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- infectious diarrhoea
- infective colitis
- inflammatory bowel disease
- endoscopic procedures
- colorectal surgery
A 64-year-old Caucasian male taxi driver was referred for colonoscopy for a six-week history of non-bloody diarrhoea (eight times a day) associated with weight loss and abdominal pain. There were no infectious contacts or relevant travel history. He had a history of hypertension (on amlodipine). Colonoscopy revealed endoscopic evidence of colitis (figure 1). Given the chronic symptoms and patchy inflammation, Crohn’s colitis was considered and urgent gastroenterology outpatient follow-up arranged. While waiting for this appointment, his symptoms worsened significantly (with diarrhoea 20 times a day) so he presented to the emergency department. On examination he had a low-grade fever, sinus tachycardia and a tender, distended abdomen. He was referred urgently to the surgical team. Initial investigations are shown in table 1. CT scan revealed colonic thickening, mesenteric stranding and hypodense liver lesions (figure 2). He was treated with empirical metronidazole, amoxicillin and gentamicin, pending the availability of histological results.
What is the diagnosis?
Histology (figure 3) and further microbiological investigations (table 2) revealed amoebic colitis (with liver abscesses confirmed on ultrasound). The patient’s treatment was changed to high-dose, intravenous metronidazole 800 mg three times a day for 10 days. This was escalated further, at 1 week, to tinidazole 2 g once daily for 5 days and then paromomycin 600 mg three times a day for 1 week (due to suboptimal clinical response).
Two-months after discharge, he had persistent diarrhoea. His weight had stabilised (total weight loss: 30 kg). Ultrasound showed resolution of the liver abscesses. Repeat colonoscopy at three months showed resolution of the inflammation but a descending colonic stricture (figure 4). Endoscopic dilatation revealed further strictures. Two months later, while awaiting repeat dilatation, he presented with bowel obstruction secondary to strictures (treated conservatively). Four weeks later, a contrast enema (figure 5) was performed. He underwent elective laparoscopic subtotal colectomy with ileosigmoid anastomosis nine months after the initial presentation. His symptoms resolved postoperatively. Resection histology confirmed benign strictures.
What was the cause of the strictures?
This is a rare case of amoebic colitis causing multiple benign colonic strictures. It indicates how amoebic colitis can cause significant short-term and long-term morbidity.
Risk factors for amoebiasis include: immunosuppression (the prescription of steroids here may have been fatal), travel (to endemic areas), diabetes, excessive alcohol intake, age over 45 years, male sex and men who have sex with men.1 We postulate our patient was infected while working (via exchange of currency with international passengers). Ingested amoebic cysts release trophozoites into the bowel lumen interrupting the intestinal mucus layer, causing colitis and occasionally liver abscesses (<1%).2 Diagnosis is made via the investigations presented (serology, microbiology, histology, radiology and endoscopy).
The WHO recommends treatment (table 3) irrespective of symptoms (90% asymptomatic). Large liver abscesses or those within 1 cm of the capsule should be drained due to risk of rupture. Dual therapy is recommended in cases where treatment fails.1 3 In the event of antimicrobial failure with necrotising colitis or toxic megacolon, colectomy is indicated (mortality >30%4 5). In the presence of colonic strictures, efforts should be made to exclude malignancy. Where strictures are multiple, precluding endoscopic dilation, colonic resection should be considered to reduce morbidity, improve quality of life and exclude malignancy. Imaging is advisable for preoperative planning.
Although our patient ultimately required subtotal colectomy, this was performed electively with a significantly lower morbidity and mortality.
Contributors SM: main content author, case presentation and literature review. RG: selection and reporting of histopathological specimens, article review. AA: selection and reporting of radiology, article review. EY: review and editing. SC: overall content review, editing and final approval.
Competing interests None declared.
Patient consent Obtained.
Provenance and peer review Not commissioned; externally peer reviewed.
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