Amebic Colitis
Endoscopic View of Amebiasis Colitis

Video Endoscopic Sequence 1 of 7.

Endoscopic View of Amebiasis Colitis.

Inflammatory bowel disease. At the beginning the macroscopic images were not specific.


Crohn´s Disease or Amebiasis colitis.?

Endoscopic diagnosis of amebic colitis can be difficult because its appearance may mimic other forms of colonic disease.

This sequence displays multiple ulcers at the rectum, but at the ascending colon and others segments it seems to be a Crohn´s disease. The rectum nodules are ulcerated and look “flask shaped” consistently with amebic colitis.

A 33 year-old male patient, who for work reasons had to live in Mexico for 5 months. 3 months earlier, he suffered an unspecified abdominal pain and diarrhea. He was hospitalized for a series of exams, to look at the endoscopic findings showed in this endoscopic sequence. 

In the majority of the cases, endoscopic findings of inflammatory bowel disease are unspecific and the diagnosis is established based on the patient’s evolution and clinical picture. The biopsies are mostly unspecified and a therapeutic trial is needed. As in this case, if colitis is caused by amebas, it should show a clinical improvement soon and a colonoscopy repeated 6 weeks later.

In countries where there is a high prevalence of Entamoeba Hystolitica, as in the case of Mexico and El Salvador, it is reasonable such therapeutic trial, where infection from this parasites is suspected. Our patient had been under treatment with metronidazole 250 mg,tid, for 10 days, and ciprofloxacin 250 mg tid. After six weeks a full after six week a full colonoscopy was performed and all lesions displayed in this endoscopic sequence, disappeared. 

Download the video clips by clicking on the endoscopic images, if you wish to observe in full screen, wait to be downloaded complete then press Alt and Enter for Windows media, Real Player Ctrl and 3. Configure the windows media in repeat is optimal. All endoscopic images shown in this Atlas contain video clips. We recommend seeing the video clips in full screen mode. 

 

Endoscopic View of Amebiasis Colitis

Video Endoscopic Sequence 2 of 7.

Endoscopic View of Amebiasis Colitis.

The image displays the rectum with a ulcerated polypoide like “flask shaped” and several tiny ulcers (aphtas).

Entamoeba histolytica:

Mature cysts are ingested via contaminated water or food.
After excystation in the small intestine, trophozoites inhabit the large intestine and can either invade the tissue (pathogenic amebas) or are eliminated in the stools. Trophozoites do not survive outside the body. This parasite was named for its remarkable ability to lyse human tissues. A prerequisite to amebic invasion is the parasite's ability to colonize and penetrate colonic mucins overlying the intestinal epithelium.

Endoscopic View of Amebiasis Colitis

Video Endoscopic Sequence 3 of 7.

Endoscopic Image of Amebiasis Colitis.

“Flask shaped ulcers”

The image and the video display multiple rectal nodular
ulcers (retroflexed image).

The diagnosis of amebic colitis can be difficult and confusing. The gross endoscopic appearance as well as the results of endoscopic biopsy can be extremely helpful in differentiating amebiasis from other forms of colitis. Clinical symptoms, laboratory studies, x-ray findings, cultures, and even serological studies may not be sufficient for making an accurate diagnosis. To illustrate the potential difficulties we are reporting three patients in whom the diagnosis of amebiasis was considered but in whom endoscopy was important for arriving at the correct diagnosis.

 

Endoscopic View of Amebiasis Colitis

Video Endoscopic Sequence 4 of 7.

Endoscopic View of Amebiasis Colitis.

The image and the video shows an ulcer of the sigmoid
colon.

 

Endoscopic View of Amebiasis Colitis

Video Endoscopic Sequence 5 of 7.

Endoscopic View of Amebiasis Colitis.

The lumen of apendix.

There are some ulcers; we introduced the colonoscope to the proximal first third of the appendiceal lumen, using a thin colonoscope (pediatric).

Endoscopic image and video clip of Amebiasis Colitis

Video Endoscopic Sequence 6 of 7.

Endoscopic image and video clip of Amebiasis Colitis

Ascending colon; multiple ulcers are displayed here; these
findings are consistent with Crohn´s disease.

 

Endoscopic image and video clip of Amebiasis Colitis

Video Endoscopic Sequence 7 of 7.

Endoscopic image and video clip of Amebiasis Colitis.

Another view of the ascending colon. Multiple ulcers are
seen.

 

Invasive amebiasis and ameboma formation

Video Endoscopic Sequence 1 of 4.

Invasive amebiasis and ameboma formation

This 76 year-old femalem, suffering of Alzheimer's disease
underwent a colonoscopy due to brisk hematochezia.

A colonoscopy was performed, therre are multiple ulcers

 

Ameboma (amebic granuloma) is a localized thickening of

Video Endoscopic Sequence 2 of 4.

Ameboma (amebic granuloma) is a localized thickening of the intestinal wall about an ulceration caused by Endamoeba histolytica which results in a lesion capable of being mistaken for a neoplasm because of the associated narrowing of the intestinal lumen and presence of a palpable mass.

Amebiasis is uncommon in developed countries. Its clinical presentation can be variable and non-specific, and the diagnosis can be easily overlooked. Among the wide variety of clinicopathologic manifestations of the intestinal amebiasis, amebomas occur rarely, resulting from the formation of annular colonic granulation tissue, usually in the cecum or ascending colon.

 

 

Ameboma is an uncommon manifestation of amebiasis, It

Video Endoscopic Sequence 3 of 4.

Invasive amebiasis and ameboma formation

Depicted thickening of the ascending colon wall and its ring-like stenosis. Because of concentric thickening of the wall and the mass-like appearance, a preliminary clinical diagnosis of cancer was made.

Ameboma is an uncommon manifestation of amebiasis, It can mimic both carcinoma and inflammatory bowel disease.

Amebiasis is an infectious disease caused by the protozoan Entamoeba histolytica. Infection rarely, but potentially may evolve into invasive colitis and formation of ameboma, which can closely resemble colorectal carcinoma. In general, the clinical spectrum of colorectal amebiasis ranges from asymptomatic carrier to severe fulminant necrotizing colitis with bleeding and perforation.

 

 

 

 

Invasive amebiasis and ameboma formation

Video Endoscopic Sequence 4 of 4.

Invasive amebiasis and ameboma formation

Histologic examination of the biopsies specimen confirmed the diagnosis of cecal ameboma.

Biopsy specimens obtained from the ulcerative lesion in the revealed a number of amebic organisms, trophozoites.

The intestinal protozoan parasite, E histolytica, is the causative agent of human amebiasis and the clinical syndrome of amebic dysentery. Transmission is mostly by ingestion of contaminated food or water, but venereal transmission via the fecal-oral route also occurs. Trophozoites are responsible for invasive disease, which sometimes results in dissemination and formation of amebic liver abscesses.

 

Amebiasis is the infection of the human gastrointestinal

Amebic Colitis.

Multiple “flask shaped” ulcers.

Amebiasis is the infection of the human gastrointestinal tract by Entamoeba histolytica, a protozoan parasite that is capable of invading the intestinal mucosa and may spread to other organs, mainly the liver. Entamoeba dispar, an ameba morphologically similar to E. histolytica that also colonizes the human gut, has been recognized recently as separate species with no invasive potential. The acceptance of E. dispar as a distinct but closely related protozoan species has had profound implications for the epidemiology of amebiasis, since most asymptomatic infections found worldwide are now attributed to this noninvasive ameba. 

 

Invasive amebiasis due to E. histolytica is more common

Amebic Colitis.

The typical ulcers and redness are seen.

Invasive amebiasis due to E. histolytica is more common in developing countries. In areas of endemic infection, a variety of conditions including ignorance, poverty, overcrowding, inadequate and contaminated wate supplies, and poor sanitation favor direct fecal-oral transmission of amebas from one person to another. Being responsible for approximately 70 thousand deaths annually, amebiasis is the fourth leading cause of death due to a protozoan infection after malaria, Chagas' disease, and leishmaniasis and the third cause of morbidity in this organism group after malaria and trichomoniasis, according to recent World Health Organization estimates.

 

Ulcers with slightly undermined edges are seen in this

Amebic Colitis.

Ulcers with slightly undermined edges are seen in this image of colonic amebiasis.

The motile form of E. histolytica, the trophozoite, lives in the lumen of the large intestine, where it multiplies and differentiates into the cyst, the resistant form responsible for the transmission of the infection. Cysts are excreted in stools and may be ingested by a new host via contaminated food or water. The parasite excysts in the terminal ileum, with each emerging quadrinucleate trophozoite giving rise to eight uninucleated trophozoites. Trophozoites may invade the colonic mucosa and cause dysentery and, through spreading via the bloodstream, may give rise to extraintestinal lesions, mainly liver abscesses.

The classic “flask shaped” ulcer in a patient with amebic

Video Endoscopic Sequence 1 of 2.

The classic “flask shaped” ulcer in a patient with amebic colitis. See the next image and video clip to appreciate another lesion in the same person.


 

Amebomas may produce symptoms that mimic cancer or

Video Endoscopic Sequence 2 of 2.

Ameboma.

Shows a large ulcerative lesion with marginal elevation

The formation of a mass lesion at sigmoid colon.
It is essential that these could not be misdiagnossed as inflamatory bowel disease or tumor.
An ameboma is a mass of tissue in the bowel that is formed by entamoeba hytolitica organisms. It can result from either chronic intestinal infection or acute amebic dysentery.
Amebomas may produce symptoms that mimic cancer or other intestinal diseases.

 

Amebic Colitis.

Amebic Colitis.

Depending on the affected organ, the clinical manifestations of amebiasis are intestinal or extraintestinal.

There are four clinical forms of invasive intestinal amebiasis, all of which are generally acute: dysentery or bloody diarrhea, fulminating colitis, amebic appendicitis, and ameboma of the colon. Dysenteric and diarrheic syndromes account for 90% of cases of invasive intestinal amebiasis. Patients with dysentery have an average of three to five mucosanguineous evacuations per day, with moderate colic pain preceding discharge, an they have rectal tenesmus. In patients with bloody diarrhea, evacuations are also few but the stools are composed of liquid fecal material stained with blood. While there is moderate colic pain, there is no rectal tenesmus. Fever and systemic manifestations are generally absent.

These syndromes constitute the classic ambulatory dysentery and can easily be distinguished from that of bacterial origin, where the patient frequently complains of systemic signs and symptoms such as fever, chills, headache, malaise, anorexia, nausea, vomiting, cramping abdominal pain, and tenesmus.

 

Rectal Amebiasis

Video Endoscopic Sequence 1 of 2.

Rectal Amebiasis.

A 45 year-old female, with rectal bleeding with dark red
color, two ulcers are observed “flask shaped” ulcer.

Download the video clip.

 

Rectal Amebiasis

Video Endoscopic Sequence 2 of 2.

Rectal Amebiasis.

Same case as above, retroflexed maneuver.

 

Endoscopic Image of Amebiasis Colitis.

Endoscopic Image of Amebiasis Colitis.

Infection of the large intestine by Entamoeba histolytica may result in an illness of variable severity, ranging from mild, chronic diarrhea to fulminant dysentery. Infection also may be asymptomatic.

Extraintestinal infection also can occur (e.g. hepatic abacess.)


Histopathology of Amebiasis

Rectal mucosa with surface erosion and Entamoeba
histolytica trophozoites.
Phagocytosis as a Virulence Factor.

 

A Close up.

Entamoeba histolytica trophozoites are able to degrade
human erythrocytes, Traditionally, erythrophagocytosis
has been the main laboratory criterion to identify
pathogenic amebas.

One of the fundamental questions of the biology of
Entamoeba histolytica directly related to the
understanding of human amebiasis concerns the nature of
the factors that determine the virulence of the parasite.
The initiation of invasive amebiasis may result from the
rupture of a host-parasite equilibrium that is maintained
while E. histolytica is restricted to a commensal phase.

 

High power detail of E. histolytica trophozoites with
eritrocytes inside.

The degree of virulence of cultured E. histolytica varies
according to the strain and culture condition The factors
responsible for these variations remain obscure. Despite a
large amount of information on the subject, ultrastructural
and biochemical studies have not been able to demonstrate
differences that could explain the variable degree of
virulence. Certain cell surface properties appear to
characterize pathogenic strains: adhesion to epithelial cells)
, susceptibility to agglutinate with concanavalin A, ability to
produce lytic effect on cultured cells and phagocytosis
oferythrocytes. Recently, a correlation between
collagenase production and virulence has been found.

 

Close up of trophozoites of E. histolytica showing the
nuclear appearance and erythrophagocytosis.

Trofozoítos de Entamoeba histolytica.

Gran aumento mostrando detalles de núcleo y eritrofagocitosis en E. histolytica .

Hepatic Amebic abscess

Sequence 1 of 16.

Hepatic Amebic Abscess

This is the case of a 78 year-old woman with Pain right hypochondrium referred to right shoulder fever 100.4 F and weight loss.

 

 

 

Hepatic Amebic abscess

Sequence 2 of 16.

Hepatic Amebic abscess

Amebic liver abscess is the most frequent extraintestinal manifestation of Entamoeba histolytica infection. This infection is caused by the protozoa E histolytica, which ascends the portal venous system. Amebic liver abscess is an important cause of space-occupying lesions of the liver, mainly in developing countries. Prompt recognition and appropriate treatment of amebic liver abscess lead to improved morbidity and mortality rates.

The signs and symptoms of amebic liver abscess often are nonspecific, resembling those of pyogenic liver abscess or other febrile diseases.

 

 

 

 

Hepatic Amebic abscess

Sequence 3 of 16.

Hepatic Amebic abscess

Liver involvement occurs following invasion of E histolytica into mesenteric venules. Amebae then enter the portal circulation and travel to the liver where they typically form large abscesses. The Gal/GalNAc lectin is an adhesion protein complex that sustains tissue invasion. The abscess contains acellular proteinaceous debris, which is thought to be a consequence of induced apoptosis and is surrounded by a rim of amebic trophozoites invading the tissue.

Time of onset

Patients with amebic liver abscess usually present acutely (duration of symptoms < 14 d), with the most frequent complaints being fever and abdominal pain. This presentation is characteristic of younger patients. The subacute presentation is characterized by weight loss, and, in less than half the cases, abdominal pain and fever are present.

Abdominal pain is the most common element in the history and is present in 90-93% of patients. The pain most frequently is located in the right upper quadrant (54-67%) and may radiate to the right shoulder or scapular area. Pain increases with coughing, walking, and deep breathing, and it increases when patients rest on their right side. The pain usually is constant, dull, and aching. Constitutional symptoms Fever is present in 87-100% of cases. Rigors are present in 36-69% of cases. Nausea and vomiting are present in 32-85% of cases. Weight loss is present in 33-64% of cases.

 

 

 

Hepatic Amebic abscess

Sequence 4 of 16.

Hepatic Amebic abscess

The right lobe of the liver is more commonly affected than the left lobe. This has been attributed to the fact that the right lobe portal laminar blood flow is supplied predominantly by the superior mesenteric vein, whereas the left lobe portal blood flow is supplied by the splenic vein.

 

 

 

Endoscopy of Liver-Duodenal Bulb Fistula.

Sequence 5 of 16.

Endoscopy of Liver-Duodenal Bulb Fistula.

This kind of Liver-Duodenal Bulb-Fistula is extremely rare

After a month and a week of hospital discharge, a routine endoscopy was performed, finding in the duodenal bulb two peculiar holes, one emerging fetid purulent secretion, Advancing the endoscope into a hole (fistula).

 

 

 

Endoscopy of Liver-Duodenal Bulb Fistula.

Sequence 6 of 16.

Another video clip of endoscopy of liver-duodenal fistula

In the fistula a material with necrosis is observed.

 

 

 

Endoscopy of Liver-Duodenal Bulb Fistula.

Sequence 7 of 16.

Another video clip of endoscopy of liver-duodenal fistula

It is trying to remove the necrotic material with a loop diathermy.

 

 

 

Endoscopy of Liver-Duodenal Bulb Fistula.

Sequence 8 of 16.

Another video clip of endoscopy of liver-duodenal fistula



 

 

 

Endoscopy of Liver-Duodenal Bulb Fistula.

Sequence 9 of 16.

Video clip of MRI of liver duodenal fistula, due to spontaneous drainage of an amebic liver abscess into the duodenal bulb.

 

 

 

Sequence 10 of 16.

Video clip of MRI liver duodenum fistula.

 

 

 

Endoscopy of Liver-Duodenal Bulb Fistula.

Sequence 11 of 16.

Video clip of MRI liver duodenum fistula.

 

 

 

Endoscopy of Liver-Duodenal Bulb Fistula.

Sequence 12 of 16.

Video clip of MRI liver duodenum fistula.

 

 

 

Endoscopy of Liver-Duodenal Bulb Fistula.

Sequence 13 of 16.

Video clip of MRI liver duodenum fistula.

 

 

 

Endoscopy of Liver-Duodenal Bulb Fistula.

Sequence 14 of 16.

Video clip of MRI of liver duodenal fistula, due to spontaneous drainage of an amebic liver abscess into the duodenal bulb.

 

 

 

Endoscopy of Liver-Duodenal Bulb Fistula.

Sequence 15 of 16.

Video clip of Fluoroscopy of fistula of liver to duodenal bulb with spontaneous drainage from Hepatic Amebic abscess.

 

 

 

Endoscopy of Liver-Duodenal Bulb Fistula.

Sequence 16 of 16.

Video clip of Fluoroscopy of fistula of liver to duodenal bulb with spontaneous drainage from Hepatic Amebic abscess

 

 

 

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