Influenza Management

Patient Selection for Antiviral Treatment

The American Thoracic Society recommends that patients older than one year with acute influenza-like illness should receive antiviral treatment if they present with fever (>38°C in adults, >38.5°C in children), within 48 hours of symptom onset 1, 2
Patients with underlying respiratory disease, such as asthma or COPD, should receive oseltamivir 75 mg orally twice a day for 5 days, initiated within 48 hours of symptom onset 3

Oseltamivir is the antiviral of choice for patients with asthma or COPD, with a standard dose of 75 mg orally twice a day for 5 days 4, 2, 3, 5
The American College of Physicians recommends adjusting the dose to 75 mg once a day if the creatinine clearance is <30 mL/min 3, 5

Antiviral treatment with oseltamivir can reduce the duration of illness by 24-53.9 hours, reduce symptom severity by up to 38%, and possibly reduce hospitalizations 1, 3
The Infectious Diseases Society of America recommends antiviral treatment to reduce the use of subsequent antibiotics 1, 3

Patients with SpO2 <92% should receive oxygen therapy, with a target SpO2 ≥92% 4, 2, 3, 5
The British Thoracic Society recommends using controlled oxygen therapy with repeated arterial blood gas monitoring to avoid CO2 retention in patients with known COPD 3, 5

The American Thoracic Society recommends antibiotic treatment for patients with influenza-related pneumonia, with coverage for S. aureus and other pathogens 1, 3, 5
First-line treatment includes co-amoxiclav (amoxicillin-clavulanate) 625 mg three times a day orally or doxycycline 200 mg initially, then 100 mg once a day 6

The CURB-65 score should be calculated immediately, with a score ≥2 indicating severe pneumonia and requiring hospitalization 4, 2, 3, 6
The American College of Emergency Physicians recommends considering hospitalization if the patient has a CURB-65 score ≥2, bilateral radiographic changes, or inability to maintain SpO2 >92% with supplemental oxygen 4, 2, 6

Patients should be monitored at least twice a day, with more frequent monitoring if severe, including temperature, respiratory rate, pulse, blood pressure, and oxygen saturation 3, 5, 6

Patients should reconsult if they experience shortness of breath at rest or with minimal activity, painful or difficult breathing, or worsening symptoms 7, 3

The American Academy of Family Physicians recommends symptomatic treatment, including paracetamol or ibuprofen for fever, myalgias, and headache, rest, and adequate fluid intake 7, 3
Aspirin is contraindicated in children under 16 years due to the risk of Reye's syndrome 7

Patients with COPD exacerbations triggered by influenza should receive oseltamivir PLUS systemic corticosteroids, short-acting bronchodilators, and antibiotics, according to the British Thoracic Society guidelines 8
The CURB-65 score should be calculated immediately for patients with suspected influenza-related pneumonia to assess severity, with a score of 0 indicating likely suitability for home treatment, scores 1-2 considering hospital referral, and scores 3-4 requiring urgent hospital referral 8
Warning signs requiring immediate re-evaluation include shortness of breath, painful breathing, coughing up bloody sputum, drowsiness, and lack of improvement after two days from starting oseltamivir, as recommended by the British Thoracic Society 8
Do not ignore worsening of pre-existing medical conditions, as these patients are at high risk of hospitalization or death and require prompt reassessment, according to the British Thoracic Society guidelines 8