2. Bacillary dysentery
• Acute infectious disease of intestines caused by dysentery
bacilli(Genus shigella)
• Place of lesion: sigmoid and rectum
• Pathological feature: diffuse fibrinous exudative inflammation
3. Epidemiology and etiology
• Source of infection
patients and carriers
• Route of transmission: fecal oral route
• Susceptibility of population
immunity after infection is short and unsteady , there is no
cross immunity
4. Etiology
Causative organism: dysenteriae bacilli, Genus Shigella
gram negative , non motile short rod
Groups : 4 serogroups and 50 serotypes
Serogroups
S.dysenteriae: the most severe
S.flexneri : epidemic group and easily turn to chronic
S. boydii: tropical
S. sonnei: the most mild
5. Pathogenicity
• Virulence
endotoxin vs exotoxin
• Invasiveness
attach then penetrate then multiply
• Resistance
strong ,1-2 weeks in fruits, vegetables and dirty soil
heat at 60 degree Celsius for 30 minutes
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10. • Site of lesion: entire large bowel, sigmoid colon and rectum
• Feature : diffuse fibrinous exudative inflammation
11. Clinical manifestations
• Incubation period: 1- 2 days( hours to 7 days)
• Common features: fever, abdominal pain, diarrhea, tenesmus, stool
mixed with mucus, blood and pus
SHOCK, TOXIC ENCEPHALOPATHY
ACUTE DYSENTERY
1. Common type
2. Mild type
3. Toxic type
12. Acute dysentery
• Common type
• Mild type
• Toxic type
Chronic dysentery
• Chronic delayed type
• Chronic obscure type
13. Common type
• Acute onset
• Shiver, high fever
• Abdominal pain/tenderness
• Diarrhea, stool mixed with
mucus, blood and pus
• Tenesmus
• 1 week
Toxic type
• Age : 2 to 7 years
• Abrupt onset
• High fever, T 40 degree celcius
• Dysphoria, lethargy, convulsion,
coma
• Circulatory and respiratory
collapse
• Diarrhea mild or absent at the
beginning
14. Mild type (atypical type)
• Caused by S. sonnei
• Low fever or no fever
• Abdominal pain is mild
• Stool mixed with mucus, without blood and pus.
• Diagnosis by isolation of bacteria
• 3-7 days
15. Chronic dysentery ( more than 2 mnths)
Chronic delayed type
• Long time and repeated abd
pain
• Diarrhea
• Fatigue
• Anaemia, malnutrition
• Stool mixed with mucus, blood
and pus
Chronic obscure type
• Acute history in 1 year
• Positive stool culture
/sigmoidoscopy
• No symptoms
16. Differentials
Acute dysentery
• Amebic dysentery
• Enteritis by E.coli, salmonella,
viral
• Intussesception
Chronic dysentery
• Ca rectum or ca colon
• Non specific ulcer colitis
• Chronic schistosomiasis( S.
Japonica)
17. Laboratory findings
• Blood picture
neutrophilic leukocytosis
• Stool examination:
Gross exam: stool mixed with mucus, blood and pus
direct microscopy: WBCs, RBCs, pus cells
• Bacteria culture
• DNA PCR
• Sigmoidoscopy( chronic cases)
shallow ulcers
scar or polyps
18. Treatment -symptomatic
• Control fever, convulsions and subhibernation
• Treatment of shock
• Treatment of cerebral edema ( 20% mannitol)
19. Chronic dysentery
• General therapy
• Diet
• Bed rest
• Etiologic therapy
sensitive ABCs used in turn or
combination according to C/S
findings
Toxic dysentery
• General therapy
• Pathogenic Rx
IV floroquinolones
beta lactamase inhibitors
20. Prevention
• Control the source of infection until culture negative
• Interrupting the route of transmission
• Protecting the susceptible population( no licensed vaccine against
shigella available)
21. Amoebic dysentery
• Amebiasis is a parasitic disease that affects the gut mucosa and liver
,resulting in dysentery, liver abscess and colitis
• The causative agent; Entamoeba histolytica is a potent pathogen and
is spread via the fecal oral route.
• Globally , amebiasis is highly prevalent and is the second leading
parasitic cause of death
22. • Only 10 % of the infected persons develop the disease
• Two types
1) intestinal type- mild to fulminant
2) extra intestinal
23. Transmission
• Direct contact of person to person ( fecal oral route)
• Venereal transmission among homosexual males( oral anal)
• Food or drinks contaminated with feces
• Use of night soil as fertilizers in agriculture
• Contamination of food by flies and cockroaches
• Incubation period : 3 days in severe disease, several months in sub-
acute and chronic form. In average case vary from 3-4 weeks.
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25. Risk factors -general
• Poor sanitary conditions
• Immigrants from developing countries
• Travelers to developing countries
• HIV positive individuals
• homosexuals
