BRONCHITIS

• Acute bronchitis affects up to 5% of the population annually and accounts for more than 10 million office visits per year in the US alone. These figures are likely underestimates, as many people do not seek medical attention for the condition. Most cases occur in the winter when respiratory viruses are circulating. [1,2,3,4]

• Acute bronchitis is a lower respiratory tract infection of the large and medium-sized bronchi, causing inflammation, sputum production and thickening, and epithelial desquamation. More than 90% of cases are caused by viruses, including influenza A and B, parainfluenza virus, respiratory syncytial virus, coronavirus, adenovirus, and rhinovirus. Bacteria account for less than 2% of cases, with Bordetella pertussis, Chlamydophila pneumoniae, and Mycoplasma pneumoniae being the most common pathogens. Acute bronchitis is typically self-limited, resolving spontaneously over 1 to 3 weeks. [1,2,3,4]

• Cough lasting 10 - 20 days with or without phlegm production. Colored or purulent phlegm is caused by inflammation and is not a sign of a bacterial infection. A residual cough lasting more than 4 weeks is not uncommon.
• Nasal congestion and postnasal drip
• Fever and malaise may be present, particularly with influenza infections
• Transient airflow obstruction and airway hyperresponsiveness (wheezing) may occur in up to 40% of healthy individuals [2,3,4]

• Overview
• Bronchitis is typically diagnosed clinically. Sputum or serum testing is not recommended since the causative organism is rarely identified. Bordetella pertussis testing may be indicated if a community outbreak or known exposure has occurred or if the cough has characteristic features (e.g., whooping sound, violent coughing spasms). If there is concern for pneumonia, a chest X-ray may be indicated (see below). [2,3]


• Bronchitis vs pneumonia
• Bronchitis and pneumonia have overlapping symptoms, which can sometimes make differentiation difficult without a chest X-ray. To help with these scenarios, the ACCP and ACP have published the following guidance:
• 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]

• 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 less than 1% of cases, are typically self-limited and do not require antibiotic therapy. Patients with confirmed or suspected Bordetella pertussis should be treated with a macrolide antibiotic or trimethoprim-sulfamethoxazole. Postexposure prophylaxis for known contacts is also recommended. [2,3]

• Symptomatic treatments
• Guaifenesin (expectorant) and dextromethorphan (cough suppressant) (e.g., Mucinex DM, Robitussin DM)
• Codeine - cough suppressant for adults
• Albuterol - may be helpful in patients with wheezing
• Analgesics (e.g., NSAIDs, acetaminophen) - pain and fever
• Intranasal steroids (e.g., Flonase, Nasonex) - nasal congestion
• Oral decongestants (e.g., Sudafed) - nasal congestion
• Topical decongestants (e.g., Afrin) - nasal congestion
• Oral antihistamines (e.g., Claritin, Allegra, Zyrtec) - may decrease secretions and suppress sneezing

• Chronic bronchitis is defined as a productive cough for ≥ 3 months in each of 2 successive years. It is typically associated with smoking and chronic obstructive pulmonary disease (COPD).

• RCT
  Prednisolone vs Placebo in Nonasthmatic Adults with Bronchitis, JAMA (2017) [PubMed abstract]
• 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.

• 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)
• 4 - Singh A, Avula A, Zahn E. Acute Bronchitis. [Updated 2024 Mar 9]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK448067/