1. AMEBIASIS

2. DEFINITION
 Amebiasis is infection with intestinal pathogen
Entameba histolytica (tissue lysing ameba)
 Most Infection are asymptomatic
 disease ranging from Dysentry to extaintestinal
infectons like liver absess
 Most of asymptomatic infection is due to E.dispar
 Endemic area Mexico,India & tropical regions of
Africa,South and Central America

3. LIFE CYCLE AND TRANSMISSION
 E. histolytica exists in two stages
multinucleate cyst Motile Trophozoite

4. TRANSMISSION
 E. histolytica are most common in areas where
poor sanitation and crowding compromise the
barrier to contamination of food and drinking water
with human feces
 Infection is acquired by ingestion of cysts in faecally
contaminated water or food
 Cysts are resistant to the acid in the stomach

5. LIFE CYCLE

6. PATHOGENESIS AND PATHOLOGY
 E.histolytica trophozoites invade through the
submucosal layer, creating the classic flask shaped
ulcers that appear on pathologic examination as
narrow-necked lesions broadening in the
submucosal region
 Ulcers tend to stop at the muscularis layer, and full-
thickness lesions and colonic perforation are
unusual

7. FLASK SHAPED ULCER

8. PATHOGENESIS AND PATHOLOGY
 In some individuals, trophozoites invade the portal
venous system and reach the liver, where they
cause amebic liver abscesses
 characteristic appearance on pathologic
examination: the roughly circular abscesses contain
a large necrotic center resembling anchovy paste

9. CLINICAL MANIFESTATIONS
 Two types- Intestinal and Extra Intestinal
 Amebic colitis generally appear 2-6 weeks after
ingestion of the cyst of parasite
 diarrhea and lower abdominal pain are the most
common complaints
 Fever is present in 40% cases
 Severe dysentry with 10-12 small volume, blood
and mucus containing stools may develop

10. CLINICAL MANIFESTATIONS
 Fulminant amebic colitis – profuse diarrhea, severe
abdominal pain, fever,and pronounced leukocytosis
 It affects young children, pregnant women,
individuals treated with steroids and in diabetes
and alcoholism
 Intestinal perforation occus in >75% of pts.with
fulminant disease
 Complications includes
 Toxic Megacolon in .5% with severe bowel dilatation and
intraluminal air
 Ameboma-presents as abd. mass

11. AMEBIC LIVER ABSCESS
 Most common extraintestinal complication
 Most individuals do not have concurrent signs or
symptoms of colitis
 The classical presentation of ALA are right upper
quadrant pain, fever and liver tenderness
 Its acute in nature lasting < 10 days
 Jaundice is uncommon
 most common laboratory findings are leukocytosis
(without eosinophilia), an elevated alkaline
phosphatase level, mild anemia, and an elevated
ESR

12. OTHER MANIFESTATIONS AND COMPLICATIONS
 Rt-sided pleural effusion - common in cases of ALA
 In 10% rupture of abscess through diaphragm may
cause pleuro-pulmonary amebiasis
 Sudden onset cough, pleuritic chest pain and
shortness of breath
 Hepatobronchial fistula is dramatic complication in
which pt has complaint of cough with content of liver
abscess
 Liver abscess may rupture into pericardial cavity
and can cause pericarditis with 30% mortality due to
cardiac temponade

13. DIAGNOSTIC TESTS
 Demonstration of E.histolytica trophozoite or cyst
in the stool or colonic mucosa of pts with diarrhea
 presence of amebic trophozoites containing red
blood cells in a diarrheal stool is highly suggestive
of E. histolytica infection
 Antigen detection based ELISAs that can
specifically identify E.histolytica in the stool
 colonoscopy with examination of brushings or
mucosal biopsies for E. histolytica trophozoites
 Amebic serology

14. DIAGNOSTIC TESTS
 Diagnosis of amebic liver abscess is based on the
detection of one or more space occupying lesions
in the liver by Ultrasound and CT scan and a
positive serology
 classically described as single, large and located in
right lobe of liver
 When a pt. with space ahs a occupying lesion in the
liver, a positive serology is highly sensitive(>94% )
and highly specific(>95%) for the diagnosis of the
liver abscess

15. CT SCAN LIVER WITH ALA IN RT LOBE

16. TREATMENT
 The nitroimidazole compounds tinidazole and
metronidazole are the drug of choice
 Tinidazole appears to be better tolerated and more
effective
 Whenever possible fulminant amebic colitis should
be managed conservatively

17. TREATMENT
 Aspiration of liver abscess reserved for
 pyogenic abscess or a bacterial superinfection is
suspected,
 for pts failing to respond to tinidazole or metronidazole (
those who have persistent fever or abdominal pain after
4 days of treatment),
 for individuals with large liver abscesses in the left lobe
 large abscess with risk of imminent rupture
 Pleuropulmonary amebiasis
 Amebic pericarditis

18. TREATMENT
 luminal agents (Paramomycin or iodoquinol) to
ensure eradication of infection
 Paramomycin is preferred agent
 Asymptomatic individuals with documented E.
histolytica infection should be treated because of
the risks of developing amebic colitis or amebic
liver abscess in the future and of transmitting the
infection to others

19. TREATMENT
Drug Dosage Duration
Amebic Colitis Or ALA
Tinidazole 2g/day with food 3
Metronidazole 750mg tid PO or IV 5-10
Luminal Infection
Paramomycin 30mg/kg qd PO in 3
divided dose
5-10
Iodoquinol 650 mg PO tid 20