How do you manage a patient with influenza (flu) symptoms and a negative Covid-19 test, who has a history of respiratory issues such as asthma or Chronic Obstructive Pulmonary Disease (COPD)?

Management of Flu Symptoms with Negative COVID-19 Test in Patients with Asthma or COPD

For patients with influenza-like illness and underlying asthma or COPD, initiate short-acting bronchodilators immediately, add systemic corticosteroids (prednisone 40 mg daily for 5 days), consider oseltamivir if within 48 hours of symptom onset, and provide antibiotic coverage if there is increased sputum purulence, volume, or dyspnea. 1, 2

Immediate Assessment and Risk Stratification

Determine severity using clinical parameters to guide disposition:

• 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 3
• Calculate CRB-65 score (1 point each for: confusion, respiratory rate >30/min, blood pressure <90/60 mmHg, age ≥65 years): score 0 = home management possible; score 1-2 = consider hospital referral; score 3-4 = urgent hospital referral 3
• Assess oxygen saturation immediately: maintain SpO2 ≥92% in most patients, or ≥90% in COPD patients with known CO2 retention 4, 1

Bronchodilator Therapy (First-Line Treatment)

Initiate aggressive bronchodilator therapy for wheezing or bronchospasm:

• 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, or use spacer devices with metered-dose inhalers 1
• Continue or initiate long-acting bronchodilators as soon as clinically stable 1, 2

Systemic Corticosteroids (Essential for COPD/Asthma Exacerbations)

Systemic corticosteroids are indicated regardless of viral trigger:

• Prednisone 40 mg orally daily for 5 days is the recommended regimen 1, 2
• Corticosteroids improve lung function, oxygenation, shorten recovery time, and reduce hospitalization duration in COPD exacerbations 1
• Do not withhold corticosteroids simply because the patient has influenza—the concern about avoiding steroids in acute flu applies only to uncomplicated influenza without underlying lung disease, not to COPD or asthma exacerbations triggered by influenza 1
• Inhaled corticosteroids should be continued in asthma patients to maintain adequate disease control 5

Antiviral Therapy

Consider oseltamivir if influenza is suspected:

• Oseltamivir 75 mg orally twice daily for 5 days if the patient presents within 48 hours of influenza symptom onset 1, 2, 6
• Reduce dose by 50% if creatinine clearance is <30 mL/minute 6
• Oseltamivir reduces illness duration by approximately 24 hours and may reduce hospitalization rates 2
• Reassess if no improvement within 48 hours of starting antiviral therapy 3

Antibiotic Coverage

Antibiotics are indicated when Anthonisen criteria are met:

• Co-amoxiclav is first-line because it covers common secondary bacterial pathogens including Streptococcus pneumoniae and Haemophilus influenzae during influenza 1, 2
• Indications for antibiotics: increased sputum purulence, increased sputum volume, or increased dyspnea 1
• Doxycycline is an alternative for patients intolerant of beta-lactams 1, 2
• Avoid macrolides as first-line therapy due to antimicrobial resistance concerns and inferior coverage 1, 2

Oxygen Management

Titrate oxygen based on underlying lung disease:

• For patients without known CO2 retention: high-flow oxygen (≥35%) can be safely used to maintain PaO2 >8 kPa or SpO2 >92% 4, 1
• For COPD patients with potential CO2 retention: start with controlled low-flow oxygen (24-28%) and titrate based on repeated arterial blood gas measurements, aiming for SpO2 >90% without causing arterial pH to fall below 7.35 4, 1
• Obtain arterial blood gases if SpO2 <92% or if patient has features of severe illness 4
• Continuous oxygen therapy is indicated for PaO2 <8 kPa, systolic blood pressure <100 mmHg, metabolic acidosis with bicarbonate <18 mmol/L, or respiratory rate >30/min 4

Additional Supportive Measures

Provide comprehensive supportive care:

• Assess for volume depletion and provide IV fluids if needed 4
• Monitor for cardiac complications including exacerbation of pre-existing cardiac disease, heart failure, or arrhythmias 4
• Obtain chest radiograph and electrocardiogram for all patients admitted to hospital with abnormal cardiorespiratory symptoms 4
• Physiotherapy may benefit selected patients with excess bronchial secretions, particularly those with concurrent COPD 4

Monitoring Strategy

Establish systematic monitoring protocols:

• Check vital signs at least twice daily: temperature, respiratory rate, pulse, blood pressure, mental status, oxygen saturation, and inspired oxygen concentration 4, 1
• Use an Early Warning Score system for convenient tracking 4
• Reassess within 30-60 minutes if severe, or within 48 hours if managing at home 1
• Repeat chest radiograph if no clinical improvement within 48-96 hours 4, 1

Non-Invasive Ventilation Considerations

NIV may be appropriate in specific circumstances:

• NIV may be helpful in COPD patients with acute hypercapnic respiratory failure 4, 1
• NIV may serve as a bridge to invasive ventilation in patients without pre-existing COPD who develop respiratory failure, particularly when critical care beds are limited 4
• Ensure appropriate infection control measures are adopted when using NIV due to risks of respiratory droplet dissemination 4

Common Pitfalls to Avoid

Critical errors that worsen outcomes:

• Do not withhold systemic corticosteroids in COPD or asthma exacerbations simply because influenza is present 1
• Do not use azithromycin as first-line when co-amoxiclav is appropriate and tolerated 1, 2
• Do not give uncontrolled high-flow oxygen to known CO2 retainers without arterial blood gas monitoring 1
• Do not delay hospital referral if warning signs are present, even if initial symptoms seem mild 3

Discharge Criteria and Follow-Up

Patients should meet stability criteria before discharge:

• Review 24 hours prior to discharge—patients with two or more unstable clinical factors should remain hospitalized: temperature >37.8°C, heart rate >100/min, respiratory rate >24/min, systolic blood pressure <90 mmHg, or oxygen saturation <90% 4
• Arrange follow-up for all patients who suffered significant complications or worsening of underlying disease 4
• Ensure annual influenza vaccination to prevent future exacerbations 1, 2
• Consider pneumococcal vaccination as part of overall COPD/asthma management 1, 2