Acute fulminant necrotizing amebic colitis (FNAC) is a rare complication of intestinal amebiasis that is associated with high mortality and requires prompt diagnosis and surgical intervention. We recently cared for a young male who came with complaints of acute onset abdominal pain, obstipation, and abdominal distension along with a past history of recurring diarrhea over a month. On examination, patient had peritoinits with masking of liver dullness. Patient was resuscitated and taken for exploratory laprotomy which revealed pyoperitoneum, flimsy bowel adhesions, gangrene of cecum, and proximal ascending colon, with multiple colonic perforations along the antimesenteric border in the remaining ascending colon and transverse colon up to the splenic flexure. An extended right hemicolectomy with exteriorization of the proximal and distal loops as an end ileostomy and mucus fistula was done. Postoperatively done amebic serology was highly positive and histopathological examination was suggestive of infective necrosis of cecum and ascending colon. Patient was started on antiamebic medication and discharged on day 16 after a satisfactory recovery. This case report lays emphasis on the prompt diagnosis and treatment of FNAC and supports the empirical use of antiamebic medication in a case of recurring diarrhea/undiagnosed colitis in endemic areas.
Keywords: Fulminant colitis, intestinal amebiasis, recurrent diarrhea
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Suhani, Ali S, Thomas S, Aggarwal L. Fulminant necrotizing colitis: A rare complication of a common entity. Ann Trop Med Public Health 2013;6:661-3
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Suhani, Ali S, Thomas S, Aggarwal L. Fulminant necrotizing colitis: A rare complication of a common entity. Ann Trop Med Public Health [serial online] 2013 [cited 2021 Mar 5];6:661-3. Available from: https://www.atmph.org/text.asp?2013/6/6/661/140248
Amebiasis is a protozoan infection common in populations living in congested localities with poor sanitation. The protozoa, Entamoeba histolytica, principally affect the colon and liver, with majority of infested humans remaining asymptomatic. However, very uncommonly the disease takes a superacute course because of the development of fulminant necrotizing amebic colitis (FNAC), which has a very high mortality if diagnosis and treatment are delayed. Diagnosis can at times be difficult and confused with inflammatory bowel disease leading to wrong treatment with steroids with devastating results.
We present a case of 21-year-old male patient who came to the surgical emergency with complaints of continuous diffuse abdominal pain for 5 days, obstipation for 3 days, and abdominal distension for 1 day. There was history of recurring diarrhea lasting for 3 days, till around 10 days back. On examination, patient had dehydration, pallor, and tachycardia. Abdomen was distended having diffuse tenderness with masking of liver dullness and absence of bowel sounds. Hematological investigations revealed anemia and leukocytosis (hemoglobin (Hb) 8 g% and total leukocyte count (TLC) 15,000 cell/mm 3 ). Chest X-ray showed pneumoperitoneum. Human immunodeficiency virus (HIV) serology was negative. Patient was resuscitated and taken up for exploratory laprotomy. On exploration, there was around 1 liter of pyoperitoneum, numerous flimsy small bowel adhesions, gangrene and sloughing out of cecum, and proximal ascending colon [Figure 1]a. The remaining ascending colon and entire transverse colon (up to the splenic flexure) had multiple small perforations along the antimesenteric border [Figure 1]b. No significant mesenteric lymphadenopathy was present. An extended right hemicolectomy with peritoneal toileting was done and an end ileostomy and mucus fistula made. Postoperatively, patient has superficial surgical site infection which was managed with daily dressings. Patient was given nutritional support for 1 week along with injectable antimicrobial and antiamebic treatment (ceftriaxone 1 g intravenous IV bd × 7 days and metronidazole 800 mg IV tds × 14 days) in the postoperative period and discharged on 16 th postoperative day after a satisfactory recovery. Postoperatively done amebic serology was highly positive 6.4 odds ratio. Histopathology of the resected specimen revealed transmural gangrene of cecum and proximal ascending colon with multiple perforations in the colon having polymorphs and occasional lymphocytes, vascular congestion and mucosal edema, presence of periodic-acid Schiff PAS positive amebic trophozoites in the mucosa, and erythrophagocytosis [Figure 1]c and d.
|Figure 1: (a) Sloughed out cecum and ascending colon (b) Multiple colonic perforations (c) Periodic-acid Schiff (PAS) positive amebic trophozoites in the mucosa and muscularis layer (d) PAS positive trophozoites with erythrophagocytosis
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Intestinal amebiasis may involve any part of the bowel, but it has a predilection for the cecum and ascending colon.  Intestinal infection can be asymptomatic or symptomatic and present as typhilitis, acute protocolitis dysentery, or fulminant colitis with perforation.  The majority 90% of humans harboring Entamoeba histolytica, fall into the group of asymptomatic carriers and live a normal life.  However, fulminant necrotizing amebic colitis, in contrast to amebic enteritis, is a disease with high mortality. Uncomplicated amebic colitis is readily treated medically and has a mortality rate of less than 0.5%.  Complications necessitating surgical intervention develop in only 6-11% of patients with symptomatic disease and have a mortality rate ranging from 55 to 100% and stems in part from delay in diagnosis and treatment. 
Most patients with fulminant necrotizing amebic colitis present with nonspecific symptoms and signs such as severe abdominal distention, sepsis, watery or bloody mucoid diarrhea, and dehydration. Early diagnosis and surgical treatment of these cases significantly decrease mortality when compared with conservative treatment. , Apart from its rarity, clinical significance of fulminant amebiasis lies in the fact that the condition is difficult to diagnose and treat, having high chance of misdiagnosis as an idiopathic inflammatory bowel disease as the clinical symptoms, laboratory studies, X-ray findings, cultures, and even serological studies may be insufficient to make an accurate diagnosis. In such cases, undesirable outcomes may occur resulting from erroneous administration of steroids and delayed antiamebic treatment. In such cases, colonoscopic appearance as well as the results of endoscopic biopsy can be extremely helpful in differentiating amebic colitis from other forms of colitis. , Large, geographic mucosal ulcers, yellow-green pseudomembranes, attenuation, and necrosis of muscularis externa with presence of trophozoites are characteristic on biopsy.
Colonic perforation is common in acute fulminant amebic colitis; having an autopsy incidence of 30.4%.  These perforations may be localized by adhesions or perforate into the abdominal cavity. The intraperitoneal perforations are characteristically multiple in almost 75% cases.  Because of poor results with nonoperative management, an international consensus indicates that early surgical treatment is the method of choice for complications of acute fulminant amebic colitis.  Complications due to fulminant amebiasis that require operative intervention include perforation, stricture, or fistula formation and obstruction. Intensive antiamebic therapy should be instituted as soon as amebiasis is confirmed; otherwise surgical therapy is likely to fail.
A staged operation is highly recommended for complicated fulminant amebic colitis with colectomy and exteriorization of both ends as an ileostomy and mucus fistula, and restoration of gastrointestinal continuity 3-6 months later.  In these cases, poor prognostic factors include male gender, age over 60 years, having an associated liver abscess, progressive abdominal pain, signs of peritonitis, leukocytosis or leukopenia, hyponatremia, hypokalemia, hypoalbuminemia, absence of surgery, large amount of trophozoites, and depth of invasion through the muscularis on microscopy. 
The key message is to emphasize the possibility of FNAC as a rare and grave complication of amebiasis. The use of appropriate antiamebic medication, and a prompt aggressive staged colectomy should be the policy to avoid complications and reduce mortality from fulminant amebic colitis. Also, antiamebic treatment should be started in all cases of suspected colitis to abort the development of this complication.
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