II. Epidemiology
- Prevalence: 10% worldwide
- Asymptomatic cyst carriage in 90% cases
- Symptomatic cases per year: 50 million worldwide
- Fatalities per year: 100,000
III. Risk factors
- Mental health institutions (High Prevalence)
- Crowded living conditions
- Poor sanitation
- Travel to endemic areas
- Asia
- Africa
- Latin America
IV. Pathophysiology
- Two forms
- Cyst (12 um diameter): Spheres with up to 4 nucleii
- Divides into trophozoites in Small Intestine
- Cysts can survive weeks in moist environment
- Trophozoite (25 um long)
- Contains 1 nucleus and ingested RBCs
- Moves via finger-like pseudopods toward colon
- Some trophozoites transform into cysts
- Cyst (12 um diameter): Spheres with up to 4 nucleii
- Results in enterocolitis
- Intraluminal disease
- Profuse Diarrhea with malabsorption
- Ulceration of colon and terminal ilium
- Intestinal bleeding
- Systemic dissemination
- Intraluminal disease
- Transmission via fecal-oral route
- See Waterborne Illness
- See Foodborne Illness
- Food preparation contaminated by poor hygiene
- Human waste used for crop fertilization
- Oral-anal sex
V. Symptoms
- Acute
- Fulminant onset
- Cramping, moderate to severe Abdominal Pain
- Bloody, profuse Diarrhea
- Mucus in stools
- Tenesmus
- Malaise
- Chronic
- Normal stools alternate with symptomatic phase
VI. Signs
- Acute
- Fever
- Diffuse abdominal tenderness
- Dehydration
- Weight loss
- Chronic
- Fever
- Tenderness and cramping of cecum and ascending colon
-
Liver Abscess (within 5 months of onset)
- Fever (10-15 of cases)
- RUQ Abdominal Pain or liver tenderness
- Liver friction rub if Liver Abscess present
- Diarrhea (33% of cases)
VII. Differential Diagnosis
- See Waterborne Illness
- See Foodborne Illness
- Appendicitis
- Inflammatory Bowel Disease (especially Crohn's Disease)
VIII. Complications
- Ameboma growth into intestinal lumen
- Risk of Bowel Obstruction
- Risk of Intussusception
- Toxic Megacolon
- Pneumatosis coli
- Abscess formation
- Lung Abscess
- Brain Abscess
- Liver Abscess
- See signs above
- Risk of rupture
- Risk factors for complication
- Multiple cysts or cysts >10 cm in size
- Superior right liver lobe involvement
- Left liver lobe involvement
- Course
- Spontaneous resolution by 6 months in 66%
- Persist >1 year in 10%
IX. Labs
- Entamoeba histolytica by stool PCR (preferred)
- Entamoeba histolytica by stool Antigen testing
- Test Sensitivity: 87%
- Test Specificity: >90%
-
Ova and Parasite exam (3 samples required)
- Precaution: Microscopy alone does not distinguish E histolytica from the benign E. dispar
- Fresh Stool Exam with Microscopy and gross exam
- Motile or encysted organisms
- Watery stool with mucus or blood
-
Liver Function Tests
- Alkaline Phosphatase increased in 75% of cases
- Serum Aminotransaferases (AST, ALT) increased in 50% of cases
- Serum Bilirubin is typically normal
- Other stool tests
- Fecal Leukocytes positive
- Occult blood positive
- Fecal Eosinophilia (Charcot-Leyden crystals present)
X. Diagnostic Testing
- Endoscopy
- Mimics Crohn's Disease
- Colonic ulcerations
- Discrete ulcers of variable depth in right colon
- Exudative hyperemic ulcers with small Hemorrhages
- Biopsy
- Intramural trophozoites at edge of ulceration
XI. Imaging
-
Barium Enema may show Ameboma
- Irregular barium distribution in ascending colon
- Right Upper Quadrant Ultrasound
- Hepatic Abscess (oval hypoechoic cyst)
XII. Management: Asymptomatic cysts
- Preferred agents
- Paromomycin 25-35 mg/kg/day orally divided three times daily for 7 days or
- Iodoquinol (Yodoxin) 650 mg orally three times daily for 20 days
- Alternative agent
- Diloxanide furoate (Furamide) 500 mg orally three times daily for 10 days
XIII. Management: Diarrhea or mild Dysentery
- Requires combined use of both tissue and luminal agent
- Tissue agents for trophozoites (choose one)
- Metronidazole (Flagyl) 500 to 750 mg orally three times daily for 7-10 days OR
- Tindazole 2 g orally daily for 3 days
- Luminal agents for cysts (choose one) - start after tissue agent course is completed
- Paromomycin 25-35 mg/kg/day orally divided three times daily for 7 days OR
- Iodoquinol (Yodoxin) 650 mg orally three times daily for 20 days
XIV. Management: Severe disease (e.g. Liver Abscess)
- Requires combined use of both tissue and luminal agent
- Tissue agents for trophozoites (choose one)
- Metronidazole (Flagyl) 750 mg IV three times daily for 10 days or
- Tindazole 2 g orally daily for 5 days
- Luminal agents for cysts (choose one) - start after tissue agent course is completed
- Paromomycin 25-35 mg/kg/day orally divided three times daily for 7 days or
- Iodoquinol (Yodoxin) 650 mg orally three times daily for 20 days
XV. References
- Gilbert (2015) Sanford Guide to Antimicrobials, accessed on IOS app 5/11/2016
- Kucik (2004) Am Fam Physician 69(5):1161-8 [PubMed]
- Petri (1999) Clin Infect Dis 29:1117-25 [PubMed]
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Related Studies
| Definition (MSHCZE) | Infekce (nákaza) některým z rozličných amébních mikroorganismů. U většiny jednotlivců se jedná o asymptomatický stav nositelů (hostitelů) infekce, ale onemocnění se může vyskytnout v různém rozsahu od chronického mírného průjmu až po fulminantní (náhlou) úplavici. |
| Definition (NCI) | A parasitic infectious disorder caused by amoebas. The parasite may cause colitis which is manifested with bloody diarrheas, abdominal pain, nausea and fever. In rare cases it may spread to the liver, brain and lungs. |
| Definition (MSH) | Infection with any of various amebae. It is an asymptomatic carrier state in most individuals, but diseases ranging from chronic, mild diarrhea to fulminant dysentery may occur. |
| Definition (CSP) | infection with any of various amebae; an asymptomatic carrier state in most individuals, but diseases ranging from chronic, mild diarrhea to fulminant dysentery may occur. |
| Concepts | Disease or Syndrome (T047) |
| MSH | D000562 |
| ICD9 | 006.9, 006 |
| ICD10 | A06 , A06.9 |
| SnomedCT | 387754006, 186122001, 111909004, 154274000, 282008000, 187278004, 111910009, 388759003, 105637008 |
| English | Amebiases, Amoebiases, Amoebiasis, Amebiasis NOS, Amebiasis, unspecified, Amoebiasis NOS, Amoebiasis, unspecified, [X]Amebiasis, unspecified, [X]Amoebiasis, unspecified, amebiasis (diagnosis), amebiasis, infection due to Entamoeba histolytica, Amebiasis [Disease/Finding], amebiases, Amoebic infections, Amoebiasis (disorder), Amebiasis (disorder), Amoebic infection (disorder), [X]Amebiasis, unspecified (disorder), Amebiasis NOS (disorder), Amebic infection, Amoebic infection, Disease due to Endamoebidae (disorder), Disease due to Endamoebidae, Infection due to Entamoeba histolytica (disorder), Infection due to Entamoeba histolytica, Amebic infection (disorder), Amebiasis, Infection due to Entamoeba histolytica, SAI, Infection due to Entameba histolytica, SAI, Infection due to Entameba histolytica, Amebic infections, amoebiasis |
| Italian | Infezioni amebiche, Amebiasi, non specificata, Amebiasi NAS, Amebiasi non specificata, Amoebiasi, Amebiasi |
| Dutch | amoebiasis niet-gespecificeerd, amoebiasis NAO, Amoebiasis, niet gespecificeerd, amoebeninfecties, amoebiasis, Amoebiasis |
| French | Amibiase, non précisée, Amibiase SAI, Infections amibiennes, Amibiase |
| German | Amoebiasis, unspezifisch, Amoebiasis NNB, Amoebiase NNB, Amoebiasis, nicht naeher bezeichnet, Amoebiasis, Infektionen durch Amoeben, Amöbiase, Amöbiasis |
| Portuguese | Amebíase NE, Amibiase, Infecções por amibas, Amebíase, Amoebíase |
| Spanish | Amebiasis no especificada, Amebiasis NEOM, [X]amebiasis, no especificada, amebiasis, SAI (trastorno), amebiasis, SAI, [X]amebiasis, no especificada (trastorno), amebiasis (trastorno), amebiasis, enfermedad causada por Endamoebidae (trastorno), enfermedad causada por Endamoebidae, infección amebiana (trastorno), infección amebiana, infección amebiásica (trastorno), infección amebiásica, infección amébica, infección por Entamoeba histolytica (trastorno), infección por Entamoeba histolytica, Infecciones por amebas, Amebiasis, Amoebiasis |
| Japanese | アメーバ症、詳細不明, アメーバ感染, アメーバ症ＮＯＳ, ｱﾒｰﾊﾞｶﾝｾﾝ, ｱﾒｰﾊﾞｼｮｳNOS, ｱﾒｰﾊﾞｼｮｳ, ｱﾒｰﾊﾞｼｮｳｼｮｳｻｲﾌﾒｲ, アメーバ肉芽腫, アメーバ症, 肉芽腫-アメーバ, ヨードアメーバ症 |
| Swedish | Amöbainfektion |
| Czech | amébiáza, Amébóza, Amébóza, blíže neurčená, Amébové infekce, Amébóza NOS, amébóza |
| Finnish | Amebiaasi |
| Russian | AMEBIAZ, ABSTSESS AMEBNYI, АБСЦЕСС АМЕБНЫЙ, АМЕБИАЗ |
| Korean | 아메바증, 상세불명의 아메바증 |
| Croatian | AMEBIJAZA |
| Polish | Amebioza, Amebiaza, Pełzakowica |
| Hungarian | Amoebiasis, nem meghatározott, amoebiasis k.m.n., Amőba fertőzések, amoebiasis, Amoebiasis, amoebiasis, nem meghatározott, Amoebiasis k.m.n. |
| Norwegian | Amøbeinfeksjoner |
Ontology: Ameboma (C0002445)
| Concepts | Disease or Syndrome (T047) |
| MSH | D000562 |
| ICD10 | A06.3 |
| SnomedCT | 20958005 |
| English | Amebomas, ameboma, ameboma (diagnosis), Ameboma NOS, Amebic granuloma, Amoeboma, Amoebic granuloma, Ameboma (disorder), Ameboma |
| Portuguese | Ameboma |
| Spanish | Ameboma, ameboma (trastorno), ameboma, granuloma amebiano, granuloma amébico |
| German | Amöbom |
| Italian | Ameboma |
| French | Amoebome, Amébome |
| Dutch | Amoeboom |
Ontology: Entamoeba histolytica (C0014323)
| Definition (MSHCZE) | Améba vyvolávající tzv. amébovou úplavici (dysenterii). U člověka se vyskytuje ve dvou formách. Forma minuta – trofozoit o velikosti 10–20 μm, tvoří čtyřjaderné cysty, které slouží jako zdroj infekce. Forma dysenterica (magna) – patogenní forma, trofozoit o velikosti 20–40 μm, který vniká do střevní sliznice, destruuje buňky. Netvoří cysty. Hematogenním rozsevem vniká do dalších orgánů (játra, plíce, mozek aj.). Přenáší se alimentárně, výskyt je kosmopolitní; E. h. je velmi rozšířena. Klinicky manifestní onemocnění vzniká jen u části osob a má různou klinickou závažnost. (cit. Velký lékařský slovník online, 2013 http://lekarske.slovniky.cz/ ) |
| Definition (MSH) | A species of parasitic protozoa causing ENTAMOEBIASIS and amebic dysentery (DYSENTERY, AMEBIC). Characteristics include a single nucleus containing a small central karyosome and peripheral chromatin that is finely and regularly beaded. |
| Definition (CSP) | species of parasitic protozoa causing entamoebiasis and amebic dysentery; characteristics include a single nucleus containing a small central karyosome and peripheral chromatin that is finely and regularly beaded. |
| Concepts | Eukaryote (T204) |
| MSH | D004748 |
| SnomedCT | 4716008 |
| LNC | LP16698-0, MTHU004659 |
| English | Endamoeba histolytica, Entamoeba histolytica, Eh - Entameba histolytica, Endamoeba histolyticas, histolytica, Endamoeba, histolytica, Entamoeba, histolyticas, Entamoeba, histolyticas, Endamoeba, Entamoeba histolyticas, entamoeba histolytica, entameba histolytica, histolytica entamoeba, ENTAMOEBA HISTOLYTICA, Eh - Entamoeba histolytica, Entamoeba histolytica (organism), Entameba histolytica |
| Swedish | Entamoeba histolytica |
| Czech | Entamoeba histolytica |
| Spanish | Entamoeba histolytica, Entameba histolytica, Entamoeba histolytica (organismo), Endamoeba histolytica |
| Finnish | Entamoeba histolytica |
| Russian | AMEBA DIZENTERIINAIA, KISHECHNAIA AMEBA, ENTAMOEBA HISTOLITICA, АМЕБА ДИЗЕНТЕРИЙНАЯ, КИШЕЧНАЯ АМЕБА |
| Japanese | 赤痢アメーバ |
| Polish | Pełzak czerwonki |
| Norwegian | Endamoeba histolytica, Entamoeba histolytica |
| French | Entamoeba dysenteriae, Entamoeba histolytica |
| German | Entamoeba dysenterica, Entamoeba histolytica |
| Italian | Entamoeba histolytica |
| Dutch | Dysenterieamoebe, Endamoeba histolytica, Entamoeba histolytica, Ingewandsamoebe |
| Portuguese | Endamoeba histolytica, Entamoeba histolytica |
Ontology: Liver Abscess, Amebic (C0023886)
| Definition (MSHCZE) | Ojedinělé nebo mnohočetné zhnisání jaterní oblasti v důsledku amébovité protozoární nákazy (AMÉBIÁZA). Běžnou formu způsobuje požití ENTAMOEBA HISTOLYTICA. |
| Definition (MSH) | Single or multiple areas of PUS due to infection by any ameboid protozoa (AMEBIASIS). A common form is caused by the ingestion of ENTAMOEBA HISTOLYTICA. |
| Concepts | Disease or Syndrome (T047) |
| MSH | D008101 |
| ICD9 | 006.3 |
| ICD10 | A06.4 |
| SnomedCT | 75119003 |
| English | Abscess, Amebic Liver, Abscesses, Amebic Liver, Amebiasis, Hepatic, Amebic Liver Abscesses, Amoebiasis, Hepatic, Hepatic Amebiasis, Hepatic Amoebiasis, Liver Abscess, Amebic, Liver Abscesses, Amebic, Abscess, Liver, Amebic, Hepatic Abscess, Amoebic, Liver Abscess, Amoebic, Abscess, Amebic, Hepatic, Abscess, Hepatic, Amebic, Abscess, Amoebic Hepatic, Abscess, Amoebic Liver, Abscesses, Amoebic Hepatic, Abscesses, Amoebic Liver, Amoebic Hepatic Abscess, Amoebic Hepatic Abscesses, Amoebic Liver Abscess, Amoebic Liver Abscesses, Hepatic Abscesses, Amoebic, Liver Abscesses, Amoebic, Amebic Liver Abscess, amebic liver abscess, amebic liver abscess (diagnosis), Liver Abscess, Amebic [Disease/Finding], abscess amoebic liver, amoebic liver abscess, hepatic amoebiasis, abscess amebic liver, hepatic amebiasis, Entameba histolytica liver abscess, Liver abscess, Amebic, Amebic liver abscess, Amoebic liver abscess, ALA - Amebic liver abscess, ALA - Amoebic liver abscess, Amebic liver abscess (disorder), hepatic; amebiasis, amebiasis; hepatic, Hepatic amebiasis, Entamoeba histolytica liver abscess, Hepatic amoebiasis, Amebic abscess of liver, Amebic liver infection |
| Dutch | amoebenleverabces, Entamoeba histolytica-leverabces, leverabces door amoeben, amoebiasis; lever, lever; amoebiasis, Amoebenabces van lever, lever-amoebiasis, Abces, amoeben-lever-, Abces, hepatisch amoeben-, Amoebenabces, hepatisch, Amoebiasis, hepatische, Hepatisch amoebenabces, Hepatische amoebiasis, Leverabces, amoeben- |
| French | Abcès amibien hépatique, Abcès hépatique à Entamoeba histolytica, Abcès amibien du foie, Amibiase hépatique, Abcès hépatique amibien, Amibiase du foie |
| German | hepatische Amoebiasis, Amoebenabszess der Leber, von Entamoeba histolytica verursachter Leberabszess, Leberabszess durch Amoeben, Amoebiasis der Leber, Abszeß, Amöben-, hepatischer, Abszeß, hepatischer Amöben-, Abszeß, Leber-, Amöben, Amöbiasis, hepatische, Hepatische Amöbiasis, Leberabszeß, Amöben-, Hepatischer Abszeß durch Amöben |
| Italian | Ascesso epatico da Entamoeba histolytica, Ascesso amebico epatico, Amebiasi del fegato, Amebiasi epatica, Ascesso amebico del fegato, Ascesso epatico amebico |
| Portuguese | Abcesso amebiano do fígado, Abcesso hepático por Entamoeba histolytica, Amibiase hepática, Abscesso Hepático Amebiano, Amebíase Hepática |
| Spanish | Absceso hepático amebiano, Absceso hepático por Entamoeba histolytica, absceso amebiano del hígado, absceso hepático amebiano (trastorno), absceso hepático amebiano, absceso hepático amébico, Amebiasis hepática, Absceso Hepático Amebiano, Amebiasis Hepática |
| Japanese | 赤痢アメーバによる肝膿瘍, ｾｷﾘｱﾒｰﾊﾞﾆﾖﾙｶﾝﾉｳﾖｳ, ｱﾒｰﾊﾞｾｲｶﾝﾉｳﾖｳ, ｶﾝｱﾒｰﾊﾞｼｮｳ, 肝膿瘍-アメーバ性, アメーバ症-肝, アメーバ性肝膿瘍, 肝アメーバ症, 膿瘍-アメーバ性-肝 |
| Swedish | Leverabscess, amöba |
| Czech | játra - absces amébový, Amébový jaterní absces, Jaterní amébóza, Jaterní absces způsobený Entamoeba histolytica, amébový absces jater, amébový jaterní absces |
| Finnish | Ameban aiheuttama maksapaise |
| Russian | AMEBIAZ PECHENI, PECHENI ABSTSESS AMEBNYI, АМЕБИАЗ ПЕЧЕНИ, ПЕЧЕНИ АБСЦЕСС АМЕБНЫЙ |
| Korean | 아메바성 간 고름집(농양) |
| Croatian | JETRENI APSCES, AMEBNI |
| Polish | Pełzakowica pozajelitowa, Ropień wątroby pełzakowy |
| Hungarian | amoebás májtályog, hepatikus amoebiasis, Entamoeba histolytica máj abscessus, Máj-amoebiasis, Amoebás máj abscessus |
| Norwegian | Hepatisk amøbiasis, Amøboid leverabscess |
Ontology: Amoeba histolytica dysentery (C0857976)
| Concepts | Disease or Syndrome (T047) |
| Dutch | Amoeba histolytica-dysenterie |
| French | Dysenterie à Amoeba histolytica |
| German | Ruhr infolge von Amoeba histolytica |
| Italian | Dissenteria da ameba istolitica |
| Spanish | Disentería por Amoeba histolytica |
| Japanese | 赤痢アメーバ性赤痢, ｾｷﾘｱﾒｰﾊﾞｾｲｾｷﾘ |
| Czech | Dyzenterie způsobená Entamoeba histolytica |
| English | Amoeba histolytica dysentery, Ameba histolytica dysentery |
| Hungarian | Amoeba histolytica dysenteria |
| Portuguese | Disenteria por ameba histolítica |
