▪️Background:
▫️Risk factors:
age ≥ 65 years, chronic comorbidities, concurrent or antecedent
respiratory viral infections, impaired airway protection, smoking, excess alcohol use, and other lifestyle factors (eg, crowded living conditions).
▫️Microbiology (common source)
• Respiratory viruses,
• typical bacteria (eg, Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis) and
• atypical bacteria (eg, Legionella spp, Mycoplasma pneumoniae, Chlamydia pneumoniae).
▫️Making the Diagnosis:
• demonstration of an infiltrate on chest imaging(PA and lat CXR) in a
patient with a clinically compatible syndrome (eg, fever, dyspnea, cough, and leukocytosis).
🔺CXR findings:
lobar consolidations, interstitial infiltrates, and/or cavitations.
🔺CT:
• high clinical suspicion for CAP but CXR is negative.
• moderate suspicion for CAP but CXR is nondiagnostic(opacities present but not clear if due to pneumonia versus pulmonary
edema, atelectasis, contusion, chronic lung disease, or other etiologies) to R/O CAP
• for immunocompromised to help distinguish among causes (eg,
invasive fungal infections, pneumocystis pneumonia, bacterial pathogens)
🔹Defining the severity of illness appropriate site of care(Algorithm)
☝🏻Determining the severity of illness is based▪️ICU:
on clinical judgement and can be supplemented by use of severity scores(e.g CURB-65 or PSI score)
✌🏻We generally prefer the PSI
• Respiratory failure requiring mechanical ventilation
OR
• Sepsis requiring vasopressor support
OR
• Three of these criteria:
- Altered mental status
- Hypotension requiring fluid support
- Temperature < 36°C (96.8°F)
- Respiratory rate ≥ 30 breaths/minute
- Arterial oxygen tension to fraction of inspired oxygen (PaO2/FiO2) ratio ≤ 250
- Blood urea nitrogen (BUN) ≥ 20 mg/dL (7 mmol/L)
- Leukocyte count < 4000 cells/microL
- Platelet count < 100,000/microL
- Multilobar infiltrates
▪️Hospital admission:
• Peripheral oxygen saturations < 92 percent on room air
(and a significant change from baseline)
OR
• PSI scores of ≥ III and CURB-65 scores ≥ 1 (or CURB-65 score ≥ 2 if age > 65 years)
OR
• Practical concerns (eg, inability to take oral medications,
cognitive or functional impairment, substance use or other social issues).
💡We obtain Blood cultures, Sputum Gram stain and culture, PCR (Covid, influenza)
▪️Ambulatory care
Most patients who are otherwise healthy with normal vital signs (apart from fever) and no concern for complication are considered to have mild pneumonia and can be managed in the ambulatory setting. These patients typically have PSI scores of I to II and CURB-65 scores of 0 (or a CURB-65 score of 1 if age > 65 years).
💡Microbiologic testing is not needed.
‼️In all cases, we modify this approach based on epidemiologic exposures, patient risk factors, and clinical features regardless of CAP severity or treatment setting.
e.g: For patients with cavitary pneumonia, we may include testing for tuberculosis, fungal pathogens,
and Nocardia.