Community Acquired Pneumonia (CAP) Flashcards
Mechanism of acquiring pneumonia
- Aspiration of oropharyngeal secretions
- Inhalation of infected aerosol
- Hematogeneous (extra-pulmonary infection)
Tests to diagnose pneumonia (5)
- Laboratory findings
- CRP
- Procalcitonin
- not rlly done cos it is non-specific - Sputum culture
- high contamination
- valid only if >10 neutrophils & <25 WBC per low power field - Lower respiratory tract culture
- Bronchoalveolar Lavage (BAL)
- need to sedate patient and insert tube to use fluids to pick up pathogens
- invasive - Blood culture
- rule out bacteremia - Urinary antigen test
- Streptococcus pneumoniae & Legionella pneumophilia
- indicate exposure to pathogen only
- not rlly used cos positive result even after effective antibiotics for days to weeks
Classifications of pneumonia
- Community Acquired Pneumonia (CAP)
- in community
- <48h after hospitalisation - Hospital Acquired Pneumonia (HAP)
- >=48h after hospitalisation - Ventilator Associated Pneumonia (VAP)
- >=48h after on mechanical ventilator
Risk factors for CAP
- > = 65y/o
- Prev hospitalisation for CAP
- Smoking
- Comorbidities (COPD, HF, DM, cancer & immunosuppresion)
Prevention of CAP
- Avoid smoking
2. Vaccination (pneumoccocal & influenza)
Pathogens of pneumonia in Outpatient, healthy patients
- Streptococcus pneumoniae
- Haemophilus influenzae
- Atypicals (not rlly)
- Mycoplasma pneumoniae
- Chlamydophilia pneumoniae
Pathogens of pneumonia in outpatient w comorbidities patients
- Streptococcus pneumoniae
- Haemophilus influenzae
- Atypicals
- Mycoplasma pneumoniae
- Chlamydophilia pneumoniae
Pathogens of pneumonia in in-patient, non-severe patients
- Streptococcus pneumoniae
- Haemophilus influenzae
- Atypicals
- Mycoplasma pneumoniae
- Chlamydophilia pneumoniae
- Legionella pneumophilia
Pathogens of pneumonia in in-patient, severe patients
- Streptococcus pneumoniae
- Haemophilus influenzae
- Atypicals
- Mycoplasma pneumoniae
- Chlamydophilia pneumoniae
- Legionella pneumophilia - Staphylococcus aureus
- Gram -ve
- Klebsiella pneumoniae
- Burkholderia pseudomallei
Infection of Burkholderia pseudomallei
Melioidosis
- pneumonia is a common presentation of this group of infection
What are used to judge severity of CAP? (risk stratification)
- Pneumonia Severity Index (PSI)
- 20 factors into 5 classes
- not rlly used - CURB-65
- 5 factors into 3 classes
- readily available parameters - IDSA-ATS
IDSA-ATS Criteria for severe CAP
Major (2)
- Mechanical ventilation required
- Severe hypotension requiring vasoactive medications
Minor (8)
- RR >= 30bpm
- PaO2/FiO2 =< 250
- Uremia >7mmol/L
- Hypothermia <36dc
- Multilobar infiltrates
- Confusion/disorientation
- Leukopenia WBC<4x10^9 /L
- Hypotension requiring aggressive fluid rescucitation
Severe CAP if :
>=1 major
>= 3 minors
Standard empiric therapy for outpatient, healthy
- PO Amoxicillin
- PO Respiratory fluoroquinolones
(Levofloxacin, Moxifloxacin)
Standard empiric therapy for outpatient w comorbidities
- PO Amoxicillin/Clavulanate or PO Cefuroxime
+ PO Azithromycin/Clarithromycin/Doxycycline
or
- PO Respiratory fluoroquinolones
(Levofloxacin, Moxifloxacin)
Standard empiric therapy for inpatient, non-severe
- IV Amoxicillin/Clavulanate or IV Ceftriaxone
+ PO/IV Azithromycin/Clarithromycin/Doxycycline
or
- PO/IV Respiratory fluoroquinolones
(Levofloxacin, Moxifloxacin)
Standard empiric therapy for inpatient, severe
- IV Amoxicillin/Clavulanate
+ IV Ceftazidime (Burkholderia pseudomallei)
+ PO/IV Azithromycin/Clarithromycin/Doxycycline
or
- PO/IV Respiratory fluoroquinolones
(Levofloxacin, Moxifloxacin)
+ IV Ceftazidime (Burkholderia pseudomallei)
What if patient has penicillin allergy & inpatient, severe pneumonia?
Only can use PO/IV Respiratory fluoroquinolones w/o Ceftazidime
When is anaerobic coverage for CAP required?
- Lung abscess
2. Empyema
Common anaerobic pathogens (4)
- Bacteriodes fragilis
- Prevotella spp
- Porphyromonas spp
- Fusobacterium spp
Antibiotics used for CAP anaerobes
- PO/IV Clindamycin
- PO/IV Metronidazole
- Amoxicillin/Clav
- Moxifloxacin
- Piperacillin/Tazobactam
Add above to treat anaerobes
When is MRSA coverage for CAP required?
- Positive respiratory cultures of MRSA within 1 year
2. Hospitalisation and IV antibiotics used within 90 days, (or locally validated risk factors) (IF SEVERE CAP ONLY)
Antibiotics used for CAP MRSA
- IV Vancomycin
- PO/IV Linezolid
Add above to treat MRSA
When is Pseudomonas aeruginosa coverage for CAP required?
- Positive respiratory cultures of Pseudomonas aeruginosa within 1 year
SEVERE CAP alr got Ceftazidime which can cover Pseudomonas (for Burkholderia)
Why is Daptomycin not used to cover MRSA?
It can penetrate lungs but it is deactivated by lung surfactant
Antibiotics used for CAP Pseudomona aeruginosa
- IV Piperacillin/Tazobactam
- IV Ceftazidime
- IV Cefepime
- IV Meropenem (save for ESBL)
- PO/IV Levofloxacin
Modify treatment to include above
Duration of treatment
5 days
MRSA/Pseudomonas - 7 days
Burkholderia - 3-6 months
Is adjunctive corticosteroids used?
No as the risk for hyperglycemia is higher than the benefits
Monitoring of therapy
- patient should improve within 48-72h
- should not escalate antibiotic therapy in the first 72h, wait for AST and culture results (time needed for antibiotics to work)
- do not use radiological findings as improvements lag behind (4-6 weeks)
Step down therapy not necessary for these pathogens (IV to PO)
- MRSA
- Pseudomona aeruginosa
- Burkholderia pseudomallei
Comorbidities in out-patient CAP
- Heart, lungs, liver and kidney failure
- DM
- Alcoholism
- Malignancy
- Asplenia
