2. Bacillary Dysentery (shigellosis) Dept. Of Infectious Disease Huang Fen

3. Definition Acute infectious disease of intestine caused by dysentery bacilli Place of lesion: sigmoid & rectum Pathological feature: diffuse fibrious exudative inflammation

4. Definition Clinical manifestation: fever, abdominal pain, diarrhea, tenesmus, stool mixed with mucus blood, & pus. even companied with shock and toxic encepholopthy.

5. Etiology Causative organism: dysentery bacilli, genus shigellae, gram-stain negative, short rod, non-motile Groups: 4 serogroups 47 serotypes S. Dysenteriae the most severe

6. Etiology S. Flexneri the epidemic group and easily turn to chronic S. Boydii tropical areas S. sonnei the most mild

7. Etiology Pathogenicity: - virulence endotoxin - interotoxin (exotoxin) - invasiveness (attach-penetrate-multiply) Resistance: Strong, 1-2week in fruits,vegetable and dirty soil, heat for 60 ℃ 30 min

8. Epidemiology Source of infection: patients and carriers Route of transmission: fecal-oral route Suceptibility of population: immunity after infection is short and unsteady, no cross-immune

9. Epidemiology Epidemic features: season: summer & fall Flexneri, Soneii, age: younger children

10. Pathogenesis number of bacteria pathogenicity  toxicity  invasiveness attachment penetration multiplication immunity

11. common Bacteria intestine normal intestinal flora sIg A prevent attaching penetrate mucus multiply in epithelia cell & proper lamina endotoxin interotoxin endogenous pyrogen fever inflammation vessel contraction superficial mucosal necrosis and ulcer diarrhea mixed with blood & pus, abdominal pain

12. Pathogenesis - toxic strong - allergy to endotoxin demethyl-adrenaline micro-circulatory failure shock, DIC, cerebral edema cerebral hernia

13. Pathology site of lesion: entire colon -sigmoid & rectum feature: acute: diffuse fibrinous exudative inflammation, hyperemia, edema, leukocyte infiltration, necrosis, superficial ulceration.

14. Pathology chronic: edema, ulceration, polypoid hyperplasia, toxic: hyperemia, edema,

15. Clinical manifestation Incubation period: 1-2 day, (hours to 7 days) Acute dysentery common type mild type toxic type

16. Clinical manifestation  common type: acute onset, shiver, high fever abdominal pain diarrhea: stool mixed with mucus, blood & pus tenesmus,

17. Clinical manifestation  mild type: caused by S. sonnei low fever or no fever abdominal pain is mild stool mixed with mucus, without blood & pus diagnosis by isolation bacteria

18. Clinical manifestation  toxic type: age: 2 to 7 yrs. abrupt onset, high fever, T> 40 o C convulsion repeatedly, altered consciousness circulatory & /or respiratory collapse diarrhea mild or absent at beginning

19. Clinical manifestation shock form: septic shock brain form: listlessness,lethargy,convulsion, coma. respiratory failure mixed form

20. Clinical manifestation chronic dysentery: > 2 months chronic delayed type chronic obscure type acute attack type

21. Clinical manifestation  chronic delayed type: long-time diarrhea and repeated  chronic obscure type: acute history in 1 year, no symptoms, stool culture positive or sigmoidscopy  acute attack type: same as common acute dysentery

22. Laboratory Findings Blood picture: WBC count increase, neutrophils increase Stool examination: direct microscopic examination: WBC, RBC, pus cells

23. Laboratory Findings bacteria culture: PCR :DNA Serologic examination: Sigmoidoscopy: chronic patients shallow ulcer scar polyp

24. Diagnosis  Epidemiologic data: contact history  Clinical manifestation:  Laboratory findings:

25. Differential diagnosis acute dysentery amebic dysentery Entamoeba histolytica stool: reddish brown, like jam flask-shaped ulcer, amebic trophozoite

26. Differential diagnosis enteritis caused by E. Coli, salmonella, virus. intussusception: jam-like stools, abdominal mass absence of fever

27. Differential diagnosis chronic dysentery rectal & colonic carcinoma: no cure for long-term, drop of weight of body non-specific ulcer colitis: no cure for long-term, culture of stool is negative,

28. Differential diagnosis sigmoidoscopy: hemorrhage, ulcer, X-ray : lead pipe. chronic schistosomiasis Japonica contact with the contaminated water hepatomegaly and splenomegaly founding the ovum of schistosomiasis

29. Differential diagnosis toxic dysentery encephalitis B: high fever,convulsion,coma. <24h circulatory failure stool examination CSF meningeal irritation specific IgM

30. Treatment Common dysentery  general treatment: isolation diet fluid and electrolyte  pathogenic treatment: norfloxacin 0.2~0.4 q6h po 5~7d Ampicillin given by po or iv Getamycin

31. Treatment  symptomatic treatment: Toxic dysentery general treatment pathogenic treatment: L-ofloxacin: 0.2 bid ivdrop cefotaxime: Ampicillin :

32. Treatment symptomatic treatment: control of high fever,convulsion: subhibernation treatment of shock: 654-2: 1- 2mg/kg treatment of cerebral edema: 20% mannitol respiratory failure

33. Treatment chronic dysentery general therapy: live, avoid overwork exercise diet

34. etiologic therapy: sensitive antibiotics, according to results of culture used in turn or combined use enema. Treatment

35. Prevention Control the source of infection: until culture negative Interrupting the route of transmission: Protecting the susceptible population: F2a: secretary IgA protect rate: 80% 6-12mon