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Bacillary Dysentery (shigellosis). Definition. Acute infectious disease of intestine caused by dysentery bacilli(genus shigella) Place of lesion: sigmoid & rectum Pathological feature: diffuse fibrious exudative inflammation. Definition. Clinical manifestation:
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Definition • Acute infectious disease of intestine caused by dysentery bacilli(genus shigella) • Place of lesion: sigmoid & rectum • Pathological feature: diffuse fibrious exudative inflammation
Definition • Clinical manifestation: fever, abdominal pain, diarrhea, tenesmus , stool mixed with mucus blood, & pus. shock, toxic-encepholopthy.
Etiology • Causative organism: dysentery bacilli, genus shigella, gram-stained negative, non-motile short rod, • Groups: 4 serogroups &47 serotypes
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
Etiology • Pathogenicity: - virulence endotoxin - 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 and carriers • Route of transmission: fecal-oral route • Suceptibility of population: immunity after infection is short and unsteady, no cross-immune
Epidemiology • Epidemic features: • season: summer & fall • Flexneri, Soneii, dysentery • age: younger children
Pathogenesis • number of bacteria • toxicity • invasiveness • attachment • penetration • multiplication • immunity
common Bacteria intestine penetrate mucus normal intestinal flora sIg A multiply in epithelia cell & proper lamina prevent attaching endotoxin inflammation vessel contraction endogenous pyrogen fever superficial mucosal necrosis and ulcer diarrhea mixed with blood & pus, abdominal pain
Pathogenesis-toxic strong - allergy to endotoxin demethyl-adrenaline DIC micro-circulatory failure shock, cerebral edema cerebral hernia
Pathology • site of lesion: entire large bowel- sigmoid colon & rectum • feature: • acute: diffuse fibrinous exudative inflammation,
Pathology hyperemia, edema, leukocyte infiltration, superficial necrosis, ulcer. • chronic: edema, polypoid hyperplasia, • toxic: colon: hyperemia, edema, micro- capillary was invaded
Clinical manifestation • Incubation period: 1-2 day, (hours to 7 days) • Acute dysentery • common type • mild type • toxic type
Clinical manifestation • common type:(typical type) • acute onset , • shiver, high fever • abdominal pain(tenderness) • diarrhea: stool mixed with mucus, blood & pus • tenesmus, • 1 week
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
Clinical manifestation • toxic type: • age: 2 to 7 yrs. • abrupt onset, high fever, T 40oC • dysphoria, lethargy, convulsion repeatedly,coma. • circulatory & respiratory collapse • diarrhea mild or absent at beginning
Clinical manifestation • shock form: septic shock • brain form: dysphoria,lethargy,convulsion repeatedly,coma, brain hernia. respiratory failure • mixed form
Clinical manifestation • chronic dysentery: > 2 months • chronic delayed type:chronic obscure type • acute attack type
Clinical manifestation • chronic delayed type: long-time and repeated abdominal pain, diarrhea, stool mixed with mucus, blood & pus. with fatigue, anemia, malnutrition.
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
Laboratory Findings • Blood picture: WBC count increase, (10~20×109/L) neutrophils increase • Stool examination: • gross examination:stool mixed with mucus, blood & pus.
Laboratory Findings • direct microscopic examination: WBC, RBC, pus cells • bacteria culture: • PCR:DNA • Sigmoidoscopy: chronic patients shallow ulcer scar polyp