【傳染病學(xué)教案】(細(xì)菌性痢疾.英文教案

1、 重慶醫(yī)科大學(xué)臨床學(xué)院教案及講稿教 案課程名稱傳染病學(xué)2007留學(xué)生授課專業(yè)教 師職稱授課方式學(xué)時4題目章節(jié)shigella dysentery教材名稱無作者無出 版 社無版次無教學(xué)目的要求1、了解細(xì)菌性痢疾的發(fā)病機制，掌握細(xì)菌性痢疾的臨床表現(xiàn)，診斷要點及治療原那么。2、熟悉細(xì)菌性痢疾的流行病學(xué)特點及預(yù)防措施。教學(xué)難點細(xì)菌性痢疾的發(fā)病機制、臨床表現(xiàn)、鑒別診斷和抗菌與補液治療。教學(xué)重點細(xì)菌性痢疾的臨床表現(xiàn)、診斷、治療原那么。外語要求英語教學(xué)方法手段多媒體教學(xué)參考資料教研室意見 教學(xué)組長： 教研室主任： 年 月 日 講 稿教學(xué)內(nèi)容輔助手段時間分配1. General conditionDefini

2、tion: Shigellosis is an infectious disease caused by a group of bacteria called Shigella. Most who are infected with Shigella develop diarrhea, fever,vomit and stomach cramps starting a day or two after they are exposed to the bacterium.The site of infection is Intestinal tract infection; The bacter

3、ium is Shigella;It is transmitted Through food or water contaminated by feces.2. EtiologyThe bacterium is Gram -negative ,facultative anaerobic, rod bacterium,and is very similar to E.coli. Shigella survives in neutral pH, resistant to stomach acids;The temperature of survives depends on serotype.It

4、 can survive at 4C for 21 days in cheese, potato,salad and mayonnaise,and Can survive and grow at under 25 C for 50 days in flour, milk, eggs, shrimp, oysters, clams.There are 4 serogroups:A: S. dysenteriaeIt can cause most severe “Bacillary dysentery in developing countries in Africa, Latin America

5、 and Asia.B: S. flexneriIt can cause most common Shigella in developing countries;and becoming more common in developed countries.C: S. boydii(mostly Indian subcontinent)D: S. sonneiIt can cause Least severe in developed countries.(In china :B and D)3. EpidemiologyShigellosis is Worldwide, major cau

6、ses of diarrhea in the world, and there are 165 million cases/year (99% in developing countries) ,In ustralia: 2.6 cases/100,000 people;In Canada: 3 to 4 cases/100,000 people;In China: 2003; 39.4 cases/100,000 people. 5-15% of all cases of diarrhea are mostly kids less than 4 years old.there are 600

7、,000 to 1.1 million deaths/year.The source of infection are acute or chronic patients and carriers;The route of transmission is food or water contaminated by feces;The susceptibility are most people ,especially in children.Most people can acquire temporary immunity after infection. Shigella only inf

8、ects humans,and the doses of infectious is very low(200 organisms). Transmission is from primarily person-to-person (fecal-oral spread),and the outbreakis because of food and waterborne. Developed country:military bases,travelerDeveloping country:refugee camps,following natural disaster4. Pathogenes

9、isIn small intestine,it produces “Shiga-toxin wich is the 1st signs,and there is little reproduction like cholera,just water stools.In large intestine the Shigella Colonization,attaches, invades and multiplies in cells,and causes inflammatory response and cell death,then formes bloody mucus stools.P

10、athogenesis of toxic dysentery:The mechanism is unclear. It maybe relative to super-allergy reaction caused by endotoxin, particularly in children with special immunity.Toxic encephalopathy is responsible for death of children.5.Clinical manifestationThe incubation is range from 1 to 2 days (up to 7

11、 days)The duration is range from 4 days to 2 weeksClinical Signs: mild watery diarrhea or mucous stools was found in lots of clinical cases.severe dysentery:Abdominal pain, watery diarrhea, fever;Bloody stools with mucus, tenesmus Possibly dehydration, acidosis and death(mostly in the young, old, im

12、munocomprimised, malnourished)Clinical typeTypical dysentery:Suddenly onsetDiarrhea:water stool initially,then bloody purulent stools, 1020 times per day.Burning sensation at Anus- tenesmus,due to nerves of rectum being stimulated by local inflammation, a symptom characterized by incomplete sense of

13、 evacuation with rectal(anus) pain.Signs:Press-pain on the left inferior abdomenWhole body toxemia :chill ,fever, fatigue, headache,Cramping abdominal pain,especially in inferior abdomen.Moderate typeMild toxemia ,no significant fever sometimes.Without typical bloody purulent stools,the frequency of

14、 the stools is less than 10 times per day.Most cases can recover completely and the rest may be developed into chronic.Toxic dysentery Usually found in healthy children with 27 years old.Suddenly fever(400C) and serious toxemia.Toxinencephalopathy Mental disorder:sleepophillic,coma and constrictions

15、,resportory failure.Infectious shock:BP decrease, skin become cold, With progression, multiorgan failure involves the kidney, lungs, and liver; disseminated intravascular coagulation (DIC) and heart failure may also occur.Without diarrhea or abdomen pain usuallyThe possible complications of Shigello

16、sis:Intestinal perforation rarely occurs,septicemia,Reactive Arthritis-Reiters syndrome (after 2 weeks of Shigellosis) .Several joints are usually affected at onceespecially the knees.It also occurs after genital tract infection(such as gonorrhea).HUS: Hemolytic Uremic Syndrome(caused by S. dysenter

17、iae or EHEC-enterhemorrhagic E. coli O157)hemolytic anemia, thrombocytopenia and acute renal failure.Chronic type Having a past history of acute bacillary dysentery;Having recurrent or persistent abdominal pain, accompanied by diarrhea or alternation of diarrhea and constipation;Intermittent appeara

18、nce of mucopurulent and blood-stained stools. 6. Laboratory examinationHaematology: WBC1020X109/LStool test route: Bloody purulent appearance. Leukocytes can be found 15/HPBacteria culture:the dysentery bacillus of the culture is a golden standard of disease diagnosis.Early,frequently,freshly collec

19、t sample-can improve culture positive rate.7.DiagnosisEpidemic data (exposed to patients)Clinical feature(typical type)Laboratory findingsAiming to toxic dysentery, checking stools by digital rectal examination (DRE) or cold salt liquid enema is the most important diagnosis method.Differential diagn

20、osisAcute dysentery: Amebic dysentery.amebic dysenteryShigellosis General conditionmild，lower fever, toxemia unusually severe, high fever, toxemia usually Frequencyless, 210 times/daymore,1030 times/dayStool volumemore each time less each time Tenesmusmild or withoutObviously Site of press-pain righ

21、t inferior abdomenleft inferior abdomenStool appearancmore fecal and less watery,contain mucus ,like fruit paste with uncomfortable odors, less fecal, contain purulent and blood,without special odorStool under microscopeFewer WBC,More RBC,Special crystal More WBC, Fewer RBCStool cultureWithout Shige

22、lla Shigellatreatment metronidazolefluoroquinolones or 3rd cephalosporin (cefotaxime)Chronic dysentery: colitis,corndisease,tumor.Depend on colon endoscope.Toxic dysentery:encephalitis(such as encephalitis B).Toxic dysentery onset are more quickly than encephalitis B.Toxic dysentery accompanying wit

23、h circulation failure or shock.checking stools by cold salt liquid enema can provide valuable clue. 8.Treatment Acute dysenteryAntibiotics medication is very important.To severe cases , treatment with antibiotics can shorten the duration of the illness. and reduce the period of excretion of the orga

24、nism. To mild cases, treatment with antibiotics is rarely helpful. Selection of antibiotics:The first line medication should be quinolones,such as norfloxacin (0.4 tid for adult) or Ciprofloxacin(0.2 tid for adult) or Ofloxacin(0.2 tid for adult) .The duration is 35 days for typical cases.For severe

25、 cases, quinoidine or 3rd cephalosporin,such as Ceftriaxone or cefotaxime were chosen with vein route.Because of high drug-resistance and unsafety , sulphonamides or chloramphenicol were not recommended Rehydration treatment:Although dehydration is not a common feature of shigellosis infection, but

26、if it occurs or the stools are watery, patients should be given the oral rehydration salt (ORS) recommended by WHO /UNICEF(United Nations International Childrens Emergency Fund).In severe dehydration, intravenous fluids is recommended.However, clinical experience indicates that ORS is beneficial in

27、all cases of shigellosis if given as routine fluid intake. Symptomatic treatmentAbdomen pain :atropine 0.5mg ,Im;High fever or toxemia:dexamethasone (DXM).Shock :High effect and broad spectrum antibiotics ,Supply enough fluid intravenously.Drugs that constrict the blood vessels may be given to boost

28、 blood flow to the brain or heart(dopamine, 1020 g/kg/min).Glucocorticoids (reduce symptom of toxemia).Toxic bacillary dysentery,Antibiotics administer intravascularly.Anti-shock:Prevent and cure hydrocephalus,Dehydration with 20% mannitol 125ml-250ml,q412h ,Inhale oxygen,Keep respiratory function n

29、ormal.9. Shigellosis: PreventionA.Control the source of infection. Individuals excreting shigellae should be isolated early until negative cultures have been obtained from the stool specimens. (Carriers! ignore )Especially food handlersB.Cutting out the rout of transmission.All individuals exposed t

30、o patients of shigellosis should wash hand with soap and water.C.Vaccination?NO vaccine available in clinic up to now.Some tips for preventing the spread of shigellosisA.wash hands with soap carefully and frequently, especially after going to the bathroom, after B.changing diapers, and before prepar

31、ing foods or beveragesC.dispose of soiled diapers properly D.disinfect diaper changing areas after using them E.keep children with diarrhea out of child care settingsF.supervise handwashing of toddlers and small children after they use the toiletG.persons with diarrheal illness should not prepare fo

32、od for othersH.avoid drinking pool water10.Case reportPatient xxx ,female,25-year-old,mess steward, Suddenly onset 2 days ago with general malaise, chill ,fever ,fatigue ,headache and cramping abdominal pain ,especially in left inferior abdomen ,then followed diarrhea with water stool initially, and

33、 then bloody purulent stools, 1020 times per day ,accompanied with burning sensation at Anus- tenesmus. Five days ago this woman had nursed a diarrhea patient.PE：T 39.5，R 30/m，P 110/m，BP 110/80mmHg。Press-pain on the left inferior abdomenBlood test route: WBC 12.5109/L。Stool test route:WBC 5060/HP，RB

34、C2030/HP.Questions1.What disease is the patient suffered from?2.What is the principle of treatment for this patient? 3.How to prevent this disease?Discuss time!8minutes7minutes10minutes15 minutes30 minutes5 minutes10 minutes20 minutes30 minutes5 minutes10 minutes10 minutes小結(jié)Definition: Shigellosis i

35、s an infectious disease caused by a group of bacteria called Shigella. Most who are infected with Shigella develop diarrhea, fever,vomit and stomach cramps starting a day or two after they are exposed to the bacterium.The site of infection is Intestinal tract infection; The bacterium is Shigella;It

36、is transmitted Through food or water contaminated by feces.Etiology:The bacterium is Gram -negative ,facultative anaerobic, rod bacterium,and is very similar to E.coli. There are 4 serogroups: A: S. dysenteriae B: S. flexneri.C: S. boydii. D: S. sonneiClinical manifestation:The incubation is range f

37、rom 1 to 2 days (up to 7 days);The duration is range from 4 days to 2 weeks;Clinical Signs: mild watery diarrhea or mucous stools was found in lots of clinical cases.severe dysentery:Abdominal pain, watery diarrhea, fever;Bloody stools with mucus, tenesmus Possibly dehydration, acidosis and death(mo

38、stly in the young, old, immunocomprimised, malnourished).Laboratory examination:Haematology: WBC1020X109/L;Stool test route: Bloody purulent appearance. Leukocytes can be found 15/HP;Bacteria culture:the dysentery bacillus of the culture is a golden standard of disease diagnosis.Early,frequently,freshly collect sample-can improve culture positive rate.Diagnosis:Epidemic data (exposed to patients);Clinical feature(typ