Pneumonia - Community-Acquired Đánh giá ban đầu

Clinical Presentation

Respiratory symptoms of pneumonia include an acute cough, which can either be nonproductive or productive of purulent or rust-colored sputum, and at least one abnormal chest finding (eg diminished breath sounds, rhonchi, crackles, or wheeze). Systemic symptoms may also occur which include pleuritic chest pain, chills or rigors, and confusion. Abnormal vital signs that prompt suspicion include a respiratory rate of >20 breaths/minute, heart rate of >100 beats/minute, and fever >37.8°C. Chest X-ray findings may show lobar consolidation, bilateral infiltrates, or cavitation. It is potentially life-threatening, especially in older adults and those with comorbid disease.

Pneumonia - Community-Acquired_Initial Assessment 1

Pneumonia - Community-Acquired_Initial Assessment 2

• Respiratory rate of <30 breaths/minute
• Heart rate of <125 beats/minute
• Temperature of >36°C or <40°C
• Systolic blood pressure of >90 mmHg
• Diastolic blood pressure >60 mmHg 

Moderate-risk Community-acquired Pneumonia (CAP)

Patients classified under moderate-risk community-acquired pneumonia may have an acute onset of altered mental state, suspected aspiration, extrapulmonary evidence of sepsis (eg endocarditis, arthritis, encephalitis, otitis media), or an unstable comorbid condition (eg uncontrolled diabetes mellitus, active malignancies, congestive heart failure class II-IV, chronic obstructive pulmonary disease in acute exacerbation, decompensated liver disease). Chest X-ray findings may show bilateral or multilobar involvement, progression of the lesion to 50% of initial finding within 24 hours, pleural effusion, or abscess.  

They also typically present with the following vital signs:

• Respiratory rate of ≥30 breaths/minute
• Heart rate of ≥125 beats/minute
• Temperature of ≤36°C or ≥40°C
• Systolic blood pressure of <90 mmHg
• Diastolic blood pressure of ≤60 mmHg 

High-risk Community-acquired Pneumonia (CAP)

Clinical Features  

Patients classified under high-risk community-acquired pneumonia exhibit either one major criterion or ≥3 minor criteria.  

The minor criteria are as follows: 

• Respiratory rate of ≥30 breaths/minute
• Arterial oxygen partial pressure/Fractional inspired oxygen (PaO₂/FiO₂) ratio of ≤250 mmHg
• Multilobar infiltrates
• Confusion or disorientation
• Blood urea nitrogen (BUN) of ≥20 mg/dL
• White blood cell count (WBC) <4000 cells/μL
• Platelet count <100,000/μL
• Core temperature <36°C
• Hypotension needing aggressive fluid resuscitation 

The major criteria are as follows:

• Septic shock needing vasopressors
• Respiratory failure needing mechanical ventilation 

Diagnosis or Diagnostic Criteria

All patients suspected of community-acquired pneumonia should have a chest radiograph to establish the diagnosis and identify complications (eg pleural effusion, multilobar disease). The definite diagnosis of community-acquired pneumonia must be based on a combination of clinical features and a chest radiograph showing lung shadowing that is likely to be new and not due to other causes. Combining history and physical examination findings may be used to presumptively identify patients with pneumonia in cases where a chest X-ray might not be easy to perform.  

Site-of-Care Decision  

Clinical judgment with a validated clinical prediction rule should be used to determine the best site of care for patients. Other factors to be considered aside from clinical severity include the ability of the patient to maintain oral intake, cognitive or functional impairment, the likelihood of medication adherence, history of substance abuse, severe comorbid illness, mental illness, and living or social circumstances.