Disease Description (Causes and Symptoms)
- Cause: Infection with the influenza virus. Outbreaks recur due to antigenic changes in the virus (antigenic drift and antigenic shift).
- Pathophysiology: Infection of respiratory epithelial cells causes a systemic inflammatory response (fever, muscle aches, etc.) and localized airway symptoms (sore throat, cough). The risk of lower respiratory tract involvement (pneumonia) and systemic complications increases in older adults, people with chronic respiratory diseases, and immunocompromised people.
- Main symptoms: Sudden fever, chills, generalized weakness and fatigue, headache, muscle aches, sore throat, and cough. Some people develop gastrointestinal symptoms such as nausea, vomiting, and diarrhea (especially children).
Treatment
- General management
- Get adequate rest and fluids; use fever reducers and pain relievers (such as Tylenol (acetaminophen) in adults). Aspirin is prohibited in children 18 years old or younger (risk of Reye syndrome).
- Symptomatic treatment to relieve symptoms (cough medicine, throat pain relief, etc.).
- Isolation and mask-wearing are recommended while contagious (generally about 5–7 days after symptom onset; this may be longer in children and patients with severe illness).
- Antiviral medications
- For high-risk groups (older adults, people with chronic heart, lung, kidney, or liver diseases, immunocompromised people, pregnant women, etc.) or people with severe or progressive symptoms, consider administering oseltamivir, zanamivir, etc. as early as possible (most effective within 48 hours of symptom onset). Antiviral treatment is recommended for patients with severe illness or those who are hospitalized.
- The treatment duration and dosage are adjusted according to age, kidney function, and pregnancy status.
- Treatment when complications occur
- If bacterial pneumonia is suspected, administer appropriate antibiotics and, if necessary, provide hospitalization and oxygen therapy.
- If emergency symptoms such as difficulty breathing, hypoxemia, dehydration, or decreased consciousness occur, receive emergency treatment and be transferred to a hospital immediately.
- Prevention and vaccination
- Annual influenza vaccination is recommended (generally September–November, before the outbreak). It takes about 2 weeks for antibodies to develop.
- Priority vaccination groups: older adults; people with chronic lung, heart, or neurological diseases; people with chronic diseases such as diabetes; immunocompromised people; healthcare workers; residents of group facilities; etc. Depending on the characteristics of recently circulating strains, the recommendation may be expanded to include everyone aged 6 months and older.
Outpatient Visit Checklist (Items to Prepare and Things to Confirm)
- Items and information to prepare
- Record the date symptoms began (when they started and how they have progressed)
- List of current symptoms (fever, cough, difficulty breathing, gastrointestinal symptoms, etc.) and temperature trends
- List of medications currently being taken (including anticoagulants and immunosuppressants) and history of allergies
- Medical history: chronic diseases (asthma, COPD, heart disease, diabetes, kidney or liver disease), immunocompromised status, and pregnancy status
- Recent vaccination history (when the influenza vaccine was received)
- Recent exposure history (contact with someone suspected of having influenza or visits to areas experiencing an outbreak)
- Results of previous tests (if necessary)
- Symptom-related measurements to take if possible
- Body temperature, respiratory rate, oxygen saturation (if available), and blood pressure
- Symptoms to report to medical staff immediately during an outpatient visit
- Difficulty breathing, chest pain, persistent high fever, marked changes in consciousness, severe dehydration, or inability to eat or drink fluids
Examples of General Questions to Ask a Doctor
- What are the expected effects and possible side effects of this medication (antiviral medication/fever reducer)?
- Do I need hospitalization or additional tests given my condition? What is the prognosis (expected recovery time)?
- When is it safe to return to daily activities (work or school)?
- Are there any interactions with my current medications, or any medications I need to stop taking?
- Is vaccination (this season’s vaccine) recommended, and when is the appropriate time to receive it?
Examples of Disease-Specific Questions
- Regarding antiviral medication: "How many hours/days after symptom onset should I start antiviral medication for it to be most effective, and which medication and treatment duration are appropriate for my age and underlying conditions?"
- Regarding pregnancy and children: "If I am pregnant or the patient is a child under 18, what safe treatment options and fever-reducer choices should be used (acetaminophen is recommended, and aspirin is contraindicated)?"