Fulminant Amebic Colitis after Corticosteroid Therapy: A Systematic Review

BACKGROUND

Amebic colitis, caused by intestinal infection with the parasite, Entamoeba histolytica, is a common cause of diarrhea worldwide. Fulminant amebic colitis is the most devastating complication of this infection, associated with both high mortality and morbidity. We conducted a review of the English literature to describe cases of fulminant amebic colitis associated with exposure to corticosteroid medications in order to identify the risk factors for poor outcome and determine difficulties in diagnosis and treatment.

METHODOLOGY AND PRINCIPAL FINDINGS

Articles reporting severe and fulminant forms of amebic colitis between 1991 and 2016 were collected. 525 records were screened to identify 24 cases for qualitative analysis associated with corticosteroid use. Cases arose from areas of high endemicity or travel to such areas. Most cases (14 of 24, 58%) were given corticosteroids for initially misdiagnosed colitis, mainly inflammatory bowel, resulting in rapid progression of disease. Nearly half of all cases underwent surgical intervention, and 25% of cases died, despite all patients eventually receiving treatment with metronidazole. The odds of death did not differ significantly by prior misdiagnosis, co-morbidities, bowel perforation or need for surgery.

CONCLUSIONS AND SIGNIFICANCE

Infection with E. histolytica should be considered prior to the administration of corticosteroids, in particular for patients residing in endemic areas or those with appropriate travel history, especially prior to the diagnosis of inflammatory bowel disease. The development of preventative and treatment interventions are needed to improve outcomes of fulminant disease.

Anterior necrotizing scleritis after strabismus surgery in a child

Anterior necrotizing scleritis is a rare but potentially devastating complication of ocular surgery that most often occurs after cataract surgery in elderly patients who may have an underlying systemic autoimmune condition(1) or, less likely, an infectious cause.(2) We describe the management and outcome of a case of bilateral anterior necrotizing scleritis after postoperative infection in a 19-month-old girl who had recently undergone strabismus surgery.

Massive Trichuris trichiura infection as a cause of chronic bloody diarrhea in a child

The differential diagnosis of chronic diarrhea is extensive and requires the investigation of several diseases, such as celiac disease, inflammatory bowel disease and irritable bowel syndrome. A few patients infected by Trichuris trichiura may present a chronic dysentery-like syndrome in the context of a massive infestation of the colon leading to anemia and growth retardation, but the rarity of that finding demands a high level of suspicion. Herein we report the case of an 8-year-old boy from the rural zone who had suffered diarrhea without blood or mucus for 4 years and was taken to our Service because his mother had noticed the presence of blood on the feces on the 3 previous months. The diagnosis of a massive Trichuris trichiura infestation as the cause of the process was only reached by colonoscopy. We stress that Trichuris trichiura infection can mimic other forms of inflammatory bowel disease and lead to physical growth retardation and that prolonged regimens of albendazole may be required to the effective treatment of massive infestations.

Expression of amoebapores is required for full expression of Entamoeba histolytica virulence in amebic liver abscess but is not necessary for the induction of inflammation or tissue damage in amebic colitis

Entamoeba histolytica trophozoites produce amoebapores, a family of small amphipathic peptides capable of insertion into bacterial or eukaryotic membranes and causing cellular lysis. Recently, E. histolytica trophozoites that are totally deficient in the production of amoebapore-A were created through a gene silencing mechanism (R. Bracha, Y. Nuchamowitz, and D. Mirelman, Eukaryot. Cell 2:295-305, 2003). Here we tested the virulence of amoebapore A(-) trophozoites in models of the two major forms of amebic disease: amebic liver abscess and amebic colitis. We demonstrate that amoebapore expression is required for full virulence in the SCID mouse model of amebic liver abscess, but E. histolytica trophozoites that do not express amoebapore-A can still cause inflammation and tissue damage in infected human colonic xenografts. These data are consistent with the concept that tissue damage may proceed by different mechanisms in amebic liver abscess compared to amebic colitis.

Epidemiologic and clinical characteristics of acute diarrhea with emphasis on Entamoeba histolytica infections in preschool children in an urban slum of Dhaka, Bangladesh

The epidemiology, clinical features, nutritional status, and causative agents of diarrhea were studied in 289 Bangladeshi children (147 boys and 142 girls) 2-5 years old. The use of improved diagnostic tests for amebiasis enabled for the first time analysis of the contribution of Entamoeba histolytica to total diarrheal illness in this community setting. The average incidence rate of diarrhea was 1.8/child-year, and the average number of diarrheal days was 3.7 days/child-year over an average observation period of 2.8 years/child. Seventy-five percent of the diarrheal episodes were < or = 2 days in duration. Persistent diarrhea was relatively uncommon (0.2% of the children) and chronic diarrhea was observed in only one episode. Compared with malnourished and/or stunted children, better-nourished children experienced significantly fewer diarrheal episodes. The diarrheal incidence rate for children with blood group A was significantly less that that of the children with blood groups O and AB. The most frequent bacterial enteropathogens isolated from diarrheal stool specimens were enterotoxigenic Escherichia coli (9%) and Aeromonas species (9%), followed by Plesimonas shigelloides (4%) and Shigella flexneri (3.8%). Rotavirus was the most common viral agent isolated from diarrheal stool samples (5%). Giardia lamblia, Cryptosporidium parvum, and E. histolytica were identified in 11%, 8.4%, and 8%, respectively, of the diarrheal stool specimens. Dysentery was observed in 7.7% of all diarrheal episodes. The most common pathogens isolated from dysenteric stool were S. flexneri (11.6%), Aeromonas sp. (10%), E. histolytica (8.7%), Campylobacter jejunii (5.8%), P. shigelloides (4.3%), and A. caviae (4.3%). The overall incidence rate of E. histolytica-associated diarrhea was 0.08/child-year. Visible blood and hemoccult test-detected blood loss was found in 7% and 25%, respectively, of cases of E. histolytica-associated diarrhea. Children who had recovered from a diarrheal episode with E. histolytica, but not E. dispar, had half the chance of developing subsequent E. histolytica-associated diarrhea, consistent with the development of species-specific acquired immunity. In conclusion, the use of modern diagnostic tests demonstrated that E. histolytica contributed to overall morbidity from diarrheal illness. Understanding the etiology, frequency, and consequences of acute diarrhea in children from a developing country should aid in the design of interventions to improve child health.

Tumor necrosis factor alpha is a key mediator of gut inflammation seen in amebic colitis in human intestine in the SCID mouse-human intestinal xenograft model of disease

We used Entamoeba histolytica infection in human intestinal xenografts to study the roles interleukin-1 (IL-1) and tumor necrosis factor alpha (TNF-alpha) in the pathogenesis of amebic colitis. We found that blockade of TNF-alpha reduced inflammation and intestinal damage in amebic infection, while inhibition of IL-1 reduced cytokine production but had less marked effects on inflammation and disease.

Treatment of infectious diarrhea in children

Diarrheal diseases remain an important cause of childhood morbidity and death in developing countries, although diarrheal deaths have significantly declined in recent years, mostly due to successes in the implementation of oral rehydration therapy (ORT), which is the principal treatment modality. Diarrhea may occur for varied reasons; however, most episodes of diarrhea in developing countries are infectious in origin. Three clinical forms of diarrhea (acute watery diarrhea, invasive diarrhea, and persistent diarrhea) have been identified to formulate a management plan. Acute diarrhea may be watery (where features of dehydration are prominent) or dysenteric (where stools contain blood and mucus). Rehydration therapy is the key to management of acute watery diarrhea, whereas antimicrobial agents play a vital role in the management of acute invasive diarrhea, particularly shigellosis and amebiasis. In persistent diarrhea, nutritional therapy, including dietary manipulations, is a very important aspect in its management, in addition to rehydration therapy. Rehydration may be carried out either by the oral or intravenous route, depending upon the degree of dehydration. Oral rehydration salts (ORS) solution (World Health Organization formula) is recommended for ORT. Intravenous fluid is recommended for initial management of severe dehydration due to diarrhea, followed by ORT with ORS solution for correction of ongoing fluid losses. Antimicrobial therapy is beneficial for cholera and shigellosis. Antiparasitic agents are indicated only if amebiasis and giardiasis are present. Appropriate feeding during diarrhea is recommended for nutritional recovery and to prevent bodyweight loss. Antidiarrheal agents do not provide additional benefit in the management of infectious diarrhea. Although some probiotics have been shown to be beneficial in the treatment of acute diarrhea due to rotavirus, their use in the treatment of diarrhea is yet to be recommended, even in developed countries. The children of developing countries might benefit from zinc supplementation during the diarrheal illness, but its mode of delivery and cost effectiveness are yet to be decided.

Treatment of infectious diarrhea in children

Diarrheal diseases remain an important cause of childhood morbidity and death in developing countries, although diarrheal deaths have significantly declined in recent years, mostly due to successes in the implementation of oral rehydration therapy (ORT), which is the principal treatment modality. Diarrhea may occur for varied reasons; however, most episodes of diarrhea in developing countries are infectious in origin. Three clinical forms of diarrhea (acute watery diarrhea, invasive diarrhea, and persistent diarrhea) have been identified to formulate a management plan. Acute diarrhea may be watery (where features of dehydration are prominent) or dysenteric (where stools contain blood and mucus). Rehydration therapy is the key to management of acute watery diarrhea, whereas antimicrobial agents play a vital role in the management of acute invasive diarrhea, particularly shigellosis and amebiasis. In persistent diarrhea, nutritional therapy, including dietary manipulations, is a very important aspect in its management, in addition to rehydration therapy. Rehydration may be carried out either by the oral or intravenous route, depending upon the degree of dehydration. Oral rehydration salts (ORS) solution (World Health Organization formula) is recommended for ORT. Intravenous fluid is recommended for initial management of severe dehydration due to diarrhea, followed by ORT with ORS solution for correction of ongoing fluid losses. Antimicrobial therapy is beneficial for cholera and shigellosis. Antiparasitic agents are indicated only if amebiasis and giardiasis are present. Appropriate feeding during diarrhea is recommended for nutritional recovery and to prevent bodyweight loss. Antidiarrheal agents do not provide additional benefit in the management of infectious diarrhea. Although some probiotics have been shown to be beneficial in the treatment of acute diarrhea due to rotavirus, their use in the treatment of diarrhea is yet to be recommended, even in developed countries. The children of developing countries might benefit from zinc supplementation during the diarrheal illness, but its mode of delivery and cost effectiveness are yet to be decided.

Raw wastewater agricultural re-use and risk of protozoal infection in Beni-Mellal, Morocco

This study was carried out to determine the potential risk of protozoal infection associated with raw wastewater use for agricultural purposes, among children of Beni-Mellal, Morocco. In a randomly-selected sample of 1343 children 740 from 5 regions which use raw wastewater for agriculture (exposed), while 603 were from 4 control regions that do not practice wastewater irrigation (unexposed). A questionnaire-interview with children and parents was used to collect data on demographic, hygienic, and risky water contact risk factors One or more protozoal infection was identified among 276(37.2%) of children living in the wastewater re-use regions, versus only among 22 (3.6%) living in control regions. The overall prevalence of 40.1% was observed among boys, and 33.3% among girls residing in exposed areas. The two identified protozoa were Entaemoeba histolytica and Giardia intestinalis, which infected 34.3% and 5.1% in the exposed population compared to only 3.3% and 0.3% in the control population, respectively. We also noted that the G. intestinalis prevalence was more than 40% among the children under 9 years, but less than 17% for those who were more than 12 years. Also, a significant excess of protozoal infection was observed among children who had risky contact with agricultural lands (p<0.001). In conclusion, raw wastewater use in Beni-Mellal can lead to a high risk of protozoal infections. Adequate treatment of wastewater prior to re-use, as well as public health education are highly recommended.

First report of invasive amebiasis in an organ transplant recipient

T-cell mediated immunity is an important defense mechanism against amebiasis. However, organ transplant recipients with severe T-cell immunosuppression are not at increased risk of having Entamoeba histolytica invasive disease. The reasons are unclear and probably multifactorial, but it is likely that the absence of intestinal colonization with pathogenic strains in countries where transplants occur and the judicious intake of possible contaminated food and water are important contributing factors. We describe the first report of a liver transplant recipient with severe E. histolytica colitis who was successfully treated with metronidazole without modifying his immunosuppression therapy.

[Amoebiasis--a problem in patients with ulcerative colitis]

The increasing problem is presented of Entamoeba histolytica invasion in patients with ulcerative colitis. The diagnostic-therapeutic management in five patients with amoebiasis is discussed in detail. This parasitic invasion occurred in five out of 103 patients with ulcerative colitis which accounts for 4.85%. This data is important for the treatment of chronically ill patients with ulcerative colitis.

Amebiasis after bone marrow transplantation

A patient undergoing BMT for acute non-lymphocytic leukemia (ANLL) developed bloody diarrhea due to amebiasis. The infection was successfully treated with intensive and prolonged antiparasitic therapy.

Inhibitory activity of saccharomyces yeasts on the adhesion of Entamoeba histolytica trophozoites to human erythrocytes in vitro

Adhesion to target cells represents the first step in infection by Entamoeba histolytica. Binding of axenic amoeba (HMI strain) to human red cells in vitro was employed as a model of the adhesion process. The influence of precontact of trophozoites with suspensions of live Saccharomyces boulardii yeasts, their fractions (membranes and yeast-content supernatant before and after filtration to eliminate the membrane) or yeast culture medium before and after fermentation was investigated. N-Acetylgalactosamine (GalNAC) was employed as the reference inhibitory sugar. The percentage of amoebae bearing red cells after pretreatment of amoebae with the various suspensions and derivates was determined. Adhesion was also evaluated by scanning electron microscopy (SEM). Pretreatment of amoebae with the live yeast suspension led to a significant reduction in the percentage of adhesion [32% vs 70% in the phosphate-buffered saline (PBS) control]. Reduced adhesion was also observed with the filtered and unfiltered supernatant of the yeast suspension homogenate [32% and 34%, respectively, vs 69% in the PBS control], yeast culture medium at the end of fermentation [49% vs 76% in the PBS control] and GalNAC [32% vs 72% in the PBS control]. SEM showed a decrease in the number of amoebae bearing red cells and a reduction in the number of red cells adhering to amoebae. We conclude that substances produced by the yeasts compete with red cells for adhesion sites on amoebae.

ABC of colorectal diseases. Tropical colonic diseases

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Asymptomatic intestinal colonization by pathogenic Entamoeba histolytica in amebic liver abscess: prevalence, response to therapy, and pathogenic potential

Since the application of isoenzyme electrophoresis to the study of Entamoeba histolytica, the prevalence and natural history of asymptomatic intestinal colonization in patients with amebic liver abscess (ALA) has not been addressed. We prospectively evaluated this enteric phase in 50 patients with ALA, using two dosage regimens of metronidazole. The overall prevalence of asymptomatic colonization was 72% (36/50). All these isolates, without exception, proved to express pathogenic zymodemes. Despite a 100% clinical response of the hepatic lesions, failure to eradicate the organism from the bowel occurred in 20 of these 36 subjects. During longitudinal posttreatment surveillance, three carriers returned with second bouts of invasive disease: one with dysentery and two with liver abscesses. Thus, in patients with ALA, there is a high prevalence of intestinal colonization with exclusively pathogenic strains, and treatment with metronidazole frequently results in a continued carrier state. These carriers have a propensity for developing recurrent invasive disease and constitute a public health hazard.

Ulcerative colitis developing after amoebic dysentery in a haemophiliac patient with AIDS

Severe diarrhoea in patients with the acquired immune deficiency syndrome (AIDS) is usually a manifestation of gastrointestinal infection by a variety of organisms. We report a patient with low CD4 T cell counts who developed ulcerative colitis after amoebic dysentery. He subsequently developed acute ulcerative colitis with toxic dilatation while he was severely immunocompromised. He responded to corticosteroids and mesalazine and remains well on maintenance therapy.

Amebiasis: clinical and laboratory perspectives

Entamoeba histolytica, the premier intestinal protozoan, has traversed time in its relentless quest for survival in its dichotomous role of parasite and pathogen. Enigmatic in its transition from human intestinal commensal to invader of human tissue, diverse in its pathogenicity for the human host, and intricate in its bacterial interrelationship in the bowel, E. histolytica has become the focal point of intensive investigation in its basic biology underscoring human pathogenicity. This review will focus on facets of cell biology, pathophysiology, clinical, therapeutic, and epidemiologic, correlates, along with diagnostic modalities and future research trends.

Amebiasis at an evacuation site on the Thai-Cambodian border

Symptomatic intestinal amebiasis was highly endemic among the Cambodians living at Green Hill, an evacuation site on the Thai-Cambodian border between June 1987 through May 1989. Monthly incidence rates of intestinal amebiasis were determined to be inversely proportional to cumulative monthly rainfall. The highest incidence of amebic dysentery was 63/1000 in children 12-23 months old. Behavioral risk factors were investigated by conducting a case-control study. A questionnaire was administered to 73 families, each having at least one member with confirmed intestinal amebiasis within the past 3 months, and to 95 randomly selected control families having no individual with diarrhea for at least 3 months. Individuals from families with greater than 4 members were at higher risk for acquiring intestinal amebiasis. No significant differences in behavioral risk factors were identified between case and control families. Eighty-six percent of 51 water samples drawn from wells where amebiasis patients obtained their drinking water had greater than 10 coliforms/100 ml. The main route of transmission of E. histolytica was not identified, but was most likely via the fecal-oral route.

[Amoebic dysentery: a relapsing case by cancer chemotherapy]

A 71-year-old man was admitted with a diagnosis of amoebic dysentery. He received a tonsillectomy 2 years prior to admission because of squamous cell carcinoma and had been treated with 5-FU. Laboratory examination showed T-lymphocytopenia and the T4/T8 ratio was markedly reduced. He experienced amoebic dysentery during World War II some 40 years ago, thus, this case report suggested that amoebiasis relapsed by depressed cellular immunity and was calculated as one of the opportunistic infections.

Role of adhesive wraps in the pathogenesis of complicated amoebic colitis

Ischaemic foci within the abdomen attract omental and peritoneal adhesions with neovascularization. Previously it has been shown that transmural amoebic colitis is an ischaemic process. An intra-operative evaluation of the peritoneal barriers in response to necrosis was undertaken during laparotomy in 82 patients with clinical transmural amoebic colitis. At operation the ischaemic colon was covered by adhesive wraps in all patients; peritonitis subsequently was absent in 23 patients (28 per cent), serous in 43 patients (52 per cent), purulent in only 9 patients (11 per cent) and faeculent in another 7 patients (9 per cent). The author regards wrapping as mechanically protective. Wrapping is also a source of neovascularization which was demonstrated on 10 angiograms of resected specimens with transmural disease. This is further supported by clinical finding of subsequent necrosis of colons in three patients whose wraps were disturbed at laparotomy without resection of the colons. Therefore, for both mechanical and vascular reasons, these wraps should not be disturbed.

Susceptibility of hamsters to caecal amoebiasis by oral infection

A method is described for successfully establishing caecal amoebiasis in hamsters which were not fed and which were pretreated with 1 ml of magnesium sulphate every 24 hours for three days and then given 12 x 10(5) trophozoites of the HM-1 axenic strain or 18 x 10(5) trophozoites of the HK-9 axenic strain of Entamoeba histolytica by the oral route. All the animals developed diarrhoea within 24 hours of infection. When the animals were killed on the fifth day after infection the caecum was swollen and fused. Large macroscopic ulcers full of pus could be seen in the caecum. None of the control animals showed any of the changes mentioned above.

The interaction between Entamoeba histolytica and Syphacia obvelata infection in mice

Mice naturally infected with Syphacia obvelata were challenged intracaecally with Entamoeba histolytica trophozoites. They showed a higher level of amoebic infection than mice without worms. Mice with the heaviest Syphacia infection were the most susceptible to amoebic infection. It appears that a concomitant infection with helminthic parasites residing in the caecum alters the outcome of an amoebic infection.

Extensive cutaneous burn complicated by severe necrotizing amebic enterocolitis. Pathogenic factors resulting in severe amebic disease

A 59-yr-old Mexican-American man developed fatal necrotizing amebic enterocolitis following an extensive cutaneous thermal injury. Those factors in the severely burned patient which predispose to amebic disease are discussed.