Acute bronchitis: symptoms and treatment

Acute bronchitis is an acute inflammation of the large airways with the main symptom being a cough, most often due to a viral infection. The disease is usually self-limited, with symptoms lasting approximately 1-3 weeks, although a significant proportion of patients may experience a lingering, so-called post-infectious cough for up to 8 weeks. Antibiotics for uncomplicated acute bronchitis do not improve outcomes and are not routinely indicated. [1]

The physician's key task is to distinguish acute bronchitis from pneumonia and other lower respiratory tract conditions that require different management. If vital signs are normal and no focal changes are detected on auscultation, additional tests are usually unnecessary. Chest radiography is indicated only if pneumonia is suspected or in high-risk patients. [2]

Lifestyle and supportive care are the mainstay of treatment. Some patients may benefit from short-term use of symptomatic cough suppressants, but the evidence for the benefit of many over-the-counter medications is limited. Honey may modestly reduce cough severity in children over 1 year of age and adults, but should not be given to infants. [3]

Epidemiology

Acute cough, including acute bronchitis, is one of the most common reasons for visits to primary care. In the vast majority of cases, the disease is viral in nature, which explains the lack of response to antibiotics and the emphasis on symptomatic management. [4]

Despite their viral etiology, antibiotic prescribing remains common. Observational data indicate high but excessive levels of antibiotic prescribing for respiratory tract infections, increasing the risk of adverse events and antimicrobial resistance. Strategies for rational use include educational approaches, delayed prescriptions, and the use of biomarkers. [5]

Seasonality coincides with periods of high circulation of respiratory viruses. Outbreaks of influenza or whooping cough influence the structure of causes, duration, and severity of cough, as well as the need for specific antiviral or antibacterial therapy when indicated. [6]

Reasons

The most common cause is viral agents of the respiratory group, including influenza, parainfluenza, rhinoviruses, coronaviruses, and others. Bacterial etiology in acute bronchitis in previously healthy individuals is rare, and sputum coloration does not allow for reliable differentiation between viral and bacterial causes. [7]

Whooping cough should be suspected in cases of spasmodic cough, paroxysms with reprise, vomiting after coughing, or a coughing episode lasting more than 2-3 weeks, as well as in cases of contact with a confirmed case. In such cases, isolation measures and antibacterial therapy with macrolides are indicated to reduce excretion of the pathogen and prevent transmission. [8]

Less commonly, acute bronchitis is triggered by environmental irritants, inhalation of smoke, dust, and vapors, as well as acute episodes associated with chronic respiratory diseases, where infection and inflammation are intertwined with bronchial hyperreactivity. In these cases, the management strategy takes into account the underlying disease. [9]

Risk factors

Risk factors include active and passive smoking, occupational and household exposure to irritants, and close contact with patients with acute respiratory infections. Elderly individuals and those with underlying medical conditions are more likely to develop complications and mistakenly masquerade pneumonia as bronchitis. [10]

Patients with chronic obstructive pulmonary disease and bronchial asthma more often experience exacerbations against the background of viral infections, which requires differentiating acute bronchitis from an exacerbation of the underlying disease, since treatment approaches differ. [11]

Lack of vaccination against influenza and whooping cough increases the risk of these infections and their complications. Vaccination reduces the frequency and severity of episodes of acute respiratory infections. [12]

Pathogenesis

Viral invasion and the subsequent inflammatory response lead to mucosal edema and mucus hypersecretion in the large airways. Irritation of cough receptors maintains the symptom even after the pathogen has been eliminated, explaining the post-infectious nature of cough for several weeks. [13]

In susceptible individuals, transient bronchial hyperreactivity with episodes of wheezing and reversible bronchospasm may occur. In these cases, symptomatic bronchodilator therapy may reduce the severity of cough and dyspnea; however, routine use of bronchodilators for uncomplicated bronchitis is not recommended. [14]

The immune response, inflammatory mediators, and mechanical factors of the cough reflex combine to form the clinical picture. High fever, severe intoxication, orthopnea, and chest pain are more characteristic of pneumonia and require a different approach. [15]

Symptoms

The leading symptom is a cough, usually dry or with a small amount of sputum, which lasts from 1 to 3 weeks and gradually regresses. Chest pain during coughing, fatigue, low-grade fever, hoarseness, wheezing, and harsh breathing on auscultation without focal consolidation are possible. [16]

Post-infectious cough is defined as a cough lasting 3 to 8 weeks with a normal chest x-ray. It is caused by inflammatory hyperresponsiveness of the airways and usually resolves gradually.[17]

"Warning signs" indicating possible pneumonia or severe progression include high fever, tachycardia, tachypnea, severe hypoxemia, unilateral moist rales, crepitations, egophony, and focal weakening of breath sounds. Such findings require further investigation. [18]

Table 1. Acute bronchitis: main symptoms and red flags

Group of features	What is typical	What's alarming
General symptoms	Cough for 1-3 weeks, low-grade fever, weakness	High and persistent fever, severe intoxication
Auscultation	Diffuse wheezing, harsh breathing, unfocused	Focal rales, crepitations, egophony
Vital signs	Normal	Heart rate over 100 beats per minute, respiratory rate over 24 beats per minute, decreased oxygen saturation
Flow	Gradual improvement	Rapid deterioration, shortness of breath at rest, chest pain when breathing

Forms and stages

Classically, a distinction is made between uncomplicated acute bronchitis in previously healthy individuals and acute bronchitis against the background of comorbid conditions, where there is a higher risk of complications and the transition to an exacerbation of the underlying disease. [19]

Post-infectious cough is considered separately as a subacute phase following an infection, lasting 3-8 weeks. The diagnosis is probable with a normal chest x-ray and the exclusion of alternatives. [20]

The pertussis-like variant with paroxysmal coughing requires specific antibacterial therapy and anti-epidemic measures. Early diagnosis and timely initiation of macrolide therapy are important for preventing transmission. [21]

Complications and consequences

The most common consequence is a lingering post-infectious cough, which disrupts sleep and quality of life but has a favorable prognosis. It usually resolves without specific therapy. [22]

Progression to pneumonia is rare, especially in the elderly and patients with comorbidities. The risk is increased by high fever, tachypnea, hypoxemia, and focal findings on examination. [23]

In patients with chronic lung diseases, virus-induced inflammation can cause an exacerbation with the need for escalation of inhalation therapy and, in some cases, antibacterial therapy according to specialized indications. [24]

Diagnostics

The diagnosis is primarily clinical: anamnesis, examination, and assessment of vital signs. If the presentation is typical and there are no "red flags," instrumental or laboratory tests are not required. [25]

Chest radiography is indicated when pneumonia is suspected or in the elderly, as well as in the presence of focal pulmonary findings, significant fever, tachycardia, tachypnea, or hypoxemia. In most patients with acute bronchitis, the image is normal.[26]

Tests for influenza or other viruses are considered only if the results will change treatment decisions, such as prescribing antiviral medications for influenza. Sputum analysis is not routinely indicated. [27]

The procalcitonin marker and C-reactive protein test in primary care may reduce antibiotic prescription for respiratory tract infections when diagnostic uncertainty remains, but their routine use in typical uncomplicated bronchitis is not required.[28]

Table 2. When tests are needed for acute cough

Situation	What to do	For what
Are there any "red flags" or old age?	Chest X-ray	Rule out pneumonia
Expressed diagnostic uncertainty	Bedside C-reactive protein	Reduce unnecessary antibiotics
Suspicion of whooping cough	PCR and culture according to local regulations	Confirm the diagnosis and conduct contact prevention
Suspected flu during the season	Quick test according to indications	Decide on antiviral treatment

Differential diagnosis

The main alternative is community-acquired pneumonia. It is characterized by focal physical findings, infiltrates on radiographs, higher temperature, and frequent respiratory failure. When in doubt, radiographic verification is used. [29]

Bronchitis should be distinguished from exacerbations of chronic obstructive pulmonary disease and asthma. In these cases, escalation of inhalation therapy is appropriate, and antibiotic indications are determined by specialized guidelines. [30]

If a cough persists for more than 8 weeks, chronic causes are considered, such as gastroesophageal reflux, postnasal drip, or asthma. If necessary, a staged diagnosis is performed. Post-infectious cough typically lasts 3-8 weeks and gradually subsides. [31]

Table 3. Acute bronchitis or pneumonia: what is the difference?

Sign	Acute bronchitis	Pneumonia
Temperature	Often normal or subfebrile	Often high
Auscultation	Diffuse wheezing without focus	Focal rales, crepitations, egophony
X-ray	Usually without infiltrates	Infiltrate is mandatory for diagnosis
Tactics	Symptomatic management	Antibiotics and observation

Treatment

Antibiotics are not indicated for uncomplicated acute bronchitis, as they do not shorten the duration of symptoms or prevent complications. Exceptions include confirmed or probable whooping cough, as well as cases where pneumonia develops or cannot be ruled out. [32]

Symptomatic therapy includes adequate fluid intake, rest, learning "conservative" breathing techniques, and, if necessary, antipyretics. Limited data support the use of certain over-the-counter medications: guaifenesin and dextromethorphan in adolescents and adults, and pelargonium extract in individuals over 12 years of age. The level of evidence is low. [33]

Inhaled beta-agonists are not routinely recommended. They may be useful for short periods in the presence of wheezing and signs of reversible obstruction. Systemic and inhaled glucocorticosteroids are not indicated for uncomplicated bronchitis. [34]

Honey can be considered as a short-term cough reliever in children over 1 year of age and adults, as confirmed by meta-analyses, but it is not superior to a number of antitussives in some patients and is contraindicated in children under 12 months. [35]

If whooping cough is suspected, macrolides are prescribed in the first weeks of the disease to reduce contagiousness, and post-exposure prophylaxis is also carried out according to epidemiological indications. [36]

Table 4. What to prescribe for acute bronchitis

Direction	Examples	Comments
General	Drink, rest, antipyretics	Basic support
Symptomatic remedies	Guaifenesin, dextromethorphan, pelargonium	Limited evidence base, short-term
Inhaled bronchodilators	Short-acting beta-agonists	Only for wheezing and bronchospasm
Antibiotics	Not shown routinely	Consider only for whooping cough or pneumonia
Antiviral	As indicated for influenza	Start early when confirmed or highly likely

Table 5. When to consider antibacterial therapy for cough

Scenario	Drug of choice	Target
Confirmed or probable whooping cough	Azithromycin, clarithromycin, erythromycin; alternative: co-trimoxazole	Reducing pathogen shedding and preventing transmission
Cough with infiltrate on radiograph	Drug regimens for community-acquired pneumonia	Treating pneumonia, not bronchitis
Immunodeficiency, severe concomitant pathology and suspected bacterial origin	According to local protocols	Individually according to indications

Prevention

Primary prevention includes regular influenza and whooping cough vaccinations, smoking cessation, reduced exposure to household and occupational irritants, and hygiene measures during the respiratory infection season. These approaches reduce the risk of illness and its complications. [37]

Secondary prevention focuses on informing patients about how long a cough is likely to last, what symptoms require immediate attention, why antibiotics are usually not needed, and how to safely use over-the-counter medications. This "deficit-free" approach reduces expectations regarding antibiotics and improves treatment satisfaction. [38]

Forecast

Most patients with acute bronchitis have a favorable prognosis, with complete resolution of symptoms within a few weeks. Even with a persistent post-infectious cough, gradual improvement is likely without specific therapy. [39]

Adverse outcomes are rare and are more often associated with advanced age, comorbidities, pneumonia, or exacerbation of chronic bronchopulmonary disease. Early recognition of "red flags" and rational management can minimize risks. [40]

FAQ

• How long does a cough last with acute bronchitis and when does it become "lingering"?

Typically 1-3 weeks. If the cough persists for 3-8 weeks with a normal chest x-ray, it is a post-infectious cough that gradually regresses. Seek medical attention again if your condition worsens or if any red flags appear. [41]

• When is an x-ray needed?

If there is high fever, tachypnea, tachycardia, low oxygen saturation, unilateral focal findings in the lungs, advanced age, or other risk factors for pneumonia, X-rays are not typically required. [42]

• Why aren't antibiotics prescribed "just in case"?

Since the cause is viral in most cases, antibiotics do not speed recovery and carry the risk of side effects and antibiotic resistance. Exceptions include whooping cough and pneumonia. [43]

• What over-the-counter remedies actually help?

Evidence is limited. Guaifenesin and dextromethorphan may be considered for adolescents and adults, and pelargonium extract for those over 12 years of age. Honey may be acceptable for cough relief in children over 1 year of age and adults, but is not suitable for infants. [44]

• What to do if you suspect whooping cough?

Consult a physician for laboratory confirmation and start a macrolide as soon as possible, and follow local isolation guidelines and post-exposure prophylaxis if needed.[45]