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Bronchiectasis

Bronchiectasis

Bronchiectasis is an abnormal and irreversible thickening of the bronchi walls, creating a reduction of the lumen. In this pathology, the shape of the bronchi is altered, which appear short and widened. Also, there is difficulty in driving air from the trachea to the bronchial tree because of the reduced diameter of these ducts.

“The lungs are continuously exposed to inhaled pathogens and have developed an advanced mechanism for trapping and removing them. The human airways are lined with ciliated epithelium with submucosal goblet cells secreting mucus that makes up the top layer of the airway surface liquid, the lower layer being the periciliary fluid that bathes the cilia and ensures they function appropriately. In healthy individuals the mucus traps inhaled pathogens and the continuously motile cilia transport the mucus and its contents out of the lung. Any defect in this mucociliary clearance mechanism can lead to the retention of pathogens resulting in the progression of airway infection, inflammation and ultimately bronchiectasis.”1

“Bronchiectasis is a relatively frequent condition in the United States, with an estimated prevalence of 4.2 per 100,000 persons 18–34 years old and 272 per 100,000 persons 75 years or older. It is defined as an ‘irreversible localized or diffuse dilatation, usually resulting from chronic infection, proximal airway obstruction, or congenital bronchial abnormality.’ On chest radiographs, bronchiectasis manifests as tram tracks, parallel line opacities, ring opacities, and tubular structures. However, chest radiographs lack sensitivity for detecting mild or even moderate disease. CT is substantially more sensitive than chest radiography for showing bronchiectasis, which is characterized by lack of bronchial tapering, bronchi visible in the peripheral 1 cm of the lungs, and an increased bronchoarterial ratio producing the so-called signet-ring sign. According to appearance and severity, bronchiectasis can be classified as cylindric, varicose, or cystic. The wide differential diagnosis of bronchiectasis can be substantially narrowed by considering both the anatomic location and the distribution of this pathology”2

Manifestations of Bronchiectasis

The most common manifestations of bronchiectasis are:

  • Continuous and chronic cough: the individual expels a large amount of sputum that has a characteristic bad smell. Also, hemoptysis may occur, which is the expulsion of blood when coughing.
  • Fatigue, tiredness, and weakness that gets worse when as it relates to continuous physical exercise.
  • Extreme difficulty in breathing. Sometimes you can hear a kind of whistling or a high pitch sound.
  • Paleness

“Bronchiectasis leads to symptoms of breathlessness, cough and a chronic infective syndrome and consequently, a poorer quality of life and clinically significant fatigue. Patients often have recurrent infective exacerbations, some of which result in costly hospital admissions. Patients with bronchiectasis are at an increased risk of anxiety and depression. In cystic fibrosis, depression and anxiety rates are higher than in the general population, and therefore annual screening is recommended. Given the potential for such psychological distress to impact upon adherence and disease management, annual screening in bronchiectasis could also be of benefit. New data has additionally shown a greater risk of coronary heart disease and stroke in patients with bronchiectasis. Multiple comorbidities are common in bronchiectasis. The burden of disease for patients and carers is clearly significant.”3

“Bronchiectasis is characterized by mild to moderate airflow obstruction that tends to worsen over time. The most widely known model of the development of bronchiectasis is Cole’s “vicious cycle hypothesis”. In this model, Cole proposed that an environmental insult often on a background of genetic susceptibility impaired muco-ciliary clearance resulting in persistence of microbes in the sinobronchial tree and microbial colonization. The microbial infection caused chronic inflammation resulting in tissue damage and impaired mucociliary motility. In turn this led to more infection with a cycle of progressive inflammation causing lung damage. The current view is that the two factors required for the development of this condition are persistent infection and a defect in host defense.

There are no well-established animal models of bronchiectasis nor have there been studies performed in the early stages of the disease. Bronchiectasis is also a very heterogeneous condition and can be considered the end result of a variety of different factors. As a consequence the pathophysiologic processes are still not well defined.”4

“Establishing the cause of bronchiectasis may be difficult. Even with exhaustive clinical, laboratory, and pathologic testing, up to 50-80% of cases of bronchiectasis may still be idiopathic.

Childhood infections, including pertussis, were thought to have caused 11% of the bronchiectasis cases and 10% of cases were related to the prior granulomatous disease. Several respiratory infections can cause not only bronchiectasis including measles, pertussis, and tuberculosis but also viruses (HIV, paramyxovirus, adenovirus, and influenza), Gram-negative bacteria (Pseudomonas aeruginosa and Haemophilus influenzae), and other atypical mycobacteria.

Non-cystic fibrosis (CF) bronchiectasis secondary to Mycobacterium avium complex infection is a typical feature of the Lady Windermere syndrome, Bronchiectasis is found typically in the middle lobe and lingula, older patients, and immunocompetent women with no smoking history or pulmonary disease. Congenital causes of bronchiectasis include CF, primary ciliary dyskinesia (PCD), and Xl-alfa 1 antitrypsin (AAT) deficiency. Congenital bronchiectasis is much rarer than previously considered. Specific causes include Williams-Campbell syndrome (bronchial cartilage deficiency), tracheobronchomegaly (Mounier-Kuhn syndrome), Marfan’s syndrome, late presenting H-type tracheobronchial, and esophagobronchial fistula.

Bronchiectasis has been reported in congenital lung malformations such as sequestration or rarely with a rib malformation. In children, aspiration of foreign bodies into the lower respiratory tract is the most common and most important obstructing lesion causing bronchiectasis with the incidence peaking in the 2nd year of life. Adults may also develop bronchiectasis secondary to aspiration of foreign material and due to endobronchial tumors although this is a rare cause of bronchiectasis. A variety of respiratory and systemic diseases may be complicated by pathological bronchial dilatation, and therefore various medical specialists will be dealing with the condition in one way or another.

Bronchiectasis has been demonstrated on high-resolution computed tomography (HRCT) in about 30% of cases of rheumatoid arthritis although it may be clinically silent and it may precede or follow the development of rheumatoid arthritis. Various hypotheses exist regarding the association between bronchiectasis and rheumatoid arthritis including chronic suppurative infections leading to bronchiectasis, treatment with disease-modifying antirheumatic drugs, or alternatively that chronic infection in a bronchiectasis patient provide additional antigenic stimuli that then triggers rheumatoid arthritis. It is also hypothesized that rheumatoid arthritis and bronchiectasis share a genetic predisposition.

Bronchiectasis is seen in 7-25% of the patients with asthma or chronic obstructive pulmonary disease (COPD) and interstitial lung disease. In these conditions, bronchiectasis is usually found in the context of severe disease and is then not considered the primary disease. Coexisting bronchiectasis and COPD may represent a more severe phenotype as also indicated by colonization or infection with potentially pathogenic organisms such as P. Aeruginosa and atypical mycobacteria. Allergic bronchopulmonary aspergillosis has as one of its key features bronchiectasis, which tends to be central in its distribution.

Osteoporosis and osteopenia have a high prevalence in patients with lung diseases. The prevalence of osteopenia and osteoporosis is high in patients with non-CF bronchiectasis. Crohn’s disease is an inflammatory bowel disease associated with a variety of systemic manifestations including large and small airway involvement. The most commonly reported airway disease is bronchiectasis.”5

Regardless of the cause, the patient will suffer from bronchiectasis their entire life since it is an irreversible chronic condition. The origin or trigger of this disorder can be congenital (the baby is born with bronchial malformations) or as a consequence of a complication of another pathology, such as those that cause the weakening of elasticity of the pulmonary wall musculature. The most frequent diseases that can cause bronchiectasis are severe pneumonia, bronchitis, pulmonary tuberculosis, cystic fibrosis, bacterial infections, asthma, chronic obstructive pulmonary disease (COPD), immunodeficiency (because it favors the development of respiratory infections), pulmonary tumors (reduce lung capacity by compressing structures), and aspiration of foreign bodies (they are lodged in the bronchi and block the passage of air).

What are the clinical features of bronchiectasis?

“First described by Laennec in 1819, bronchiectasis refers to abnormal permanently dilated airways, which are typically described as cylindrical, varicose or cystic in appearance. The condition is characterized by a vicious cycle of persistent bacterial infection and excessive neutrophilic inflammation owing to impairment of airway defense mechanisms. Risk factors for bronchiectasis are related mainly to cause of the disease, with prevalence higher in patients with autoimmune or connective tissue diseases, chronic infections such as HIV12 and chronic lung disease such as chronic obstructive pulmonary disease and asthma. Both rhinosinusitis and gastroesophageal reflux are also common among patients with bronchiectasis. […] The most common symptom that should prompt suspicion of a diagnosis of bronchiectasis is a persistent cough productive of mucopurulent or purulent sputum.”6

We can differentiate two subtypes of bronchiectasis depending on the affected area:

  • Unilateral: the disease only affects one lung.
  • Bilateral: the alteration has spread to both lungs of the individual.

In both cases, the condition appears more frequently in the lower region of the lungs. The greater the extension of the affected area, the greater the severity, making the patient’s commitment to improving their condition vital. Another way to classify bronchiectasis is according to the final shape of the bronchi:

  • Cylindrical: the bronchial tubes reflect the loss of the normal tapering of the airways.
  • Varicose: some bronchi appear inflamed while others are contracted.
  • Saccular: in this case the bronchial tubes don’t present damages of the disease at first sight. However, pathologists can appreciate the destruction under the microscope, including inflammation and excess secretion. Normally, techniques that are used for their identification are chest x-ray and a CT scan (Computerized Axial Tomography). However, other tests may be recommended in order to study the underlying disease in the case of acquired bronchiectasis.

“Given that bronchiectasis is a pathologic diagnosis it is possible to have evidence of bronchiectasis on c-HRCT without symptoms of chronic airway inflammation and suppuration. This may be related to relatively quiescent or minor disease or the fact that the cause of the airway dilatation is not related to a process affecting the airway directly, but rather a process involving the lung parenchymal with secondary fibrosis and retraction of the structures supporting the airway. This entity, typically seen in interstitial lung diseases and termed, ‘traction bronchiectasis’, is not usually considered as bronchiectasis per se unless there is evidence of associated airway suppuration and its management it typically directed at the underlying interstitial lung disease.”7

Treatment

Currently, an effective cure for this disorder has not yet been developed. Nevertheless, the physician can administer medications and even recommend surgery if necessary, in order to improve the patient’s life.

“Therapies shown to be effective in cystic fibrosis are often provided to patients with bronchiectasis, without definitive evidence of benefit. In recent years, there has been increased interest in validating and developing new therapies for patients with noncystic fibrosis bronchiectasis. While inhaled tobramycin improves microbiologic parameters, improvements in outcomes have been more difficult to demonstrate, in part due to the occurrence of bronchospasm in a significant minority of treated patients. Outcome data from studies of inhaled aztreonam and ciprofloxacin have not yet been reported, although the microbiologic data appear to be promising. Preliminary data regarding inhaled hyperosmolar agents such as hypertonic saline and mannitol are also promising, but these therapies cannot yet be recommended for routine therapy of patients with bronchiectasis. Macrolide antibiotics have anti-inflammatory properties in patients with chronic suppurative lung disease, through a variety of mechanisms. They have been proven to be beneficial in diffuse panbronchiolitis and are commonly being used in patients with bronchiectasis. Many small studies support their use in this population, although several had methodologic flaws. Thus, although chronic low-dose macrolide therapy is often used in these patients, more conclusive evidence is awaited.”8

The pharmacological spectrum includes antibiotics (they treat bacterial infections, a frequent complication of this disease), bronchodilators (to expand the airways), and expectorants (to promote the expulsion of sputum).

Surgical procedures are carried out in the most severe cases and consist in the removal of the affected lung, but in general, this option is not chosen so easily. Generally, we can adopt certain habits that can help us prevent this disease and improve our respiration. For example, unhealthy habits such as smoking and alcohol consumption are factors that increase the risk of suffering from many pulmonary afflictions.

 

References:

(1) Bilton, D., & Jones, A. L. (2011). 1 Bronchiectasis: Epidemiology and causes. European Respiratory Monograph, 52, 1-10. Available online at http://www.sppneumologia.pt/uploads/files/spp/PDF75.pdf

(2) Cantin, L., Bankier, A. A., & Eisenberg, R. L. (2009). Bronchiectasis. American Journal of Roentgenology, 193(3), W158-W171. Available online at https://www.ajronline.org/doi/pdf/10.2214/AJR.09.3053

(3) Hester, K. L., Newton, J., Rapley, T., & De Soyza, A. (2018). Patient information, education and self-management in bronchiectasis: facilitating improvements to optimise health outcomes. BMC pulmonary medicine, 18(1), 80. Available online at https://www.researchgate.net/publication/325309283_Patient_information_education_and_self-management_in_bronchiectasis_Facilitating_improvements_to_optimise_health_outcomes

(4) King, P. T. (2009). The pathophysiology of bronchiectasis. International journal of chronic obstructive pulmonary disease, 4, 411. Available online at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2793069/

(5) Piroddi, I. M. G., Rosales, E., Cilloniz, C., Ceccato, A., & Nicolini, A. (2016). Bronchiectasis in rare pulmonary diseases: A case series. Community Acquired Infection, 3(4), 129. Available online at http://www.caijournal.com/article.asp?issn=2225-6482;year=2016;volume=3;issue=4;spage=129;epage=134;aulast=Piroddi

(6) Smith, M. P. (2017). Diagnosis and management of bronchiectasis. CMAJ, 189(24), E828-E835. Available online at http://www.cmaj.ca/content/cmaj/189/24/E828.full.pdf

(7) Maguire, G. (2012). Bronchiectasis: a guide for primary care. Australian family physician, 41(11), 842. Available online at https://www.racgp.org.au/download/Documents/AFP/2012/November/201211maguire.pdf

(8) Metersky, M. L. (2010). New treatment options for bronchiectasis. Therapeutic advances in respiratory disease, 4(2), 93-99. Available online at https://journals.sagepub.com/doi/pdf/10.1177/1753465810366858

 

Robert Velasquez
16 July, 2019

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Hello everyone, my name is Robert Velazquez. I am a content marketer currently focused on the medical supply industry. I studied Medicine for 5 years. I have interacted with many patients and learned a lot...read more:

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