Pneumonia

• What is pneumonia?

  Acute inflammation of lung parenchyma
• What causes pneumonia?

  Microbial agents like bacteria, viruses, fungi
• What is the pathophysiology of pneumonia?

  • Inflammation of alveoli & bronchioles
  • Leads to edema & fluid accumulation
  • Decreased lung compliance (stiff lungs)
  • Reduced expansion & gas exchange
  • Causes hypoxemia (low O₂ in blood)
  • Results in difficulty breathing and cyanosis
• What is a common symptom of hypoxemia in pneumonia?

  Cyanosis
• What are the routes of infection for pneumonia?

  1. Aspiration from nasopharynx or oropharynx
  2. Inhalation of microbes (e.g., Mycoplasma pneumoniae)
  3. Hematogenous spread from other infections (e.g., Staphylococcus aureus)
• What is the most common route of infection for pneumonia?

  Aspiration from nasopharynx or oropharynx
• What is the most common bacterial cause of pneumonia?

  Streptococcus pneumoniae
• What are the common causes of pneumonia?

  • Bacterial:
  • Streptococcus pneumoniae
  • Staphylococcus aureus
  • Haemophilus influenzae
  • Klebsiella pneumoniae
  • Viral:
  • Influenza
  • SARS-CoV-2
  • RSV
  • Fungal:
  • Pneumocystis jirovecii (common in immunocompromised)
  • Aspiration pneumonia:
  • Gastric contents enter lungs (seen in stroke, alcohol intoxication)
• Which virus is a common cause of pneumonia?

  Influenza
• What is a common fungal cause of pneumonia in immunocompromised patients?

  Pneumocystis jirovecii
• What is aspiration pneumonia?

  Gastric contents enter lungs
• In which conditions is aspiration pneumonia commonly seen?

  Stroke and alcohol intoxication