Bronchial Asthma PDF

Bronchial Asthma BY Dr. Haggagy Mansour Lecturer of Chest Diseases South-Vally University  Definition: Asthma is a heterogenous disaese , usually characterized by chronic airway inflammation. It is defined by the history of respiratory symptoms such as wheezing, shortness...

Bronchial Asthma BY Dr. Haggagy Mansour Lecturer of Chest Diseases South-Vally University  Definition: Asthma is a heterogenous disaese , usually characterized by chronic airway inflammation. It is defined by the history of respiratory symptoms such as wheezing, shortness of breath , chest tightness, and coughing, particularly at night or in the early morning. These episodes are usually associated with widespread but variable airflow obstruction that is often reversible either spontaneously or with treatment. Epidemiology The exact prevalence of asthma worldwide is unknown because of historic differences in definition, diagnostic criteria, and methods of data collection. The International Study of Asthma and Allergies in Children (ISAAC) and the European Community Respiratory Health Survey (ECRHS) have been monitoring the prevalence of asthma worldwide and have reported an increase since the 1960s, with significant variation between countries. Risk Factors: HOST FACTORS: Genetic predisposition  Atopy  Airway hyper-responsiveness  Gender  Race/ethnicity Genetic factors: The risk of having an asthmatic child is greater if both parents have the disease than if one does, and greater if one has it than if neither does. Recent studies , in which atopy has been defined in terms of one or more positive skin tests, positive specific IgE or raised total IgE levels, have produced somewhat contradictory results. Atopy: The production of abnormal amount of IgE antibodies in response to contact with environmental allergen. Airway hyper-responsiveness:: A state in which the airways narrow too easily & too much in response to a provoking stimuli. The interpretation of spirometry: Improvement in symptoms and in spirometry 20 minutes after a bronchodilator is administered (200 μg inhaled salbutamol or 2.5 mg of nebulized salbutamol) is diagnostic of asthma if the FEV1 increases by at least 15% of the baseline value or by more than 200 ml. Spirometry values are also used to establish the severity of asthma, which determines the management.  Spirometry and lung function tests may be normal in patients with mild asthma in between exacerbations and in those with cough‐variant asthma. Exercise can also be used to provoke airway hyperresponsiveness. Exhaled NO levels are increased in patients with asthma and bronchiectasis but will be normal in VCD and hyperventilation, so can be useful in differentiating between these conditions. Thank You