CAP Flashcards
what is pneumonia
lower respiratory tract infection, of the lung parenchyma
- proliferation of microbial patho in alveolar level
mechanism of bacterial entry
- aspiration of oropharyngeal secretions: bacteria in the oropharyngeal sections enter lungs
- inhalation of aerosols: aerosolised droplets that contain bacteria
- hematogenous spreading: bacteremia from extra-pulmonary source
signs and symptoms of pneumonia
- cough, chest pains, SOB, hypoxia
- fever >38 degree, chills
- tachypnea, tachycardia, hypotension
- leukocytosis
- fatigue, anorexia, Nausea, change in mental status
physical examination to diagnose pneumonia
- diminished breath sounds over the affected are
2. inspiratory crackles during lung expansion
radiographic findings for pneumonia
- chest XR or CT
2. new infiltrates or dense consolidations
lab findings for pneumonia
eg. c-reactive protein, procalcitonin
1. non-specific
2. limited discriminatory potential
3. not recommended for routine use to guide antibiotic initiation or discontinuation
respiratory cultures for pneumonia
sputum:
- low yield, frequent contamination by oropharyngeal secretions
- quality sample: > 10 neutrophils % < 25 epithelial cells per low power field
lower respiratory tract samples:
- less contamination
- invasive sampling (eg. bronchoalveolar lavage BAL)
purpose of blood cultures
to rule out bacteremia
urinary antigen test for pneumonia
- strepococcus pneumonia and legionella pneumophilia
- not routinely used due to limitations:
- indicate exposure to respective patho but remain positive for days-weeks despite tx
classification of pneumonia
- CAP community acquired: <48h after hosp admission
- HAP hospital acquires: >=48h after hosp admission
- VAP ventilator acquired: >=48h after mechanical ventilation
- HCAP healthcare-associated: is obsolete, <48h after hosp admission + (either from (a) nursing home; (b) hospitalised >=48h last 90d; (c) wound care/ IV antibioticss chemo in last 30d; (d) Hemodialysis patients
risk factors of CAP
- age >=65 yo
- previous hospitalisation for CAP
- smoking
- COPD, DM, HF, cancer, immuno
prevention of CAP
- smoking cessation
2. immunisation (influenza & pneumococcal)
bacterial causes of outpatient CAP
- streptococcus pneumoniae
- haemophilus influenzae
- atyps (Mycoplasma pneumoniae, chlamydophila pneumoniae)
bacterial causes of non severe inpatient CAP
- streptococcus pneumoniae
- haemophilus influenzae
- atyps (Mycoplasma pneumoniae, chlamydophila pneumoniae), legionella pneumoniae
bacterial causes of severe inpatient CAP
- streptococcus pneumoniae
- haemophilus influenzae
- atyps (Mycoplasma pneumoniae, chlamydophila pneumoniae, legionella pneumoniae)
- staphylococcus aureus
- gram neg bacilli (eg. klebsiella pneumonia, Burkholderia pseudomallei)
who to stratify risk of CAP
- pneumonia severity index (STI)
2. CURB-65 score
variables in CURB 65 score
- confusion
- urea >7mmol/L
- RR >30 bpm
- BP <90/60
- age >65yo
how to score curb 65 score
outpatient: 0-1
inpatient: 2
inpatient ICU: >=3
major criteria for severe CAP
any one:
- mechanical ventilation
- septic shock requiring vasoactive medications
minor criteria for severe CAP
any three:
- RR >= 30bpm
- PaO2/FiO2 <250
- multilobar infiltrates
- confusion/ disorientation
- uremia (urea >7mmol/L)
- leukopenia (WBC <4 x10^9/L)
- hypothermia (core temp <36degree)
- hypotension requiring aggressive fluid resuscitation
empiric regimen for generally healthy outpatient
- PO beta-lactam (amoxi 1g TDS), or
2. PO respi FQ (levo 750mg OD /moxi)
empiric regimen for chronic outpatient
pt usually have: chronic heart, lung, renal disease, DM, alcoholism, malignancy, asplenia
- PO beta lactam (amoxi/clav 625mg TD or 2g BD, or cefuroxime 500mg BD) + PO macrolide (clarithro 500mg BD/azithro 500mg OD)
- PO beta lactam (amoxi/clav 625mg TD or 2g BD, or cefuroxime 500mg BD) + PO doxycycline 100mg BD
- PO respiratory FQ (levo 750mg OD/moxi)
empiric regimen for non severe inpatient
- IV beta lactam (amoxi/clav 1.2g q8h, or ceftriaxone 1-2g q24h)+ PO macrolide (clarithro 500mg BD/azithro 500mg OD) OR + PO doxycycline 100mg BD
- IV beta lactam (pipe/tazo, or ceftazidime 2g q8h) + PO doxycycline 100mg BD (if pseudomonal coverage needed)
- IV respiratory FQ (levo 750mg q24h- psuedomonal /moxi)
IV FQ/ BL step down to PO later if possible, macro & doxy given PO
empiric regimen for severe inpatient
- IV beta lactam (amoxi/clav 1.2g q8h, or ceftazidime 2g q8h) + PO macrolide (clarithro 500mg BD/azithro 500mg OD)
- IV beta lactam (amoxi/clav 1.2g q8h, or ceftazidime 2g q8h) + PO doxycycline 100mg BD
- IV respiratory FQ (levo 750mg q24h- psuedomonal /moxi) + IV ceftazidime 2g q8h
IV FQ/ BL step down to PO later if possible, macro & doxy given PO
purpose of ceftazidime in CAP
treat Burkholderia pseudomallei
purpose of macrolide/ doxycyclines in CAP
treat atypical, hence given orally would be usually sufficient since atyps usually not main problem
indication for Anaerobic coverage for CAP
- lung abscess
2. empyema
common anerobic species present for CAP
- bacteriodes fragilis
- prevotella sspp.
- porphyromonas spp.
- fusobacterium spp.
add ons for anerobic coverage for CAP
inpatient only!!
- clindamycin IV/PO
- metronidazole IV/PO
(if current regimen dont have amox/clav or moxi)
indication for MRSA coverage for CAP
- prior respiratory isolation of MRSA in last 1 year
2. severe CAP only: hospitalisation and received IV antibiotics within last 90d (locally validated risk factors)
add on for MRSA coverage for CAP
- Vancomycin IV 15mg/kg q8-12h
2. linezolid IV/PO 600mg BD
why should daptomycin not be use for MRSA coverage for CAP
against airway acquired pneumonia since it is inactivated by alveolar surfactant (not cause it cannot enter the lungs!!)
indication for pseudomonal coverage in CAP
prior respiratory isolation of pseudomonas aeruginosa in last 1 year
add on for pseudomonal coverage in CAP
modify regimen to include either:
- pipe/tazo IV 4.5g q6-8h
- ceftazidime IV 2g q8h
- cefepime IV 2g q8h
- meropenem IV (avoid unless ESBL)
- levo IV/PO
why are fluoroquinolones not first line drugs in CAP
- more severe ADR (tendonitis, tendon rupture, neuropathy, QTc, CNS, hypoglycemia)
- development of resistance with overuse (collateral damage)
- preserve activity for other gram neg infection since it is the only PO option for pseudomonas aeruginosa
- delay diagnosis of TB (suppressive effect)
adjunctive corticosteroid therapy
- decrease inflammation in lungs
- eg. dexamethasone 50mg IV q24h x 4d
- eg. prednisolone 40mg PO q24h x 7d
- may decrease length of stay and time to clinical stability
- an impact is small and likely outweighed by increase in hyperglycemia
- not routinely recommended
efficacy of therapy
- clinical improvements expected in 48-72h (elderly pt / comorbidities may take longer)
- should not escalate antibiotic therapy in the first 72h (unless culture directed or significant clinical deterioration)
- radiographic improvement lags behind, up to 4-6w for resolution (repeat only if clinical deterioration)
measures regarding empiric coverage of MRSA and/or pseudomonas in CAP
may be stopped in 48h if not found on culture and pt improving
when to step down for IV tx of CAP
all must be achieved
- hemodynamically stable
- clinically improved/ improving
- afebrile >=24h
- normally function GIT
- able to digest PO meds
general benefits of stepping down
- greater patient comfort and mobility
- lower risk of nosocomial acq blood stream infection
- decrease phlebitis
- decrease preparation and administration time
- lower cost
- facilitates discharge
treatment duration of CAP
until clinical stability achieved for at least 5d
- usually achieve in 48-72h
- except MRSA/ pseudomonas - 7d
- except Burkholderia psudomallei: 3-6months (usually culture and do direct tx)
what are signs of clinical stability
- afebrile
- able to maintain oral intake
- normal vital signs
- oxygen saturation
- mental status
