Pertussis and COPD

Worldwide public health is confronted with substantial problems from two distinct but related respiratory conditions: pertussis and chronic obstructive pulmonary disease (COPD). The respiratory system is the main target of the extremely contagious bacterial infection pertussis, which is characterised by violent coughing fits. Conversely, COPD is a collective term for a set of progressive lung conditions, such as emphysema and chronic bronchitis, that are defined by symptoms related to breathing and restricted airflow. Despite the differences in the aetiology and pathophysiology of these disorders, their co-occurrence creates challenging therapeutic situations. Given the potential for pertussis infection to exacerbate COPD symptoms and the increased susceptibility of COPD patients to serious pertussis-related consequences, a comprehensive understanding of both pertussis and COPD is crucial for successful care and preventative initiatives. 

Introduction

Pertussis is also known as whooping cough. This name was derived from its characteristic, a strong persistent cough that leaves the victim breathless and exacerbated over a long period with some lasting up to months. This condition is caused by the bacteria Bordetella pertussis, hence the recognised name pertussis.¹ It is an airborne pathogen that is usually contracted from the cough or sneeze droplets from infected people. Chronic Obstructive Pulmonary Disease (COPD) has a similar clinical presentation of forceful coughs and severe breathlessness characterised by the obstructive airflow in the respiratory tract. This condition is caused by prolonged exposure to foreign particles and pathogens from the environment.² Hence, people with secondhand smoke or who work in a mine are more susceptible to the risk of developing COPD. 

While both pertussis and COPD involve issues with the respiratory tract, they are inherently different. However, people with COPD have an increased risk of contracting infectious agents like Bordetella pertussis alongside experiencing more severe symptoms compared to healthy individuals.² It is important to bring light to the importance of understanding both COPD and pertussis as comorbidity can be potentially fatal. 

Pertussis

The Bordetella pertussis bacteria tends to adhere to cilia cells which line the respiratory tract. This infectious agent is transmitted through the cough/sneeze droplets of those infected, making it highly contagious as it is airborne. It can also settle on surfaces which could also infect others if it is touched and transferred to the eyes or nose. Whooping cough has three stages of illness.³ The 1 to 2 weeks of contraction is called the catarrhal stage, where non-specific and mild clinical symptoms are present. It resembles a normal cold or flu, with nasal congestion, sore throat, cough etc. Then, the paroxysmal phase, which can last 2 to 6 weeks. More severe symptoms present, including 5-10 coughs during each expiration, leaving the individual breathless which causes a forceful inspiratory effort – a characteristic “whooping”. Common phenomena are vomiting, cyanosis, and (night) apnea. The coughing also increases substantially in frequency and severity throughout the night. Lastly, the convalescent phase, where is also defined as the recovery period. It can last 1 to 12 weeks but the frequency and severity of the coughing fits, whooping, and vomiting decreases substantially. However, exposure to irritants could still trigger strong coughing episodes. 

Pertussis is often overlooked and underdiagnosed as it can present as a common flu or cold. Especially for those who are partially or fully immunised, the cough may not have the characteristic “whooping” inspiration, making it challenging to accurately diagnose. While testing for pertussis is not usually readily available in the emergency room, there are polymerase chain reaction (PCR) lab tests and cultures that can be administered. PCR is accurate in the first three weeks, but after that, the bacterial DNA diminishes which makes it susceptible to false negatives.⁴ Culture of the Bordetella organisms from a nasopharyngeal swab under a specialised growing medium is also a good option for identifying pertussis as it has high specificity and accuracy.¹

Treatment for pertussis

Antibiotics are often administered to patients with pertussis. These include erythromycin (oral) which was administered since the 1970s, macrolides azithromycin, and clarithromycin.¹ In addition, as whooping cough is highly contagious, isolation is recommended when hospitalised to prevent a spread and also for monitoring. A spread of the whooping cough could potentially be dangerous, especially to infected infants which has reflected a high mortality rate. Vaccinations have also proven to be effective in preventing the rapid spread of the bacteria due to the concept of herd immunity. The pertussis vaccinations are called DTaP and TdAP which both abbreviations stand for Diphtheria, Tetanus, and Pertussis. They are named differently due to their suitability for different ages. According to the CDC, infants and children younger than 7 years old receive DTaP, while individuals older than that should receive the TdAP vaccine.¹² Pregnant women can also choose to have vaccinations to prevent newborns from whooping cough, which could have adverse symptoms of brain damage and pneumonia. For more information, see this link from the NHS. 

Chronic obstructive pulmonary disease

Chronic Obstructive Pulmonary Disease is caused by environmental and occupational factors which result in prolonged exposure to foreign and harmful particles and gases.⁵ Secondhand smokers contracting COPD are particularly common, alongside mine workers which requires work in an enclosed area with harmful particles. The prevalence of developing this disease increases with age and the amount of exposure to harmful particles. COPD is often underdiagnosed like pertussis as it is often overlooked as a cold or flu. Essentially, COPD is an inflammatory condition that occurs in the respiratory tract (which includes the airways, lung parenchyma, and pulmonary vasculature). A defining characteristic of COPD is emphysema, the destruction of alveolar air sacs due to lost elasticity and recoil, which result in respiratory collapse during exhalation. Smoking is a major risk factor for not only COPD but also numerous other health conditions and diseases due to the intake of carcinogenic substances. 

The clinical manifestations of COPD include dyspnea (also known as shortness of breath), cough and wheezing, prolonged expiration and respiratory distress, and inflated chest wall diameter (also known as barrel chest). The prevalence of COPD also increases substantially in colder and drier months of autumn and winter. To diagnose COPD, a spirometer is crucial as it allows the measurement of the forced expiratory volume (FEV), which in turn provides useful insight into the lung capacity.⁶ By taking the ratio of the forced expiratory volume in one second to forced vital capacity (FEV1/FVC), we can confirm the diagnosis of COPD if the value is less than 0.7. Imaging studies like X-rays of the chest and computed tomography (CT) can also be used to evaluate the severity of the condition.²

Treatment for COPD

Bronchodilator drugs like the beta-2-agonists are commonly administered to prevent dyspnea. The mechanism of action of beta-2-agonists is that they act on beta-2 receptors that line the smooth muscles of the respiratory tract and cause them to relax. An example of a common beta-2-agonist is salbutamol. Antimuscarinic bronchodilators are used to target muscarinic receptors and act antagonistically to prevent bronchoconstriction. Recent studies have shown that azithromycin, an antibiotic also used for pertussis, has shown a reduction in the number of exacerbations.⁷ For more severe cases of COPD manifestation, bullectomy (surgical removal of a bulla, airspace in the lung parenchyma), or lung transplantation could be necessary.¹

Pertussis in patients with COPD

Patients with COPD have a higher susceptibility to contracting pertussis with more severe symptoms. This particular study in South Korea has shown that individuals aged 50 years or more with preexisting asthma or COPD conditions are at a higher risk of contracting pertussis and require the utilisation of more healthcare resources than those who do not.⁸ Comorbidity of these two conditions would greatly decrease quality of life and also become a nuisance in lifestyle. Pertussis is also very contagious, hence it is advised to have vaccinations that prevent exacerbated symptoms of whooping cough and COPD. According to the World Health Organisation (WHO), COPD is the third leading cause of death worldwide. Generally speaking, lung cancer and cardiovascular disease are the most common causes of mortality in patients with COPD, and simultaneously it is also the leading cause of death worldwide. The condition of COPD itself causes several other health conditions that can prove fatal.⁹ As COPD causes reduced general airflow and overall FEV due to “obstruction”, the addition of pertussis increases more restriction in airflow, substantially worsening the severity of the condition. Furthermore, comorbidity of COPD and pertussis would substantially increase the risk of ear or sinus infections, or pneumonia. These conditions could ultimately lead to further health complications. 

According to the American Lung Association, vaccinations against pertussis are highly recommended for patients with COPD as a cough can be, as the title says, “downright dangerous”.¹⁰ Research has suggested that pertussis vaccination has an immunological efficiency that is deemed responsive even to COPD patients.¹¹ As the treatment for both pertussis and COPD is similar, the treatment considerations for a patient with both would probably be a combination of stronger pharmacological approaches. As each case differs, individuals with comorbidity should consult healthcare professionals. 

Summary

The co-occurrence of pertussis and COPD presents significant obstacles, reducing life expectancy and making treatment plans more difficult. Highly contagious respiratory infections like pertussis worsen the symptoms of COPD and can result in potentially fatal complications from additional airflow restrictions. For COPD patients, vaccination against pertussis is highly advised to reduce the possibility of developing severe symptoms. Recent findings provide promise for better results by indicating that pertussis immunisation is immunologically beneficial even in COPD patients. Patients with simultaneous COPD and pertussis may benefit from a combination of more potent pharmaceutical treatments that are customised for each patient, highlighting the significance of speaking with medical professionals for individualised therapy. With the ever-developing technological advancements, further research and development of COPD and pertussis treatment and prevention would continue to improve.