Management of Flu-Like Symptoms in Patients with History of Infectious Mononucleosis
Treat flu-like symptoms in patients with a history of infectious mononucleosis using standard influenza management protocols, as prior EBV infection does not alter influenza treatment or increase risk of complications.
Initial Assessment and Risk Stratification
Determine if antiviral therapy is indicated by assessing three criteria: acute influenza-like illness, fever >38°C, and symptom duration ≤48 hours 1, 2. If all three are met, initiate oseltamivir 75 mg twice daily for 5 days 1, 3.
Assess for hospital admission criteria by checking for two or more unstable clinical factors 1, 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
Antiviral Management
Oseltamivir is the treatment of choice when initiated within 48 hours of symptom onset, reducing illness duration by approximately 24 hours 2, 3. Standard adult dosing is 75 mg orally every 12 hours for 5 days 1, 3.
Dose adjustment is required if creatinine clearance is <30 ml/min—reduce to 75 mg once daily 1, 4.
Consider antiviral therapy even without documented fever in patients who may have blunted febrile response, though this typically applies to immunocompromised or very elderly patients rather than those with prior mononucleosis 1.
Antibiotic Decision-Making
Do not routinely prescribe antibiotics for previously well adults with acute bronchitis complicating influenza in the absence of pneumonia 1, 4.
Add antibiotics immediately if the patient develops worsening symptoms including recrudescent fever or increasing dyspnea 1.
First-line oral antibiotic choices include co-amoxiclav or tetracycline 1. Macrolides (clarithromycin or erythromycin) or fluoroquinolones active against Streptococcus pneumoniae and Staphylococcus aureus are alternatives for penicillin-intolerant patients 1.
Monitoring and Supportive Care
Monitor vital signs at least twice daily, including temperature, respiratory rate, pulse, blood pressure, mental status, and oxygen saturation 1, 2, 5. Use an Early Warning Score system for systematic tracking 1, 2.
Provide oxygen therapy for hypoxic patients with the goal of maintaining PaO2 >8 kPa and SaO2 ≥92% 1, 2.
Ensure adequate hydration and rest as the mainstay of supportive care 6. Activity level should be guided by the patient's energy level rather than enforced bed rest 6.
Key Clinical Pitfalls
Do not confuse current influenza with reactivation of EBV. Infectious mononucleosis is a self-limited disease caused by Epstein-Barr virus that does not "trigger" or reactivate with influenza infection 7, 8. The history of mononucleosis is clinically irrelevant to current influenza management.
Do not withhold antibiotics if bacterial superinfection is suspected, particularly in patients with worsening symptoms after initial improvement 1, 5.
Do not assume normal fever response in all patients—while this is primarily a concern in immunocompromised or elderly patients, any patient with high clinical suspicion for influenza may warrant antiviral therapy 1, 5.
Discharge Planning
Review patients 24 hours prior to discharge to ensure clinical stability, with particular attention to the unstable clinical factors listed above 1.
Arrange follow-up for patients who suffered significant complications or worsening of underlying disease, either with their general practitioner or in a hospital clinic 1.