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Information ⬇

Author(s): Sophia Savva and Andrew Dixon

Acute lower gastrointestinal bleeding can present with melaena or haematochezia (the passage of liquid blood or clots per rectum). Causes are given in Tables 74.1 and 74.2.

An upper gastrointestinal source must always be excluded in patients with evidence of severe bleeding, and these patients should be managed accordingly (see Chapter 73). Haematochezia usually originates from the left side of the colon or rectum, and bleeding stops without intervention in most cases.

Priorities ⬆ ⬇

  1. Consider (and exclude by urgent endoscopy) an upper gastrointestinal source of bleeding in patients with severe bleeding
    • Look for clinical clues (Table 73.2): is there a history of liver disease, excess alcohol consumption, known varices, haematemesis, upper abdominal pain or NSAID use? Are there signs of major blood loss? Is the blood urea raised (Table 73.3), suggesting an upper GI source?
    • If there is reason to suspect severe upper GI bleeding, management hinges on vigorous resuscitation, followed by upper GI endoscopy as soon as the patient is stabilized. Please refer to Chapter 73 for detailed advice on the management of upper GI bleeding.
    • Focused assessment of the patient with acute lower GI bleeding is summarized in Table 74.3, and investigation needed urgently in Table 74.4.

  2. Involve the surgical team promptly if there is acute lower GI bleeding with haemodynamic compromise or major blood loss

    Although 85% of lower GI bleeding is self-limiting, surgery can be life-saving if bleeding is severe and persistent.

  3. Consider correction of clotting abnormalities
    • Consider stopping or reversing antiplatelet and anticoagulant drugs at presentation (Chapter 103). In cases of minor self-limiting rectal bleeding, this may not be necessary. If there is more severe or persistent bleeding, the decision may be difficult, and the risk of further bleeding has to be balanced against the risk of stopping these medications, for example in the patient with recent coronary stent placement.
    • Correction of clotting abnormalities is described on in Chapters 102 and 103. Seek advice from a haematologist.

  4. Blood transfusion

    Blood transfusion is rarely necessary in cases of lower GI bleeding. As with other causes of blood loss, the transfusion threshold should be a haemoglobin<80g/L, or haemoglobin <100g/L if there is ongoing bleeding. This is a guideline only and the decision should include careful clinical assessment of the patient.

  5. Admit or discharge?
    • Patients with minor lower GI bleeding that stops spontaneously can be investigated by early outpatient sigmoidoscopy and clinic review.
    • Admit patients with moderate or severe bleeding, persistent bleeding, or significant comorbidities.

Further Management ⬆ ⬇

Outline

Once clotting abnormalities have been corrected, 85% of lower GI bleeding stops without intervention.

Flexible Sigmoidoscopy!!navigator!!

Once the patient is stabilized, the source of bleeding must be identified. In most cases flexible sigmoidoscopy is a reasonable first investigation; the earlier it is undertaken, the higher the diagnostic yield. Blood in the GI tract acts as a laxative, so often flexible sigmoidoscopy can be undertaken without bowel preparation by means of an enema.

Lower GI Bleeding with Negative Sigmoidoscopy!!navigator!!

  • If bleeding continues and its cause cannot be determined by flexible sigmoidoscopy, a full colonoscopy and/or CT angiogram is needed. If these do not reveal a cause, mesenteric angiography and technetium-labelled RBC scanning may localize the source of bleeding.
  • For mesenteric angiography to be diagnostic, bleeding has to be ongoing at a rate of >0.5 mL/minute to be diagnostic. Trans-catheter embolization can follow angiography to stop the bleeding.
  • If the bleeding stops and its cause cannot be determined by flexible sigmoidoscopy, a full colonoscopy should be performed as an urgent outpatient procedure.
  • On the rare occasions where there is ongoing bleeding and the above investigations have failed to identify the source, upper GI endoscopy, push enteroscopy or capsule endoscopy may be considered.

Endoscopic Haemostasis!!navigator!!

  • Bleeding points, for example post-polypectomy or from a bleeding diverticulum, can be treated endoscopically by the application of endoclips or heater probe.
  • Angiodysplasia or radiation proctitis can be treated using argon plasma coagulation.
  • Bleeding tumours are often harder to treat endoscopically as there may not be a single bleeding point; haemostasis is sometimes achieved using the above methods.

Emergency Surgery!!navigator!!

  • If there is persistent severe bleeding despite supportive measures and attempts at endoscopic haemostasis, emergency surgery may be needed,
  • Efforts should be directed at identifying the source of bleeding prior to surgery as this improves outcomes. Pre-operative localization of the source of bleeding (i.e small bowel, right or left colon) is important to minimize the duration of the operation and minimize the length of bowel needed to be resected.

Bleeding from Inflammatory Bowel Disease!!navigator!!

  • See Chapter 76. Patients with a flare of ulcerative colitis typically have bloody diarrhoea. The bleeding usually settles with medical management but a colectomy may be needed to treat the colitis itself. Crohn's disease can present with a large lower GI bleed with minimal pre-existing symptoms. Ulceration in the ileo-caecal region is the usual cause. The diagnosis is usually clear from the history, but in a new presentation differentiation from infective colitis or ischaemic colits can be difficult and treatment may be started empirically.
  • LMWH prophylaxis for venous thromboembolism should be given as these patients are at high risk.
  • Blood transfusion may be needed to maintain a haemoglobin of about 100g/L.

Further Reading ⬆

Cirocchi R, Grassi V, Cavaliere D, et al. (2015) New trends in acute management of colonic diverticular bleeding: a systematic review. Medicine 94, e1710.

Strate LL, Gralnek IM (2016) American College of Gastroenterology Clinical Guideline: Management of patients with acute lower gastrointestinal bleeding. Am J Gastroenterol 111, 459–474.