Overview of Disease: Asthma - Assignment Example

Asthma Overview of Disease Definition Asthma has been defined to be a disease of the airways resulting from chronic inflammations of various aetiologies. In this disease, the tracheobronchial airways become extremely responsive to a variety of stimuli. As a result of this, there is widespread narrowing of the air passages leading to various respiratory symptoms mainly centred on breathing difficulties. This is very common disease with immense social impact (Enright, 2003). Epidemiology Bronchial asthma spares no ages with 50% of the cases developing before the patients reach the age of 10. The next most prominent group comprises of individuals before age 40. Predominantly males have this disease, and this preponderance is evident also in the childhood. It is very highly prevalent disease in the United Kingdom. According to statistics, the current number of patients in the United Kingdom is 5.1 million. This number has increased from the previous study. About 8% adults and 13% children are affected, and this increased trend has been postulated to be due to a combination of genetic, environmental, and population growth factors. There is a number of emergency hospital admission and death due to this disease (SIGN and BTS 2009). Aetiology Asthma is heterogeneous in terms of aetiology. Atopy is a common cause, and genetic factors are involved in transmission of these atopic traits. Some environmental factors which the individual may be exposed in the domestic or occupational environments may also trigger asthma. These are viruses, allergens, dust mites and others. These also contribute to asthma trigger and continuance of the disease. The most important risk factor is allergic diathesis or atopy. In many cases, no such links have been described (Satta, 2000). Pathophysiology Asthma leads to subacute inflammation of the airways. The persistent nature of this inflammation leads to oedema of mucous membranes. With inflammation, the inflammatory cells infiltrate the mucosa. This also leads to increased congestion in the blood vessels due to slowing of circulation. With the external triggering agent, the inflammatory cells accumulated in the mucosal epithelium which release inflammatory mediators leading to amplification of the basic inflammatory process, which culminates into an intense and immediate inflammatory reaction leading to constriction of airways, vascular congestion, oedema, increased mucus production, and inability expectorate due to impaired mucociliary transport. These events are followed by a chronic inflammatory stage giving the disease a characteristic acute, chronic, and acute-on-chronic picture (Nici et al, 2006). Clinical Features Cough, dyspnoea, and wheezing are the main symptoms. Typically, in most cases, all these three symptoms are encountered. The cough is nonproductive. The dyspnoea is associated with generalised constriction of the airways, which leads to an associated sense of constriction while breathing. The airway resistance increases leading to harsh breath sounds that can be heart without any hearing aids. In the phases of both inspiration and exhalation, wheezing is prominently heard. Moreover there is difficulty in passive air passage in expiration. With a prolonged expiration, air is trapped, and this increases the drive of breathing due to hypercapnia and hypoxemia. These in turn lead to tachypnoea, systolic hypertension or mild grade, and a compensatory tachycardia. With air trapping, the lungs keep on gathering air, are inflated, and the thoracic diameter increases anteroposteriorly. With the impairment of pulmonary function, the breathing is laborious despite which the patient becomes hypoxaemic (MacNee, 2008). Assessment For assessment, the physical exertion is assessed, and the amount is less than that required to produce asthma symptoms. This is usually equivalent to relative work rate of 75% of age-predicted maximal heart rate. A pre-prescription assessment must include a detailed history and clinical assessment. The history of medications, inhalation therapies, and conditions that help precipitate asthma attack is also important components of the asthma prescription. Lung function measurements such as FEV1 and FVC indicate the respiratory reserve, reversibility of the pulmonary pathology, and an estimate of exercise tolerance (Enright, 2003). Thus airflow limitation indicated by a fall in FEV1 to below the predicted of about 80% and the ratio of FEV1/FVC falls to less than 65%, which are the main consideration for the exercise prescription. A short acting bronchodilator test and flow-volume loops may indicate reversibility and emphysema. Peak expiratory flow measurement may help monitoring (Miller et al. 2005). Exercise-induced asthma assessment is performed through a symptom-limited maximum on either a bicycle or treadmill in short work intervals of 2-min stages with increase in workload of approximately 1 metabolic equivalent. In a chosen protocol, the patient's maximal effort should be elicited between 8 to 12 minutes. The same assessment criteria may be applicable for those without suspected exercise induced asthma. However, it must be considered that there remains a great variability in pathophysiological processes, hence the exercise responses (Clark and Cochrane, 2003). Many patients may not tolerate even walk across a room. Moreover, there may be temporal differences in exercise capability in the same individual based on the stage of the disease and efficacy of treatment (Singh, 2009). Prescription Exercise training may not demonstrate changes in static lung function measurements or bronchial hyper-responsiveness related to exercise training. However, in bronchial asthma patients there are consistent changes in minute ventilation and subjective responses. Generally based on assessment, the best mode is to begin exercise at a level of patient comfort for 5 minutes with increasing them to sessions of 20 to 60 minutes per session as tolerable. If the patient is able to do that, then these sessions are to be performed three to five times per week (Enright, 2003). In each session, the exercise intensity is to be increased by 5% in each session, and in this way the maximal level of exercise intensity may be reached, when duration can be increased by 5%. The aerobic exercise is performed by Treadmill 5 times per week in 20-30 minute sessions with the intensity remaining just below anaerobic threshold. Walking and running in a track or sidewalk or swimming in the same schedule as alternatives have also been advised (Carlin and Singh, 2009). References Clark, CJ. and Cochrane, LM., (2003) Asthma (Chapter 19) in Durstine, JL. and Moore, GE., (2003) (Eds) ACSM's exercise management for persons with chronic diseases and disabilities. American College of Sports Medicine. Human Kinetics, 2003, Leeds, United Kingdom, 143-149. Carlin, BW. and Singh, A (2009) Asthma in Ehrman, JK., Gordon, PM., Visich, PS., and Keteyian, SJ. (Eds) (2009). Clinical Exercise Physiology. Human Kinetics, 2009, Leeds, United Kingdom 443-460 MacNee, W., (2008). Update in Chronic Obstructive Pulmonary Disease 2007. Am J Respir Crit Care Med Vol 177. pp 820-829. Miller, MR. et al. (2005). Standardisation of spirometry. Eur Respir J; 26: 319-338 Nici, L. et al on behalf of the ATS/ERS Pulmonary Rehabilitation Writing Committee, (2006). American Thoracic Society/European Respiratory Society Statement on Pulmonary Rehabilitation. Am J Respir Crit Care Med Vol 173. pp 1390-1413. Enright, S. (2003). Management of Respiratory Diseases in Porter, SB. (eds), Chapter 14. Tidy's Physiotherapy. BUTTERWORTH-HEINEMANN, London, P. 291-332. Satta, A., (2000). Exercise training in asthma. J Sports Med Phys Fitness; 40(4): 277-83. SIGN and BTS (2009). British Guideline on the Management of Asthma: A National Clinical Guideline. SIGN and BTS, London, 4-132, accessed from http://www.sign.ac.uk/guidelines/published/numlist.html on February 2, 2010 Singh, S., (2009). Incremental Shuttle Walking Test. The Australian Lung Foundation and Australian Physiotherapy Association available from http://www.pulmonaryrehab.com.au/welcome.asp accessed on February 2, 2010 Read More