肺炎.docx

1、肺炎PneumoniaPneumonia is an acute infection of the parenchyma of the lung, caused by bacteria, fungi, virus, parasite etc. Pneumonia may also be caused by other factors including X-ray, chemical, allergen. It is the common disease in our country, 2500000 cases occur annually, 125000 cases die of this

2、 disease. In aged or immunocompromised patient (using immunosuppressive agents, transplantation, diabetes mellitus, uremia, alcoholism) with pneumonia. The mortality is much higer.Pneumonia can be classified by pathogen or anatomy. According to the pathogen classification, it is most useful to treat

3、 the patients by choosing convenient antimicrobial agents. In diagnosis, two classification can be combined altogether.Classification by pathogenMicroscopic examination in site of infection (alveolar, bronchi or lung), sputum culture, biopsy of lung tissues are useful to identifier the pathogen of t

4、he infection.1. Bacterial pneumonia (1) Aerobic Gram-positive bacteria, such as streptococcus pneumoniae, staphylococcus aureus, Group A hemolytic streptococci. (2) Aerobic Gram-negative bacteria, such as klebsiella pneumoniae, Hemophilus influenzae, Escherichia coli. (3) Anaerobic bacteria. 2. Atyp

5、ical pneumonia includes legionnaies pneumonia, Mycoplasmal pneumonia and Chlamydia pneumonia and ects.3. Fungal pneumoniae Fungal pneumonia is commonly caused by candida.4. Viral pneumoniaViral pneumonia may be caused by adenoviruses, respiratory syncytial virus, influenza, cytomegalovirus, herpes s

6、implex.5. Pneumonia caused by other pathogen.Rickettsias (a fever rickettsia), chlamydia psittaci, parasites, protozoa.Classification by anatomy1. Lobar: Involvement of an entire lobe.2. Lobular: Involvement of parts of the lobe only, segmental or of alveoli contiguous to bronchi (bronchopneumonia).

7、3. Interstitial. Classification by acquired environment1. Community acquired pneumonia (CAP)CAP refers to pneumonia acquired outside of hospitals or extended-care facilities . Streptococcus pneumoniae remains the most commonly identified pathogen. Other pathogens include Haemophilus influenzae, myco

8、plasma pneumoniae, Chlamydophilia pneumoniae, Moraxella catarrhalis and ects.2. Hospital acquired pneumonia (HAP)HAP refers to pneumonia acquired in the hospital setting. Enteric Gram-negative organisms, S. aureus, Pneudomonas aeruginosa, ects.Pneumococcal pneumoniaPneumococcal pneumonia is produced

9、 by streptococcus pneumoniae. It is the most commonly occurring bacterial pneumonia. Patients have the symptoms of shaking chill, sharp pain, cough, and blood-flecked sputum.Etiology, pathogenesis and pathologyStreptococcus pneumonia are encapsulated, gram-positive cocci that occur in chains or pair

10、s. The capsule which is a complex polysaccharide has specific antigenicity. At least 86 different immunogenic types exist by serologic test. Type 3 is the most virulent, usually causing severe pneumonia in adults, but type 6,14,19 and 23 are virulents is children. The pneumonia is directly proportio

11、nal to the innoculum size and virulence of the organisms, and inversely related to the adequacy of pulmonary host defenses.PathologyOnce a sufficient inoculum of sufficiently virulent pneumococci has reached the alveoli, pneumonia develops, first there is alveolar capillary congestion, stage of cong

12、estion, than fluid pours out from capillaries to fill the alveoli, spreading to adjacent alveoli. This infected tide carries pneumococci into contiguous areas until in flow is stopped by an anatomic barrier, usually the visceral pleura investing a segment or a lobe of the lung. This stage of pneumon

13、ia is called “red hepatization” because of the liver-like, reddish appearance of the consolidated lung. A few hours after pulmonary capillaries dilate and edema fluid pours into the alveoli, polymorphnuclear leukocyte enter the alveolar spaces, rapidly fill the alveoli, and consolidate the lung (cal

14、led grey hepatization). Finally, macrophages migrate into the consolidated alveoli and ingest the debris left behind as the acute infection resolves (called resolution). All of the four main stages of the inflammatory reaction described above may be present at the same time. In most cases, recovery

15、is complete with restoration of normal pulmonary anatomy. In 5% to 10% of patients, infection may extend into the pleural space and result in an empyema or in 15% to 20% of patients, bacteria may enter the blood stream (bacteremia) via the lymphatics and thoracic dust. Invasion of the blood stream b

16、y pneumococci may lead to serious metastatic disease at a number of extra pulmonary sites (meningitis, arthritis, pericarditis, endocarditis, peritonitis, otitis media etc).Clincal manifestationMany patients have had an upper respiratory infection for several days before the onset of pneumonia. Onse

17、t usually is sudden, half cases with a shaking chill. The temperature rises during the first few hours to 39-40. The pulse accelerates. Sharp pain in the involved hemi thorax. The cough is initially dry with pinkish or blood-flecked sputum. Gastrointestinal symptoms such as, anorexia, nausea, vomiti

18、ng, abdominal pain, diarrhea may be mistaken as acute abdominal inflammation.SignsThe acutely ill patient is tachypneic, and may be observed to use accessory muscles for respiration, and even to exhibit nasal flaring. Fever and tachycardia are present, frank shock is unusual, except in the later sta

19、ges of infection or DIC. Auscultation of the chest reveals bronchovesicular or tubular breath sounds and wet rales over the involved lung. A consolidation occurs, vocal and tactile fremitus is increased.ComplicationsComplications are less seen recently. If sepsis occurs, the patient may become dusky

20、, cyanotic, confused and shock.1. sepsis 2. lung abscess or empyema3. pleural effusion, pleuritis4. ARDS , ARF5. pneumothorax6. Extrapulmonary infectionsLaboratory examinationThe peripheral white blood cell (WBC) count is often 10-30109/L, of 80% in the polymorphonuclear leukocytes. However, in alco

21、holics or immunosuppressed patients. It may be normal or low of more value is the WBC differential, which consists predominantly of polymorphonuclear leukocytes (left shift). Before using antibiotic, the culture of blood of 20% is positive. Microscopic examination and culture of expectorated purulen

22、t sputum between 24-48 hours can be used to identify pneumococci. Colony counts of bacteria from bronchoalveolar lavage washings obtained during endoscopy are seldom available early in the course of illness. Use of the PCR may amplify pneumococcal DNA and improve potential for detection.X-ray examin

23、ationChest radiographs reveal a lobar distribution and an air space pattern of disease. If blunting of the costophrenic angle is noted, the finding is believed to represent an effusion.Diagnosis and differential diagnosisThe clinical picture and radiographic features associated with, it is not diffi

24、cult to make the diagnosis.1. pulmonary tuberculosis2. Other microbial pneumonias: Klebsiella pneumonia, staphylococal pneumonia, pneumonias due to G (-) bacilli, viral and mycoplasmal.3. Acute lung abscess4. Bronchogenic carcinoma5. Pulmomary infarctionTreament1. Antibiotic therapyAll patients with

25、 suspected pneumococcal pneumonia should be treated as promptly as possible with penicillin G. The dose and route of delivery may have to be on the basis of patients status adverse reaction or complication that occur. For patients who are believed to be allergic to penicillin, one may select a first

26、 or second generation cephalosporin or erythromycin, clindamycin, or a fluoroquinolone. Treatment with any effective agent should be given for at least 5 to 7 day or after the patients have been afebrile for 2-3 days.2. Supportive measureSupportive measure are generally used in the initial managemen

27、t of acute pneumococcal pneumonia: Such measures include bed rest; monitoring vital signs and urine output; administering an occasional analgesic to relieve pleuritic pain; replacing fluids, if the patient is dehydrated; correcting electrolytes; oxygen therapy. When relieving pleuritic pain or provi

28、ding sedation in situations requiring it, care should be taken to not use excessively high doses of analgesics or sedatives that might depress the respiratory center. If possible, antipyretics should also be avoided because these agents interfere with the evaluation of fever as a measurement of the

29、patients progress, and cause a dehydration.3. Treatment of complicationsEmpyema develops in appoximately 5% of patients with pneumococcal pneumonia, although pleural effusion commonly develop in 10%-20% patients. Chest X-ray with lateral decubitus films are often useful in the early recognition of p

30、leural effusion, pleural fluid that is removed should be subjected to routing examination. If pneumococcal bactermia occurs, extra pulmonary complications such as arthritis, endocarditis must be excluded, because their therapy requires higher dosages.4. Treament of infections shock(1) Treatment in i

31、ntensive care units(2) cardiac rhythm, blood pressure, cardiac performance, oxygen delivery, and metabolic derangements can be monitored(3) Adequate oxygenation and ventilatory support (sometimes mechanical ventilation)(4) Effective antibiotic therapy(5) Maintain blood pressure, including maintain c

32、irculation blood volume, use of dopamine5. PrognosisPrognosis is much better. Any of the following factors makes the prognosis less favorable and convalescence more prolonged elderly; involvement of 2 or more lobes; underlying chronic diseases (heart lung kedney) normal temperature and WBC count 5000; immunodeficiency with severe complication.PreventionThe most important preventive tool available is using a poly valent pneumococcal vaccine in those with chronic lung diseases, chronic liver diseases, splenectomy, diabetes mellitus a