Pneumonia is an infection of the lungs that can be caused by various organisms, including bacteria, viruses, and fungi. It’s characterized by inflammation of the alveoli, the air sacs in the lungs. Pneumonia can range from mild to life-threatening and is classified as either typical or atypical based on the causative organisms and clinical presentation.
Causes:
- Typical Pneumonia:
- Often caused by bacteria, such as Streptococcus pneumoniae, Haemophilus influenzae, Klebsiella pneumoniae, and Staphylococcus aureus.
- Characterized by sudden onset of symptoms.
- Atypical Pneumonia:
- Caused by other bacteria, such as Mycoplasma pneumoniae, Legionella pneumophila, or Chlamydophila pneumoniae.
- Viruses can also cause atypical pneumonia, especially in children.
- Gradual onset and less severe symptoms compared to typical pneumonia.
Diagnosis:
- Clinical Assessment: Including history of symptoms like cough, fever, chest pain, and difficulty breathing.
- Physical Examination: Noting signs such as decreased oxygen saturations, increased respiratory rate, changes in breath sounds, crackles, or wheezing.
- Blood Tests: Including full blood count (FBC), CRP and blood cultures.
- Sputum Culture: To identify the causative organism.
- Chest X-Ray: To detect lung infiltrates indicative of pneumonia.
- CT scan for a more detailed lung view
- Bronchoscopy in severe cases.
Differential Diagnosis:
- Bronchitis: Inflammation of the bronchial tubes, usually without alveolar involvement.
- Bronchiectasis: A chronic condition characterized by permanent enlargement and damage to the airways and its symptoms, which include chronic cough, production of sputum, and recurrent respiratory infections, can mimic or overlap with those of pneumonia
- Tuberculosis: Caused by Mycobacterium tuberculosis, with a more chronic course.
- Lung Cancer: Particularly in older patients or smokers with persistent symptoms.
- Pulmonary Embolism: Blood clots in the lungs can mimic pneumonia symptoms.
Management:
- Typical Pneumonia:
- Antibiotics: Empirical antibiotic therapy is initiated based on the suspected organism and local resistance patterns
- Children:
- Mild: Amoxicillin oral TDS
- Moderate: Amoxicillin oral TDS
- Severe: Ceftriaxone IV
- Can use Doxycycline BD as alternative if allergy
- Adults
- Mild: Amoxicillin oral TDS (can be + Doxycycline if follow up @ 48 hours uncertain)
- Moderate: Benzylpenicillin IV 6/24 + Doxycycline 100mg oral BD
- Severe: Ceftriaxone 2g IV + Azithromycin 500mg IV daily
- Supportive Care: Includes hydration, rest, and antipyretics for fever and pain.
- Oxygen Therapy: For patients with respiratory distress or low oxygen levels.
- Atypical Pneumonia:
- Antibiotics: Macrolides, tetracyclines, or fluoroquinolones are often used, as atypical pathogens are generally less responsive to standard antibiotics.
- Supportive Care: As with typical pneumonia.
- Consideration of Antivirals: In cases of viral pneumonia.
- Prevention:
- Vaccination: Pneumococcal vaccines for certain age groups and risk factors; annual flu vaccines.
- Hand Hygiene: Effective hand washing to reduce the spread of infections.
- Avoiding Smoking: Smoking cessation as it increases the risk of respiratory infections.
- Follow-Up:
- Patients should be monitored for improvement in symptoms and resolution of the infection. Follow-up chest X-rays may be needed in severe cases or if symptoms persist.
Special Considerations:
- Community-Acquired Pnumonia (CAP): Pneumonia developing in outpatients.
- Hospital-Acquired Pneumonia (HAP): Pneumonia developing 48 hours or more after hospital admission.
- Ventilator-Associated Pneumonia (VAP): Occurs in people on mechanical ventilation.
- Aspiration Pneumonia: Caused by inhaling food, liquid, or vomit into the lungs.
In managing pneumonia, it’s important to tailor antibiotic therapy to the likely causative organisms and adjust based on culture results and clinical response. Early diagnosis and appropriate treatment are crucial for a good outcome.