OVERVIEW

What is acute bronchitis?

Acute bronchitis refers to acute inflammation of the bronchial mucosa, usually caused by various pathogenic microorganisms such as viruses, bacteria, and mycoplasma, with viral infections being the most common ^[1].

Patients may experience symptoms such as cough, sputum production, and fever, typically lasting for 2 weeks and usually not severe.

Most cases of acute bronchitis are caused by viruses, and antibacterial treatment is ineffective against viruses. Therefore, treatment is primarily symptomatic, including drinking plenty of fluids (recommended daily intake of around 2000 mL, not exceeding 3000 mL, with intermittent rather than large amounts at once), using antipyretics, and, if necessary, under medical guidance, nebulization therapy or antitussive medications. Antibiotics (such as amoxicillin or cefixime) are generally not used unless the cough persists for more than 10 days or pathogen culture results rule out viral infection, in which case antibiotic treatment may be administered under a doctor's recommendation.

Is acute bronchitis common?

Yes, it is common ^[2].

In recent years, according to incomplete statistics, among all acute respiratory diseases caused by pathogenic microorganisms, viral-induced acute respiratory infections account for about 80%, making it a highly prevalent disease worldwide.

Acute bronchitis often follows upper respiratory tract infections and is a common respiratory disease in childhood, particularly among infants and young children ^[3].

However, comprehensive epidemiological data are currently lacking.

SYMPTOMS

What are the symptoms of acute bronchitis?

The main symptoms are cough and sputum production. Initially, the cough is mostly dry, but gradually progresses to coughing up sputum. The sputum may start as white and sticky, and if symptoms persist, it may turn yellow or green. Fever or chills may also accompany these symptoms. Some individuals may experience wheezing or shortness of breath ^[1].

What are the complications of acute bronchitis?

People in good health generally experience few complications, but those with weakened immune systems (such as infants, the elderly, or pregnant women) may develop complications like acute otitis media, acute sinusitis, cervical lymphadenitis, or viral myocarditis ^[4].

CAUSES

What are the causes of acute bronchitis?

Under normal circumstances, the human body has immune functions, and the respiratory tract has protective mechanisms to shield the body from harmful external factors. If a person's immune function declines due to cold, fatigue, high stress, etc., and is simultaneously exposed to the following stimuli ^[1], they are more likely to develop bronchitis.

1. Microorganisms: Mainly viruses (commonly adenovirus, influenza virus, coronavirus, rhinovirus, herpes simplex virus, respiratory syncytial virus, and parainfluenza virus) and bacteria (commonly Haemophilus influenzae, Streptococcus pneumoniae, Moraxella catarrhalis, etc.). Viral infections are the most common cause, and bacterial infections may also occur secondary to viral infections. In recent years, infections caused by Chlamydia and Mycoplasma have also significantly increased.
2. Physical and chemical factors: Cold air, dust, or irritating gases and fumes (such as chlorine, ammonia, sulfur dioxide).
3. Allergic reactions: Allergies to pollen, animal fur, fungal spores, etc.

Who is more susceptible to acute bronchitis?

1. Children and the elderly: Children (generally those under 12 years old) have underdeveloped physiological structures and immature immune systems. Elderly individuals (those over 60 years old) experience declining bodily functions, weaker constitutions, and reduced immunity with age. Therefore, exposure to a higher number of harmful substances like bacteria and viruses makes them more prone to illness ^[5].
2. Patients with weakened immunity: Those with underlying lung diseases, heart failure, chronic nephritis, nephrotic syndrome, diabetes, connective tissue diseases, malignant tumors, or other conditions that impair immune function are also more susceptible to acute bronchitis.

Is acute bronchitis contagious?

Yes, it is contagious ^[1].

When a person with bronchitis coughs, the expelled droplets may carry pathogenic microorganisms such as viruses, bacteria, or Mycoplasma. If others inhale a large number of these contaminated droplets and have weakened immunity, they may also fall ill.

However, acute bronchitis is not classified as a legally notifiable infectious disease (those mandated by national regulations for enhanced management). Its contagiousness is relatively low, and cases typically occur sporadically without epidemic potential.

DIAGNOSIS

What tests are needed to diagnose acute bronchitis?

Doctors can usually diagnose it by reviewing the patient's medical history and symptoms, along with a general physical examination (such as lung auscultation). However, sometimes laboratory and imaging tests are needed to assist in the diagnosis. Commonly used tests include complete blood count (CBC), nasopharyngeal bacterial culture, and chest X-ray.

1. Complete Blood Count (CBC): Helps identify the type of pathogenic microorganism causing the infection. Note that CBC results alone cannot confirm the diagnosis—doctors primarily rely on clinical symptoms.
2. Nasopharyngeal Bacterial Culture: Gram staining and sputum culture are usually not helpful for diagnosis. However, if persistent or paroxysmal coughing continues for 10–14 days, or if there’s exposure to confirmed pertussis (whooping cough, an acute respiratory infection caused by Bordetella pertussis), a nasopharyngeal swab test may be performed.
3. Chest X-ray: Helps rule out other conditions, typically used when symptoms are severe, such as high fever (axillary temperature above 39.1°C), rapid breathing, or lethargy ^[6].

When should a patient with acute bronchitis seek medical attention?

Coughing from acute bronchitis often lasts a long time, sometimes up to 3 weeks before improvement. Medical attention is usually unnecessary unless the following symptoms occur:

1. High fever (axillary temperature above 39.1°C).
2. Chest pain, rapid breathing, wheezing, or coughing up blood during coughing or expectoration.
3. Barking cough (croup-like) causing difficulty speaking.
4. Symptoms persist for over 3 weeks without improvement ^[7].

What information should a patient provide when consulting a doctor for acute bronchitis?

Patients should describe their symptoms in detail, including duration and progression, as well as any treatments or medications already tried. Additionally, they should disclose any drug allergies and other medical conditions (e.g., hypertension, diabetes, asthma) to help the doctor assess the situation accurately and prescribe appropriate treatment.

Are bronchitis and pneumonia the same?

No. Pneumonia occurs when inflammation from the bronchi spreads further into the lungs. Pneumonia may resemble severe bronchitis (typically presenting with fever, fatigue, and dry cough), requiring a doctor’s evaluation with professional tools. For pneumonia, a stethoscope may reveal fine crackles (rales) in the lungs, or a chest X-ray may show lung shadows ^[7].

Therefore, if coughing worsens and is accompanied by difficulty breathing, seek medical attention promptly to determine whether it’s pneumonia.

TREATMENT

Which department should I visit for acute bronchitis?

1. Adult patients should visit the respiratory medicine department. If the condition worsens rapidly, they should go to the emergency department. If the community hospital does not have specialized departments, they can visit the internal medicine or general practice department.
2. Pediatric patients can visit the pediatric respiratory medicine or pediatric internal medicine department. If severe symptoms occur, such as high fever, extremely high fever, shortness of breath, limb twitching, irritability, or crying, they should prioritize visiting the pediatric emergency department.

Does acute bronchitis require hospitalization?

Generally, hospitalization is not required. However, if there is recurrent fever or significant difficulty breathing, patients should follow the doctor's advice for hospitalization.

What medications are needed for the treatment of acute bronchitis?

1. Fever-reducing medications: Such as ibuprofen or acetaminophen. These medications help reduce fever and alleviate symptoms like headaches, muscle pain, and joint pain. Consult a doctor regarding the type, dosage, and frequency of these medications, and take them as prescribed. Incorrect use may cause side effects such as stomach bleeding, liver, or kidney damage.

   • Ibuprofen may cause kidney damage. Patients with kidney disease, stomach ulcers, or aspirin allergies should avoid it.
   • Acetaminophen may cause liver damage. Avoid alcohol while taking it.
   • Medications containing aspirin, such as lysine acetylsalicylate, can also reduce fever but should only be taken by those aged 18 or older.

2. Cough suppressants: Generally not recommended for routine use, as they may hinder sputum expulsion. For patients with severe dry coughs, doctors may prescribe cough suppressants such as dextromethorphan or pentoxyverine.

   • Dextromethorphan is not suitable for those with excessive or thick sputum.
   • Pentoxyverine may cause sedation and drowsiness, so caution is needed when performing tasks requiring high concentration.

3. Expectorants: If sputum is difficult to expel, expectorants or mucolytics can help, such as sustained-release guaifenesin or ambroxol.

   • Sustained-release guaifenesin should not be used for more than 14 days. If symptoms persist after 5 days, consult a doctor.
   • Ambroxol is contraindicated for pregnant or breastfeeding women and patients with glaucoma.

4. Bronchodilators: For patients with severe coughing or wheezing, indicating heightened airway reactivity or bronchospasm, doctors may prescribe β₂ receptor agonists or corticosteroids to ease breathing.

   • β₂ receptor agonists: Such as inhaled salbutamol. If ineffective, consult a doctor rather than increasing the dose or frequency.
   • Corticosteroids: Such as budesonide suspension, which is not a bronchodilator and should not be used for rapid relief of acute bronchospasm.

5. Antibiotics: Since most acute bronchitis cases are viral, antibiotics are ineffective, and the condition often resolves without medication. Antibiotics should only be used under a doctor's guidance if a bacterial infection is confirmed. Misuse can lead to side effects and antibiotic resistance.

   Common antibiotics include amoxicillin and ampicillin. For penicillin-allergic patients, second-generation cephalosporins, macrolides, or respiratory quinolones may be prescribed.

   • Amoxicillin requires a penicillin skin test before use; those with positive reactions should avoid it.
   • Second-generation cephalosporins (e.g., cefaclor, cefuroxime) are contraindicated for those allergic to cephalosporins or with a history of penicillin-induced anaphylaxis.
   • Macrolides (e.g., azithromycin, roxithromycin) are taken orally and contraindicated for those allergic to macrolides.
   • Respiratory quinolones (e.g., gatifloxacin, levofloxacin, gemifloxacin, moxifloxacin) are suitable for patients aged 18 or older.

Can acute bronchitis be completely cured?

Yes, it can be fully cured. Once the infection is controlled, the bronchial mucosa gradually repairs and returns to normal.

How long does it usually take to recover from acute bronchitis?

If caused by a virus, acute bronchitis typically resolves on its own within one to two weeks.

If caused by a bacterial infection or secondary bacterial infection, the antibiotic course depends on the pathogen, usually lasting around 7–10 days.

Are there any sequelae after recovering from acute bronchitis?

Acute bronchitis is a benign respiratory condition. Unless severe complications occur, no sequelae remain after recovery.

Do patients with acute bronchitis need frequent follow-ups during treatment?

Generally, follow-ups are unnecessary unless symptoms recur, worsen, or change. Re-evaluation may be needed to adjust medications.

When should patients with acute bronchitis seek follow-up care?

1. Fever returns after subsiding.
2. Itchy skin or rash after taking medication.
3. Cough, sputum, or wheezing symptoms persist or worsen.
4. No improvement in cough after treatment.
5. Coughing up blood.
6. Concerns or questions about health.

When should patients with acute bronchitis call emergency services?

Call 120 or visit the emergency department if:

1. Fainting occurs.
2. Lips or tongue swell.
3. Difficulty breathing or swallowing.

DIET & LIFESTYLE

What should patients with acute bronchitis pay attention to in daily life?

1. Avoid alcohol: Alcohol reduces the frequency of coughing and sneezing. When suffering from bronchitis, the body needs to clear the airways through coughing and sneezing. Alcohol can also cause dehydration, making phlegm in the lungs thicker and harder to expel. Additionally, alcohol must be strictly avoided while taking medication.
2. Avoid airborne irritants.
   • Do not smoke and minimize exposure to secondhand smoke.
   • Avoid chemicals, fumes, and dust. If the patient must work in dusty or smoky environments, wear a mask.
   • Stay indoors during periods of severe air pollution.
   • If the patient has allergies, stay indoors during spring and summer when pollen levels are high. Avoid aerosol products such as deodorant sprays, insect repellents, and hairsprays.
3. Prevent the spread of pathogens ^[7]:
   • Wash hands frequently with soap and running water before meals, after using the toilet, and after returning from outdoors. If soap and water are unavailable, use hand sanitizer.
   • Avoid touching the eyes, nose, or mouth with unwashed hands.
   • Cover the mouth and nose with a tissue or sleeve when coughing. Discard used tissues promptly and wash hands.
   • Avoid crowded places to prevent spreading the infection to others.
4. Stay hydrated: Most people should drink at least eight glasses of water daily. When suffering from acute bronchitis, patients may need to drink more to keep the airways moist and facilitate expectoration.
5. Get plenty of rest: Avoid strenuous exercise. Rest immediately if feeling fatigued during daily activities, and ensure adequate sleep (preferably 10 hours during illness).
6. Use a humidifier: A cool-mist humidifier can increase air humidity, making breathing more comfortable and reducing coughing.
7. Maintain indoor ventilation: In colder winter months, ventilate the room three times a day for about 15 minutes each time.

What dietary precautions should patients with acute bronchitis take?

There are no specific dietary restrictions for acute bronchitis patients; a healthy, balanced diet is sufficient.

1. When cooking, use less salt, oil, and high-sodium seasonings. Avoid pickled vegetables and meats.
2. Choose protein-rich, easily digestible foods such as eggs, dairy, chicken, and fish.
3. Vegetarians can consume more beans and bean products to supplement protein.
4. Eat plenty of fresh fruits and vegetables, such as apples, oranges, bananas, spinach, and lettuce, to replenish vitamins.

PREVENTION

How to Prevent Acute Bronchitis?

1. Pay attention to physical exercise to enhance your physique and improve resistance, such as jogging, swimming, or playing badminton.
2. Maintain ventilation to reduce the concentration of pathogens in the air.
3. Wash hands frequently, especially after returning from crowded public places, after using the toilet, and before eating. Rinse with running water and use hand soap to thoroughly wash away most bacteria.
4. For children, the elderly, those with underlying lung diseases, or people with weakened immunity, regular vaccinations such as flu vaccines and pneumonia vaccines can be administered (click directly on "Pneumococcal Vaccine" or "Flu Vaccine" to learn about suitable groups and vaccination timing) to improve defenses against common viruses and bacteria.