Bacillary Dysentery
(shigellosis)
Dept. Of Infectious Disease
Wang Jingyan
Definition
 Acute infectious disease of intestine caused by
dysentery bacilli
 Place of lesion: sigmoid & rectum
 Pathological feature: diffuse fibrious exudative
inflammation
 Clinical manifestation: fever, abdominal pain,
diarrhea, tenesmus , stool mixed with blood,
mucus & pus. Even companied with marked
toxicity and shock,toxic-encepholopthy.
Etiology
 Causative organism: dysentery bacilli, genus
shigella, gram-stain negative, short rod,non-motile
 Groups: 4 groups & 50 serotypes
- S. Dysenteriae-the most sever
- S. Flexnerii-the epidemic group and
easily turn to chronic
- S. Boydii-tropical and subon
- S. sonnei-the most mild
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
Epidemiology
 Source of infection:
- patients
- carriers
 Route of transmission: fecal-oral route
 Suceptibility of population:immunity after
infection is short and unstead,no cross-immune
 Epidemic features:
- season: summer & fall
- Flexneri, Soneii, dysentery
- age: younger children
Pathogenesis
 Number of bacteria
 toxicity
 immunity
 invasiveness
- attachment
- penetration
- multiplication
Pathogenesis-common
Bacteria
intestine
Penetrate mucus
Multiply in epithelia
cell & proper lamina
Inflammation
vessel contraction
Normal bacteria flora
sIg A
Prevent attaching
endotoxin
Endogenous pyrogen
Superficial mucosal in,nec and
ulcer
Diarrhea mixed with blood & pus,
abdominalache
fever
Pathogenesis-toxic
Strong - allergy to endotoxin
Demethyl-adrenaline
Micro-circulatory failure
Shock, DIC, cerebral edema
cerebral hernia
Pathology
 Site of lesion: entire large bowel-colone,
sigmoid & rectum
 Feature:
 acute: diffuse fibrinous exudative
inflammation, hyperemia, edema,
leukocyte infiltration, superficial necrosis
 chronic: edema, polypoid hyperplasis
 toxic: endothelial cell of micro-capillary
necrosis
Clinical manifestation
 Incubation period: 1-2 day, (Hrs. To 7 days)
 Acute dysentery
 common




type:
onset in sudden, shiver, high fever
abdominal pain
diarrhea:stool mixed with blood, mucus & pus
tenesmus, continence
Clinical manifestation
 Acute dysentery
 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
Clinical manifestation
 Acute dysentery:
Toxic type:





Age: 2 to 7 yrs.
Abrupt onset, high fever, Trise to 40oC
Listlessness,lethargy,convulsion,coma.
circulatory & respiratory collapse
diarrhea mild or absent at beginning
shock form: septic shock
brain form: respiratory failure
mixed form
Clinical manifestation
 Chronic dysentery: > 2 months
 Chronic
delayed type:diahhrea long-time
and repeated
 Chronic obscure type: acute history in 1
year, no symptoms, stool culture Pos. or
sigmoidscopy
 Acute
attack type: same as common acute
dysentery
Laboratory Findings
 Blood picture: total WBC count increase,
neutrophils increase
 Stool examination:
 direct microscopic exam.: WBC, RBC, pus cells
 bacteria culture:
 Sigmoidoscope: shallow ulcer,scar, polyps
Differential diagnosis
 Acute dysentery
 Amebic



dysentery
Entameba histolytica
stool: reddish brow, like jam
flask-shaped ulcer,Amebic trophozoite
 Enteritis
caused by E. Coli,
salmonella,viral diarrhea
 Intussusception: jelly-like stools, abdominal
mass and absence of fever
Differential diagnosis
 Chronic dysentery
 Rectal & colonic carcinoma: no cure for longterm,drop of weiht of body
 non-specific ulcer colitis: no cure for long-term,culture
of stool is negetive, sigmoidoscope:hemorrhage,
ulcer,lead pipe.
 Chronic schistosomiasis Japonica
a. co ntact with the disease-water
b. hepatomegaly and splenomegaly
c .founding the ova of schistosomiasis Japonica
 Toxic dysentery
 Encephalitis B
brain form:Japaness B encephalitis
a.stool
b.CFS-IgM
c.slowly
d.shock rarely
Treatment
 Common dysentery
 Toxic dysentery
 general
treatment
 Pathogenic treatment :ofloxine or Amp. Given
by IV
 Synptomatic treatment:Control high fever,
convulsion: sub-winter sleep
 Treatment of shock:same as ECM
 Treatment of cerebral edema: same as EBC
Treatment
 Chronic dysentery
 General
therapy:live,nurishing,diet,avoid
overwork,excise.
 Etiologic therapy: sensitive antibiotics used
in turn or combined use;according to results of
culture;enema;expectant treatment.
Prevention
• Control the source of infection: until
culture negative
• Interruptted the route of transmission:
method of mainly
• Protct the susceptability:F2a-secratory
IgA protect 80%-6-12mon
• return