What is the management approach for a patient with post-influenza bronchitis, particularly one with a history of Chronic Obstructive Pulmonary Disease (COPD) or asthma?

Management of Post-Influenza Bronchitis in Patients with COPD or Asthma

For patients with post-influenza bronchitis and underlying COPD or asthma, immediately initiate short-acting bronchodilators, add systemic corticosteroids (prednisone 40 mg daily for 5 days), consider oseltamivir if within 48 hours of symptom onset, and provide antibiotic coverage with co-amoxiclav if there is increased sputum purulence, volume, or worsening dyspnea. 1

Immediate Assessment and Risk Stratification

Determine severity using clinical parameters to guide disposition 1:

• Send to emergency room immediately if: respiratory rate >30/min, blood pressure <90/60 mmHg, shortness of breath at rest, confusion, hemoptysis, or bilateral chest signs suggesting pneumonia 2, 1
• Calculate CURB-65 score for pneumonia severity assessment: 1 point each for Confusion, Respiratory rate >30/min, Blood pressure <90/60 mmHg, age ≥65 years 2, 3
• CURB-65 interpretation: Score 0 = home treatment; Score 1-2 = consider hospital referral (especially score 2); Score 3-4 = urgent hospital referral 2

Bronchodilator Therapy

Start short-acting inhaled β2-agonists with or without short-acting anticholinergics as first-line treatment 1:

• Use nebulizers if the patient is too breathless to use standard inhalers effectively 1
• Alternatively, use spacer devices with metered-dose inhalers 1
• Continue or initiate long-acting bronchodilators (LABA or LAMA) as soon as clinically stable 3

Systemic Corticosteroids

Prednisone 40 mg orally daily for 5 days is the indicated regimen 1, 3:

• Corticosteroids improve lung function, oxygenation, shorten recovery time, and reduce hospitalization duration in COPD exacerbations 1, 3
• This applies to both COPD and asthma exacerbations triggered by influenza 2

Antiviral Therapy

Consider oseltamivir 75 mg orally twice daily for 5 days if the patient presents within 48 hours of influenza symptom onset 1, 3:

• Oseltamivir reduces illness duration by approximately 24 hours and may reduce hospitalization rates 1, 3
• Reduce dose by 50% (75 mg once daily) if creatinine clearance is less than 30 mL/minute 2, 3
• Patients unable to mount adequate febrile response (immunocompromised) should still be considered for treatment even without documented fever 2

Antibiotic Coverage

Co-amoxiclav 625 mg orally three times daily is first-line antibiotic coverage 2, 1, 3:

• Covers common secondary bacterial pathogens including Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, and Staphylococcus aureus 2, 1
• Indications for antibiotics include: increased sputum purulence, increased sputum volume, or increased dyspnea 1
• Alternative regimens: Doxycycline 200 mg loading dose then 100 mg daily for patients intolerant of beta-lactams 2, 3
• Avoid macrolides as first-line due to 10-19% resistance rates among S. pneumoniae and poor activity against H. influenzae 2
• Fluoroquinolones (levofloxacin 500 mg daily or moxifloxacin 400 mg daily) are alternatives if increased likelihood of resistance or local resistance patterns dictate 2

Common Pitfall to Avoid

Previously well adults with acute bronchitis complicating influenza, in the absence of pneumonia, do not routinely require antibiotics 2. However, patients with underlying COPD or asthma who are sufficiently ill to require hospital admission with an exacerbation will require antibiotics 2.

Oxygen Management

Titrate oxygen to maintain SpO2 ≥92% in most patients 1, 3:

• For COPD patients with known CO2 retention, target SpO2 ≥90% and use controlled oxygen therapy 1
• Start with controlled oxygen and titrate based on repeated arterial blood gas measurements in patients with pre-existing COPD complicated by ventilatory failure 2, 3
• Obtain arterial blood gases if SpO2 <92% or if the patient has features of severe illness 1
• High concentrations of oxygen can safely be given in uncomplicated pneumonia without pre-existing COPD 2

Monitoring Strategy

Check vital signs at least twice daily: temperature, respiratory rate, pulse, blood pressure, mental status, oxygen saturation, and inspired oxygen concentration 2, 1:

• Use an Early Warning Score system for convenient tracking 2, 1
• In patients not progressing satisfactorily, perform full clinical reassessment and repeat chest radiograph 2

Non-Invasive Ventilation

Consider non-invasive ventilation (NIV) in COPD patients with acute hypercapnic respiratory failure 2:

• NIV may be helpful in patients with pre-existing COPD complicated by ventilatory failure 2
• In patients without pre-existing COPD who develop respiratory failure, NIV may serve as a bridge to invasive ventilation when ICU beds are in high demand 2
• Respiratory and critical care units experienced in NIV use are best placed to ensure appropriate infection control measures 2

Discharge Criteria

Review patients 24 hours prior to discharge and ensure stability criteria are met 2, 1:

Patients with two or more of the following unstable factors should remain in hospital 2:

• Temperature >37.8°C
• Heart rate >100/min
• Respiratory rate >24/min
• Systolic blood pressure <90 mmHg
• Oxygen saturation <90%
• Inability to maintain oral intake
• Abnormal mental status

Follow-Up and Prevention

Arrange follow-up for all patients who suffered significant complications or worsening of underlying disease 2, 1:

• Follow-up can be with general practitioner or in hospital clinic 2
• At discharge or follow-up, provide information about illness, medications, and follow-up arrangements 2

Ensure annual influenza vaccination to prevent future exacerbations 2, 1:

• Influenza vaccination is recommended for all patients with COPD and asthma 2
• Pneumococcal vaccinations PCV13 and PPSV23 are recommended for all patients ≥65 years of age 2
• PPSV23 is also recommended for younger patients with COPD or asthma with significant comorbid conditions 2

Additional Supportive Care

Assess for cardiac complications and volume depletion 2:

• Provide intravenous fluids as needed 2
• Nutritional support should be given in severe or prolonged illness 2