SurgicalInfection外科感染.ppt

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1、Surgical InfectionDing Ding YueYue Department of Department of OrthopaedicOrthopaedic Surgery SurgerySecond Affiliated Hospital of Second Affiliated Hospital of SunYat-senSunYat-sen University University ParonychiaErysipelasGas gangreneDefinition Presence of infection that must be resolved by surgic

2、al procedure including the infection complicated with trauma,operation,burn or et al.The pathogens causing surgical infections are frequently mixed,and usually originate from the patients own endogenous flora.These pathogens are opportunistic,often depending on an acquired epithelial defect to cause

3、 infection.ClassificationAccording to pathogensn n Nonspecific infectionn n Specific infectionAccording to coursen n Acute infection 2MAccording to origination of pathogensn n Endogenous infection (viscus)n n Exogenous infectionOther classificationn n Primary infection n n Secondary infectionn n Opp

4、ortunistic infectionn n Surperinfectionn n Nosocomial infection(from hospital)Bacterial Factors:n n The deposition and growth of bacteria within wounds are a prerequisite for the development of infection.n n The kind and number of bacteria contribute to the establishment of infection.Studies of trau

5、matic wounds in healthy subjects have shown that bacterial contamination with more than 105 organisms frequently causes infection.The development of infection is also affected by the toxins produced by the organism and the organisms ability to resist phagocytosis and intracellular destruction.n n Gr

6、amnegative bacteria have surface components(endotoxin or lipopolysaccharide)that are toxic.n n Grampositive bacteria produce powerful exotoxins.Syndromes of the inflammatory responsen n Systemic inflammatory response syndrome(SIRS)n n Septicaemian n Sepsisn n Septic shock SIRS:The essential clinical

7、 findings were an abnormal body temperature,tachycardia,tachypnea,and an aberrant white blood cell count.Sepsis:is the circumstance of a patient with findings consistent of SIRS and a documented infection.Severe sepsis:is defined as occurring when a patient with sepsis has critical organ dysfunction

8、 and hypoperfusion including hypotension.Septic shock:is the most serious clinical problem and exists if a patient has severe sepsis,is resuscitated appropriately with intravenous fluid infusion,and remains in shock.Death rate:n n SIRS 7%n n Sepsis 16%n n Severe sepsis 20%n n Septic shock 46%Sepsis,

9、severe sepsis,and septic shock can be further divided into subsets of confirmed infection and suspected infections unconfirmed by positive culture.Culturesepsis+Severe sepsis+Septic shock+SubclassificationSystemic inflammatory response syndromePathophysiology:n n The pathophysiology is complex and i

10、nvolves all of the multiple interlacing and interacting systems that are involved in inflammation and the response to an immune or perfusion challenge.n n These systems include,but are not limited to,complement,cytokine cascades,arachidonic acid metabolites,cellmediated immunity,the clotting cascade

11、and hormonal immune m e c h a n i s m s.Diagnosis of SIRSBody temperature38,or 90 bpmBreath20/min,or PaCO2 12109/L,or 10%S e p s i sCauses:n n Suspect intravenous(IV)line infections when other sources of sepsis are eliminated and the IV line has been in for,usually,more than a week.n n Central IV l

12、ines are the lines most commonly associated with bacteremia or s e p s i s.n n Patients with an intraabdominal or pelvic source of infection usually have a history of antecedent conditions predisposing to perforation or abscess.n n The urinary tract source is suggested by an antecedent history of py

13、elonephritis,stone disease,congenital abnormal collecting system,prostate enlargement,and previous prostate or renal surgery.n n Patients with diabetes,systemic lupus erythematosus(SLE),alcoholism,or who are taking steroids also are at increased risk for bacteremia.Patients who are hypothermic at th

14、e onset of sepsis or septic shock had a poor prognosis.Patients with a core body temperature below 35.5 had a higher death rate(62%)than patients with sepsis syndrome whose body temperature was normal or elevated(23%).Organ failure develop among patients who experience progressive deterioration in o

15、rgan function that begins within hours of successful reversal of the initial event.After an episode of acute disruption of homeostasis,dysfunction and failure of one or more of the following organ systems occurs:respiratory,renal,hepatic,cardiovascular,hematologic,neurologic,o r G I.TreatmentTreatme

16、nt of the infection The treatment of sepsis,septic shock begins with prompt treatment of the infection site.To be effective,the proper antibiotics must be administered in adequate doses to achieve cytotoxic levels for invading organisms.Medical caren n Offer supportive therapy aimed at maintaining o

17、rgan perfusion.n n Provide respiratory support,when necessary.Fungal infection Pathogens from the Candida genus,may be seen frequently as an opportunistic invader in patients with serious surgical infections who have received broadspectrum antibiotic treatment suppressing normal e n d o g e n o u s

18、f l o r a.These infections are best avoided through judicious use of systemic broadspectrum antibiotics and through prophylaxis with oral nystatin or ketoconazole when broadspectrum antibacterial therapy is required.Treatment Surgical patients with fungal colonization of multiple sites or with fungi

19、 in welldrained abscesses have been managed successfully with total doses of Amphotericin ranging from 3 to 5 mg per kg administered over 10 to 14 days for a total dose of 300 to 500 mg.TetanusConception A disease caused by tetanospasmin,a powerful protein toxin produced by Clostridium Tetani.Tetanu

20、s usually occurs after an acute injury,such as a puncture wound or laceration.Etiology and Pathophysiology:n n Tetanus results from infection with C tetani,a mobile,sporeforming,anaerobic,grampositive bacillus.This bacillus is found in or on soil,manure,dust,clothing,skin,and 1025%of h u m a n G I t

21、 r a c t s.n n The spores need tissue with the proper anaerobic conditions to germinate;the ideal medium is wounds with tissue necrosis.n n Under anaerobic conditions,the spores germinate and produce 2 toxins:Tetanolysin(a hemolysin with no recognized pathologic activity)and Tetanospasmin.The action

22、 of the latter helps explain the clinical manifestations of the disease.n n Tetanospasmin is synthesized as a single chain and is cleaved to generate toxins with 2 chains joined by a single disulfide bond.The heavy chain is responsible for specific binding to neuronal cells and for protein transport

23、The light chain blocks the release of neurotransmitters.n n The toxin binding may be irreversible;recovery depends on the sprouting of new axonal terminals.n n Once the toxin is synthesized,it moves from the contaminated site to the spinal cord in 214 days.When the toxin reaches the spinal cord,loc

24、alized or cephalic tetanus may occur initially,followed by generalized tetanus.History:n n Most cases occur in patients with a history of only partial immunization.Persons who inject drugs also constitute a highrisk group.Symptom:n n Symptoms usually begin 8 days after the infection,but onset may ra

25、nge from 3 days to 3 weeks.n n Patients may report a sore throat with dysphagia(early sign).n n Localized tetanus causes muscle rigidity at the site of spore inoculation.n n The initial manifestation may be local tetanus,in which the rigidity affects only 1 limb or area of the body where the clostri

26、diumcontaining wound is located.Physical examination:n n Common first signs of tetanus are headache and muscular stiffness in the jaw(ie,lockjaw),followed by neck stiffness,difficulty swallowing,rigidity of abdominal muscles,spasms,and s w e a t i n g.n n Patients often are afebrile.n n Severe tetan

27、us results in opisthotonos,flexion of the arms,extension of the legs,periods of apnea resulting from spasm of the intercostal muscles and diaphragm,and rigidity of the abdominal wall.n n Late in the disease,autonomic dysfunction develops,with hypertension and tachycardia alternating with hypotension

28、 and b r a d y c a r d i a.OpisthotonosDiagnosis:Depend on clinical findings,Laboratory findings are not diagnostically valuable.Differentiation:n nTardive Dystonian n Strychnine poisoningn nDental infectionsn nLocal infectionsn nHysterian nNeoplasmsn nEncephalitis Complicationsn n Spasm of the voca

29、l cords and/or spasms of the respiratory muscles that cause interference with breathing .n n Fractures of the spine or long bonesn n Hypertensionn n Abnormal heartbeatsn n Coman n Generalized infectionn n Pneumonian n DeathTreatment Passive immunization with human tetanus immune globulin(TAT)shorten

30、s the course of tetanus and may lessen its severity.A dose of 1500 U appears as effective as larger doses.The goals of pharmacotherapy are to prevent complications and to reduce m o r b i d i t y.Gas gangreneConception:A clostridial infection typically involves underlying muscle,is also termed clost

31、ridial myonecrosis.An anaerobic,grampositive,sporeforming bacillus of the genus Clostridium causes gas gangrene.The most common organisms are C.perfringens,C.novyi,and C.septicum.Etiology and pathophysiology These organisms are in soil,dust,and isolated from the GI tract and the female genital tract

32、Clostridia are obligate anaerobes,but some species are relatively aerotolerant.Other bacteria capable of producing gas,and nonclostridial organisms have been isolated in 6085%cases of gas gangrene.C perfringens produces at least 20 exotoxins.The important exotoxins and their biologic effects are as

33、 follows:n n Alpha toxin Lethal,*lecithinase,necrotizing,hemolytic,cardiotoxic n n Beta toxin Lethal,*necrotizing n n Epsilon toxin Lethal,*permease n n Iota toxin Lethal,*necrotizing n n Delta toxin Lethal,*hemolysin n n Phi toxin Hemolysin,cytolysin n n Kappa toxin Lethal,*collagenase,gelatinase,n

34、ecrotizing n n Lambda toxin Protease n n Mu toxin Hyaluronidase n n Nu toxin Lethal,*deoxyribonuclease,hemolytic,necrotizing n n *Lethal as tested by injection in mice Anatomically,these infections are marked by a layer of necrotic tissue,which is not walled off by a surrounding inflammatory reactio

35、n and thus does not present a clear boundary.Symptom:n n Sudden onset of pain is usually the first symptom.The pain gradually increases in severity but spreads only as the underlying infection spreads.n n Patients sometimes report a feeling of heaviness in the affected extremity.n n A lowgrade fever

36、 and apathetic mental status may develop.These infections are marked by the absence of clear local boundaries or palpable limits.This lack of clear boundaries accounts both for the severity of the infection and for the frequent delay in recognizing its surgical nature.Physical examination:In additio

37、n,the overlying skin has a relatively normal appearance in the early stages of infection,and the visible degree of involvement is substantially less than that of the underlying tissues.Rapid progression of a soft tissue infection,a failure to respond to conventional nonoperative therapy may be the e

38、arliest signs of a necrotizing soft tissue infection.Tachycardia disproportionate to body temperature is common,and the patient may report a feeling of impending doom.Late signs include hypotension,renal failure,and a paradoxical heightening of mental acuity.In summary,the typical signs and symptoms

39、 of gas gangrene are severe pain and tenderness,local swelling to massive edema,skin discoloration with hemorrhagic blebs and bullae,crepitus,fever,relative tachycardia,and altered mental status.Diagnosis:n n Clinical findingsn n A Gram stain of the exudate or infected tissues reveals large gramposi

40、tive bacilli without neutrophils.Differentials:n nNecrotizing fascitisn nNonclostridial crepitant cellulitis/mycosisn nClostridial necrotizing fascitis Complicationsn n Massive hemolysisn n Disseminated intravascular coagulation(DIC)n n Acute renal failuren n Acute respiratory distress syndromen n S

41、hockTreatment The combination of aggressive surgical debridement and effective antibiotic therapy is the determining factor for successful treatment of this lifethreatening infection.Surgical caren n Fasciotomy for compartment syndrome may be necessary immediately and should not be delayed in patien

42、ts with extremity involvement.n n Perform daily debridement as needed to remove all necrotic tissue.n n Amputation of the extremity may be necessary and lifesaving.n n Abdominal involvement requires excision of the body wall musculature.n n Uterine gas gangrene following septic abortion usually nece

43、ssitates hysterectomy.Acquired Immunodeficiency Syndrome(AIDS)AIDS continued to increase as a result of unsafe sexual practices and in recipients of blood products.Classifications of AIDSStage Stage Proliferation of virus in blood and lymph Proliferation of virus in blood and lymph nodes;nodes;seroc

44、onversionseroconversion illness that resolves illness that resolvesStage Stage Early immune deficiency (CD4 count,Early immune deficiency (CD4 count,500/l),asymptomatic.500/l),asymptomatic.Stage Stage Intermediate immunodeficiency(CD4 count,Intermediate immunodeficiency(CD4 count,500200/500200/ll),)

45、immunosuppressionimmunosuppression appear.appear.Stage Stage Advanced immune deficiency(CD4 count,Advanced immune deficiency(CD4 count,200/l),infection and malignancy appear.200/l),infection and malignancy appear.The initial clinical presentation may include fever,perspiration,malaise,myalgia,arthr

46、algia,headache,and sore throat.n n Gastrointestinal symptoms,low abdominal cramping,weight loss,diarrhea,tenesmus,proctalgia,and the bleeding.n n Abnormal liver function.n n Opportunistic infection include Pneumocystis cainii,toxoplasmosis,cryptosporidiosis,isoporiasis,and the fungal infection.n n C

47、ytomegalovirus(CMV)infection.n n Malignancy,such as Kaposis sarcoma and nonHodgkins lymphoma.General Principles Of TreatmentAntibiotics:n n Penicillinsn n Cephalosporinsn n Monobactamsn n Carbapenemsn n Quinolonesn n Aminoglycosidesn n Antianaerobesn n Macrolidesn n Tetracyclinesn n Glycopeptidesn n

48、 Streptograminsn n Oxazolidinones Prophylactic systemic antibiotics reduce infection with clinical benefit in the following circumstances:Prophylactic systemic antibiotics n n Highrisk gastroduodenal procedures n n Highrisk biliary procedures n n Resection and anastomosis of the colon or small intes

49、tine n n Cardiac procedures through a median sternotomy.n n Vascular surgery of the lower extremities or abdominal aorta.n n Amputation of an extremity with impaired blood supply,particularly in the presence of a current or recent ischemic ulcer.n n Vaginal or abdominal hysterectomy.n n Primary cesa

50、rean section.n n Operations entering the oral pharyngeal cavity in continuity with neck dissections.n n Craniotomy.n n The implantation of any permanent prosthetic material.n n Any wound with known gross bacterial contamination.n n Accidental wounds with heavy contamination and tissue damage.n n Inj