1-entamoeba histolytica

Dept. of Infectious Diseases

杨绍基

Amebic dysentery• Definition

Parasitic disease, Entamoeba histolytica,

trophozoites induce submucosal ulcerations

abdominal pain, diarrhea, strawberry jam-like stool

• Etiology

Five species of Entamoeba:

E. histolytica (Pathogenic), E. dispar

E. coli, E. hartmanni, E. gingivalis

Life cycle :

cyst postcyst

precyst large trophozoite

• Epidemiology

Source of infection

Route of transmission

Susceptibility

Epidemiological characteristics

• Pathogenesis

E. histolytica trophozoites

cytolytic enzymes and pseudopodia

invade colonic tissue

flask-shaped submucosal ulcerations

may cause amebic liver abscess, bleeding, perforation, peritonitis

• Clinical Manifestations

Incubation period: 1~4 weeks

Clinical forms: acute typical form

mild form

fulminant form

asymptomatic form

chronic form

• Laboratory findings

normal leukocyte count

eosinophilia

fecal microscopy: RBC, WBC and mucus

erythrophagous mobile trophozoites

cysts with four nucleuses

• Complications

amebic liver abscess

intestinal perforation, peritonitis

intestinal hemorrhage

intestinal ameboma

amebic appendicitis

perianal rectal fistulas

• Diagnosis

Epidemiological data

Clinical manifestations

Laboratory findings

• Differential Diagnosis

Shigellosis

Schistosomiasis

Colonic carcinoma

Rectal cancer

Non-specific ulcerative colitis

• Treatment

Supportive treatment

Symptomatic treatment

Etiological treatment

metronidazole 400mg tid for 10 days, for adults or

tinidazole 2.0 qd 5 days, for adults

furamide 500mg tid for 10 days

Emetine chloroquine paromomycine chiniofon etc are out of day.

• Prophylaxis

To control the sources of infection

To interrupt the routes of transmission

No vaccine is available

AMEBIC LIVER ABSCESS

commonest complication of

intestinal amebiasis

• Pathogenesis and pathology

E. histolytica trophozoites portal vein

pseudopodia

amebic liver abscess liver tissue

cytolytic enzymes

rupture

peritonitis

• Clinical Manifestations

gradual onset

abdominal pain

fever

anemia

lose of appetite and body weight

• Diagnosis

Epidemiological data

eating habit, history of diarrhea

Clinical manifestations

gradual onset, pain in liver region,

fever, anemia, lose of body weight,

tenderness of the enlarged liver

Laboratory findings

liquefied space-occupying lesion,

specific antibodies, specific antigen

• Differential diagnosis

bacterial liver abscess

congenital liver cyst

primary hepatocellular carcinoma

liver metastasis of carcinomas

liver hydatid disease

liver tuberculosis

• Treatment

Supportive treatment

Symptomatic treatment

Etiological treatment

metronidazole 400mg tid for 10

days or

tinidazole 2.0 qd for 5 days

antibiotics if necessary

SHIGELLOSIS

• Etiology

non-motile, non-spore-forming,

Gram negative bacillus

four species:

Shigella dysenteriae

S. flexneri

S. boydii

S. sonnei

• Epidemiology

Source of infection

patients and carriers

Route of transmission

fecal-oral

Susceptibility

universal

Epidemiological characteristics

• Pathogenesis

Shigella living in colonic epithelial cells

release endotoxin multiply

superficial mucosal ulcerations

• Clinical Manifestations

acute typical form:

acute onset, high fever, abdominal pain, diarrhea, tenesmus, stool with blood,

mucus, non-mixed with fecal material, little amount each time

mild form

toxic form

chronic form

• Complications

Shigella septicemia

arthritis

hemolytic uremic syndrome

• Diagnosis

Epidemiological data

Clinical manifestations

Laboratory findings

pathogenic bacteria culture

yield Shigella

• Differential diagnosis

amebic dysentery

bacterial food poisonings

campylobacter enteritis

Escherichia enteritis

acute schistosomiasis

ulcerative colitis

rectal carcinoma

Japanese encephalitis for toxic form

• Treatment

Supportive treatment

Symptomatic treatment

Etiological treatment

quinolones: ofloxacin, ciprofloxacin

ampicillin and gentamicin for toxic form cases

• Prevention

Control the source of infection

Interrupt the route of

transmission

Protect susceptible persons

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