- ACRONYMS AND DEFINITIONS
- ACCP - American College of Chest Physicians
- ACP - American College of Physicians
- CDC- Center for Disease Control
- RCT - Randomized controlled trial
- EPIDEMIOLOGY
- Acute bronchitis is a lower respiratory tract infection marked by inflammation of the bronchi, the large airways of the lungs
- Acute bronchitis occurs in up to 5% of the general population and it accounts for > 10 million physician office visits per year in the US alone
- Viruses cause > 90% of bronchitis cases and bacteria account for < 2%
- Viruses associated with bronchitis include influenza A and B viruses, parainfluenza virus, respiratory syncytial virus, coronavirus, adenovirus, rhinovirus, and others
- Bacteria associated with bronchitis include Bordetella pertussis, Chlamydophila pneumoniae, and Mycoplasma pneumoniae [1,2,3]
- SYMPTOMS
- Symptoms of acute bronchitis include the following:
- Cough for up to 6 weeks with or without phlegm production. Phlegm production whether colored or not is a sign of inflammation and does not indicate a bacterial infection.
- Nasal congestion and postnasal drip
- Fever and malaise may be present, particularly if caused by influenza virus
- Transient airflow obstruction and airway hyperresponsiveness (wheezing) may occur in up to 40% of healthy individuals [2,3]
- DIAGNOSIS
- The diagnosis of bronchitis is typically based on clinical symptoms
- Sputum or serum testing for an etiology including Chlamydophila pneumoniae and Mycoplasma pneumoniae is not recommended since the responsible organism is rarely identified in clinical practice
- Testing for Bordetella pertussis may be indicated if a community outbreak or known exposure has occurred
- A chest X-ray may be indicated if there is concern for pneumonia. See pneumonia vs bronchitis for more. [2,3]
- PNEUMONIA VS BRONCHITIS
- Overview
- Since bronchitis is a self-limited infection that requires no treatment, it's important to distinguish it from pneumonia where treatment is indicated
- If pneumonia is suspected, a chest X-ray should be performed to confirm the diagnosis (see pneumonia for more)
- The ACCP and the ACP give the following guidance when differentiating bronchitis from pneumonia
- For healthy adults < 70 years old, the absence of all the following makes the diagnosis of pneumonia very unlikely and a chest X-ray is not indicated:
- Tachycardia (heart rate > 100 beats/min)
- Tachypnea (respiratory rate > 24 breaths/minute)
- Fever (oral temp > 38° C or 100.4° F)
- Abnormal findings on chest exam including egophony (increased resonance of voice sounds heard when auscultating the lungs), fremitus (voice vibrations transmitted to the chest wall that are heard or felt with the hands), and rales (rattling sound) [2,3]
- TREATMENT
- Antibiotics
- The CDC, ACP, and ACCP state that antibiotics are not useful for acute bronchitis and should not be offered
- Chlamydophila pneumoniae and Mycoplasma pneumoniae which account for < 1% of acute bronchitis cases are typically self-limited infections that do not require antibiotic treatment
- Patients with confirmed or suspected Bordetella pertussis infection should be treated with a macrolide antibiotic or trimethoprim-sulfamethoxazole. Postexposure prophylaxis for contacts is also recommended. [2,3]
- Symptomatic treatments
- Guaifenesin (expectorant) and dextromethorphan (cough suppressant) (e.g. Mucinex DM, Robitussin DM) - can suppress cough and loosen chest congestion
- Codeine - in adults and children > 12 years old, codeine may be used as a cough suppressant
- Albuterol - in patients with reactive airway symptoms (wheezing), albuterol may be useful
- Analgesics - medications like NSAIDs (e.g. ibuprofen, naproxen) and acetaminophen can be used for pain and fever
- Intranasal steroids (e.g. Flonase, Nasonex) - intranasal steroids help relieve nasal congestion
- Oral decongestants (e.g. Sudafed) - oral decongestants can help alleviate congestive symptoms
- Topical decongestants (e.g. Afrin) - topical decongestants can help alleviate congestive symptoms. Limit use to 3 - 5 days to prevent rebound congestion.
- Oral antihistamines (e.g. Claritin, Allegra, Zyrtec) - oral antihistamines may decrease secretions and suppress sneezing
- CHRONIC BRONCHITIS
- Chronic bronchitis is defined as a productive cough for ≥ 3 months in each of 2 successive years
- Chronic bronchitis is a condition associated with smoking and chronic obstructive pulmonary disease (COPD) and is not covered here
- ANTIBIOTIC STUDIES
- The ARTIC PC trial enrolled 432 children with symptoms consistent with acute bronchitis
Main inclusion criteria
- Age 6 months - 12 years
- Acute cough as predominant symptom
- Symptoms less than 21 days
- Presence of shortness of breath, sputum, or pain
Main exclusion criteria
- Non-infectious cause
- Likely viral cause (e.g. croup)
- Immunocompromised
- Pneumonia likely or severely ill
Baseline characteristics
- Average age 3.2 years
- History of asthma - 10%
- Abnormal chest exam - 35%
- Sputum or chest rattle - 76%
- Fever during illness - 78%
- Shortness of breath - 46%
- Tachypnea - 14%
Randomized treatment groups
- Group 1 (221 patients): Amoxicillin 50 mg/kg/day in 3 divided doses for 7 days
- Group 2 (211 patients): Placebo
Primary outcome: Duration of symptoms rated moderately bad or worse (measured using a validated diary) for up to
28 days or until symptoms resolved
Results
| Duration: 28 days | |||
| Outcome | Amoxicillin | Placebo | Comparisons |
|---|---|---|---|
| Primary outcome | 5 | 6 | HR 1.13, 95%CI [0.90 to 1.42] |
| Return for new or worsening symptoms | 30% | 38% | RR 0.80, 95%CI [0.58 to 1.05] |
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Findings: Amoxicillin for uncomplicated chest infections in children is unlikely to be clinically effective either
overall or for key subgroups in whom antibiotics are commonly prescribed. Unless pneumonia is suspected, clinicians
should provide safety-netting advice but not prescribe antibiotics for most children presenting with chest infections.
- A study published in the BMJ randomized 416 patients with acute bronchitis to augmentin, ibuprofen, or placebo
Main inclusion criteria
- Respiratory infection for < 1 week with cough as the predominant feature
- Discolored sputum
- At least one of the following: dyspnea, wheezing, chest discomfort, or chest pain
Main exclusion criteria
- Use of antibiotic, anti-inflammatory, or corticosteroid in previous two weeks
- Respiratory rate > 25 breaths per minute
- Heart rate > 120 bpm
- History of asthma or COPD
- Pneumonia on X-ray
Baseline characteristics
- Average age 45 years
- Current smoker - 39% | Former smoker - 15%
- Reported dyspnea - 34%
- Wheezing on exam - 30%
- Average number of days with cough at randomization - 4
Randomized treatment groups
- Group 1 (137 patients) - Augmentin® 500/125 mg 3 times a day for 10 days
- Group 2 (136 patients) - Ibuprofen 600 mg 3 times a day for 10 days
- Group 3 (143 patients) - Placebo
- Symptomatic treatment except for antibiotics and NSAIDs were allowed
Primary outcome: Number of days with frequent cough after the first visit as recorded in the patient's symptom diary
Results
| Duration: 30 days | ||||
| Outcome | Augmentin | Ibuprofen | Placebo | Comparisons |
|---|---|---|---|---|
| Primary outcome (# of days with frequent cough) | 11 | 9 | 11 | p=0.25 |
| Cure or improvement at end of treatment | 78% | 86% | 86% | p=0.13 |
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Findings: No significant differences were observed in the number of days with cough between patients with uncomplicated
acute bronchitis and discolored sputum treated with ibuprofen, Augmentin, or placebo
- A study published in Lancet Infectious Disease randomized 2061 patients with bronchitis to amoxicillin or placebo
Main inclusion criteria
- Acute cough (≤ 28 days) or lower-respiratory tract infection considered most probable diagnosis
Main exclusion criteria
- Focal chest signs (focal crepitations, bronchial breathing) and systemic features (high fever, vomiting, severe diarrhea)
- Cough thought to be of noninfectious cause (e.g. PE, reflux, allergies)
Baseline characteristics
- Average age 49 years
- Present or past smoker - 53%
- COPD or asthma - 15%
- Sputum production - 79%
- Discolored sputum - 49%
Randomized treatment groups
- Group 1 (1038 patients) - Amoxicillin 1000 mg 3 times a day for 7 days
- Group 2 (1023 patients) - Placebo for 7 days
Primary outcome: Number of days with symptoms rated by patients as “moderately bad” or worse after initial presentation
Results
| Duration: 28 days | |||
| Outcome | Amoxicillin | Placebo | Comparisons |
|---|---|---|---|
| Primary outcome (median # of days) | 6 | 7 | HR 1.06, 95%CI [0.96 - 1.18] p=0.23 |
| Worsening of illness during follow-up | 15.9% | 19.3% | OR 0.79, 95%CI [0.63 - 0.99] p=0.043 |
| Nausea, rash, or diarrhea | 28.7% | 24% | p=0.025 |
Findings: When pneumonia is not suspected clinically, amoxicillin provides little benefit for acute
lower-respiratory-tract infection in primary care both overall and in patients aged 60 years or more, and causes slight harms.
- A study published in the Lancet randomized 220 patients with acute bronchitis to a Z-pak or Vitamin C
Main inclusion criteria
- Cough for 2 - 14 days with or without sputum production
- Diagnosed with acute bronchitis by physician
Main exclusion criteria
- History of COPD or asthma
- Current treatment with bronchodilators or glucocorticoids
- Temp > 102°
- Respiratory rate ≥ 25 breaths/minute
- Infiltrates on chest X-ray
Baseline characteristics
- Average age 46 years
- Median number of days with cough - 5
- Wheezing on exam - 12%
- Current smoker - 36%
Randomized treatment groups
- Group 1 (112 patients) - Azithromycin 500 mg X 1 day, then 250 mg a day for 4 days (Z-Pak®)
- Group 2 (108 patients) - Vitamin C 500 mg X 1 day, then 250 mg a day for 4 days
- All participants were also given an albuterol inhaler to use as needed for cough. No other medications were allowed.
Primary outcome: Health-related quality of life on day 7 of follow-up. Health-related quality of life was measured on 4 domains:
symptom effects on daily activities, coughing and shortness of breath, general symptoms, and emotional functioning
Results
| Duration: 7 days |
|
Findings: Azithromycin is no better than low-dose Vitamin C for acute bronchitis. Further studies are needed to
identify the best treatment for this disorder
- STEROID STUDY
- Design: Randomized, placebo-controlled trial (N=401, length = 28 days) in nonasthmatic adults diagnosed with acute bronchitis
- Treatment: Prednisolone 40 mg once daily for 5 days vs Placebo
- Primary outcome: Duration of moderately bad or worse cough
- Results:
- Primary outcome (median days): Prednisolone - 5 days, Placebo - 5 days (p=0.36)
- Of note, 47% of patients had wheezing at baseline and 70% reported shortness of breath
- Findings: Oral corticosteroids should not be used for acute lower respiratory tract infection symptoms in adults without asthma because they do not reduce symptom duration or severity.
- BIBLIOGRAPHY
- 1 - PMID 17108344 - NEJM review
- 2 - PMID 16428698 - ACCP GL
- 3 - PMID 26785402 Appropriate Antibiotic Use for Acute Respiratory Tract Infection in Adults: Advice for High-Value Care From the American College of Physicians and the Centers for Disease Control and Prevention, Ann Intern Med (2016)