Bronchial infection disorder, commonly known as bronchitis, signifies inflammation of the bronchial tubes—the airways that channel air into the lungs.

This respiratory disorder can manifest in two primary forms: acute bronchitis, which is typically transient and self-limiting, and chronic bronchitis, characterized by persistent inflammation often associated with long-term irritant exposure.

Pathophysiology and Causes

Bronchitis involves inflammation of the bronchial mucosa, leading to swelling, increased mucus production, and impaired clearance of secretions. In acute bronchitis, the inflamed bronchi narrow due to mucosal edema and mucus accumulation, restricting airflow and precipitating cough and breathing difficulty.

This inflammation primarily affects the large and mid-sized airways without extending into the lung parenchyma, distinguishing bronchitis from pneumonia.

The predominant cause of acute bronchitis is viral infection, accounting for approximately 90–95% of cases in healthy. Viruses such as rhinovirus, influenza, adenovirus, and respiratory syncytial virus invade the respiratory epithelium, triggering an immune response that results in bronchial irritation and mucus hypersecretion. Bacterial infections are less common but may involve atypical pathogens like Mycoplasma pneumoniae and Chlamydia pneumoniae.

Chronic bronchitis is primarily driven by prolonged exposure to irritants. This continuous insult leads to persistent mucosal inflammation, goblet cell hyperplasia with excessive mucus production, and impaired mucociliary clearance. Chronic bronchitis is a major phenotype within the chronic obstructive pulmonary disease (COPD) spectrum, contributing to airflow obstruction and elevated morbidity.

Clinical Presentation

The hallmark symptom of bronchial infection is a cough, either dry or productive of sputum, which may persist for several weeks particularly in acute bronchitis. Sputum coloration can range from clear to yellow or green depending on mucus composition and infection stage.

Other symptoms often include wheezing or a whistling sound during breathing, chest tightness or discomfort due to persistent coughing, low-grade fever, fatigue, headache, sore throat, and nasal congestion.

In chronic bronchitis, symptoms are more insidious with prolonged cough featuring copious mucus production persisting for at least three months annually over two consecutive years. Exacerbations marked by increased cough severity, sputum volume, or purulence may frequently occur, especially during colder seasons or following infections.

The differentiation between acute and chronic bronchitis is important as the latter suggests more profound airway remodeling and functional impairment. Persistent or recurrent bronchitis symptoms warrant medical evaluation to exclude asthma, bronchiectasis, or early COPD.

Diagnostic Evaluation

Diagnosis primarily relies on clinical history and physical examination. Inspection may reveal prolonged expiration, wheezes, or crackles on auscultation. Because bronchitis mimics other respiratory illnesses, further investigations help confirm diagnosis and exclude complications.

Chest X-rays are generally unremarkable in bronchitis but are crucial to rule out pneumonia when symptoms are severe or prolonged. Pulmonary function tests may be advised in chronic cases to assess airflow limitation and bronchial hyperresponsiveness. In selected cases, sputum analysis and microbiological cultures can identify causative pathogens guiding antibiotic therapy when bacterial infection is suspected.

Treatment and Management

Treatment approaches differ between acute and chronic bronchial infections, with an emphasis on symptom relief, infection control, and prevention of complications. Acute bronchitis is predominantly viral; therefore, antibiotics are generally discouraged except in confirmed bacterial infections or high-risk patients.

Supportive therapies include adequate hydration to loosen mucus, rest, and use of over-the-counter medications such as analgesics or antipyretics to alleviate pain and fever.

Dr. Guy Marks, a highly respected respiratory physician and epidemiologist, states "Bronchiectasis continues to be a widely misunderstood and underdiagnosed respiratory disease, affecting individuals around the world."

Bronchial infection disorder or bronchitis encompasses inflammatory conditions affecting the bronchial tree, often triggered by viral pathogens or chronic irritant exposure. Characterized by cough, mucus production, and airway inflammation, its clinical spectrum ranges from self-limited acute illness to chronic debilitating respiratory disease.

A thorough clinical and diagnostic assessment guides management, which integrates supportive care and targeted therapies to mitigate symptoms, prevent complications, and enhance respiratory health.