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Asthma Epidemiology, Etiology, Pathophysiology and Management in the Current Scenario
Published in Suvardhan Kanchi, Rajasekhar Chokkareddy, Mashallah Rezakazemi, Smart Nanodevices for Point-of-Care Applications, 2022
Manu Sharma, Aishwarya Rathore, Sheelu Sharma, Kakarla Raghava Reddy, Veera Sadhu, Raghavendra V. Kulkarni
Asthma is one of the most common chronic lower respiratory diseases associated with airway hyper-responsiveness which results in recurrent episodes of wheezing, chest tightness, persistent cold and cough, breathlessness, etc. It is a major healthcare problem observed in both children and adults. The disease is non-communicable and greatly affects the quality of life of the patient. Worldwide 339 million people suffer from asthma and the high mortality rate is observed in the elderly and patients belonging to the low-/middle-income group [1]. Elderly patients have a high mortality rate because of poor diagnosis of the disease. Many elderly citizens confuse asthma symptoms with the signs of aging and end up with a severe asthmatic condition. Symptoms of asthma aggravate over time if they remain untreated for a long period of time. It is predicted by many healthcare professionals and researchers that the disease is likely to shoot up to 439 million patients by the end of 2025 [2].
Human Health Studies
Published in Barry L. Johnson, Impact of Hazardous Waste on Human Health, 2020
Direct action of inhaled toxicants (gases, solids, or liquid aerosols) on the lung can be acutely and chronically important to health (Metcalf and Williams, 1993). Environmental toxicants can cause damage to the lung and respiratory system, including irritation, necrosis and edema, fibrosis, and allergic responses. The most common effect of chemical substances on the respiratory tract is irritation. Toxicity can result from the irritant and/or corrosive properties of a chemical, which can be reversible, or can, in more extreme cases, cause permanent disability or death. Various materials can cause cellular damage (i.e., necrosis) (Metcalf and Williams, 1993). Breakdown of the epithelium leads to edema by allowing fluid to leak into the lungs. Fibrosis is a nonspecific inflammatory response of the alveolar wall. Physiologic changes include a decrease in lung volume, compliance, and diffusing capacity. Allergic diseases depend on the body’s immunologic response to environmental stimuli. In the case of asthma, the reaction is mediated by an immunoglobulin, immunoglobulin E (IgE). Asthma is characterized by reversible airway obstruction. Persons with asthma have hyper-responsive airways, which means that nonallergic stimuli (e.g., viral infection, irritants, cold air, exercise) also can produce asthma attacks.
Physiology of the Airways
Published in Anthony J. Hickey, Sandro R.P. da Rocha, Pharmaceutical Inhalation Aerosol Technology, 2019
Anthony J. Hickey, David C. Thompson
Spirometry is the measurement of the volume of air moving into or out of the airways. In this process, various ventilatory maneuvers are undertaken that permit an estimation of pulmonary volumes and capacities (Figure 2.6). Such measurements are valuable for diagnosis of airway disease because pathological conditions can modify specific pulmonary volumes. Definitions of the specific lung volumes are provided in Table 2.4. Measurements of lung volumes are generally normalized for a subject’s body size (weight, height, or surface area), age, and gender. This process permits a comparison with standardized or predicted lung volumes, thereby allowing identification of lung pathophysiologies using a simple procedure. Some examples of the way in which airway disorders alter lung volumes are described in the following. During an episode of airway obstruction (as in asthmatic bronchospasm), expiration of air is difficult, and air becomes trapped in the lower airways. This results in an increase in the residual volume and functional residual capacity and a decrease in vital capacity. In conditions that adversely affect respiratory muscles, such as poliomyelitis or spinal cord injuries, voluntary control of inspiratory or expiratory movement is diminished (or absent) and vital capacity is reduced.
Computational modelling of airflow in distal airways using hybrid lung model
Published in Mathematical and Computer Modelling of Dynamical Systems, 2023
Olusegun J. Ilegbusi, Adnan Islam, Anand P. Santhanam
The human airway is a branching structure that forms the pathway necessary for gas exchange between the body and the environment during respiration. Computational fluid dynamics (CFD) analysis for flow in the human airways requires the flow path of the airway in the respiratory tract constructed and discretized. This process poses a major challenge for CFD analysis as the human airway geometry varies widely in scale from the trachea to the terminal bronchioles. Inter-subject variability of airway structure, particularly curvature of the upper and middle airways, affects flow significantly [1,2]. These factors in addition to limitation of current imaging technology and computation intensity of resolving the entire airway structure have limited analysis of flow in the distal airways. The distal airways are defined as the non-cartilaginous airways characterized by internal diameter of less than 2 mm. The objective of this study is to develop a computationally cost-effective model embracing the entire airway tree from the trachea to the terminal bronchioles, for the analysis of airflow in human distal airways.
PM2.5 aggravates airway inflammation in asthmatic mice: activating NF-κB via MyD88 signaling pathway
Published in International Journal of Environmental Health Research, 2023
Lei Wang, Yanzhi Cui, Hu Liu, Jing Wu, Jie Li, Xiansheng Liu
Asthma is characterised by chronic allergic inflammation of the airway, and its significant clinic feature includes acute exacerbation, accompanied by cough, chest tightness and dyspnoea. The severity of asthma attack is correlated with the local PM2.5 pollution (Dougherty and Fahy 2009). The PM2.5 level in the environment is correlated with the emergency visits, the number of hospitalized children with asthma, and the deterioration of wheezing and dyspnoea (Ma et al. 2019). In addition, asthma incidence rate is correlated with increasing concentration of PM2.5 (Venkataramanan et al. 2019). Moreover, PM2.5 could aggravate asthma symptoms by affecting ROS levels in the mouse model of allergic asthma (Wang et al. 2019). However, the mechanism in which PM2.5 affects asthma remains unclear.
The combined effect of ambient ozone exposure and toxic air releases on hospitalization for asthma among children in Harris County, Texas
Published in International Journal of Environmental Health Research, 2018
Nnamdi C. Nnoli, Stephen H. Linder, Mary A. Smith, Gretchen L. Gemeinhardt, Kai Zhang
Asthma is a complex and chronic airway disorder characterized by variable and recurring symptoms, airway inflammation, intermittent airflow obstruction, and bronchial hyperresponsiveness (NHLBI 2007). The disease is characterized by chest tightness, shortness of breath, coughing, and wheezing (Hua et al. 1999). Coughing often occurs at night or early in the morning (NHLBI, 2007). Asthma is associated with significant morbidity, mortality, and health-care use (Akinbami et al. 2012; CDC, 2015). Asthma-related morbidity covers a spectrum from reduced physical activity, absent days at work/school, physician office visits, emergency care, and hospitalization (Paulu and Smith 2008).