Amoebic colitis: A case series of a recurring missed diagnosis

Abstract

Entamoeba histolytica, a pathogenic protozoan that causes amoebiasis, remains the second leading cause of death from parasitic infections worldwide. We present a case series of patients presenting to metropolitan tertiary gastroenterology units in Melbourne, Australia, highlighting the complexities of diagnosing amoebic colitis and the potential for misdiagnosis. These cases illustrate four key lessons in the identification of amoebic colitis: (i) obtaining a thorough travel and exposure history, (ii) having a high index of suspicion, (iii) understanding the limitations of available investigations, and (iv) being aware that amoebic colitis may masquerade as other common conditions.

Diversity and Plasticity of Virulent Characteristics of Entamoeba histolytica

“…In particular, in groups containing individuals who present with subacute/chronic gastrointestinal symptoms, some individuals are initially misdiagnosed with Inflammatory bowel disease (IBD) [ 25 ]. The main reasons for the wrong diagnosis are as follows; (1) presentation (abdominal symptoms, intermittent episodes, and chronic time course) of amebic colitis is often similar to symptoms of IBD; (2) non-specific endoscopic findings for physicians who did not recognize the parasite infection as a differential diagnosis; and (3) non-specific pathological findings based on the hematoxylin and eosin stain, which sometimes make it technically hard for all physicians bar well-experienced laboratory staff to distinguish these cells from inflammatory cells [ 18 , 26 , 27 , 28 ]. This misdiagnosis could lead to the inappropriate use of corticosteroid therapy and induce the exacerbation of amebic colitis to severe status.…”

“…Certainly, in some cases, the parasite does not suffer from any parasite-related bowel complaints and can be eradicated spontaneously [ 20 ]. However, the appropriate treatment is currently warranted in all cases of infection with E. histolytica , even in asymptomatic individuals, because there a lot of personal factors influencing the transformation of the silent disease into more severe disease, such as age, pregnancy, corticosteroid, malignancy, malnutrition, and alcoholism [ 1 , 27 , 29 ].…”

Parasitic infections in hematopoietic stem cell transplant recipients

“…26 Although most patients are asymptomatic, around 10% of patients can manifest with abdominal pain, watery and/or bloody diarrhea, weight loss, and fevers. [27][28][29] Extraintestinal spread is rare, even in immunocompromised patients, seen in around 1.8% of HIV patients with amebiasis 30 and only one reported case seen in an SOT patient. 31 In some patients, the diarrhea seen with intestinal amebiasis can be mistaken for GVHD.…”

“…32 Hence, other tests with higher sensitivity such as fecal polymerase chain reaction (PCR), fecal and/or serum antigen detection, and serology can be done. 29 The best diagnostic results are yielded by a combination of serology and antigen testing. 33 Confirmation of diagnosis can be made with colonoscopy and biopsy; however, it is not recommended for routine diagnosis.…”

“…However, this has low sensitivity and is time‐consuming 32 . Hence, other tests with higher sensitivity such as fecal polymerase chain reaction (PCR), fecal and/or serum antigen detection, and serology can be done 29 . The best diagnostic results are yielded by a combination of serology and antigen testing 33 .…”