tailieunhanh - Acute Respiratory Infections in Children

Angina is the characteristic pain of IHD. It is caused by atherosclerosis leading to stenosis (partial occlusion) of one or more coronary arteries. Patients with chronic stable angina have an average annual mortality of 2 percent or less. Acute myocardial infarction (AMI) is the total occlusion of a major coronary artery with a complete lack of oxygen and nutrients leading to cardiac muscle necrosis. AMI is usually diagnosed by changes in the electrocardiogram; by elevated serum enzymes, such as creatine phosphokinase and troponin T or I; and by pain similar to that of angina. Thirty-day mortality after an AMI is high: even with best medical therapy it remains at about 33. | Chapter 25 Acute Respiratory Infections in Children Eric A. F Simoes Thomas Cherian Jeffrey Chow Sonbol Shahid-Salles Ramanan Laxminarayan and T. Jacob John Acute respiratory infections ARIs are classified as upper respiratory tract infections URIs or lower respiratory tract infections LRIs . The upper respiratory tract consists of the airways from the nostrils to the vocal cords in the larynx including the paranasal sinuses and the middle ear. The lower respiratory tract covers the continuation of the airways from the trachea and bronchi to the bronchioles and the alveoli. ARIs are not confined to the respiratory tract and have systemic effects because of possible extension of infection or microbial toxins inflammation and reduced lung function. Diphtheria pertussis whooping cough and measles are vaccine-preventable diseases that may have a respiratory tract component but also affect other systems they are discussed in chapter 20. Except during the neonatal period ARIs are the most common causes of both illness and mortality in children under five who average three to six episodes of ARIs annually regardless of where they live or what their economic situation is Kamath and others 1969 Monto and Ullman 1974 . However the proportion of mild to severe disease varies between high- and low-income countries and because of differences in specific etiologies and risk factors the severity of LRIs in children under five is worse in developing countries resulting in a higher casefatality rate. Although medical care can to some extent mitigate both severity and fatality many severe LRIs do not respond to therapy largely because of the lack of highly effective antiviral drugs. Some million children die each year Black Morris and Bryce 2003 . Estimates indicate that in 2000 million of them died because of ARIs 70 percent of them in Africa and Southeast Asia Williams and others 2002 . The World Health Organization WHO estimates that 2 million children under five die of