Pulmonology · Lower Respiratory Tract Infections
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Acute bronchitis is a clinical diagnosis characterized by a self-limited cough lasting more than 5 days, typically following an upper respiratory infection.
The vast majority of acute bronchitis cases are caused by viral pathogens, most commonly influenza A and B, parainfluenza, and RSV.
Antibiotics are not indicated for the treatment of acute bronchitis in immunocompetent patients, regardless of the duration of the cough.
The presence of purulent sputum or discolored mucus does not indicate a bacterial infection and is not an indication for antibiotic therapy.
Chest X-ray is only indicated if there is clinical suspicion of pneumonia, such as fever, tachycardia, tachypnea, or rales/crackles on lung auscultation.
Management of acute bronchitis is strictly supportive, focusing on analgesics, antitussives, and hydration.
Pertussis should be considered in patients with a paroxysmal cough lasting longer than 2 weeks, especially if accompanied by post-tussive emesis or an inspiratory whoop.
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A 34-year-old male presents to the clinic with a 10-day history of a non-productive cough that began after a sore throat and rhinorrhea. He reports no fever, chills, or shortness of breath. On physical examination, his temperature is 98.6°F, heart rate is 78 bpm, and respiratory rate is 14 bpm. Lung auscultation reveals clear breath sounds bilaterally with no wheezing or crackles. The patient is otherwise healthy and has no significant past medical history.
What is the most appropriate management for this patient?
Supportive care with symptomatic treatment
The patient's presentation is classic for acute bronchitis, which is viral in origin; therefore, antibiotics are not indicated, and management should focus on supportive care.
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Etiology / Epidemiology
Primarily viral (adenovirus, influenza) in immunocompetent patients; self-limiting inflammation of the tracheobronchial tree.
Clinical Manifestations
Persistent cough (>5 days, up to 3 weeks) with or without sputum; absence of fever helps distinguish from pneumonia.
Diagnosis
A clinical diagnosis; chest X-ray is indicated only to rule out pneumonia if vitals are abnormal.
Treatment
Supportive care with fluids and NSAIDs; antibiotics are not indicated for routine cases.
Prognosis
Self-limiting; cough resolves in 1-3 weeks in 90% of patients.
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Epidemiology & Etiology
Acute bronchitis is most commonly caused by respiratory viruses including influenza A and B, parainfluenza, and RSV. It is a leading cause of outpatient antibiotic misuse. Smoking and COPD are significant risk factors for increased symptom severity.
Pertinent Anatomy
Inflammation involves the trachea and bronchi, leading to mucosal edema and increased mucus production. The distal lung parenchyma remains unaffected, distinguishing it from pneumonia.
Pathophysiology
Viral infection triggers an inflammatory response in the bronchial epithelium, causing epithelial cell desquamation and hypersecretion of mucus. This results in bronchial hyperreactivity and the characteristic persistent cough. The process is typically self-limiting as the epithelium regenerates.
Clinical Manifestations
Patients present with a cough that may be productive or non-productive. Red flags requiring further workup include tachypnea, tachycardia, or hypoxia, which suggest pneumonia. Rusty sputum or high-grade fever should prompt consideration of bacterial superinfection.
Diagnosis
Diagnosis is clinical. A chest X-ray is the gold standard to exclude pneumonia, but it is only indicated if there is fever >38°C, tachycardia >100 bpm, or tachypnea >24 bpm. Routine testing for influenza is only performed if it changes management.
Treatment
Management is supportive. NSAIDs or acetaminophen are used for symptom control. Antibiotics are not indicated as the etiology is viral; overprescribing contributes to resistance. Bronchodilators are only used if there is evidence of wheezing.
Prognosis
Most patients recover fully within 3 weeks. Persistent cough is the most common lingering symptom. Patients should be advised to return if symptoms worsen or fail to resolve after 21 days.
Differential Diagnosis
Pneumonia: presence of focal consolidation on CXR or systemic toxicity
Asthma: history of recurrent wheezing and reversible airflow obstruction
Pertussis: whooping cough and post-tussive emesis
GERD: cough associated with heartburn or nocturnal symptoms
Post-nasal drip: cough associated with rhinorrhea and cobblestoning