Definition

Bronchopneumonia: Inflammation of the Lower Airways

• Definition: Inflammation and infection of bronchi, bronchioles, and alveoli.
• Characteristics: Patchy inflammatory consolidations in lobules, often located basally in lungs.
• Subtypes: Also known as lobular pneumonia.
• Affected Population: Common in children and the elderly.

Aetiology

Microorganisms Causing Bronchopneumonia/HAP

Bacteria:

• Streptococcus pneumoniae
• Haemophilus influenzae
• Staphylococcus aureus
  • Including methicillin-resistant Staphylococcus aureus (MRSA)
• Klebsiella pneumoniae
• Pseudomonas aeruginosa
• Escherichia coli

Viruses:

• Respiratory syncytial virus
• Influenza virus

Fungi:

• Histoplasma capsulatum
  • Particularly dangerous in immunocompromised individuals.

Other Causes:

• Secondary Infections: Following respiratory viral infections.
• Aspiration: Inhaling fluids or foreign matter into the lungs.

Risk Factors

Risk Factors for Bronchopneumonia:

• Age: Young children and older adults are more vulnerable.
• Weakened immune system.
• Underlying respiratory conditions (COPD, bronchiectasis, chronic pulmonary diseases).
• Smoking.
• Aspiration.
• Exposure to specific environments (hospitals, care facilities).
• Other conditions (oesophageal diseases)
• Decreased consciousness
• Previous antibiotic exposure

Pathophysiology

Pathogenesis of Bronchopneumonia:

1. Inhalation or Aspiration: Microorganisms enter lower respiratory tract.
2. Infection and Inflammation: Bronchioles and adjacent lung tissue become infected and inflamed.
3. Accumulation: Inflammatory cells, fluid, and cellular debris build up.
4. Consolidation: Lung tissue consolidates.
5. Impaired Gas Exchange: Results in impaired oxygen exchange.
6. Respiratory Symptoms: Presents with respiratory symptoms.

Differential Diagnosis

Differential Diagnosis of Bronchopneumonia:

• Other Types of Pneumonia: Like lobar pneumonia.
• Bronchiolitis
• Pulmonary Oedema
• Lung Abscess
• Other Respiratory Infections

Epidemiology

Prevalence and Setting of Bronchopneumonia:

• Challenging Prevalence: Difficult to ascertain due to underreporting and diagnostic variations.
• Hospital/Healthcare-Associated: More frequently observed in healthcare settings.
• Higher Risk Groups: Particularly prevalent in older adults and those with underlying health issues.

Clinical Presentation

Bronchopneumonia Symptoms and Signs:

Common Symptoms:

• Cough (with or without sputum).
• Fever.
• Chest pain.
• Shortness of breath.
• Fatigue.
• General signs of infection.

Severe Cases:

• Respiratory distress.
• Cyanosis (bluish skin discoloration).
• Confusion.
• Signs of sepsis.

Infants and Young Children:

• Irritability.
• Poor feeding.
• Breathing difficulties.

Diagnosis:

• Clinical diagnosis with support from new infiltrates on imaging.
• Suspicion if a patient presents with fever, productive cough, leucocytosis/leukopenia, dyspnea, and decreased oxygen saturation.
• Auscultation may reveal rales/crackles and reduced lung sounds.
• Pulse oximetry may show low oxygen saturation, indicating respiratory difficulties.

Investigations

Diagnostic Tests for Bronchopneumonia:

Imaging:

• Chest X-ray (CXR):
  • Gold-standard for imaging.
  • Reveals multiple small patchy opacities.
  • Bilateral distribution, mainly involving lower lobes.
• Computed Tomography (CT) Scan:
  • Used if CXR is inconclusive.
  • Shows multiple opacities with a lobular pattern (“tree-in-bud” appearance).
  • Opacities primarily located in centrilobular regions.

Microbiological Analysis:

• Sputum Culture:
  • Identifies the causative microorganism.
  • Guides antibiotic therapy.
• Bronchoalveolar Lavage (BAL):
  • Cultures from BAL can identify the causative pathogen in severe cases.
• Serology:
  • Useful in the diagnosis of specific infections like Histoplasma capsulatum.

Blood Tests:

• Full Blood Count (FBC):
  • Detects leucocytosis with a high number of granulocytes, indicating bacterial infection.
• Inflammatory Markers:
  • C-reactive Protein (CRP) and Procalcitonin (PCT):
    • Elevation indicates infection and inflammation.

Management

Management of Bronchopneumonia:

Antimicrobial Therapy:

• Outpatient: Local antimicrobial policy, e.g., amoxicillin, clarithromycin.
• Hospital-Acquired: Tailored to risk factors for multidrug-resistant (MDR) pathogens.
  • No MDR risk: Single agent against Pseudomonas and MSSA.
  • MDR risk: Dual agents for Pseudomonas, gram-negative, and MRSA.

Empiric and Specific Therapy:

• Empiric: Broad-spectrum therapy based on clinical condition.
• Specific: Narrowed based on microbiological analysis.

Duration and Monitoring:

• Usually around 7 days of therapy.
• Procalcitonin (PCT) monitoring for antibiotic response.

Histoplasmosis Treatment:

• Antifungals like ketoconazole, itraconazole.
• Amphotericin B for severe cases.

Supportive Care:

• Rest and symptomatic relief.
• Hydration, especially IV if hospitalized.
• Oxygen therapy to maintain O2 saturation.
• CURB-65 criteria for hospitalization.

Prevention:

• Smoking cessation counseling.
• Influenza and anti-pneumococcal vaccination.

Prognosis

Prognosis of Bronchopneumonia:

• Favourable Outcome: Majority recover fully with timely treatment.
• Factors Influencing Prognosis:
  • Overall health and age.
  • Causative pathogen.
  • Promptness of treatment.
• High-Risk Groups: Older adults and individuals with underlying health conditions.

Complications

Complications of Bronchopneumonia:

• Short-Term Complications:
  • Lung abscess formation.
  • Respiratory failure.
  • Sepsis.
  • Pleural effusion (fluid around lungs).
  • Acute respiratory distress syndrome (ARDS) in severe cases.
• Long-Term Complications:
  • Lung scarring.
  • Recurrent respiratory infections.