CCM Notes
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Pulmonology · Infectious Disease
Community-Acquired Pneumonia
CURB-65 Severity · Antibiotic Selection by Severity · Gulf Organisms · Treatment Duration
📊 CURB-65 Severity Score (BTS Guidelines)
C
Confusion
New onset disorientation
U
Urea
>7 mmol/L (BUN >20 mg/dL)
R
Respiratory Rate
≥30 breaths/min
B
Blood Pressure
SBP <90 or DBP ≤60 mmHg
0–1
Low severity
30-day mortality ~1–3%
Outpatient treatment
2
Moderate severity
30-day mortality ~9%
Consider inpatient
3–4
Severe
30-day mortality ~22%
Inpatient; consider ICU
5
Very severe
30-day mortality ~57%
ICU admission
💊 Antibiotic Selection by Severity (IDSA/ATS 2019)
| Setting | First-Line Regimen | Alternative | Duration |
|---|
OutpatientCURB 0–1
No comorbidities |
Amoxicillin 500 mg PO TID
or Doxycycline 100 mg PO BID |
Azithromycin 500 mg PO Day 1, then 250 mg OD (check local resistance) |
5 days |
OutpatientCURB 0–1
With comorbidities |
Amoxicillin-clavulanate 875/125 mg PO BID + Azithromycin 500 mg OD
or Levofloxacin 750 mg PO OD (monotherapy) |
Moxifloxacin 400 mg PO OD |
5 days |
InpatientCURB 2–3
Non-ICU ward |
Amox-Clav IV + Azithromycin 500 mg IV/PO
or β-lactam + Levofloxacin 750 mg IV OD |
Ceftriaxone 1–2g IV OD + Azithromycin 500 mg IV OD |
5–7 days |
ICUCURB 4–5
Severe CAP |
Ceftriaxone 2g IV OD + Azithromycin 500 mg IV OD
or Piperacillin-tazobactam + Levofloxacin IV |
If Pseudomonas risk: Pip-Tazo + Ciprofloxacin IV
If MRSA risk: add Vancomycin or Linezolid |
7–10 days |
🌍 Common Pathogens
Typical Organisms
Streptococcus pneumoniae — most common overall
Haemophilus influenzae — COPD, smokers
Klebsiella pneumoniae — Gulf: alcoholics, DM (rare)
Staphylococcus aureus — post-influenza, ICU
Atypical Organisms
Mycoplasma pneumoniae — young adults, gradual onset
Legionella pneumophila — AC systems (Gulf: high exposure)
Chlamydophila pneumoniae
📋 Management Checklist
Cultures: blood × 2, sputum (before antibiotics if possible)
Legionella urinary antigen (if severe or epidemiological risk)
Pneumococcal urinary antigen (ICU/severe)
CXR (PA + lateral); CT chest if complex
Oxygen: target SpO₂ ≥94% (88–92% in COPD)
Switch IV→PO when: afebrile ×24h, HR <100, RR <24, tolerating PO
Pneumococcal + influenza vaccination before discharge
Follow-up CXR at 6 weeks (exclude malignancy)
⚠️ Severe CAP Criteria (IDSA/ATS Major / Minor)
●Major criteria: Invasive mechanical ventilation OR septic shock requiring vasopressors → direct ICU admission
●Minor criteria (≥3): RR ≥30, PaO₂/FiO₂ ≤250, multilobar infiltrates, confusion, BUN ≥20, WBC <4000, platelets <100k, hypothermia, hypotension requiring aggressive fluids
●Gulf: Legionella risk from hotel/hospital AC — check urinary antigen in all hospitalized patients
●High T2DM prevalence → impaired immunity; Klebsiella and fungal pneumonia more common in Gulf diabetics