What is the treatment guideline for acute pneumonitis?

Treatment Guidelines for Acute Pneumonitis

The treatment of acute pneumonitis should focus on supportive care with appropriate oxygen therapy, fluid management, and corticosteroids when indicated, while addressing the underlying cause. 1

Initial Assessment and Management

Severity Assessment

• Evaluate severity using clinical parameters:
  • Respiratory rate, pulse, blood pressure, mental status
  • Oxygen saturation and inspired oxygen concentration
  • Temperature
  • Presence of bilateral/multilobe involvement on chest radiograph 1

Immediate Interventions

1. Oxygen Therapy

   • Provide appropriate oxygen therapy with monitoring of oxygen saturations
   • Maintain PaO2 >8 kPa and SaO2 >92% 1
   • High concentrations of oxygen can safely be given in uncomplicated pneumonitis
   • For patients with pre-existing COPD complicated by ventilatory failure, guide oxygen therapy with repeated arterial blood gas measurements 1

2. Fluid Management

   • Assess for volume depletion
   • Provide intravenous fluids as needed 1
   • Monitor fluid status to avoid overhydration which may worsen respiratory status

3. Rest and Supportive Care

   • Advise patients to rest and maintain adequate hydration 1
   • Provide analgesia (e.g., paracetamol) for pleuritic pain if present 1

Pharmacological Management

Antimicrobial Therapy

If infectious etiology is suspected or cannot be ruled out:

• For outpatient management:

  • Amoxicillin as preferred agent (higher dose than standard) 1
  • Alternative: Macrolide (erythromycin or clarithromycin) for penicillin-allergic patients 1

• For hospitalized patients:

  • Combined oral therapy with amoxicillin and a macrolide (erythromycin or clarithromycin) 1
  • For adults with community-acquired pneumonia, azithromycin dosing: 500 mg as a single dose on Day 1, followed by 250 mg once daily on Days 2 through 5 2

Corticosteroids

• Consider corticosteroids for non-infectious pneumonitis (e.g., hypersensitivity pneumonitis, drug-induced pneumonitis) 3
• For immune checkpoint inhibitor-related pneumonitis, corticosteroid therapy is the mainstay of treatment 3

Monitoring and Follow-up

During Hospitalization

• Monitor vital signs, mental status, oxygen saturation, and inspired oxygen concentration at least twice daily
• More frequent monitoring for severe cases or those requiring regular oxygen therapy 1
• Remeasure CRP levels and repeat chest radiograph in patients not progressing satisfactorily 1

Follow-up Planning

• Clinical review should be arranged for all patients at around 6 weeks 1
• Chest radiograph need not be repeated prior to hospital discharge if clinical recovery is satisfactory 1
• Arrange follow-up chest radiograph for patients with:
  • Persistent symptoms or physical signs
  • Higher risk of underlying malignancy (especially smokers and those over 50 years) 1
• Consider further investigations including bronchoscopy for patients with persisting signs, symptoms, and radiological abnormalities about 6 weeks after completing treatment 1

Special Considerations

Severe Cases Requiring ICU

• Patients admitted to ICU should be managed by specialists with appropriate training in intensive care and respiratory medicine 1
• Consider non-invasive ventilation which can reduce:
  • Risk of death in the ICU
  • Need for endotracheal intubation
  • Complications
  • ICU length of stay 4
• Bronchoscopy may be valuable to:
  • Remove retained secretions
  • Obtain samples for culture or other microbiological investigations
  • Exclude endobronchial abnormality 1

Nutritional Support

• Provide nutritional support in prolonged illness 1
• Consider nutritional supplements for patients with extended recovery periods 1

Common Pitfalls to Avoid

1. Failing to identify the underlying cause of pneumonitis (infectious vs. non-infectious)
2. Inadequate oxygen monitoring in patients with pre-existing COPD
3. Delaying appropriate antimicrobial therapy when infectious etiology is suspected
4. Overlooking the need for corticosteroids in non-infectious pneumonitis cases
5. Insufficient monitoring of clinical response to treatment
6. Missing follow-up evaluation for patients with persistent symptoms or risk factors for underlying malignancy