Upload
walter-ferguson
View
216
Download
3
Embed Size (px)
Citation preview
AMEBIASIS
Two morphologically identical but genetically distinct species of Entamoeba commonly infect humans.
1-Entamoeba dispar, the more prevalent species
2-E. histolytica, the pathogenic species can become invasive
Infection is established by ingestion of parasite cysts.
ETIOLOGY
Cysts are resistant to environmental conditions such as low temperature and the concentrations of chlorine commonly used
can be killed by heating to 55°C cyst, which is resistant to gastric acidity and
digestive enzymes→excysts in the small intestine to form 8
trophozoites→colonize the lumen of the large intestine and
may invade the mucosal lining.
Food or drink contaminated with Entamoeba cysts and direct fecal-oral contact are the most common means of infection
Untreated water and human feces used as fertilizer are important sources of infection.
EPIDEMIOLOGY
range from asymptomatic cyst passage to amebic colitis, amebic dysentery, ameboma, and extraintestinal disease.
. E. histolytica infection is asymptomatic in about 90% of persons, but it has the potential to become invasive and should be treated
Severe disease is more common in young children, pregnant women, malnourished
Extraintestinal disease usually involves only the liver, but rare extraintestinal manifestations include amebic brain abscess, pleuropulmonary disease, ulcerative skin, and genitourinary lesions.
CLINICAL MANIFESTATIONS
occur within 2 wk of infection or be delayed for months
colicky abdominal pains Diarrhea Stools are blood stained and contain a fair
amount of mucus with few leukocytes fever documented in only ⅓ of patients incidence is strikingly high in children 1–5
yr of age amebic dysentery is associated with sudden
onset of fever, chills, and severe diarrhea
Amebic Colitis
is uncommon in children. Amebic liver abscess may occur months to
years after exposure. In children, fever is the hallmark and is
frequently associated with abdominal pain, distention, and enlargement and tenderness of the liver.
Amebic Liver Abscess
unremarkable in uncomplicated amebic colitis in amebic liver abscess :leukocytosis,
moderate anemia, high erythrocyte sedimentation rate, and elevations of hepatic enzyme (particularly alkaline phosphatase) levels.
Stool examination negative results in >50% of patients with documented amebic liver abscess.
Ultrasonography, CT, or MRI can localize and delineate the size of the abscess cavity
LABORATORY FINDINGS
amebic colitis :detection of antigens in stool by ELISA
examination of stool samples microscopy cannot differentiate between E.
histolytica and E. dispar unless phagocytosed erythrocytes, which are specific for E. histolytica, are seen.
DIAGNOSIS
Invasive amebiasis is treated with metronidazole (35–50 mg/kg/day in 3 divided doses for 7–10 days)or tinidazole (50 mg/kg/day once daily for 3 days)
followed by treatment with a luminal amebicide : paromomycin(7 days), iodoquinol(20 days) OR Diloxanide furoate (7 days)
Asymptomatic intestinal infection with E. histolytica should be treated with paromomycin, which is preferred, or iodoquinol or diloxanide furoate.
TREATMENT.