Download AMEBIASIS

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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