Pneumonia Lecture Notes

Overview

• Definition: Pneumonia is an inflammatory condition of the lung, primarily affecting alveoli.
• Symptoms: Productive or dry cough, chest pain, fever, difficulty breathing.
• Severity: Variable, can range from mild to severe.

Epidemiology

• Frequency: Affects 450 million people annually (7% of the global population).
• Mortality: Causes 4 million deaths per year.
• High-Risk Groups: Very young, elderly, and chronically ill, especially in developing countries.

Causes

• Infectious Agents: Primarily caused by bacteria and viruses, less commonly by fungi and parasites.
• Common Pathogens:
  • Bacteria: Streptococcus pneumoniae, Haemophilus influenzae, Mycoplasma pneumoniae
  • Viruses: Influenza virus, rhinoviruses, coronaviruses
  • Fungi: Histoplasma capsulatum, Pneumocystis jiroveci
  • Parasites: Toxoplasma gondii, Plasmodium malariae

Risk Factors

• Medical Conditions: Cystic fibrosis, COPD, diabetes, heart failure.
• Lifestyle Factors: Smoking, alcohol use, exposure to air pollution.
• Other Factors: Immunodeficiency, very young or old age, chronic kidney or liver disease.

Diagnosis

• Methods: Based on symptoms and physical examination. Confirmation via chest X-rays, blood tests, sputum cultures.
• Complications: Differentiating from conditions like COPD, asthma, and pulmonary embolism.

Prevention

• Vaccinations: Against Streptococcus pneumoniae, influenza, and others.
• Hygiene Practices: Handwashing, avoiding smoking.
• Environmental Controls: Reducing indoor pollution.

Treatment

• General Strategy: Dependent on underlying cause.
• Medications:
  • Bacterial pneumonia: Antibiotics are primary treatment.
  • Viral pneumonia: Antivirals like oseltamivir for influenza.
  • Fungal infections: Antifungal medications.
• Supportive Care: Oxygen therapy, hospitalization in severe cases.

Prognosis

• Recovery: Most bacterial pneumonias stabilize within 3-6 days, complete recovery may take weeks.
• Complications: Risk of pleural effusion, lung abscess, or acute respiratory distress syndrome.

Global Impact

• Economic Cost: Significant global economic burden, with high healthcare costs in both developed and developing countries.

Historical Context

• Historically a major cause of death; management improved with antibiotics and vaccines.

Important Considerations

• Differential Diagnosis: Distinguishing pneumonia from other respiratory conditions.
• Microbiology: Determining the causative organism is critical for appropriate treatment but often challenging.