Acute amebic appendicitis in early pregnancy

Abstract

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.

Introduction

Parasitic infections of the intestine are a major health problem, which is found more prevalent in developing countries such as India.¹ They are one of the important causes of morbidity and mortality among people all over the world. The World Health Organization estimates that one person in every four harbours parasitic worms.² Among these parasites, Entamoeba histolytica and Enterobius vermicularis are responsible and are causative agents for the majority of intestinal parasitic infections occurring in 0.5–2.0% of all cases of acute appendicitis.³ Acute amoebic appendicitis is one of 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.

Case report

A 24-year-old female patient, primigravida, with uterine pregnancy of 7-wk duration, presented to the emergency department with pain in the right side of the abdomen of three days duration with moderate to high grade fever, along with nausea and vomiting. There was no preceding history of diarrhoea or bleeding per rectum. Abdominal examination showed marked tenderness in the right iliac fossa with rebound tenderness. Laboratory investigations revealed haemoglobin of 11.9 g/dL and polymorphonuclear leucocytosis of 22,100/cmm with absolute neutrophilia (84% polymorphs). Clinically, the patient was diagnosed with acute appendicitis. The ultrasonography (USG) of the abdomen showed features of acute appendicitis. The patient was started on piperacillin–tazobactam injection as single-antibiotic therapy in view of high-grade fever and significant leucocytosis. The patient underwent laparoscopic appendicectomy. A grossly thickened, inflamed appendix was found which was adherent to the mesentry and omentum. There was a fecolith at the tip of the appendix. No perforation was found. The patient continued to have high spikes of fever and significant tachycardia on the first postoperative day. The USG abdomen showed no intra-abdominal collection. Neutrophilic leucocytosis persisted. In view of continuing features of acute systemic infection, in consultation with the gynaecologist, metronidazole injection was added on the first postoperative day and was continued for seven days. The patient became afebrile and made an uneventful recovery.

The specimen of the appendix was sent to the histopathology laboratory in 10% buffered formalin. The appendix measured 6 cm in length with attached mesappendix and congested serosal surface. On longitudinal section, the tip showed the faecal matter. The mucosal surface was markedly congested and showed areas of ulceration. Histological sections on microscopic examination revealed mucosal ulceration with formation of lymphoid aggregates in the submucosa. Dense transmural mixed inflammation was seen comprising predominantly of polymorphs along with few eosinophils infiltrating the muscularis propria and extending till the serosa. Numerous trophozoites forms of Entamoeba histolytica were seen infiltrating the ulcerated mucosa. Few trophozoites showed ingested red blood cells (erythrophagocytosis). There was vascular congestion on the serosal surface. Periodic Acid Schiff (PAS) staining was performed which showed better morphology of the trophozoites. The diagnosis of acute amoebic appendicitis was made on histomorphology (Fig. 1). Patient consent for inclusion in the study was obtained.

Fig. 1.

Histopathological photomicrograph showing the acute amebic appendicitis.

Discussion

Acute appendicitis is one among the most frequently found surgical emergency in patients presenting in the emergency department with complains of abdominal pain.⁴ Acute appendicitis is also well known to occur in pregnancy. The reported incidence from various previous studies ranges from 0.15 to 2.10 cases in 1000 pregnancies.⁵ Acute appendicitis caused because of Entamoeba histolytica is relatively rare, and the literature contains only few case reports with the exact frequency still not known. A study by Gupta et al⁶ reported a frequency of 0.5% for the acute amoebic appendicitis, whereas Guzman-Valdivia⁷ revealed a higher frequency of cases diagnosed as amoebic appendicitis (2.3%). A systematic review on amoebic appendicitis⁸ showed that the mean age of the patients diagnosed as acute amoebic appendicitis was 23.5 years, of which majority were male patients (74.0%).

In many cases of systemic amoebiasis, parasites (trophozoites of Entamoeba histolytica) in the appendix lumen do not invade the mucosa/submucosa or cause acute inflammation. It is thought that the inflammation of the appendix occurs secondary to the obstruction of its lumen which is due to mucosal oedema and it is caused by the presence of trophozoites (active form of Entamoeba histolytica). Under poor hygiene conditions, humans ingest the cystic form of Entamoeba histolytica, which then gives rise to trophozoites. The trophozoites of Entamoeba histolytica reside in the lumen of the colon or may invade the wall and cause the formation of chronic inflammatory lesion known as an amoeboma, which itself may resemble acute appendicitis. The cyst can travel via the portal vein to the liver and to other organ systems of the body. Stool examination, serological test, culture and non-invasive imaging of the liver are the most important procedures in the diagnosis of amoebiasis. The definitive diagnosis of amoebic infection is made by the demonstration of hematophagus trophozoites of Entamoeba histolytica.⁹

In our case, the patient did not have associated diarrhoea in the clinical presentation, and stool examination was unremarkable. Histologically, sections taken from various levels of the appendix demonstrated trophozoites of Entamoeba histolytica. Hence, this case reported as acute amoebic appendicitis represents a rare form of appendicitis. Appendicectomy combined with antimicrobials is the treatment of choice. Appendicectomy removes the focus of infection, and antimicrobials reduce the incidence of septic complications. This case report highlights acute appendicitis of amoebic origin and emphasises the importance of thorough examination of the appendix at various levels during histopathological examination.

Conflicts of interest

The authors have none to declare.