Bacillary dysentery (shigellosis

Acute infectious disease of intestine caused by dysentery bacilli(genus shigella)
Place of lesion: sigmoid & rectum
Pathological feature:
diffuse fibrious exudative
inflammation

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

2. Definition
Acute infectious disease of intestine
caused by dysentery bacilli(genus
shigella)
Place of lesion: sigmoid & rectum
Pathological feature:
diffuse fibrious exudative
inflammation

3. Definition
Clinical manifestation:
fever, abdominal pain, diarrhea,

tenesmus , stool mixed with
mucus blood, & pus.
even companied with shock,
toxic-encepholopthy.

4. Etiology
Causative organism:
dysentery bacilli, genus shigella,

gram-stained negative,
non-motile short rod,
Groups: 4 serogroups &47 serotypes

5. Etiology
S. dysenteriae: the most severe
S. flexneri: the epidemic group
and easily turn to chronic
S. boydii: tropical and subon
S. sonnei: the most mild

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

7. 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

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

9. Pathogenesis
number of bacteria
toxicity
invasiveness
attachment
penetration
multiplication
immunity

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

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

12. Pathology
site of lesion:
entire large bowel-
sigmoid colon & rectum
feature:
acute: diffuse fibrinous
exudative inflammation,

13. Pathology
hyperemia, edema, leukocyte

infiltration, superficial
necrosis,
ulcer.
chronic: edema,
polypoid hyperplasia,
toxic:
colon: hyperemia, edema,
micro- capillary was invaded

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

15. Clinical manifestation
common type: (typical type)
acute onset ,
shiver, high fever
abdominal pain(tenderness)
diarrhea: stool mixed with
mucus, blood & pus
tenesmus,
1 week

16. Clinical manifestation
mild type: ( atypical type)
caused by S. sonnei
low fever or no fever
abdominal pain is mild
stool mixed with mucus, without

blood & pus
diagnosis by isolation of bacteria
3~7d

17. Clinical manifestation
toxic type:
age: 2 to 7 yrs.
abrupt onset, high fever, T 40
o
C
dysphoria, lethargy, convulsion
repeatedly,coma.
circulatory & respiratory collapse
diarrhea mild or absent at
beginning

18. Clinical manifestation
shock form: septic shock
brain form:
dysphoria,lethargy,convulsion

repeatedly,coma, brain
hernia.
respiratory failure
mixed form

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

20. Clinical manifestation
chronic delayed type:
long-time and repeated abdominal
pain, diarrhea, stool mixed with
mucus, blood & pus.
with fatigue, anemia, malnutrition.

21. Clinical manifestation

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,
(10~20×10
9
/L)
neutrophils increase
Stool examination:
gross examination: stool mixed with
mucus, blood & pus.

23. Laboratory Findings
direct microscopic examination:
WBC, RBC, pus cells
bacteria culture:
PCR:DNA
Sigmoidoscopy:
chronic patients
shallow ulcer
scar
polyp

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

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

26. 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,

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

28. Differential diagnosis
toxic dysentery
encephalitis B:
highfever,convulsion,coma.
•<24h
•circulatory failure
•stool examination
•CSF
•meningeal irritation
•Specific IgM

29. Treatment
Common dysentery
Toxic dysentery
general treatment
pathogenic treatment :
ofloxine
Ampicillin given by IV

30. Treatment
symptomatic treatment:
•control of high fever,convulsion:
subhibernation
•treatment of shock: same as ECM
•treatment of cerebral edema:
20% mannitol

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

32. etiologic therapy:
sensitive antibiotics
used in turn or combined use
according to results of culture
enema
expectant treatment.
Treatment

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