Chronic bronchitis is a component of COPD, which is one of the five leading causes of death in the United States. (See Chapter 26
for a discussion of COPD.) The standard description/definition of chronic bronchitis is productive cough and sputum production for 3 months per year for at least two consecutive years. An acute exacerbation of chronic bronchitis is defined as worsening of respiratory symptoms such as increased cough, sputum, and dyspnea that warrants a change in medications. Chronic bronchitis primarily affects adults and occurs more commonly in men than in women. Over 10% of the adult population in the United States aged 40 or older is afflicted with chronic bronchitis, which accounts for a large amount of health care expenditures and lost wages (Kim & Criner, 2013
). Patients with chronic bronchitis are more likely to have frequent and severe episodes of acute bacterial bronchitis. Exacerbations of COPD account for more than 50% of the overall cost related to the treatment of COPD (Qureshi et al., 2014
). Because many infections are untreated, the exact morbidity of acute exacerbations of chronic bronchitis is unknown.
Several factors are implicated in the pathogenesis of chronic bronchitis, leading to chronic inflammation and sputum production. The predominant factor in chronic bronchitis is
cigarette smoke, a well-known respiratory irritant, and most patients with chronic bronchitis have a history of cigarette smoking. However, chronic bronchitis has been noted in 4% to 22% of patients who never smoked (Kim & Criner, 2013
), suggesting other causative factors. Occupational dust, fumes, and environmental pollution are some additional risk factors that contribute to the etiology of the disease. The presence of gastroesophageal reflux and hypersecretion of mucus in patients with asthma has also been shown to yield symptoms of chronic bronchitis. Evidence suggests that recurrent respiratory infections may predispose a person to development of chronic bronchitis, although the exact reason for this is unclear.
Colonization of the lower airways with bacteria such as H. influenzae
, M. catarrhalis
, and S. pneumoniae
has been frequently detected in patients with chronic bronchitis. Up to 25% of patients with stable COPD have been found to be colonized with these bacteria. These and other microorganisms harbored in the bronchial epithelium act as reservoirs for infection when patient host defenses become compromised. In patients with acute exacerbations of COPD, 70% to 80% of cases are triggered by bacterial or viral infections (Liapikou & Torres, 2014
). Viral infections account for nearly one third of acute exacerbations. Other bacteria such as Pseudomonas aeruginosa
and Enterobacteriaceae are more likely to be associated with acute exacerbations in patients with frequent exacerbations and advanced stages of COPD. Exposures to environmental pollution or unknown factors contribute to the remainder of acute exacerbations. The frequency and severity of exacerbations of chronic bronchitis are more frequent and severe with increasing stages of COPD.
As with acute bronchitis, cough is the hallmark of chronic bronchitis. Cough, with sputum production, can be mild or severe and may be stimulated by simple conversation. Many patients with chronic bronchitis expectorate a large quantity of white to yellow tenacious sputum in the morning. Because of the characteristics of sputum, many patients complain of a foul taste in the mouth.
Clinical assessment and the patient’s medical history contribute to the diagnosis of chronic bronchitis. Other diseases such as bronchiectasis, cardiac failure, cystic fibrosis, tuberculosis, pulmonary emboli, and lung carcinoma must be excluded before diagnosing a patient with chronic bronchitis or an acute exacerbation of chronic bronchitis. Patients with chronic bronchitis must have a cough with sputum production for at least 3 consecutive months for 2 consecutive years.
Physical examination of patients with chronic bronchitis is usually unremarkable except that chest auscultation reveals inspiratory and expiratory rales, rhonchi, and mild wheezing; normal breath sounds are diminished. As the severity of the disease progresses, an increase in the anteroposterior diameter of the thoracic cage (barrel chest appearance), hyperresonance on percussion, and limited mobility of the diaphragm are observed. Pulmonary function tests demonstrate a decrease in vital capacity and prolongation of expiratory flow. Other features of disease progression include clubbing of the fingers, cor pulmonale, hepatomegaly, and edema of the lower extremities.
The diagnosis of an acute exacerbation of chronic bronchitis relies on the clinical presentation of an acute change in symptoms. Since an acute exacerbation of chronic bronchitis is defined as worsening of respiratory symptoms that warrants a change in medications, diagnosis focuses on early changes in symptoms such as an increase in frequency and severity of cough. Other symptoms include increased sputum production, purulent sputum, hemoptysis, chest congestion and discomfort, increased dyspnea, and wheezing. Malaise, loss of appetite, and fever may also be present. True chills (rigors) and high-grade fever suggest pneumonia rather than an acute exacerbation of chronic bronchitis. This finding requires a chest x-ray for diagnosis. The duration of worsening or new symptoms, number and frequency of previous exacerbations, severity of underlying disease, comorbidities, and current treatment regimen for COPD are helpful in assessing a patient who presents with an acute exacerbation of chronic bronchitis. In these patients, pulse oximetry is useful for tracking and/or adjusting supplemental oxygen therapy. An electrocardiogram (ECG) may help in the diagnosis of or to rule out cardiac problems. A complete blood count (CBC) will help to identify leukocytosis.
To determine the need for hospitalization during an acute exacerbation of chronic bronchitis, the presence of severe symptoms including use of accessory muscles, worsening or new cyanosis, development of peripheral edema, hemodynamic instability, or deterioration in mental status needs to be assessed. A sputum gram stain can assist in empiric antibiotic prescribing. Sputum culture and susceptibility testing may guide the clinician in choosing appropriate antibiotic therapy. In outpatients, sputum cultures are not often feasible or practical, as they take too long to return and frequently do not provide reliable results (i.e., more than 4 hours often elapses between expectoration of sputum and analysis in the laboratory). However, a sputum culture should be considered, especially in patients with frequent exacerbations requiring
antibiotic use, failing current antibiotic therapy, known or suspected resistant pathogens, severe airflow limitation, and/or exacerbations requiring mechanical ventilation. Additionally, procalcitonin, a biomarker specific for bacterial infections, can be obtained to help in determining the presence of active infection. However, this test is currently reserved for patients in acute care settings, given the cost, lack of widespread availability, and delayed turnaround time for results.
TABLE 27.2 Classification of Chronic Bronchitis and Treatment Options for Acute Exacerbations
Simple chronic bronchitis
Increased sputum production and purulence, no major risk factors, less than 3 exacerbations/year
S. pneumoniae, H. influenzae, and M. catarrhalis (low risk for antibiotic resistance)
First-line: amoxicillin, doxycycline, macrolide, or sulfamethoxazole/trimethoprim
Second-line: amoxicillin-clavulanate (Augmentin); second- or third-generation cephalosporin
Complicated chronic bronchitis
FEV1 < 50% of predicted value, advanced age (over 65 y of age), significant comorbidity (e.g., cardiac disease, diabetes, renal or hepatic insufficiency), home oxygen use, antibiotic use in the past 3 mo, and/or 3 or more exacerbations/year
S. pneumoniae, H. influenzae, M. catarrhalis, (resistance to beta-lactam antibiotics common)
First-line: amoxicillin-clavulanate (Augmentin XR); second- or third-generation oral cephalosporin; doxycycline
Second-line: macrolide; fluoroquinolone (levofloxacin, moxifloxacin, gemifloxacin)
Severe complicated chronic bronchitis
FEV1 < 35% of predicted value with risk factors for P. aeruginosa (frequent or recent antibiotic use, chronic corticosteroid use, advanced disease, and/or history of bronchiectasis)
The above microorganisms and Enterobacteriaceae, P. aeruginosa (more likely to have antibiotic-resistant bacteria)
levofloxacin or ciprofloxacin
Data from Global Initiative for Chronic Obstructive Lung Disease (GOLD). (2015). Retrieved from www.goldcopd on July 10, 2015.
A classification system for patients with chronic bronchitis is frequently used to identify high-risk patients and select the appropriate antimicrobial therapy for acute exacerbations according to the suspected microorganism. Table 27.2
outlines the classification system and treatment options, taking into consideration the baseline clinical status, risk factors, and common pathogens.
Patients with uncomplicated chronic bronchitis have little or no lung impairment and no major risk factors for antibiotic resistance. The most common pathogens include H. influenzae, M. catarrhalis, and S. pneumoniae. Viral infections should be considered before bacterial infections in this patient category. Although antibiotic resistance is less common in this group, over 50% of H. influenza and M. catarrhalis produce beta-lactamase, making amoxicillin ineffective. This should be considered especially in patients who fail amoxicillin therapy.
Patients with complicated chronic bronchitis include those with moderate to severe (FEV1 50% less than predicted) lung impairment, those who are elderly (over 65 years of age), those who have frequent exacerbations, and those who have comorbid illnesses such as congestive heart failure, diabetes mellitus, chronic renal failure, or chronic liver disease. The most common pathogens isolated in severe chronic bronchitis are H. influenzae, S. pneumoniae, and M. catarrhalis. Frequent exacerbations in this population increase the likelihood of antibiotic use and the risk for antibiotic resistance, including penicillin-resistant S. pneumoniae.
Patients with severe complicated chronic bronchitis have characteristics similar to those in the previous group, but they have severe airflow obstruction and often have constant purulent sputum production. The same microorganisms found in the other groups should be considered in these patients; however, gram-negative microorganisms such as P. aeruginosa and Enterobacteriaceae should also be suspected.