CAP Flashcards
What is pneumonia?
- Lower respiratory tract infection
- Infection of lung parenchyma
- Proliferation of microbial pathogens in alveolar level
- Most common is bacterial pneumonia
What are the 3 mechanisms for pathogenesis of pneumonia?
- Aspiration of oropharyngeal secretions
- Inhalation of aerosols
- Hematogenous spreading
Signs and symptoms of pneumonia?
Pulmonary symptoms: cough, chest pain, shortness of breath, hypoxia
Systemic signs and symptoms: fever > 38, chills, tachypnea, tachycardia, hypotension, leukocytosis (elevated whites)
Elderly often present with symptoms that are more subtle and non specific, e.g. fatigue, anorexia, nausea, changes in mental status
Physical examination of pneumonia?
- Diminished breath sounds over affected area
- Inspiratory crackles during lung expansion
Radio graphic findings for pneumonia?
- chest x ray or CT scan
- look for new infiltrates or dense consolidations
Respiratory cultures for pneumonia?
Sputum cultures are of low yield -> frequent contamination by oropharyngeal secretions
Lower respiratory tract samples
- less contamination
- invasive sampling, e.g. BAL (bronchoalveolar lavage)
Blood culture
- to rule out bacteremia
What are the classifications of pneumonia?
- Community Acquired Pneumonia (CAP) - onset in community or <48h after hospital admission
- Hospital Acquired Pneumonia (HAP) - onset at least 48h after hospital admission
- Ventilator Associated Pneumonia (VAP) - onset at least 48h after mechanical ventilation
Risk factors for CAP?
- Age of 65 years or more
- Previous hospitalisation for CAP
- Smoking
- COPD,DM,HF,cancer,immunosuppression
Prevention strategies for CAP?
- smoking cessation
- immunisation (influenza, pneumococcal)
Microbiology for CAP?
For outpatient:
- streptococcus pneumoniae
- haemophilus influenzae
- atypical organisms, e.g. mycoplasma pneumoniae, chlamydophila pneumoniae
Inpatient (non-severe):
- streptococcus pneumoniae
- haemophilus influenzae
- atypical - mycoplasma pneumoniae, chlamydophila pneumoniae, Legionella pneumophilia
Inpatient (severe):
- streptococcus pneumoniae
- haemophilus influenzae
- atypical - mycoplasma pneumoniae, chlamydophila pneumoniae, Legionella pneumophilia
- staphylococcus aureus
- other gram neg bacilli e.g. klebsiella pneumonia, Burkholderia pseudomallei
What are some tools for risk stratification for CAP?
- Pneumonia Severity Index (PSI)
- CURB-65 score
Criteria for SEVERE CAP?
2 Major criteria:
Mechanical ventilation
Septic shock requiring vasoactive medications
8 Minor criteria:
RR ≥ 30 breaths/min
PaO /FiO ≤ 250
Multilobar infiltrates
Confusion/disorientation
Uremia (urea > 7 mmol/L)
Leukopenia (WBC < 4 x 109/L)
Hypothermia (core temperature < 360C)
Hypotension requiring aggressive fluid resuscitation
Severe CAP: 1 or more major criterion OR 3 or more minor criteria
For outpatient CAP, generally healthy patients, what is the standard regimen?
PO Beta lactam (amoxicillin) 1g PO TDS
OR
PO Respiratory FQ (levofloxacin 750mg PO OD or moxifloxacin) *USED IN PATIENTS WITH SEVERE PENICILLIN ALLERGY
For outpatient CAP, if there is Chronic heart, lung, liver or renal diseases, diabetes mellitus, alcoholism, malignancy, asplenia, what would the standard regimen be?
PO Beta Lactam (amoxicillin/clavulanate 625mg PO TDS or 2g PO BD; or cefuroxime 500mg PO BD)
+ PO Macrolide (clarithromycin 500mg PO BD or azithromycin 500mg PO OD);
OR Doxycycline 100mg PO BD (to cover atypical)
OR Respiratory FQ (levofloxacin 750mg PO OD or moxifloxacin) (if pt has severe beta lactam allergy)
Standard regimen for NON-SEVERE INPATIENT?
IV Beta lactam (amoxicillin/clavulanate 1.2g IV Q8H OR ceftriaxone 1-2g IV Q24H)
+ PO Macrolide (clarithromycin 500mg PO BD or azithromycin 500mg PO OD) OR PO doxycycline 100mg PO BD —> for atypical coverage
OR
IV Respiratory FQ (levofloxacin 750mg IV Q24H or moxifloxacin) (for severe beta lactam allergy)
If cannot tolerate PO Macrolide or doxycycline, use IV Azithromycin 500mg IV Q24H or IV Clarithromycin 500mg IV Q12H
Step down from IV to PO later
