What is the recommended management for a patient presenting with flu symptoms, particularly those with underlying chronic conditions such as asthma or chronic obstructive pulmonary disease (COPD)?

Management of Influenza

For patients with flu symptoms, especially those with underlying chronic respiratory conditions like asthma or COPD, initiate oseltamivir 75 mg orally twice daily for 5 days within 48 hours of symptom onset, and never prescribe zanamivir to patients with any underlying airways disease due to risk of fatal bronchospasm. 1, 2, 3

Antiviral Treatment Selection

Oseltamivir as First-Line Therapy

• Oseltamivir is the only appropriate antiviral for patients with asthma, COPD, or any underlying airways disease 1, 2, 4
• Standard adult dosing is 75 mg orally twice daily for 5 days 1, 2, 4
• Adjust dose to 75 mg once daily if creatinine clearance is <30 mL/min 1, 2, 4

Absolute Contraindication of Zanamivir

• Zanamivir is absolutely contraindicated in patients with asthma or COPD due to risk of serious bronchospasm, including fatalities 1, 3
• The FDA explicitly warns that zanamivir is not recommended for treatment or prophylaxis in individuals with underlying airways disease 3
• Serious cases of bronchospasm and deaths have been reported during treatment with zanamivir in patients with and without underlying airways disease 3
• In Phase 3 trials, 10% of subjects with underlying asthma or COPD experienced >20% decline in FEV1 following zanamivir treatment 3

Timing of Antiviral Initiation

• Treatment should ideally be initiated within 48 hours of symptom onset for maximum benefit 2, 5
• Initiation within the first 12 hours after fever onset can reduce total median illness duration by 74.6 hours (3.1 days) compared to intervention at 48 hours 5
• High-risk patients with asthma or COPD may still benefit even when started slightly beyond 48 hours 1
• Earlier administration progressively increases therapeutic effects at every time point of intervention 5

Benefits of Oseltamivir Treatment

• Reduces duration of illness by 24-53.9 hours 2
• Reduces symptom severity by up to 38% 2
• May reduce hospitalizations 2
• Reduces the need for subsequent antibiotics 2

Management of COPD Exacerbations Triggered by Influenza

Comprehensive Treatment Approach

• Patients with COPD exacerbations triggered by influenza should receive oseltamivir PLUS systemic corticosteroids, short-acting bronchodilators, and antibiotics 6, 4
• Manage according to current COPD guidelines for acute exacerbations 6

Corticosteroid Therapy

• Prednisone 40 mg daily for 5 days improves lung function, oxygenation, and shortens recovery time 4

Bronchodilator Therapy

• Initiate short-acting inhaled β2-agonists with or without short-acting anticholinergics as first-line treatment 4
• If patients are scheduled to use an inhaled bronchodilator at the same time as oseltamivir, use the bronchodilator BEFORE taking oseltamivir 3
• Continue or initiate long-acting bronchodilators as soon as possible 4

Antibiotic Coverage

• Co-amoxiclav (amoxicillin-clavulanate) 625 mg three times daily orally is first-line because it covers common secondary bacterial pathogens 2, 4
• Doxycycline 200 mg initially, then 100 mg once daily is an alternative for patients intolerant of beta-lactams 2, 4
• Antibiotics are not routinely indicated for uncomplicated influenza with asthma exacerbation in the absence of bacterial pneumonia 1

Oxygen Management

• Assess oxygen saturation immediately and maintain SpO2 ≥92% 2, 4
• For patients with known COPD and potential CO2 retention, use controlled oxygen therapy with repeated arterial blood gas monitoring to avoid CO2 retention 2, 4

Assessment of Pneumonia Severity

CURB-65 Score for Severity Assessment

• Calculate CURB-65 score immediately for patients with suspected influenza-related pneumonia 6, 2
• Score 1 point for each: Confusion, Respiratory rate >30/min, Blood pressure (SBP <90 mmHg or DBP <60 mmHg), age ≥65 years 6

Hospital Referral Criteria

• CURB-65 score of 0: Likely suitable for home treatment 6
• CURB-65 score of 1-2: Consider hospital referral, particularly with score 2 6
• CURB-65 score of 3-4: Urgent hospital referral 6
• Any score with bilateral chest signs of pneumonia: Consider hospital referral 6
• Patients with bilateral chest signs (crackles) should be considered for hospital referral due to risk of rapid and fulminant primary viral pneumonia 6

Indications for Re-consultation

Warning Signs Requiring Immediate Re-evaluation

• Shortness of breath at rest or while doing very little 6, 2
• Painful or difficult breathing 6, 2
• Coughing up bloody sputum 6
• Drowsiness, disorientation, or confusion 6
• Fever for 4-5 days and not starting to get better (or getting worse) 6
• Started to feel better then developing high fever and feeling unwell again 6
• Lack of any improvement after two days from starting oseltamivir 6

Symptomatic Treatment

• Paracetamol or ibuprofen for fever, myalgias, and headache 2
• Rest and adequate fluid intake 2
• Aspirin is contraindicated in children under 16 years due to risk of Reye's syndrome 2

Monitoring

• Monitor vital signs at least twice daily, including temperature, respiratory rate, pulse, blood pressure, and oxygen saturation 2, 4
• More frequent monitoring if severe 2

Common Pitfalls to Avoid

• Never prescribe zanamivir to patients with any underlying airways disease, regardless of severity 1, 3
• Do not withhold oseltamivir from high-risk patients (asthma, COPD, smokers) even if presenting slightly beyond 48 hours, as they may still benefit significantly 1
• Do not routinely prescribe antibiotics for uncomplicated influenza without evidence of bacterial pneumonia 1
• Do not ignore worsening of pre-existing medical conditions—these patients are at high risk of hospitalization or death and require prompt reassessment 6