Bronchitis

Bronchitis is the inflammation of the bronchi, the large and medium-sized airways in the lungs, leading to coughing and other respiratory symptoms. It can be classified into acute and chronic forms, each with distinct characteristics and treatment approaches.

Location of the lungs and bronchial tubes (A), normal bronchial tube (B), and bronchial tube with bronchitis (C).

Signs and Symptoms

Bronchitis is characterised by a range of symptoms, primarily:

• Coughing up mucus: This is the hallmark symptom and can vary in severity.
• Wheezing: A high-pitched sound while breathing due to narrowed airways.
• Shortness of breath: Difficulty in breathing, especially during physical exertion.
• Chest discomfort: Pain or a feeling of tightness in the chest.

Acute Bronchitis

Acute bronchitis, also known as a chest cold, is a short-term inflammation of the bronchi. It typically presents with:

• Coughing: Lasting around three weeks, often producing sputum.
• Fever: Mild if present.
• Wheezing and chest discomfort: Common accompanying symptoms.

Diagram illustrating acute bronchitis.

Cause

In over 90% of cases, acute bronchitis is caused by viral infections, such as rhinovirus, adenovirus, parainfluenza, or influenza. Risk factors include exposure to tobacco smoke, dust, and air pollutants. Bacterial infections, such as Mycoplasma pneumoniae or Bordetella pertussis, are less common causes.

Diagnosis

Diagnosis is primarily based on clinical signs and symptoms. The colour of sputum does not distinguish between viral and bacterial infections. Chest X-rays may be performed to rule out pneumonia.

Treatment

Treatment focuses on symptomatic relief and includes:

• Rest and hydration: Essential for recovery.
• Paracetamol (acetaminophen) and NSAIDs: To manage fever and discomfort.
• Cough medicines: Generally not recommended, especially in children under six.
• Salbutamol: May be used for wheezing, though it can cause nervousness and tremors.
• Antibiotics: Typically not necessary unless the cause is bacterial, e.g., pertussis.
• Honey and pelargonium: Tentative evidence suggests these may help with symptoms.

Chronic Bronchitis

Chronic bronchitis is defined by a productive cough lasting for at least three months per year for two consecutive years. It is often associated with chronic obstructive pulmonary disease (COPD).

Cause

The most common cause is tobacco smoking. Other risk factors include air pollution, occupational exposure to irritants, and genetic factors.

Diagnosis

Diagnosis involves clinical history and symptoms. Chronic bronchitis is marked by mucus hypersecretion due to increased goblet cells and enlarged submucosal glands.

Treatment

• Smoking cessation: Very important to slow the decline in lung function.
• Medications: Inhaled bronchodilators, steroids, and mucolytics such as guaifenesin and erdosteine are used. Erdosteine is noted for its antioxidant properties and efficacy in reducing exacerbations.
• Pulmonary rehabilitation: Helps improve respiratory function.
• Oxygen therapy: May be required for severe cases.

Epidemiology

Acute bronchitis is highly prevalent, affecting about 5% of adults and 6% of children annually, particularly in winter. Chronic bronchitis affects about 3.4% to 22% of the population, with higher prevalence in smokers and those exposed to air pollutants. In the United States, 8.6 million individuals were diagnosed with chronic bronchitis in 2016, with a death rate of 0.2 per 100,000.

Special Forms of Bronchitis

Eosinophilic Bronchitis

A chronic dry cough with increased eosinophils, presenting normal X-ray results and no airflow limitation.

Protracted Bacterial Bronchitis

In children, characterised by a productive cough and positive bronchoalveolar lavage resolving with antibiotics.

Plastic Bronchitis

A rare condition where thickened secretions form bronchial casts, obstructing airflow and typically occurring in children.

Plastic bronchitis bronchial casts.

Aspergillus Bronchitis

Part of the Aspergillosis spectrum, involving fungal infection of the bronchi, which can affect both immunocompromised and non-immunocompromised individuals.

Self-assessment MCQs (single best answer)

What is the hallmark symptom of bronchitis?

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Which of the following is not a common cause of acute bronchitis?

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For a diagnosis of chronic bronchitis, a productive cough must last for at least how many months per year for two consecutive years?

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What is the primary focus of treatment for acute bronchitis?

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Which medication is noted for its antioxidant properties and efficacy in reducing exacerbations of chronic bronchitis?

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Which of the following is a risk factor for chronic bronchitis?

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Which form of bronchitis involves thickened secretions forming bronchial casts, typically in children?

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What is the primary cause of chronic bronchitis?

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Which diagnostic tool may be used to rule out pneumonia in cases of acute bronchitis?

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Which treatment is generally not recommended for acute bronchitis, especially in children under six?

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