As non-medical prescribers, we often come across patients suffering from bronchitis during the winter months. However, it is essential to question if we fully understand what bronchitis is, and how it can be accurately diagnosed and managed. Acute bronchitis is a clinical condition characterised by the self-limited inflammation of the large airways of the lungs, resulting in a cough without pneumonia (Wenzel and Fowler, 2006). Typically, it is caused by viral infections such as rhinovirus, enterovirus, influenza A and B, parainfluenza, coronavirus, human metapneumovirus and respiratory syncytial virus (Clark et al, 2016). Although bacteria have been found in 1-10% of cases of acute bronchitis, they are less frequent and include Mycoplasma pneumoniae, Chlamydophila pneumoniae and the less common Bordetella pertussis (Clark et al, 2016).
Symptoms
One of the primary symptoms of acute bronchitis is a cough, which can be productive or unproductive. Other symptoms or clinical signs that may suggest lower respiratory tract infection and no alternative explanation should also be considered (ERS White book, 2022). Clinical signs can include but not limited to; tachypnoea, pyrexia, tachycardia. Additional investigations may be required to consider the causes of these symptoms including blood tests (ESR, CRP, WCC) and a chest x-ray. According to Tackett and Atkins (2012), the pathogenesis of acute bronchitis is because of the inflammation of the bronchial epithelium, which is often secondary to an airway infection or environmental trigger. This inflammation results in constriction of the large airways, causing an increase in resistance during inhalation and exhalation.
Presentation
Patients with acute bronchitis typically experience a cough that can persist for 2-3 weeks and airway hyperresponsiveness that may last for up to 5-6 weeks (NHS, 2019). Airway hyperresponsiveness is a condition in which the airways have an increased tendency to narrow in response to stimuli that would have little or no effect on healthy individuals, such as pollution or aerosols (Porsbjerg et al, 2013). The innate immune response triggered by a viral infection induces respiratory epithelial cells and immune cells to release inflammatory cytokines and chemokines, contributing to both systemic and local symptoms. This immune response is believed to be the cause of prolonged airway hyperreactivity (Walsh, 2015).
Identifying the causative pathogen responsible for acute bronchitis can be challenging, and most clinical studies report positive identification in less than 30% of cases (ESR White book, 2022). According to Albert (2010), the causative pathogen for bronchitis is rarely identified. However, clinical studies suggest that viruses cause approximately 90% of acute bronchitis infections.
It is important to differentiate acute bronchitis from other common diagnoses such as pneumonia and asthma, as treatment approaches differ (Albert, 2010). In addition to viral infections, other factors such as allergens, pollens, bacteria, and irritants like smoke, dust and chemicals in polluted air can cause airway hypersensitivity. Cigarette smoke and chemicals in cigarettes can exacerbate bronchitis and increase the risk of developing chronic bronchitis or Chronic Obstructive Pulmonary Disease (NHS, 2019). NICE (2021) emphasises that clinicians must be aware that an acute cough can also be a sign of a more serious condition like pulmonary embolism or lung cancer.
Diagnosis
There are no specific diagnostic criteria for bronchitis, therefore, diagnosis is primarily clinical and excludes other differential diagnoses. Tackett and Atkin (2012) highlight many patients misdiagnosed with acute bronchitis present with an acute cough because of an asthma exacerbation, the common cold or an acute exacerbation of chronic obstructive pulmonary disease (COPD). Therefore, it is important to ensure a correct diagnosis by taking the history and conducting a physical examination of the patient. An upper respiratory tract infection can be ruled out if there is no nasal congestion and symptoms have not resolved in 7-10 days, as is seen in the common cold (Albert, 2010). In all reports of ongoing cough, after 3 weeks differential diagnosis should be considered. To exclude differential diagnosis, radiological tests may be required, such as a chest x-ray to rule out pneumonia. When examining the chest, an auscultation wheeze is likely to be heard (Albert, 2010; Tackett and Atkins, 2015, Walsh, 2014). Approximately 10% of patients presenting with a cough which lasts longer than two weeks have evidence of B. pertussis infection (Philipson et al, 2013).
Box 1.Immediate antibiotic prescription/backup antibiotic prescription for a person at higher risk of complications
- A pre-existing comorbid condition such as heart, lung, kidney, liver, or neuromuscular disease, immunosuppression or cystic fibrosis
- Older than 65 years of age with two or more of the following, or older than 80 years with one or more of the following:
- – Hospital admission in the previous year
- – Type 1 or type 2 diabetes mellitus
- – History of congestive heart failure
- – Current use of oral corticosteroids.
Adapted from NICE (2021)
Acute bronchitis is defined as a lower respiratory tract infection that causes inflammation in the bronchi (BMJ, 2018; NICE, 2021). Chronic bronchitis is characterised by a cough and the production of phlegm for at least 3 months of the previous 2 consecutive years (NICE, 2021). Bronchitis is typically uncomplicated when diagnosed in healthy adults. However, in patients with underlying lung diseases such as COPD or bronchiectasis, or other diseases such as congestive heart failure or compromised immune systems, they could be at risk of developing complications such as pneumonia (Tackett and Atkins, 2015).
Management
While bronchitis itself is not contagious, the viruses that cause it to develop are (NHS, 2019). These viruses are contained in millions of tiny droplets that are released from the nose and mouth when someone coughs or sneezes, and are therefore described as airborne (Wang et al, 2019). They can spread up to approximately one metre and can survive for up to 24 hours on hard surfaces (Greatorex et al, 2011; NHS, 2019; Wang et al, 2021).
Managing bronchitis can vary depending on the identified or likely causative agent. Tackett and Atkins (2015) emphasise that evidence does not consistently support treatment, as acute bronchitis is a self-limiting condition. The ESR white book (2013) reports that the European Respiratory Society (ERS), European Society of Clinical Microbiology and Infectious Diseases (ESCMID) guidelines state that cough suppressants, expectorants, mucolytics, antihistamines, inhaled corticosteroids and bronchodilators should not be prescribed for acute bronchitis in primary care.
Tackett and Atkins (2015) found that, on average, 70-90% of visits for acute bronchitis resulted in the patient receiving an antiviral or an antimicrobial medication. They reported on a study by Mainous et al (1996) that found 75% of patients presenting with acute bronchitis were prescribed an antibiotic. Similarly, Albert (2010) noted that although 90% of bronchitis infections are caused by viruses, approximately two-thirds of patients in the US diagnosed with the disease are treated with antibiotics. Albert (2010) and Tacketts and Atkins (2015) recommend that antimicrobial therapy should be reserved for cases when pathogens are isolated or when patients are at high risk of developing complications. Most systematic reviews have found no benefits to using antibiotics in treating acute bronchitis symptoms or reducing the risk of developing complications such as pneumonia. Certainly, Smith et al (2014) suggest that antibiotics may have a modest beneficial effect on some patients such as frail, elderly people with multimorbidity. Kinkade and Long (2016) and NICE (2019b) highlight that they only reduce the cough or illness by about half a day, and have adverse effects, including allergic reactions, nausea and vomiting and Clostridium difficile infection. Certainly, point-of-care CRP testing in primary care may reduce this inappropriate antibiotic prescribing (Huang et al, 2013; Francis et al, 2020).
This may lead to challenging conversations, as clinicians should not routinely offer antibiotics to treat the acute cough associated with acute bronchitis in people who are not systemically very unwell or at higher risk of complications (NICE, 2021). Clinicians have previously prescribed antibiotics to over 65% of adults with acute bronchitis, despite guidelines stating that antibiotics are not indicated (Dempsey et al., 2014). One recent study from the US showed that antibiotic prescribing for acute bronchitis is still high, despite evidence against it (Morley et al, 2020). Thankfully, UK antibiotic prescribing rates have recently declined for upper respiratory infections, although out-of-hours prescribing is still high in community settings (Williams et al, 2017). This highlights the need for more education and peer support in these services.
Albert (2010) suggests that patients with bronchitis expect medications for symptom relief, and clinicians have the difficult task of convincing patients that they are not necessary. The role of the clinician should be to educate the patient that bronchitis is a self-limiting illness and that the cough only lasts for 3-4 weeks. Antibiotics are only prescribed if the person is systemically very unwell, or if the patient is at high risk (NICE, 2021).
Patients presenting with acute bronchitis may have bronchospasm, similar to those experiencing bronchospasm because of an exacerbation of asthma. Tackett and Atkins (2015) suggest that there is consistent data to support the use of beta-2-agonist therapy in decreasing the duration of cough in patients with troublesome coughs and airway hyperresponsiveness. Additionally, patients with baseline airflow obstruction and wheezing may benefit from beta-2-agonist therapy. Singh et al (2021) also reported that beta-agonists are routinely used in acute bronchitis patients with wheezing.
Box 2.Self-care treatments for acute bronchitis
- Honey
- Pelargonium-herbal medicine
- Over-the-counter cough medicines containing guaifenesin as an expectorant
- Over-the-counter cough medicines containing cough suppressants (except codeine) if the person does not have a persistent cough or excessive secretion.
Adapted from NICE (2021)
Albert (2010) reports a trial of an antitussive medication to suppress the cough, such as codeine, dextromethorphan or hydrocodone, may be reasonable despite the lack of consistent evidence for their use, given their benefit in patients with chronic bronchitis. However, the National Institute for Health and Care Excellence (NICE, 2021) do not recommend the prescription of bronchodilators, oral or inhaled corticosteroids or antimuscarinics for acute bronchitis unless they have an underlying diagnosis of airway disease such as asthma. They highlight that patients may try some self-care remedies such as honey, herbal teas or over-the-counter cough medicines but report limited evidence on the use of antihistamines, decongestants and codeine-containing cough medicines that do not help cough symptoms.
Certainly, the herbal preparation Pelargonium sidoides has some reported modest effectiveness in the treatment of acute bronchitis, but the quality of evidence is considered low. However, it is on the list of recommended treatments from NICE (2021). In one Cochrane review, honey has also been suggested to reduce the severity and duration of cough and can be an alternative treatment for children under one year old, although the evidence is scarce (Oduwole et al, 2014).
Summary
Acute bronchitis is a clinical term that can be defined as an acute illness characterised by self-limited inflammation of the large airways of the lung, which is accompanied by a cough without pneumonia (Wenzel and Fowler, 2006). Typically, acute bronchitis is uncomplicated when diagnosed in healthy adults. However, in patients with underlying lung diseases such as COPD or bronchiectasis, congestive heart failure, or immunocompromised, there could be a risk of other complications (NICE, 2012; Tackett and Atkins, 2015).
Treatment for acute bronchitis usually involves symptom control using self-care treatments such as honey or the herbal medicine Pelargonium. Antibiotics are not prescribed unless the patient is clinically unwell or is in an at-risk group (NICE, 2021).