In this article, we will discuss the Investigative Evaluation of Bleeding Per Rectum. So, let’s get started.
1. Anopractoscopy: It is done to detect underlying lesions (e.g. haemorrhoids, rectal ulcer or cancer, proctitis etc.).
2. Colonoscopy: It is the investigation of choice in all patients with lower GI bleeding unless massive bleeding precludes this procedure. It is done both for diagnostic (visual examination of the lesion, biopsy) and therapeutic purposes (an application of sclerotherapy/heater probe/thermal ablation). Colonoscopy can detect many lesions that are often missed on barium enema studies. Colonoscopy also helps in localisation of the lesion (right or left colon) and to determine its possible aetiology (characteristic vascular spots in angiodysplasia).
3. Angiography: Angiography is a tool
in expert hands to localise the lesion.
Angiography may also disclose lesions like angiodysplasia (vascular spots as reminiscent of spider naevi) and diverticulosis even when active bleeding has stopped. During this procedure, vasopressin can be given intra-arterially. Gelfoam or steel coils can be injected into a bleeding vessel to stop the bleeding. This procedure is available only at specialised centres is indicated in patients with massive lower GI bleed and hematochezia.
4. Nuclear bleeding scan (technetium labelled RBC scanning): It is useful to detect lesions with low rates of bleeding but can be normal in up to 30% of cases with bleeding from colonic site. Tc⁹⁹m pertechnetate scans are useful to detect ectopic gastric epithelium in Meckel’s diverticulum in children and adolescents. In the presence of massive GI bleed (an emergency), angiography is preferred over scan. Accordingly angiograms are performed in patients with positive scan.
5. Small intestine push enteroscopy or capsule imaging: In minority of cases, small intestine bleeding may present as lower GI bleed. It is very difficult to evaluate this source of bleeding by upper endoscopy and colonoscopy. Therefore, the small intestine is investigated in patients with unexplained recurrent hemorrhage of obscure origin.
6. Upper GI endoscopy: It should be done if no lesion is found on investigations in lower GI bleed. About 5 to 10% of patients with bleeding per rectum may have a lesion found on upper GI endoscopy. It is advisable to perform upper GI endoscopy in each and every case of lower GI bleed to rule out upper GI lesion even when nasogastric aspirate is negative for blood.