肺炎.docx

肺炎.docx

《肺炎.docx》由会员分享，可在线阅读，更多相关《肺炎.docx（6页珍藏版）》请在冰豆网上搜索。

肺炎

Pneumonia

Pneumoniaisanacuteinfectionoftheparenchymaofthelung,causedbybacteria,fungi,virus,parasiteetc.PneumoniamayalsobecausedbyotherfactorsincludingX-ray,chemical,allergen.Itisthecommondiseaseinourcountry,2500000casesoccurannually,125000casesdieofthisdisease.Inagedorimmunocompromisedpatient（usingimmunosuppressiveagents,transplantation,diabetesmellitus,uremia,alcoholism）withpneumonia.Themortalityismuchhiger.

Pneumoniacanbeclassifiedbypathogenoranatomy.Accordingtothepathogenclassification,itismostusefultotreatthepatientsbychoosingconvenientantimicrobialagents.Indiagnosis,twoclassificationcanbecombinedaltogether.

Ⅰ.Classificationbypathogen

Microscopicexaminationinsiteofinfection（alveolar,bronchiorlung）,sputumculture,biopsyoflungtissuesareusefultoidentifierthepathogenoftheinfection.

1.Bacterialpneumonia

（1）AerobicGram-positivebacteria,suchasstreptococcuspneumoniae,staphylococcusaureus,GroupAhemolyticstreptococci.

（2）AerobicGram-negativebacteria,suchasklebsiellapneumoniae,Hemophilusinfluenzae,Escherichiacoli.

（3）Anaerobicbacteria.

2.Atypicalpneumoniaincludeslegionnaiespneumonia,MycoplasmalpneumoniaandChlamydiapneumoniaandects.

3.Fungalpneumoniae

Fungalpneumoniaiscommonlycausedbycandida.

4.Viralpneumonia

Viralpneumoniamaybecausedbyadenoviruses,respiratorysyncytialvirus,influenza,cytomegalovirus,herpessimplex.

5.Pneumoniacausedbyotherpathogen.

Rickettsias（afeverrickettsia）,chlamydiapsittaci,parasites,protozoa.

Ⅱ.Classificationbyanatomy

1.Lobar:

Involvementofanentirelobe.

2.Lobular:

Involvementofpartsofthelobeonly,segmentalorofalveolicontiguoustobronchi（bronchopneumonia）.

3.Interstitial

Ⅲ.Classificationbyacquiredenvironment

1.Communityacquiredpneumonia（CAP）

CAPreferstopneumoniaacquiredoutsideofhospitalsorextended-carefacilities.Streptococcuspneumoniaeremainsthemostcommonlyidentifiedpathogen.OtherpathogensincludeHaemophilusinfluenzae,mycoplasmapneumoniae,Chlamydophiliapneumoniae,Moraxellacatarrhalisandects.

2.Hospitalacquiredpneumonia（HAP）

HAPreferstopneumoniaacquiredinthehospitalsetting.EntericGram-negativeorganisms,S.aureus,Pneudomonasaeruginosa,ects.

Pneumococcalpneumonia

Pneumococcalpneumoniaisproducedbystreptococcuspneumoniae.Itisthemostcommonlyoccurringbacterialpneumonia.Patientshavethesymptomsofshakingchill,sharppain,cough,andblood-fleckedsputum.

Etiology,pathogenesisandpathology

Streptococcuspneumoniaareencapsulated,gram-positivecoccithatoccurinchainsorpairs.Thecapsulewhichisacomplexpolysaccharidehasspecificantigenicity.Atleast86differentimmunogenictypesexistbyserologictest.Type3isthemostvirulent,usuallycausingseverepneumoniainadults,buttype6,14,19and23arevirulentsischildren.Thepneumoniaisdirectlyproportionaltotheinnoculumsizeandvirulenceoftheorganisms,andinverselyrelatedtotheadequacyofpulmonaryhostdefenses.

Pathology

Onceasufficientinoculumofsufficientlyvirulentpneumococcihasreachedthealveoli,pneumoniadevelops,firstthereisalveolarcapillarycongestion,stageofcongestion,thanfluidpoursoutfromcapillariestofillthealveoli,spreadingtoadjacentalveoli.Thisinfectedtidecarriespneumococciintocontiguousareasuntilinflowisstoppedbyananatomicbarrier,usuallythevisceralpleurainvestingasegmentoralobeofthelung.Thisstageofpneumoniaiscalled“redhepatization”becauseoftheliver-like,reddishappearanceoftheconsolidatedlung.Afewhoursafterpulmonarycapillariesdilateandedemafluidpoursintothealveoli,polymorphnuclearleukocyteenterthealveolarspaces,rapidlyfillthealveoli,andconsolidatethelung（calledgreyhepatization）.Finally,macrophagesmigrateintotheconsolidatedalveoliandingestthedebrisleftbehindastheacuteinfectionresolves（calledresolution）.Allofthefourmainstagesoftheinflammatoryreactiondescribedabovemaybepresentatthesametime.Inmostcases,recoveryiscompletewithrestorationofnormalpulmonaryanatomy.In5%to10%ofpatients,infectionmayextendintothepleuralspaceandresultinanempyemaorin15%to20%ofpatients,bacteriamayenterthebloodstream（bacteremia）viathelymphaticsandthoracicdust.Invasionofthebloodstreambypneumococcimayleadtoseriousmetastaticdiseaseatanumberofextrapulmonarysites（meningitis,arthritis,pericarditis,endocarditis,peritonitis,otitismediaetc）.

Clincalmanifestation

Manypatientshavehadanupperrespiratoryinfectionforseveraldaysbeforetheonsetofpneumonia.Onsetusuallyissudden,halfcaseswithashakingchill.Thetemperaturerisesduringthefirstfewhoursto39-40℃.Thepulseaccelerates.Sharppainintheinvolvedhemithorax.Thecoughisinitiallydrywithpinkishorblood-fleckedsputum.Gastrointestinalsymptomssuchas,anorexia,nausea,vomiting,abdominalpain,diarrheamaybemistakenasacuteabdominalinflammation.

Signs

Theacutelyillpatientistachypneic,andmaybeobservedtouseaccessorymusclesforrespiration,andeventoexhibitnasalflaring.Feverandtachycardiaarepresent,frankshockisunusual,exceptinthelaterstagesofinfectionorDIC.Auscultationofthechestrevealsbronchovesicularortubularbreathsoundsandwetralesovertheinvolvedlung.Aconsolidationoccurs,vocalandtactilefremitusisincreased.

Complications

Complicationsarelessseenrecently.Ifsepsisoccurs,thepatientmaybecomedusky,cyanotic,confusedandshock.

1.sepsis

2.lungabscessorempyema

3.pleuraleffusion,pleuritis

4.ARDS,ARF

5.pneumothorax

6.Extrapulmonaryinfections

Laboratoryexamination

Theperipheralwhitebloodcell（WBC）countisoften10-30×109/L,of80%inthepolymorphonuclearleukocytes.However,inalcoholicsorimmunosuppressedpatients.ItmaybenormalorlowofmorevalueistheWBCdifferential,whichconsistspredominantlyofpolymorphonuclearleukocytes（leftshift）.Beforeusingantibiotic,thecultureofbloodof20%ispositive.Microscopicexaminationandcultureofexpectoratedpurulentsputumbetween24-48hourscanbeusedtoidentifypneumococci.Colonycountsofbacteriafrombronchoalveolarlavagewashingsobtainedduringendoscopyareseldomavailableearlyinthecourseofillness.UseofthePCRmayamplifypneumococcalDNAandimprovepotentialfordetection.

X-rayexamination

Chestradiographsrevealalobardistributionandanairspacepatternofdisease.Ifbluntingofthecostophrenicangleisnoted,thefindingisbelievedtorepresentaneffusion.

Diagnosisanddifferentialdiagnosis

Theclinicalpictureandradiographicfeaturesassociatedwith,itisnotdifficulttomakethediagnosis.

1.pulmonarytuberculosis

2.Othermicrobialpneumonias:

Klebsiellapneumonia,staphylococalpneumonia,pneumoniasduetoG（-）bacilli,viralandmycoplasmal.

3.Acutelungabscess

4.Bronchogeniccarcinoma

5.Pulmomaryinfarction

Treament

1.Antibiotictherapy

AllpatientswithsuspectedpneumococcalpneumoniashouldbetreatedaspromptlyaspossiblewithpenicillinG.Thedoseandrouteofdeliverymayhavetobeonthebasisofpatientsstatusadversereactionorcomplicationthatoccur.Forpatientswhoarebelievedtobeallergictopenicillin,onemayselectafirstorsecondgenerationcephalosporinorerythromycin,clindamycin,orafluoroquinolone.Treatmentwithanyeffectiveagentshouldbegivenforatleast5to7dayorafterthepatientshavebeenafebrilefor2-3days.

2.Supportivemeasure

Supportivemeasurearegenerallyusedintheinitialmanagementofacutepneumococcalpneumonia:

Suchmeasuresincludebedrest;monitoringvitalsignsandurineoutput;administeringanoccasionalanalgesictorelievepleuriticpain;replacingfluids,ifthepatientisdehydrated;correctingelectrolytes;oxygentherapy.Whenrelievingpleuriticpainorprovidingsedationinsituationsrequiringit,careshouldbetakentonotuseexcessivelyhighdosesofanalgesicsorsedativesthatmightdepresstherespiratorycenter.Ifpossible,antipyreticsshouldalsobeavoidedbecausetheseagentsinterferewiththeevaluationoffeverasameasurementofthepatient’sprogress,andcauseadehydration.

3.Treatmentofcomplications

Empyemadevelopsinappoximately5%ofpatientswithpneumococcalpneumonia,althoughpleuraleffusioncommonlydevelopin10%-20%patients.ChestX-raywithlateraldecubitusfilmsareoftenusefulintheearlyrecognitionofpleuraleffusion,pleuralfluidthatisremovedshouldbesubjectedtoroutingexamination.Ifpneumococcalbactermiaoccurs,extrapulmonarycomplicationssuchasarthritis,endocarditismustbeexcluded,becausetheirtherapyrequireshigherdosages.

4.Treamentofinfectionsshock

（1）Treatmentinintensivecareunits

（2）cardiacrhythm,bloodpressure,cardiacperformance,oxygendelivery,andmetabolicderangementscanbemonitored

（3）Adequateoxygenationandventilatorysupport（sometimesmechanicalventilation）

（4）Effectiveantibiotictherapy

（5）Maintainbloodpressure,includingmaintaincirculationbloodvolume,useofdopamine

5.Prognosis

Prognosisismuchbetter.Anyofthefollowingfactorsmakestheprognosislessfavorableandconvalescencemoreprolongedelderly;involvementof2ormorelobes;underlyingchronicdiseases（heartlungkedney）normaltemperatureandWBCcount<5000;immunodeficiencywithseverecomplication.

Prevention

Themostimportantpreventivetoolavailableisusingapolyvalentpneumococcalvaccineinthosewithchroniclungdiseases,chronicliverdiseases,splenectomy,diabetesmellitusa