医学英语课件资料：Anthrax in ER

1、AnthraxBy Emergency Specialist: IN ERFrameworkBasic informationStructuresGeneral symptomsEpidemiologyPathogenesisDiagnosisHistory & examinationTestsTreatmentMild cutaneous diseaseInhalational or GI or severe cutaneous diseaseMeningo-encephalitisPreventionPrimary preventionSecondary preventionPrognos

2、isHistory & examinationTestsThe Fundamental AreaBasic Information for AnthraxBacillus anthracisclassification: Inhalational, GI, cutaneous anthraxPernicious, easy spreading, Strong survivabilityspore-forming, long-timeWorld-wide, especially in Asia, South America General symptoms: Heat, shock, hypot

3、ension, and sudden death; Carbon-like tissues, ulcer, abscessus Hematosepsis, pneumonia, encephalitisCutaneous anthraxPhotos source: https:/wiki/AnthraxStructuresLarge size of cell bodyL: 510mW:13mGram -Rod-shape, Special flats at the endsNo flagella, no motivationAmphimicrobian, or aerobic( Spore f

4、ormation in oxygen rich)Line as bamboo, long-chain in vitro, short-chain in vivoNo capsula in vitro but in vivoStructures Antigen structures:CapsulaCell bodyProtective antigen( part of toxin)Spores( target for diagnosis)Structures EpidemiologyAnimals: come into contact with or ingest the spores.Huma

5、n: in contact with animals or their products.( include the excreta and waste of animals)cutaneous anthrax cause 95% human infection. by skin exposureInhalational and Gastrointestinal anthrax rare in human influence. by inhaling or intakingEpidemiologysusceptible population: Those who work or live wi

6、th animals or animals productThey touch, inhale, intakePathogenesis秦立楠 201201061Humans become infected incidentally by contact with infected animals or their products.In animals, the portal of entry is the mouth and the gastrointestinal tract. Spores from contaminated soil find easy access when inge

7、sted with spiny or irritating vegetation.Human InfectionInjured skin (cutaneous anthrax)Mucous membrane (gastrointestinal anthrax): rarelyInhalation into lung (inhalation anthrax)ProcessThe spores germinate in the tissue at the site of entry.Growth of the vegetative organisms results in formation of

8、 a gelatinous edema and congestion. Bacilli spread via lymphatics to the bloodstream.They multiply freely in the blood and tissues shortly before and after the animals death.Pathogenesis factorCapsule The capsule is composed of poly-D-glutamic acid, which can protect the capsule from phagocytosis. B

9、 anthracis isolates that do not produce a capsule are not virulent and do not induce anthrax in test animals.Pathogenesis factorAnthrax toxin PA: Protective antigen EF: Edema factor LF: Lethal factorPAPA binds to specific cell receptors, and after proteolytic activation, it forms a membrane channel

10、that mediates entry of EF and LF into the cell.EF EF is an adenylate cyclase; with PA, it forms a toxin known as edema toxinLFLF plus PA form lethal toxin, which is a major virulence factor and cause of death in infected animals and humansUnfortunatelyThe exact mechanism of action of both toxins is

11、not entirely clear.GenomepXO1: anthrax toxinpXO2: capsuleDiagnosis & Treatment江宁 201201064FrameworkDiagnosisHistory & examinationTestsTreatmentMild cutaneous diseaseInhalational or GI or severe cutaneous diseaseMeningo-encephalitisDiagnosisHistory & examinationEnvironmental exposure is the strongest

12、 risk factor.Animals & animal products (wool, animal hides, etc)Symptomsnecrotic skin lesions Oedema (Painless)Influenza-like illnessRespiratory symptomsOropharyngeal ulcerationCutaneousInhalationalPainless or pruritic papule or pustuleVesicular or ulcerative lesionBlack escharGastrointestinalEnviro

13、nmental exposure: the strongest risk factor.Animals & animal productsWorkers who are exposed to dead animals and animal productsInhalation anthrax & wool sorterDiagnosisHistory & examinationEnvironmental exposure is the strongest risk factor.Animals & animal products (wool, animal hides, etc)Symptom

14、snecrotic skin lesions Oedema (Painless)Influenza-like illnessRespiratory symptomsOropharyngeal ulcerationCutaneousInhalationalPainless or pruritic papule or pustuleVesicular or ulcerative lesionBlack escharGastrointestinalDiagnosisWBC countelevated above laboratory normsWound Gram stain and culture

15、gram-positive bacilli in short chains; flat, non-haemolytic mucoid colonies on 5% sheeps blood agarChest X RayEssential in all suspected casesInhalational or systemic B anthracis infectionBlood Gram stain and cultureEssential in all suspected casesWorks well in prior casesCutaneous anthrax suspected

16、Wound Gram stain and culture: Best diagnostic tool of cutaneous anthraxSampling the skin lesionSensitivity is limited (60% to 65%), usually due to prior antibiotic use in infected patientsBlood cultures highly recommendedInhalational anthrax suspectedChest x-ray often pathognomonic: widened mediasti

17、num with pleural effusions, without infiltrates.Late in the course of infection, Gram stain of bloodOnly vegetative, encapsulated bacilli are present in tissues during infection, typically spores are not seenGI(Gastrointestinal) anthrax suspectedExceedingly rareCultures of blood, peritoneal fluid, o

18、r oropharyngeal secretionsMeningo-encephalitisLumbar punctureHaemorrhagic cerebrospinal fluid characterised by neutrophilic pleocytosisBlood Gram stain and cultureTreatmentmild cutaneous diseaseinhalational or GI or severe cutaneous diseasemeningo-encephalitisMild cutaneous diseaseOral antimicrobial

19、 drugsQuinolonesDoxycyclineAntibiotic sensitivity data helpQuinolonea family of synthetic broad-spectrum antibacterial drugsBlock bacterial DNA synthesisKilling G(-) bacteria by inhibiting topoisomerase II (DNA gyrase)Killing G(+) bacteria by inhibiting topoisomerase IVInhalational or GI or severe c

20、utaneous diseaseIntravenous antibiotic therapy is warrantedInitial therapy with two or more agents is reasonableModify the regimen once culture susceptibility data are availableMeningo-encephalitisIntravenous antibiotic treatment with three or more agentsGood CNS penetration is essential (Doxycyclin

21、e should not be used)Prevention & Prognosis钱龙201201016PreventionPrimary preventionSource of infectionPathway of infectionSusceptibleSecondary preventionPost-exposure prophylaxis (PEP) Primary preventionSource of infection A disease of herbivores (食草动物)AnimalPatientEmergency Plan Quarantine and Inoculation & Control measures (检疫) (接种)Primary preventionPathway of infectionInjury cutaneous anthraxMucous membrane gastrointestinal anthrax (rare)Inhalation inhalation anthraxSusceptibleWho are at risk?People Who Handle Animal ProductsVeterina