Bronchitis, Acute

Definition, Etiology, PathogenesisTop

Acute bronchitis is an acute infection of the bronchi, the diagnosis of which is established only after excluding pneumonia. It characteristically presents as a cough, which can be productive or nonproductive and is usually self-limiting, with symptoms lasting <3 weeks.

Causes: Most frequently, respiratory viruses (influenza A and B viruses, parainfluenza viruses, respiratory syncytial virus, coronaviruses [other than severe acute respiratory syndrome coronavirus 2, or SARS-CoV-2], adenoviruses, or rhinoviruses). Bacterial infections are found in <10% of patients and are most commonly caused by Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, Staphylococcus aureus, Mycoplasma pneumoniae, and rarely Bordetella pertussis.

Clinical Features and Natural HistoryTop

1. Symptoms: Low-grade fever, malaise, muscle pain, and cough with or without purulent sputum. Symptoms of a viral infection of the upper respiratory tract (see Common Cold (Nonspecific Infections of the Upper Respiratory Tract)) often occur initially, followed by symptoms of a lower respiratory tract infection. It is uncommon to see a recurring high-grade fever (>38 degrees Celsius), and this should prompt further investigations to exclude pneumonia or empyema.

2. Signs: Wheezes and rhonchi may be audible over the entire lungs.

DiagnosisTop

Pneumonia must be excluded; chest radiography should be ordered if features suggesting pneumonia are present:

1) Heart rates >100 beats/min.

2) Respiratory rates >24 breaths/min.

3) Body temperature (oral) >38 degrees Celsius.

4) Abnormal chest examination findings, such as crackles on auscultation.

Absence of the above-mentioned symptoms decreases the likelihood of pneumonia.

Further laboratory testing, usually by polymerase chain reaction (PCR), can be undertaken if suspicion for infections such as influenza coronavirus disease 2019 (COVID-19), and pertussis remain high.

Symptoms are usually self-limiting; however, if they persist >8 weeks, referral for further evaluation is necessary.

TreatmentTop

1. Symptomatic treatment: Antipyretics and cough suppressants may be used.Evidence 1Weak recommendation (benefits likely outweigh downsides, but the balance is close or uncertain; an alternative course of action may be better for some patients). Low Quality of Evidence (low confidence that we know true effects of the intervention). Quality of Evidence lowered due to the lack of experimental data. This suggestion is based on the current pattern of practice.

2. There is limited evidence to support the use of antibiotics unless there is evidence of bacterial growth or risk of deterioration in patients with underlying respiratory disease and a history suggestive of bacterial infection.Evidence 2Weak recommendation (downsides likely outweigh benefits, but the balance is close or uncertain; an alternative course of action may be better for some patients). Moderate Quality of Evidence (moderate confidence that we know true effects of intervention). Quality of Evidence lowered due to inconsistency of findings among different outcomes. Smith SM, Fahey T, Smucny J, Becker LA. Antibiotics for acute bronchitis. Cochrane Database Syst Rev. 2014 Mar 1;3:CD000245. doi:10.1002/14651858.CD000245.pub3. Review.PMID: 24585130.

3. In patients with symptoms of acute bronchitis during an influenza epidemic, consider administration of antiviral agents active against influenza viruses within 48 hours of the onset of symptoms.Evidence 3Weak recommendation (benefits likely outweigh downsides, but the balance is close or uncertain; an alternative course of action may be better for some patients). Moderate Quality of Evidence (moderate confidence that we know true effects of intervention). For the effect on symptoms in previously healthy participants, Quality of Evidence is not downgraded. For the effect on reducing complications, Quality of Evidence downgraded to moderate because of imprecision, diagnostic uncertainty in measuring outcomes, indirectness to high-risk individuals, and potential publication bias. The interpretation of existing evidence differs (see http://www.bmj.com/content/345/bmj.e7303). Jefferson T, Jones M, Doshi P, Spencer EA, Onakpoya I, Heneghan CJ. Oseltamivir for influenza in adults and children: systematic review of clinical study reports and summary of regulatory comments. BMJ. 2014 Apr 9;348:g2545. doi:10.1136/bmj.g2545. Review. PMID: 24811411; PMCID: PMC3981975. Kaiser L, Wat C, Mills T, Mahoney P, Ward P, Hayden F. Impact of oseltamivir treatment on influenza-related lower respiratory tract complications and hospitalizations. Arch Intern Med. 2003 Jul 28;163(14):1667-72. PMID:12885681.

4. Use of inhaled short-acting beta2-agonists (SABAs) may be of limited benefit in patients without obstructive airways disease.Evidence 4Weak recommendation (benefits likely outweigh downsides, but the balance is close or uncertain; an alternative course of action may be better for some patients). Moderate Quality of Evidence (moderate confidence that we know true effects of intervention). Quality of Evidence lowered due to imprecision and subgroup analysis. Becker LA, Hom J, Villasis-Keever M, van der Wouden JC. Beta2-agonists for acute bronchitis. Cochrane Database Syst Rev. 2011 Jul 6;(7):CD001726. doi:10.1002/14651858.CD001726.pub4. Review. PMID: 21735384.

5. Increased frequency of inhaled corticosteroids combined with a fast-acting long-acting beta2-agonist (LABA) is recommended in patients with worsening bronchitis symptoms who have a prior diagnosis of asthma (see Asthma).Evidence 5Strong recommendation (benefits clearly outweigh downsides; right action for all or almost all patients). High Quality of Evidence (high confidence that we know true effects of the intervention). Beasley R, Harrison T, Peterson S, et al. Evaluation of Budesonide-Formoterol for Maintenance and Reliever Therapy Among Patients With Poorly Controlled Asthma: A Systematic Review and Meta-analysis. JAMA Netw Open. 2022 Mar 1;5(3):e220615. doi: 10.1001/jamanetworkopen.2022.0615. Erratum in: JAMA Netw Open. 2022 May 2;5(5):e2216068. doi: 10.1001/jamanetworkopen.2022.16068. PMID: 35230437; PMCID: PMC8889464. Sobieraj DM, Weeda ER, Nguyen E, et al. Association of Inhaled Corticosteroids and Long-Acting β-Agonists as Controller and Quick Relief Therapy With Exacerbations and Symptom Control in Persistent Asthma: A Systematic Review and Meta-analysis. JAMA. 2018 Apr 10;319(14):1485-1496. doi: 10.1001/jama.2018.2769. PMID: 29554195; PMCID: PMC5876810.