Overview Of Asthma, Its Mechanisms, Factors, Diagnosis And Treatment Options

Introduction

Asthma is a restrictive and obstructive pulmonary disorder characterized by chronic inflammation of the bronchi preventing the natural movement of air in and out of the lungs due to airway restriction. Asthma affects adults and children worldwide, making it the top respiratory disease in the United States. The purpose of this paper is to further discuss pathophysiological mechanisms of chronic asthma and acute asthma exacerbation and factors that may contribute to their manifestations, as well as how they are diagnosed and the proper treatments that follow.

Chronic Asthma

The pathologic feature of asthma is the inflammation of the airways resulting in hyper responsiveness of the immune response and the cause is a type I hypersensitivity immune response involving the activity of antigen, IgE, mast cells, eosinophils, and other inflammatory cells and mediators. Eosinophils play the main role in hyper-responsiveness they cause mast cell degranulation with the release of large numbers of inflammatory mediators such as histamine, prostaglandins, and leukotrienes. Interleukin-5, 8, and 13 stimulates the activation, migration, and proliferation of eosinophils, causing tissue injury, increased bronchial hyper-responsiveness, airway scarring, impaired muco-ciliary clearance resulting in hypersecretions respectively.

Acute Exacerbation

An acute asthma exacerbation, or “asthma attack” as it is commonly referred to, is an intensified state of the chronic condition and a temporary loss of disease control that progressively gets worse if not reversed. An acute exacerbation can be triggered by environmental factors such as allergens, smoke, chemicals, or bacterial and viral illness. During exacerbation, a person experiences chest tightness, expiratory wheezing, dyspnea, non-productive coughing, prolonged expiration, tachycardia, and tachypnea. The airway obstruction causes increased resistance to airflow and air trapping and hyperinflation occur distal to the obstructions resulting in severe dyspnea. Alveolar gas pressures increase causing perfusion to the alveoli to diminish and an imbalance occurs resulting in hypoxemia. Attempts are made to restore balance by inducing hyperventilation through the respiratory center, causing PaCO2 to decrease and pH to increase resulting in respiratory alkalosis. Eventually, if oxygen balance is not restored, the respiratory center efforts being to fail and carbon dioxide is retained off causing the pH to increase and the body takes an acidotic state and ultimately respiratory failure takes place.

Genetic Factors

Ethnicity has a large impact on the outcome of asthma. According to the American Lung Association, children of minority groups have substantially higher incidences of asthma exacerbations and mortality. African American children are twice more likely to have an acute exacerbation and require hospitalization than Caucasian children and sadly, four times more likely to die from them while Native American children are 6 times more likely. Families with socio-economic disparities may be exposed to more environmental irritants and may not have the education and resources to manage the disease as a whole.

Diagnosis

Diagnosing asthma starts with the symptoms that are being exhibited. If a child begins to have difficulty with physical activity, chronic coughing at bedtime, or sudden complaints of shortness of breath during peak allergy seasons-these could all be signs that lead a parent to contact their healthcare provider. A thorough history and physical exam should be obtained complete with family history of allergies or breathing disorders. Pulmonary function testing should also be done. Treatments The treatment of chronic asthma includes long term use of inhaled corticosteroids or leukotrienes. During an acute asthma exacerbation, an assessment of arterial blood gases, expiratory flow rates, and search for underlying triggers, such as infection or exposure to irritants. Oxygen should be administered along with inhaled beta-agonist bronchodilators and mechanical ventilation may be required if hypercapnia ensues and repeated peak flow rates should be done to determine the response to treatment.

Conclusion

Asthma affects various people all over and is a serious lung condition. It can quickly lead to a life threatening situation. Knowing how to properly diagnosis and treat asthmatic patients can aid in healthcare providers in the early intervention and prevention of acute asthma exacerbations. </p>