultures: use AST to narrow spectrum/ PO abx
- no positive cultures:
(deescalate) stop empiric cover for MRSA, Pseudomonas, Burkholderia in 48hrs
- IV to PO either same abx or same class
- still need cover Strep pneumoniae, Haemophilus influenzae, atypicals
CAP: tx duration
- minimum 5 days tx
- 7 days if suspected MRSA, Pseudomonas
- longer courses for:
-> CAP complicated with deep-seated infections (eg meningitis, lung abscess) - 2-3 weeks
-> infection with less common pathogens (Burkholderia, Mycobacterium tuberculosis, endemic fungi) - 3-6 weeks (TB 6mths)
CAP: step 4 monitor response
- achieve clinical stability within 48-72hrs
(resolution of vital abnormalities, able to take oral, baseline mental status) - elderly, comorbidities pt take longer
- first 72hrs do not escalate abx
- no need repeat radiographic tests (unless clinical deterioration) or microbiological tests
- ADR/ DDI
HAP/VAP: RF
- pt related factors
- elderly, smoking, COPD, cancer, immunosuppressive, prolong hospitalisation, coma, unconscious, malnutrition - infection control related factors
- lack hand hygienes, contaminated respiratory care devices - healthcare related factors
- prior abx use, sedatives, opioids analgesics, mechanical ventilation, supine position
HAP/VAP: prevention
- hand hygiene
- appropriate use of abx and meds with sedative effects
- VAP specific:
- limit duration of mechanical ventilation
- minimise sedation
- elevate head of bed by 30 degrees
HAP/VAP: pathogens
Pseudomonas spp
Acinetoabcter spp
Enteric gram negative bacilli (enterobacter, Kleb, E coli)
Staph aureus
MUST empirically cover:
- Pseudomonas aeruginosa
- Staphylococcus aureus
- Enterobacteriaceae
HAP/VAP: when to cover for MRSA
- isolation of MRSA in last 1 year (not need respiratory isolation already, serious case!)
- prior IV abx use in last 90 days
- hospitalised in unit where >20% S.aureus are MRSA
- high risk of mortality (eg ventilator support due to HAP/ septic shock)
HAP/VAP: when to use double antipseudomonal abx for empiric tx
any one of the following:
1. RF for antimicrobial resistance
- isolation of pseudomonas in last 1 year (anywhere not respi only)
- prior IV abx use within 90 days
- acute renal replacement therapy prior to VAP onset
- hospitalisation unit where >10% pseudomonas are resistant to monotherapy
- high risk of mortality (eg ventilator support due to HAP/ septic shock)
if not give one anti-pseudomonal agent
- avoid use of AG as sole anti-pseudomonal agent
why is AG not good as monotherapy for pseudomonas in HAP/VAP
deep seated infection like pneumonia, AG not effective (need aerobic environment)
HAP/VAP: abx treatment
anti-pseudomonal agents:
- IV piperacillin-tazobactam
- IV cefepime
- IV ceftazidime (avoid use if no MRSA coverage)
- IV meropenem
- IV imipenem
AND/OR
- IV levofloxacin
- IV ciprofloxacin (dont use without MRSA coverage)
OR
- IV amikacin (avoid in monotherapy)
(MRSA RF)
PLUS IV vancomycin, IV/PO linezolid
(PO linezolid has good oral F as IV, still can use)
HAP/VAP - deescalation/ IV to PO conversion
when:
- pt is hemodynamically stable (good BP, RR, vitals)
- improving clinically
- able to digest oral
how:
- positive cultures: use AST to narrow spectrum/ PO abx, for pseudomonas use single (for culture directed tx, empiric can use 2)
- no positive cultures:
(deescalate) cover for pseudomonas, enteric GN, MSSA - IV to PO if possible
HAP/VAP: duration of tx
7 days regardless of pathogen for pt who achieved clinical stability
- resolution of vitals
- for HAP - baseline mental status
longer tx for complicated HAP/VAP with deep seated infections (eg meningitis, lung abscess)
HAP/VAP: step 4 monitor repsonses
- clinical stability within first 48 - 72hrs
- elderly pt with comorbidities take longer
- dont escalate within the first 72hrs unless culture directed or severe deterioration
- no need retest for radiographic/ microbiology unless clinical deterioration
- ADR of abx
