Table of Contents
Definition and Background
Chronic bronchitis is defined as chronic productive cough for three months in two consecutive years in a patient in whom other causes of chronic cough have been excluded, such as bronchiectasis. Airflow limitation may precede the development of chronic bronchitis.
Chronic bronchitis is considered one of the top conditions for which patients seek medical attention. The main characteristic of the condition is an inflammation of the bronchial tubes or bronchi, and the air passage extending from the trachea into the small airways and alveoli.
An episode of acute bronchitis is characterized by irritation of the cells of the bronchial-lining tissue, in addition to hyperemia and edema in the mucous membrane, which result in decreased bronchial mucociliary function, leading to clogged airways by debris and increases in the irritation. The characteristic cough of bronchitis is developed due to the development of copious secretion of mucus.
The attachment of the organism (Mycoplasma pneumoniae) to the respiratory mucosa results in bronchial irritation, leading to sloughing of the affected cells. Bronchopneumonia may develop if the inflammation extends downward to the bronchioles.
Approximately 8.7 million cases in the United States were diagnosed with chronic bronchitis during the 2014 year, which is around 3.6 % of the population.
The term bronchitis is commonly used to describe a self-limited nonspecific cough, which results in overdiagnosis of the condition, hence increasing its incidence even though many patients do not actually have bronchitis.
Acute bronchitis is usually diagnosed among children younger than 5 years of age; however, chronic bronchitis is more common among patients above the age of 50. The incidence appears to be higher in males than in females, and it usually affects people with low socioeconomic status.
Symptoms of chronic bronchitis
- Complete thorough history with information regarding smoking and exposure to toxic substances is important.
- Patients presenting with bronchitis are usually overweight and cyanotic.
- The most important symptom in chronic bronchitis patients is cough. Other symptomsmay include:
Signs of chronic bronchitis
Findings on physical examination may include:
- Pharyngeal erythema
- Localized lymphadenopathy
- Coarse rhonchi
- Use of accessory muscles
- Inspiratory stridor
- Heave along the left sternal border
- Clubbing or peripheral cyanosis may be observed in cases of cystic fibrosis
Smoking and irritants
- The most predominant cause for the development of chronic bronchitis is cigarette smoking.
- Other causes include exposure to irritants, such as chemicals, and pollution.
Viral and bacterial infections in acute bronchitis
The most common viruses that may cause acute bronchitis include:
- Influenza A and B
- Respiratory syncytial virus
Bacterial infections that may result in the development of acute bronchitis may include:
- Mycoplasma species
- Chlamydia pneumoniae
- Streptococcus pneumoniae
- Moraxella catarrhalis
- Haemophilus influenzae
Other medical conditions to consider include the following:
- Bacterial tracheitis
- Exercise-induced asthma
- Cystic fibrosis
- Retained foreign body
- Hyperreactive airway disease
- Acute sinusitis
- Occupational exposures
- Alpha1-Antitrypsin deficiency
- Bacterial pharyngitis
- Chronic sinusitis
- Chronic Obstructive Pulmonary Disease (COPD)
- Group A streptococcal infections
- Gastroesophageal reflux disease
- Viral pharyngitis
Patients with acute respiratory infection suffering from cough are suspected to have bronchitis; however, bronchitis is considered a diagnosis of exclusion because there are many serious respiratory diseases that may cause similar picture.
Blood and microbiology tests in chronic bronchitis
- Complete blood count with differential is obtained.
- Bacterial infections can be distinguished from nonbacterial infections using procalcitonin levels, which helps guide therapy and reduce the use of antibiotics.
- It may be useful to do influenza tests. However, serologic tests for atypical pneumoniaare not suggested.
- If a cough is persistent, it might be helpful to use sputum cytology.
Imaging studies in chronic bronchitis
- Patients with physical findings suggestive of pneumonia should have chest radiographs. However, elderly patients may not have any signs of pneumonia, but still they need chest radiographs to rule out pneumonia.
Bronchoscopy is used to rule out many conditions such as tuberculosis, tumors, foreign body aspiration, and other chronic diseases of the lungs and the tracheobronchial tree.
- Epiglottitis can be excluded using laryngoscopy.
- Cultures are obtained for Mycoplasma pneumoniae, Bordetella pertussis, and influenza virus.
- In cases of bacterial superinfection, it might be helpful to use blood cultures.
- Characteristic findings found in small airways in chronic obstructive pulmonary disease (COPD) include mucosal and submucosal inflammatory cells, edema, increased smooth muscle, intraluminal mucous plugs, peribronchial fibrosis, and goblet cell hyperplasia.
- Patients suffering from bronchitis usually have significant bronchospasm with a large reduction in forced expiratory volume in one second (FEV1). Spirometry may be useful in these patients.
Management of bronchitis focuses on the elimination of the symptoms. A combination of drugs may be prescribed to open obstructed bronchial airways and thin obstructive mucus making it easily coughed. Bed rest is recommended for these patients and adequate oxygenation should be ensured.
It is important to avoid cigarette smoking and other environmental irritants to control cough and sputum production in patients with chronic bronchitis.
Symptomatic treatment of chronic bronchitis
- It is recommended to use central cough suppressants such as codeine for short-term symptomatic relief in patients suffering from acute or chronic bronchitis.
- Symptoms such as dyspnea, bronchospasm, and chronic cough may be controlled with beta-agonists such as theophylline and ipratropium bromide.
- Patients suffering from underlying lung disease with a cough and wheezing may benefit from beta2-agonist bronchodilators.
- Pain and other constitutional symptoms of acute bronchitis may be treated using non- steroidal anti-inflammatory drugs (NSAIDS).
- Mucolytics may be used to reduce acute exacerbations.
Antibiotic therapy of chronic bronchitis
- The use of antibiotics is recommended in patients suffering from acute exacerbations. However, it is not recommended if there is no risk of serious complications.
- Elderly patients with acute cough and history of hospitalization in the past year, and also have congestive heart failure or diabetes mellitus, or receiving steroids may need antibiotic therapy.
- The risk of upper respiratory tract infections is reduced with influenza vaccine, which results in reduction of the incidence of acute bacterial bronchitis.
- Most studies have shown that the use of zinc is beneficial against influenza A.
Long-term monitoring in chronic bronchitis
- If symptoms worsen, such as high fever, shortness of breath, persistent cough, and vomiting; then an alternative diagnosis should be considered.
- Further investigations are recommended in cases of symptoms recurrence (more than 3 episodes per year).
The answers are below the references.
1. A 66-year-old male patient, who is a smoker, died of chronic bronchitis. His medical history is not significant for other medical problems or conditions. Which of the following is the least to be observed in the autopsy of his lungs?
- Mucous gland enlargement
- Patchy squamous metaplasia
- Thickened bronchial walls
- Neutrophil infiltration
2. A 44-year-old male patient presented to your office complaining of chronic productive cough for the past few years. He is a smoker for the past 25 years and he smokes one pack per day. An enlarged heart was revealed on his chest x-ray. The pulmonary function tests seen in this patient would be similar to those seen in a patient suffering from:
- Prior lung radiation
- Asymptomatic asthma
- Coal worker’s pneumonitis
3. A 72-year-old male patient visits the office of his pulmonologists for a checkup. He has a history of chronic obstructive pulmonary disease (COPD) for the past 10 years. Physical examination revealed digital clubbing and cyanosis. Bilateral lung wheezes were revealed by auscultation. He is suffering from a productive cough with a thick yellow sputum. Which one of the following findings is most likely found in this man?
- Increased arterial blood pH
- Increased compliance of the right ventricle
- Decreased arterial carbon dioxide content
- Increased cerebral vascular resistance