Amebic acute appendicitis: systematic review of 174 cases

Amebiasis as a sexually transmitted infection: A re-emerging health problem in developed countries

Amebiasis, which is caused by Entamoeba histolytica (E. histolytica), is the second leading cause of parasite-related death worldwide. It manifests from asymptomatic carriers to severe clinical conditions, like colitis and liver abscesses. Amebiasis is commonly seen in developing countries, where water and food are easily contaminated by feces because of the poor sanitation. However, a recently challenge in many developed countries is the increase in domestic cases of invasive amebiasis as a sexually transmitted infection (STI amebiasis). In contrast to food-/ waterborne transmission of E. histolytica in developing countries, transmission of STI amebiasis occurs directly through human-to-human sexual contact (e.g., men who have sex with men and people who engage in oral-anal sex); in this setting, asymptomatic infected individuals are the main reservoir of E. histolytica. The Development of screening methods for the early diagnosis of asymptomatic E. histolytica infection is the key to epidemiologic control. Moreover, delay in diagnosis of severe cases (e.g., fulminant amebiasis) leads to death even in developed countries. It is also important to increase clinical awareness of domestically transmitted STI amebiasis in the clinical settings. This review considers the changing epidemiology and clinical manifestations of STI amebiasis, and finally discusses the future strategies for the better practice.

What is important to the GP in recognizing acute appendicitis in children: a delphi study

BACKGROUND

For diagnostic research on appendicitis in registration data, insight is needed in the way GPs generate medical records. We aimed to reach a consensus on the features that GPs consider important in the consultation and medical records when evaluating a child with suspected appendicitis.

METHODS

We performed a three-round Delphi study among Dutch GPs selected by purposive sampling. An initial feature list was created based on a literature search and features in the relevant Dutch guideline. Finally, using a vignette describing a child who needed later reassessment, we asked participants to complete an online questionnaire about which consultation features should be addressed and recorded.

RESULTS

A literature review and Dutch guideline yielded 95 consultation features. All three rounds were completed by 22 GPs, with the final consensus list containing 26 symptoms, 29 physical assessments and signs, 2 additional tests, and 8 further actions (including safety-netting, i.e., informing the patient about when to contact the GP again). Of these, participants reached consensus that 37 should be actively addressed and that 20 need to be recorded if findings are negative.

CONCLUSIONS

GPs agreed that negative findings do not need to be recorded for most features and that records should include the prognostic and safety-netting advice given. The results have implications in three main domains: for research, that negative findings are likely to be missing; for medicolegal purposes, that documentation cannot be expected to be complete; and for clinical practice, that safety-netting advice should be given and documented.

Amebic appendicitis: a case report

Changing the paradigm of treatment of acute appendicitis to non-operative management can miss unusual etiologies that can only be diagnosed on pathologic analysis. Presented is a case of amebic appendicitis in which antibiotic management was dictated by post-operative pathology findings.

Acute amebic appendicitis in early pregnancy

Parasitic infections of the intestine are a major health problem, which is found more prevalent in developing countries such as India. They are one of the important causes of morbidity and mortality among people all over the world. Acute amoebic appendicitis is a rare entity. We came across a case of acute appendicitis in a young pregnant woman, which revealed colonies of Entamoeba histolytica trophozoites in the mucosal epithelium and submucosal layer of the appendix with marked evidence of acute appendicitis. This report highlights acute appendicitis of amoebic origin and emphasises the importance of thorough examination of the appendix at various levels during histopathology and about the combined treatment of appendicectomy combined with antimicrobials as the treatment of choice. Appendicectomy removes the focus of infection, and antimicrobials reduce the incidence of septic complications.

Amebiasis and Amebic Liver Abscess in Children

Although rare in the developed world, amebiasis continues to be a leading cause of diarrhea and illness in developing nations with crowding, poor sanitation, and lack of clean water supply. Recent immigrants or travelers returning from endemic regions after a prolonged stay are at high risk of developing amebiasis. A high index of suspicion for amebiasis should be maintained for other high-risk groups like men having sex with men, people with AIDS/HIV, immunocompromised hosts, residents of mental health facility or group homes. Clinical presentation of intestinal amebiasis varies from diarrhea to colitis and dysentery. Amebic liver abscess (ALA) is the most common form of extraintestinal amebiasis. Various diagnostic tools are available and when amebiasis is suspected, a combination of stool tests and serology should be sent to maximize the yield of testing. Treatment with an amebicidal drug such as metronidazole/tinidazole and a luminal cysticidal agent such as paromomycin for clinical disease is indicated. However, for asymptomatic disease treatment with a luminal cysticidal agent to decrease chances of invasive disease and transmission is recommended.

Successful treatment with metronidazole and paromomycin for fulminant amoebic colitis during cytotoxic chemotherapy in a patient with small-cell lung cancer

We report the case of a 64-year-old man with advanced small-cell lung cancer who developed fulminant amoebic colitis during cytotoxic chemotherapy. During the first cycle of carboplatin/etoposide treatment, febrile neutropenia and grade 4 neutropenia developed. Because diarrhea, abdominal pain, and bloody stool were observed, abdominal computed tomography was performed, showing intussusception, and extensive colectomy and colostomy were performed. Histopathology of the colon revealed gastrointestinal necrosis and perforation due to Entamoeba histolytica infection. Amoebiasis improved after treatment with metronidazole and paromomycin. The second cycle of carboplatin/etoposide with dose reduction was completed, resulting in a partial response to small-cell lung cancer.

The results of this case suggest that paromomycin is an additional option for amoebiasis during cytotoxic chemotherapy, and persistent diarrhea during cytotoxic chemotherapy should alert clinicians to consider the development of amoebiasis.

Unusual histopathological findings in appendectomy specimens with clinical diagnosis of acute appendicitis: A retrospective cohort analysis

INTRODUCTION

While appendicitis is considered one of most common acute surgical conditions, several studies have reported abnormal histopathological findings in appendectomy specimens; however, sending all appendices to histopathology is not yet routinely done.Here we report many unusual findings. Those unusual findings played a role not only in confirming acute appendicitis as a cause of the presentation in some cases but also discovering etiologies that mimic it with great impact on its management.

METHODS

Between January 2011 and December 2017, a total of 1510 patients were operated with appendectomy for a primary diagnosis of acute appendicitis. Among them, a total of 72 patients had incidental histopathologic findings in association with acute appendicitis or other pathologies instead of acute appendicitis. A retrospective analysis for those 72 patients was performed with all data being retrieved from the electronic health record system.

RESULTS

Patients ages ranged between 4 and 71 years with a mean age equal to 23.1 years (SD = 14.2). Majority of patients were women (n = 52; 72.2%). Sixty of the seventy-two cases were seen in patients with negative appendectomies (n = 333) with an overall rate of 18% among this group of patients. The remaining 12 patients had additional findings in histopathology specimens beside acute appendicitis (n = 1131) with an overall rate of 1%. The most commonly reported pathologies were serositis, ovarian cysts, and Enterobius vermicularis in descending frequency.

CONCLUSION

Identification of unusual histopathological findings during microscopic examination of resected appendices is more common in female patients and in patients with negative appendectomy. histopathologic assessment of specimens will allow detection of congenital, infectious or malignant pathologies that mimic acute appendicitis clinically even in the absence appendicitis microscopically.

Clinical features of amoebic appendicitis in children: A study of 23 cases

AIM OF THE STUDY

To describe the clinical, surgical, and pathological features of children with acute appendicitis and amebiasis.

MATERIALS AND METHODS

The medical records of children diagnosed with appendicitis and amebiasis treated at Fundación Hospital la Misericordia were retrospectively reviewed. Patients were classified into two groups according to the location of the amoebas: the amoebic appendicitis (AA) group (when the amoebic infection involved the appendiceal wall), and the appendicitis with incidental amoebiasis (IA) group (when amoebas were only found in the appendiceal lumen). We compared demographics and outcomes.

RESULTS

We identified 23 children with appendicitis and amoebiasis. The mean age was 9 (3-15) years, and 52% were male. The main duration of the pain at the time of presentation was 1.8 (1-4) days. Fever and diarrhea were observed in 64% and 43% of the patients, respectively. Four patients had perforated appendicitis, all of them within the AA group. Anti-parasitic therapy was used only in 2 subjects (all other patients were diagnosed after discharge and were asymptomatic on follow up). AA was diagnosed in 11 patients and IA in 12. AA and IA patients shared similar characteristics regarding age, clinical findings, radiologic features, and preoperative laboratory results. Appendiceal necrosis and perforation were only found within the AA group (4 patients).

CONCLUSIONS

AA is a rare condition in children. It seems to have a greater risk of perforation than cases of appendicitis with IA, which is in agreement with the more severe histological findings in our series. Anti-parasitic treatment is not necessary in cases of AA or IA.

Spectrum of CT findings in amebic colitis

Entamoeba histolytica is distributed throughout the world. Invasive amebiasis affects millions of people globally, and the associated complications cause 40,000-100,000 deaths per year. In countries where fecal-oral transmission is unusual, amebic colitis is not common, and the infection may be seen in travelers to and emigrants from endemic areas. Without adequate treatment, amebic colitis may develop into fulminant and become rapidly fatal. With the current increase in global mobility, amebic colitis should be suspected even in patients not in the endemic areas. CT plays an important role in the diagnosis of amebic colitis by demonstrating the presence of colitis with the typical involvement of the cecum and rectum. Pathological features of atypical involvement are also demonstrated. Since preoperative diagnosis can reduce the mortality associated with necrotizing colitis, radiologists need to recognize the typical as well as atypical CT findings of amebic colitis. Considering this requirement, this paper aims to describe the histopathologic features of amebic colitis and to illustrate the spectrum of corresponding CT findings.

A, Pontón P, Molina GA, Constante JE, Delgado JA. Amebiasis, a rare cause of acute appendicitis

Acute appendicitis is one of the most common abdominal emergencies, even though most cases of appendicitis will be due to obstruction of the appendiceal lumen, in rare occasions and mostly due to poor sanitary conditions a parasitic infection may cause appendicitis. Entamoeba histolytica is a common parasite and has a broad clinical spectrum from an asymptomatic disease to a life-threatening condition. In rare occasions, trophozoites can invade the appendiceal wall causing appendicitis. Preoperative diagnosis of acute amebic appendicitis is usually difficult, yet surgical treatment as in non-amebic appendicitis is the treatment of choice. However, due to the increased rate of postoperative complications associated with acute amebic appendicitis, a course of nitroimidazoles, and increased awareness in basic sanitary measures is usually recommended. We present a case of a 29-year-old woman, she presented with abdominal pain and appendicitis was suspected. After successful surgery, pathology confirmed acute amebic appendicitis.

A case of amebiasis with negative serologic markers that caused intra-abdominal abscess

A 23-year-old Japanese woman presented with abdominal distention following fever, diarrhea, and abdominal pain during a stay in Taiwan. Serology for the detection of amebic-antibodies and stool microscopic examination were both negative. A computed tomography scan showed a 13 cm diameter abscess spreading from the lower abdominal wall to the pelvic retroperitoneal space. Needle aspiration of the abscess was done under computed tomography guidance, and microscopy of the aspirated fluid revealed trophozoites of Entamoeba. The patient was diagnosed as amebiasis with negative serologic markers that caused intra-abdominal abscess. Intravenous metronidazole treatment for two weeks did not result in any improvement of the abscess. After irrigation and drainage of the abscess, her symptoms resolved. This case report highlights that amebiasis should be considered when indicated by patient history, including travelers returning from endemic areas, and that further evaluation is necessary for diagnosis, even if the serology and stool test are negative.

Underestimated Amoebic Appendicitis among HIV-1-Infected Individuals in Japan

Entamoeba histolytica is not a common causative agent of acute appendicitis. However, amoebic appendicitis can sometimes be severe and life threatening, mainly due to a lack of awareness. Also, its frequency, clinical features, and pathogenesis remain unclear. The study subjects were HIV-1-infected individuals who presented with acute appendicitis and later underwent appendectomy at our hospital between 1996 and 2014. Formalin-fixed paraffin-embedded preserved appendix specimens were reexamined by periodic acid-Schiff (PAS) staining and PCR to identify undiagnosed amoebic appendicitis. Appendectomies were performed in 57 patients with acute appendicitis. The seroprevalence of E. histolytica was 33% (14/43) from the available stored sera. Based on the medical records, only 3 cases were clinically diagnosed as amoebic appendicitis, including 2 diagnosed at the time of appendectomy and 1 case diagnosed by rereview of the appendix after the development of postoperative complications. Retrospective analyses using PAS staining and PCR identified 3 and 3 more cases, respectively. Thus, E. histolytica infection was confirmed in 9 cases (15.8%) in the present study. Apart from a significantly higher leukocyte count in E. histolytica-positive patients than in negative patients (median, 13,760 versus 10,385 cells/μl, respectively, P = 0.02), there were no other differences in the clinical features of the PCR-positive and -negative groups. In conclusion, E. histolytica infection was confirmed in 9 (15.8%) of the appendicitis cases. However, only 3, including one diagnosed after intestinal perforation, were diagnosed before the present analyses. These results strongly suggest there is frequently a failure to detect trophozoites in routine examination, resulting in an underestimation of the incidence of amoebic appendicitis.

Parasitic colitis

Over one billion people worldwide harbor intestinal parasites. Parasitic intestinal infections have a predilection for developing countries due to overcrowding and poor sanitation but are also found in developed nations, such as the United States, particularly in immigrants or in the setting of sporadic outbreaks. Although the majority of people are asymptomatically colonized with parasites, the clinical presentation can range from mild abdominal discomfort or diarrhea to serious complications, such as perforation or bleeding. Protozoa and helminths (worms) are the two major classes of intestinal parasites. Protozoal intestinal infections include cryptosporidiosis, cystoisosporiasis, cyclosporiasis, balantidiasis, giardiasis, amebiasis, and Chagas disease, while helminth infections include ascariasis, trichuriasis, strongyloidiasis, enterobiasis, and schistosomiasis. Intestinal parasites are predominantly small intestine pathogens but the large intestine is also frequently involved. This article highlights important aspects of parasitic infections of the colon including epidemiology, transmission, symptoms, and diagnostic methods as well as appropriate medical and surgical treatment.

Amebiasis presenting as acute appendicitis: Report of a case and review of Japanese literature

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The overall mortality rate reported in the studies in Japan (25%) is considerably higher than that reported in a systematic review conducted of similar studies in other countries (3.3%).

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Japan is a low-risk area for amebiasis, and many physicians fail to consider amebiasis in the differential diagnosis of acute appendicitis. In all of the cases, the diagnosis occurred only after surgery.

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It is important to conduct further examinations, including those for amebiasis, when appendectomy does not resolve acute appendicitis.

INTRODUCTION

Outside of these high-risk regions, acute amebic appendicitis is considerably rarer and the mortality rate is much higher than with non-amebic appendicitis.

PRESENTATION OF CASE

A 31-year-old woman presented with fever and right lower abdominal pain with no history of traveling abroad or sexual infection. Computed tomography revealed a dilated appendix and thickened cecal and ascending colon walls. She underwent an appendectomy for appendicitis. Owing to a lack of symptom resolution, we performed a pathologic examination of the appendix again that revealed multiple Entamoeba histolytica trophozoites; the serum amebic antibody was positive. She was treated postoperatively with metronidazole for amebiasis and discharged on postoperative day 12.

DISCUSSION

The mortality rate and frequency of severe postoperative intraabdominal complications were higher in the Japanese literature (1995–2013) (25% and 33%, respectively) than in other developed countries (3.3% and 19.4%, respectively). Japan is a low-risk area for amebiasis; many physicians fail to consider amebiasis in the differential diagnosis of acute abdomen. It is important to conduct further examinations, including those for amebiasis, when appendectomy does not resolve acute appendicitis.

CONCLUSION

We report a case of acute amebic appendicitis in a 31-year-old woman and review the ages at presentation, causative factors, treatments, and outcomes of 11 cases reported in Japan between 1995 and 2013.