胡必杰肺炎.ppt

Dr.HU Bijie Respiratory Diseases Pneumonia Epidemiology 6th leading cause of death in U.S. Number one Among the infectious diseases 5.6 million patients annually in US Incidence 5~10/1,000/year Mortality in OPD patients 1-5 %, but Inpatients 25%, ICU 50-60% Definition Pneumonia is the inflammation of lower respiratory tracts including alveoli, interstitial tissues, and broncioles by the microorganisms, chemical irritations or by an immunological process Classifications Terminology Mild, moderate, severe Lobar vs interstitial Infections vs. noninfections Bacterial, viral, fungal, parasitic Primary vs. Secondary Community Acquired Pneumonia Nosocomial Pneumonia Ventilator Associated Pneumionia Typical vs. Atypical Immune compromised vs. Normal immunity Causative pathogens in 5,961 adults admitted to hospital with CAP identified in 26 prospective studies from 10 European countries Pathogens of Hospital Acquired Pneumonia (HAP) Mild to moderate HAP or early severe HAP Streptococcus pneumoniae Haemophilus influenza MSSA Klebsiella Pneumoniae Enterobacter, E coli, Proteus, Serratia Severe HAP Pseudomonas Acinetobacter MRSA Pneumococcal Pneumonia Etiology：S. pneumonia Gram-postive coccus most common identifiable cause of bacterial pneumonia and accounts for 2/3 of bacteremic CAP Pneumococcal pneumonia generally occurs sporadically but most frequently in winter It occurs most commonly in persons at age extremes. 5 to 25% of healthy persons are carriers of pneumococci, with the highest rates noted in winter for children and parents of young children. There are 80 serotypes (based on antigenically distinct capsular polysaccharides). Pathogenesis Host defenses impaired Inoculum sufficient to cause infection enters lower respiratory tract Virulent organism Pathogenesis Pneumococci usually reach the lungs by inhalation or aspiration. (Routes of entry for nosocomial pneumonia: Microaspiration, Inhalation, Hematogenous spread, Direct extension, Via ET tu