Bronchial Asthma - Research Paper Example

Bronchial Asthma I. Introduction: A. Historical Background of Asthma A series of theories were proposed to account for the pathophysiology of asthma over the past 100 years. The models of the pathogenesis of asthma have been consistent with its nature which is a complex disease per se and over time, became more progressively complex (Walter and Holtzman, 2005). A marked progress in defining the behaviours of the airways in terms of cellular and molecular mechanisms is noted. After that, research has moved forward and came up from a functional approach that is descriptive in nature to the one with cellular and molecular biology, immunology, microbiology, genetics, and pathophysiologic in nature (Walter and Holtzman, 2005). The aforementioned approached allowed current researchers to define heterogeneity of asthma in terms of quantitative and molecular approach and were able to determine its exact function on the inflammatory process of the airways that accounted likely for the initiation and progression of the disease (Walter and Holtzman, 2005). Currently, an attempt to incorporate the innate and adaptive immune system influence and the function of host genetics and environmental stimuli were proposed. As a result, they were able to make a considerable progress currently progressing in an accelerating pace (Walter and Holtzman, 2005). Furthermore, they believed that the identification and characterization of distinct pathways that are mechanistic for driving the phenotype of asthma will be aided with the advances in the research of genetics, genomics, proteomics, and lipidomics, which would later on provide biomarkers that are good enough and effective in the prevention and treatment regimens for individuals suffering from asthma (Walter and Holtzman, 2005). B. Epidemiology of Asthma 1. Worldwide Around 5 – 10 percent or an estimated 23.4 million of the population is affected by asthma. Among individuals who have no allergies or asthma, the overall prevalence rate of bronchospasm that is reportedly induced by exercise is 3-10 percent to the general population (Morris, 2012). An estimated 300 million individuals worldwide are assessed to have been affected by asthma. According to the records of World Health Organisation (WHO), there are approximately about 15 million “disability – adjusted life – years are lost,” and 250,000 deaths due to asthma are reported around the world. 2. In Australia According to the Australian Institute of Health and Welfare (2008), the epidemiology of asthma in Australia remains unclear and reliable statistics still needs to be developed to describe this particular problem. The Australian Institute of Health and Welfare (2008) note that the Centre for Epidemiology and Research reported that in 2007, sometime in their lives, an estimated 3, 979, 476 or an equivalent to 20.3 percent Australians were diagnosed by doctors or nurses with asthma based on the data gathered in the surveys. In New South Wales, a significant increase from 16.6 percent to 19.3 percent of new cases was reported in 2006, with higher percentage noted among males than females (Australian Institute of Health and Welfare, 2007). C. The Prevalence of Asthma Worldwide and in Australia: 1. Worldwide Among industrialised nations, asthma is reported as a common respiratory problem and the prevalence rate of the severe type ranges from 2 – 10 percent and this rate is said to be reportedly increasing (Morris, 2012). Factors such as urbanisation, pollution of air, passive smoking, and change exposure to allergens in the environment were among the causes that were implicated in the pathogenesis of asthma. Morris (2012) noted that in childhood, asthma occurs predominantly in boys with a ratio of 2:1 in favour of male, until puberty. However, this has changed to increase ration among females in cases of adult – onset asthma. Also, due to airways responsiveness and lower levels of the function of the lungs, the prevalence rate of asthma is increased among the very young and very old individuals (Morris, 2012). Lastly, a decrease or disappearance of symptoms occurs in early childhood in approximately half of the children diagnosed to have asthma (Morris, 2012). 2. In Australia The prevalence of asthma in Australia is high by international standards. According to the National Asthma Council in Australia (2012) that more than two (2) million Australians are diagnosed to have asthma with the corresponding ratio of 1 is to 10 adults and 1 is to 9 or 10 children; however, the rate in the children had notably decreased but remained stable in the adults in the past decade. The National Asthma Council in Australia (2012) also reported that asthma affects more male children than female, but this sex preponderance is reversed by the time they reach the age of 15 where asthma will affect more women than men. Also the National Asthma Council in Australia (2012) reported that more indigenous Australians are affected with asthma than other Australians. The latest figure obtained by the National Asthma Council in Australia in asthma mortality was 416 having the elderly on the number one list as its highest risk. II. Physiology of the Respiratory System The primary function of the respiratory system is to obtain oxygen to be used by the cells in the body and to eliminate the carbon dioxide produced by the cells. The pathway of the airways starts from the nasal cavities towards the alveoli where the exchange of gases is taking place (Ritchison, 2010). In between the alveoli and the blood, oxygen diffuses from the alveoli to the blood through the process of simple diffusion and vice versa, the carbon dioxide from the blood towards the alveoli (Ritchison, 2010). Since the concentration gradient is required in the process, the oxygen concentration must be kept higher in the alveoli by continuously breathing fresh air and inhaling it towards the lungs and the alveoli. The skeletal muscles contraction is required during the process of breathing since it is an active process (Ritchison, 2010). The external intercostal muscles and the diaphragm are the primary muscle needed during the inspiratory process. In the process of inspiration, the external intercostal muscles contracts and elevates the ribs and sternum increasing the thoracic cavity’s anterior and posterior dimension with resultant lowering of the pressure of the lungs and movement of the air into the lungs (Ritchison, 2010). On the other hand, the diaphragm functions by moving downward during the process of contraction with resultant increase of the thoracic cavity’s vertical dimension lowering the lung air pressure and facilitating movement of air towards the lungs (University of Leicester, undated). The physiologic mechanism of expiration is due to the “natural elasticity of the lungs,” and if they are not held against the walls in the thorax, would collapse with resultant release of the gas to the atmosphere (University of Leicester, undated). III. Pathophysiology of Bronchial Asthma A. Definition of Terms: 1. Asthma: Asthma is defined as the chronic inflammation of the bronchial airways resulting to total and partial difficulty of breathing secondary to swelling and narrowing of the airways (Szeftel, 2012). Churchill (2011) that 90 percent of death and 75 percent of hospital admission secondary to asthma can be prevented. 2. Bronchospasm: Bronchospasm is an IgE – mediated anaphylaxis or nonallergic mechanism causing immediate hypersensitivity reaction triggered by mechanical factors such as bronchospasm induced intubation or it can be triggered by pharmacologic mechanism producing bronchoconstriction among patients who have reportedly underlying uncontrolled hyperreactivity of the airways (Pascale, et al, 2011). Bronchospasm can be confirmed by auscultatory wheezing or decreased breath sounds (Pascale, et al, 2011). Rhinitis and asthma which are linked with common inflammatory cells, mediators and cytokines are known as the common pathogenic process of bronchospams leading to systemic propagation of the inflammatory process of the airways (Bjermer, 2010). 3. Inflammation: The key pathologic ingredient in asthma is inflammation, and inflammation in the local airways such as nose, sinuses and small airways leads to remodelling and dysfunction of the airways that are irreversible (Bjermer, 2007). The central feature of asthma as well as other chronic lung diseases is inflammation, and these involve inflammatory cell recruitment and activation as well as changes in the lung cell structure, although, the specific characteristics of responses of inflammation and the inflammatory site may differ from these lung diseases (Adcock and Lane, 2003). These various lung diseases are characterised by an expression increase of the inflammatory cascade mediators such as the cytokines, chemokines, growth factors, enzymes, receptors, and adhesion molecules which is then regulated by pro – inflammatory factors of transcription such as the nuclear factors. In asthmatic patients, these inflammatory cells and transcription factors are activated markedly in their epithelial cells regulating the factors of transcriptions of inflammatory genes expressed abnormally among asthmatic patients (Adcock and Lane, 2003). 4. Correlation of Inflammation and Bronchospasm with Asthma Asthma, bronchospasm, and inflammation cannot be separated from each other since inflammation and bronchospasm goes together with asthma. Without those, it will be hard to detect impending asthma, and patients cannot be diagnosed with asthma. Inflammation, bronchospasm, and hyperactivity are the three major factors causing narrowing of bronchial airways (Szeftel, 2012). Understanding the pathogenesis of asthma would help us appreciate how the three correlate to each other. Inflammation is the first and most important factor that causes bronchial tube narrowing. The inflammatory process makes the bronchial tube red, irritated, and swollen resulting to an increase of thickness of the wall of the bronchial tube as a consequence to airflow obstruction secondary to smaller passageway (Szeftel, 2012). An increase in the amount of sticky mucus in an inflamed tissue produces clumping of the mucus forming a plug clogging the smaller airways. Otherwise, tissue damage often results from the accumulation of inflammatory cells and tissue at the site of damage in the bronchus (Szeftel, 2012). On the other hand, Szeftel (2012) stated that bronchospasm is the constriction of the airway muscles causing further narrowing of the airways. Precipitants of bronchospasm include chemical mediators and nerves in the bronchial tube as well as inhalation of cold or dry air (Szeftel, 2012). Asthma has a complex pathophysiology that involves an inflammation of the airways, intermittent obstruction of the airflow, and hyperresponsiveness of the bronchus. The inflammatory mechanism of asthma is acute, subacute, and chronic which oftentimes manifests as obstruction of the airflow and reactivity of the bronchus as a result of the oedema of the airways and secretion of the mucus (Morris, 2012). It involves infiltration of mononuclear cell and eosinophil as well as hypersection of the mucus, desquamation of the epithelium, hyperplasia of the smooth muscle, and remodelling of the airways. Morris (2012) stated that this also involves infiltration of eosinophil and mononuclear cell in varying degree as well as hypersecretion of the mucus, epithelial desquamation, hyperplasia of the smooth muscle, and remodelling of the airways. In asthma, numerous exogenous and endogenous stimuli results to an exaggerated hyperresonsiveness of the airways or hyperreactivity of the bronchus and the involved mechanism includes direct airway smooth muscle stimulation and indirect pharmacologically active substances stimulation (Morris, 2012). These substances come from the mast cells or nonmyelinated sensory neuron. The clinical severity of asthma is correlated with the degree of hyperresponsiveness of the airways (Morris, 2012). To establish the diagnosis of asthma, spirometry with postbronchodilator response remains as the primary test that should be obtained. Among patients with exercise induced bronchospasm, exercise spirometry remains to be the standard method for patient assessment. Although in most individual, chest radiography remains as the initial imaging evaluation, its findings is usually normal or would indicate a sign of hyperinflation (Morris, 2012). IV. Clinical Presentation of Asthma A. Signs and Symptoms The most common signs and symptoms of asthma include coughing, wheezing, tightness of the chest, and shortness of breathing (National Heart Lung and Blood Institute, 2011). In asthmatic individual, coughing is usually worse during night time and in early morning that result to lack of sleep (National Heart Lung and Blood Institute, 2011). Wheezing is one of the unique features of asthma and presents as whistling or squeaky sounds upon breathing, particularly during the process of exhalation (National Heart Lung and Blood Institute, 2011). Chest tightness presents as a squeezing sensation on the chest as if someone is sitting on the chest (National Heart Lung and Blood Institute, 2011). Lastly, shortness of breathing is presented as gasping of air like someone feels out of breath and felt like he can’t breathe the air out of his lungs (National Heart Lung and Blood Institute, 2011). B. Clinical Manifestations of Asthma The clinical manifestations of asthma vary and ranges from mild, to severe episodes of asthma and are discussed by below. 1. Mild Asthma Patients with mild asthma may have the following episodes even after a simple physical activity (Morris, 2012). This include walking, breathlessness even after talking a few sentences, and agitation (Morris, 2012). Patients may be observed to have increased respiratory rate and end expiratory wheezing (Morris, 2012). 2. Moderately Severe Asthma An increased respiratory rate with use of accessory muscles of respiration associated with supraclavicular and intercostals retractions as well as nasal flaring are observed in patients with moderately severe episodes of asthma (Morris, 2012). An increase of heart rate to 100 to 120 beats per meaning with visible auscultatory expiratory wheezing are also noted in patients with moderately severe asthma (Morris, 2012). Patients may also experience breathlessness and assumes sitting position (Morris, 2012). 3. Severe Asthma Patients with severe episode of asthma are noted to be breathless even at rest (Morris, 2012). Morris (2012) noted that patients have no appetite in eating and usually agitated and talks in words not sentences. The respiratory rate of patients increases to more than 30 per minute with corresponding use of accessory muscles as well as increase in heart rate to more than 120 bpm (Morris, 2012). Patients will usually assume a hunched over position of sitting and loud biphasic wheezing is noted during auscultation (Morris, 2012). C. Physical Diagnosis of Asthma The best way to diagnose patients with asthma is by carefully and thoroughly extracting the medical history of the patient (Kaplan, et al, 2009). The objective of doing further diagnostic test for asthma is to confirm that the healthcare practitioner is coming up with the correct diagnosis (Kaplan, et al, 2009). Hence, spirometry testing and result is done to confirm the history and physical diagnosis of asthma before initiating lifelong management best for the patient (Kaplan, et al, 2009). Other diagnostic monitoring used in asthma is the serial peak flow monitoring and challenge test. Other ancillary testing done in asthmatic patient include chest x – ray, which help to rule out other existing medical problems. The National Heart Lung and Blood Institute (2011) noted that the best way to ascertain that someone is having asthma is to perform a lung function test together with proper medical history and physical examination since the aforementioned signs and symptoms of asthma are not all experienced by individuals having this type of respiratory problem, and likewise does not always mean that the aforementioned symptoms are experienced by these individuals (National Heart Lung and Blood Institute, 2011). Hence, it is important to treat its symptoms upon its diagnosis to prevent death (National Heart Lung and Blood Institute, 2011). V. Review of Literature on Asthma To understand asthma better, literatures that talks about asthma and its pharmacological management, as well as inflammation and bronchospasm are reviewed and noted in the next paragraphs. A literature on the Effect of Budesonide in Combination with Formoterol for Reliever therapy in Asthma Exacerbations: A randomised controlled, double – blind study dated 2006 by Rabe, et al., noted that this study compares the efficacy and safety of the strategies of the three relievers such as the traditional short acting beta – 2 – agonist, rapid onset LABA, formoterol, and budesonide – formoterol, an inhaled corticosteroid in patients who are symptomatic, since it was not fully established in the past the contributions of the as – needed inhaled corticosteroids and long acting beta – 2 – agonist. A double blind, parallel group study in 3,394 patients was done in 12 months, in 289 centres and in 20 countries (Rabe, et al., 2006). It was found out during the study that with budesonide – formoterol versus formoterol alone, the time to first severe exacerbation took longer compared to the as needed formoterol versus terbutaline alone (Rabe, et al., 2006). The severe exacerbation rate was highest with terbutaline and lowest with budesonide formoterol (Rabe, et al., 2006). In all treatment groups, it was noted that asthma control days were increased to a similar extent; however, the symptoms did not improve significantly with as needed formoterol although all treatment were tolerated well during the study (Rabe, et al., 2006). It was concluded that “both monocomponents of budesonide – formoterol given as needed contribute to enhanced protection from severe exacerbations in patients receiving combination therapy for maintenance” (Rabe, et al., 2006). Another study by Sears, et al., dated 2008 entitled Budesonide/Formoterol Maintenance and Reliever Therapy: Impact on Airway Inflammation in Asthma aimed to compare budesonide/formoterol maintenance’ effectiveness, safety and health economics and a novel reliever therapy with persistent asthma in Canada. From the study, it was found out that budesonide/formoterol maintenance and reliever therapy compared to that what’s in conventional best practice were able to achieve similar or improved clinical control and had lowered significantly the dose and cost of total inhaled corticosteroid while at the same time maintaining eosinophilic inflammation control (Sears, et al., 2008). VI. Current Management and Therapy of Bronchial Asthma Management of asthma is a holistic approach and its goal in treating asthmatic patients is to control the disease process since long term diseases like asthma has no cure(National Heart Lung and Blood Institute, 2011). In managing asthma in the children, partnering with the doctor where parents are also taking an active role in their children’s ordeal is very important (National Heart Lung and Blood Institute, 2011). These include avoidance of triggering factors that may worsen asthma such as foods that may cause allergies and extreme physical activities that may exacerbate the symptoms of asthma (National Heart Lung and Blood Institute, 2011). An action plan in managing asthma include proper taking of medicines, avoidance of triggers of asthma, tracking asthma control level, responding to a worsening asthma, and when needed, seeking emergency care. There are two types of medicines used in treating asthma(National Heart Lung and Blood Institute, 2011). These are the long – term control, which acts in reducing the inflammation of the airways thereby preventing the symptoms of asthma and medicines that may provide quick relief, which alleviates the symptoms of asthma every time it flares up (National Heart Lung and Blood Institute, 2011). Long – term medications include inhaled corticosteroids, inhaled long acting beta -2 agonist, leukotriene modifiers, and theophylline (National Heart Lung and Blood Institute, 2011). On the other hand, quick reliever of asthma includes inhaled short acting beta –2 agonist (National Heart Lung and Blood Institute, 2011). In managing asthma, it is important to educate the patient and the family as the pharmacological care is integrated in the treatment (Morris, 2012). It is important that the members of the healthcare team should know the basics of asthma and asthma control in order for them to provide education to the patients (Morris, 2012). Patients should be taught the basic facts of asthma management as well as techniques in self – monitoring and the role of medications and control measures in the environment (Morris, 2012). It is important to develop a written, individualized, and plan of daily self- management for the patient to follow and for the clinicians to carefully review (Morris, 2012). A. Advantages and Disadvantages: Asthma patients need careful management planning with their clinicians to avoid unexpected side effects that may often cause potential harm to the patient, and even death (Newman, 2005). There are several advantages and disadvantages noted in pharmacological asthma management (Newman, 2005). This includes the varied instructions from different pharmaceutical companies that may confuse the patients and healthcare providers and may often result to the misuse of inhalers resulting to minute or negligible amount of drug being deposited or delivered to the lungs, which may result to the absence of any pharmacologic effect and would result to an effective pharmacotherapeutic action (Newman, 2005). VII. How to Prevent Recurrence of Asthma in the Future: A. Monitoring the Progress of the Patient: To prevent further recurrence of asthma in the future, it is important to keep the records of asthmatic patients, “check your peak flow number using a peak flow meter, and get regular asthma checkups” (National Heart Lung and Blood Institute, 2011). B. Dietary Restrictions According to Subbarao, et al (2009), diet, nutrition, stress, antibiotic use, and mode of childbirth may greatly affect the development of allergy and asthma in the early stage of child development. Foods and vitamins containing anti – inflammatory properties such as omega – 3- fatty acids, vitamin E and zinc are known to decrease the risk of acquiring eczema and atopic wheezing especially when they are taken during pregnancy (Subbarao, et al., 2009). C. Exercise It is also recommended that proper breathing techniques and relaxation is important in preventing future recurrence of asthma and is used by a large proportion of individuals who suffers from asthma (Ernst, 2000). Ernst (2000) in his study noted that physiotherapeutic breathing techniques were able to provide some potential benefits among asthmatic patients based from the results of collective data gathered in his study. I. Conclusion Asthma is a disease which becomes progressively complex over time involving the genetics and environmental stimuli as part of its pathogenesis. The hallmark of its diagnosis is the combination of bronchospasm and inflammation causing narrowing of the airways and its presentation of expiratory wheezing during auscultation is the benchmark of patients with asthma. Asthma is a lifetime disease with no known treatment but when properly managed, results to the control of further exacerbation in the future. II. References: Adcock, I. and Lane, S., 2003. Mechanism of Steroid Action and Resistance in Inflammation. Journals of Endocrinology, 178(2003): 347 – 355. Australian Government, Australian Institute of Health and Welfare, 2007. Asthma in Australia. 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Journal of the Royal Society of Medicine, 103(3): 98-106. Subbarao, P., Mandhane, P., and Sears, M., 2009. Asthma: Epidemiology, Etiology, and Risk Factors. Canadian Medical Association Journals, 181(9): E181-190. Szeftel, A.,2012. Asthma. [Online] Available at: [Accessed 15 March 2012]. University of Leicester., 2012. Anatomy and Physiology of the Respiratory System. Available at: [Accessed 30 March 2012]. Walter, M., and Holtzman, M., 2005. A Centennial History of Research on Asthma Pathogenesis. American Journal of Respiratory Cell and Molecular Biology, 32(6): 483-496. Read More