Overview

Pneumonia is infection in the lower respiratory tract and is characterised by fevers, purulent sputum, leucocytosis, low oxygen levels and new lung infiltrates (consolidation) on radiographic imaging. The infection is identified by the site of consolidation. Consolidation is where the lung tissue is filled with fluid (ie. water, blood, pus, microbes). Types of pneumonia include lobar pneumonia (infection affects a whole lobe of a lung) and bronchopneumonia (affects the bronchioles through out a lung lobe).

Aetiology and Risk Factors

Risk Factors

• Elderly >65yo
• Smoking
• Recent travel
• Antibiotics use
• Immunocompromised
• Recent respiratory tract infection
• Underlying respiratory disease (cystic fibrosis)

Clinical Manifestation

Examination findings include signs of consolidation on affect side and lobe

• Decreased chest expansion on affected side
• Dullness on percussion
• Bronchial breath sounds and whispering pectoriloquy +/- crackles/rales on site of consolidation
• +/- increase vocal fremitus and resonance

Causative agent

¹ Enterobacterales includes Klebsiella, Escherichia coli and Enterobacter spp.; therefore, a separate Klebsiella column is unnecessary.
² Important CAP risk factors include previous respiratory isolation and advanced structural lung disease.

Classification

Classification by location acquired

• Community Acquired Pneumonia (CAP)
• Hospital Acquired Pneumonia (HAP) also known as Nosocomial Pneumonia
• Ventilator associated pneumonia

Classification by microorganism

• Viral
• Bacterial
  • Typical bacterial pneumonia
  • Atypical bacterial pneumonia
• Fungal
• Parasite

Classification by lung involvement

• Lobar pneumonia
• Broncho-pneumonia
• Pleural Pneumonia

Treatment

Management depends on where the pneumonia was acquired and what the causative agent is or might be. The standard is antibiotic therapy.

Assessment of severity

There are scoring criteria’s that exists to help identify whether a patient should be admitted to hospital. These include PSI and CURB-65 (CORB-65)

Some patients with mild illness, good social circumstances and no significant co-morbidities may be safely discharges with oral antibiotics, simple analgesia for pleuritic chest pain and follow up with doctors.

For patients with a high severity score (CURB-65 or SMART-COP or PSI index) admission to hospital is advised with commencement of IV antibiotics.