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

Definition Acute infectious disease of intestine caused by dysentery bacilli 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. even companied with shock and toxic encepholopthy.

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

Etiology S. Flexneri the epidemic group and easily turn to chronic S. Boydii tropical areas 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 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, age: younger children

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

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

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

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

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

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

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

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

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

Clinical manifestation shock form: septic shock brain form: listlessness,lethargy,convulsion, coma. 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 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

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

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

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

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

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

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,

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

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

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

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

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

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

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

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