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- HCAP healthcare-associated: is obsolete, 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