Colonoscopy has an established low morbidity and mortality and a yield of 72% to 86% [5]. It also allows certain treatments to be carried out at the same time.

Guidelines published by the American Society for Gastroenterology strongly recommend that Colonoscopy should be the initial diagnostic procedure for nearly all patients presenting with acute LGIB. In patients with high-risk clinical features and signs or symptoms of ongoing bleeding, a rapid bowel purge should be initiated following hemodynamic resuscitation and performed within 24 h of patient presentation [13].

A limitation of this investigation, however, is the difficulty in visualising the mucosa during or soon after a bleed (making it difficult to accurately identify the bleeding site).

During colonoscopy, it is possible to perform coagulation to stop the bleeding (thermal contact or epinephrine injection), particularly for AVMs. However, it is vital to consider the risk of perforation when using this treatment modality. Other treatments available at colonoscopy include haemoclips and band ligation [16].

Learning bite

Colonoscopy is the investigation of choice in most patients with lower GI bleeds.