The emergent presentation of rectal bleeding has several well-recognised causes, including diverticular disease, colonic angiodysplasia and iatrogenic causes such as recent RBL of haem- orrhoids and colonoscopic polypectomy (Table 13.3). The clinical spectrum can vary from a frightened but well patient with minimal volume loss, to a patient in haemorrhagic shock. The first practical decision is which patients with rectal bleeding require admission.
Factors that should be assessed in a patient presenting with emergency room rectal bleeding include the following:
● Patient’s, relative’s or nursing attendant’s account of the bleeding
● Record of comorbidity and social isolation
● Drug history, e.g. aspirin, clopidogrel, warfarin
● Absence or presence of anaemia, rectal examination and bedsheet/bedpan findings
● Pulse rate and blood pressure monitoring
● Haemoglobin and haematocrit estimation
● Urine output if catheterised.
Haemodynamic compromise is an absolute indication for admission. Advanced age, large witnessed blood loss, comorbidity, social isolation, anticoagulant therapy and anaemia all argue in favour of admission for assessment.
Management
Of those patients admitted for observation, two distinct clinical groups can be distinguished:
● No significant blood loss after admission: this is the large majority of patients, who spend 48–72 h in hospital, with no further bleeding. Flexible sigmoidoscopy after enema preparation in these patients usually demonstrates some old blood limited to the left colon and excludes any neoplas- tic lesion. If the patient is on anticoagulants, then these medications should be reviewed against the severity of the initial indication. After discharge, complete colonic examination may be con- sidered as determined by the patient’s general fitness and any residual colonic symptoms.
● Continuing significant rectal blood loss: this is the minority of patients, but they constitute a difficult problem. As well as resuscitation, blood transfusion and correction of any clotting abnormality, attempts need to be made to localise the bleeding point and arrest continuing haemorrhage. The principal diagnostic and therapeutic modalities for these patients include colonoscopy, selective mesenteric angiography, technetium-labelled red blood cell scan and helical computed tomogra- phy (CT) scanning.
Colonoscopy
This must be combined with gastroscopy and can be performed in the unprepared colon, after enema preparation or after a colonic purge with oral polyethylene glycol (PEG) solution (Hoedema and Luchtefield, 2005). The overall diagnostic yield of colonoscopy in acute lower gastrointestinal bleeding is 69–80 per cent (Zuccaro, 1998).
Clinical series suggest that colonoscopy has a therapeutic role in diverticular haemorrhage (Jensen et al., 2000). Of 17 patients with definite signs of diverticular haemorrhage (active bleeding in six, non-bleeding visible vessels in four, adherent clots in seven) and no thera- peutic intervention, nine patients rebled and six patients required colectomy. By contrast, of a subsequent ten patients with definite signs of diverticular haemorrhage (active bleeding in five, non-bleeding visible vessels in two, adherent clots in three) and treated endoscopically
LOWER GASTROINTESTINAL BLEEDING 172
(injection of adrenaline or bipolar coagulation), none had recurrent bleeding and none required surgery.
Colonic angiodysplasia is usually found in the right colon (Ghosh et al., 2002). Bipolar probe coagulation, argon plasma coagulation or laser therapy may be used to ablate angiodys- plastic lesions. Possible complications of therapy include perforation, delayed haemorrhage and post-coagulation syndrome (self-limited abdominal pain and peritonism caused by serosal burns).
Selective mesenteric angiography
Angiography localises the site of bleeding in 40–84 per cent of patients presenting with lower gastrointestinal bleeding. Provocative measures, such as vasodilators, heparin and throm- bolytic agents, may further increase the yield (Hoedema and Luchtefield, 2005). Diverticular haemorrhage is most likely to produce extravasation of contrast; this is less likely with bleeding Table 13.3 Common causes of acute lower gastrointestinal bleeding
Lesion Frequency Comments
Diverticular disease 17–40% Stops spontaneously in 80% of patients Surgery unlikely if < 4 units red cell transfusion given in 24 h, but required in 60% of patients receiving > 4 units in 24 h Colonic angiodysplasia 2–30% Frequency varies widely in clinical series
Acute bleeding appears to be due more frequently to lesion in proximal colon Colitis (ischaemic, infectious, 9–21% Ischaemic colitis often presents with inflammatory bowel disease, abdominal pain and self-limited rectal radiation enteritis) bleeding; colitis is segmental, most often
affecting splenic flexure
Bloody diarrhoea is most frequent symptom of infectious colitis and inflammatory bowel disease of the colon
Colonic neoplasia, 11–14% Post-polypectomy bleeding is frequently post-polypectomy bleeding self-limiting and may occur up to 14 days
after polypectomy
Anorectal causes (e.g. haemorrhoids, 4–10% Anoscopy/proctoscopy should be included secondary haemorrhage after RBL, in initial evaluation
rectal varices)
Upper gastrointestinal sites (including 0–11% Gastroscopy mandatory in severe lower duodenal/gastric ulcer, varices) gastrointestinal bleeding
Small bowel sites (including Crohn’s 2–9% Diagnosed by radiological studies or ileitis, vascular ectasia, Meckel’s enteroscopy after acute bleeding episode
diverticulum, tumours) has resolved
RBL, rubber-band ligation. Based on Zuccaro (1998).
Rectal bleeding in the emergency room 173 angiodysplasia. Angiographic haemostasis may be possible using vasopressin or superselective embolisation (Zuccaro, 1998).
Technetium-labelled red blood cell scanning
Although this technique is well described (Jensen et al., 2000) the author has never seen this technique be of practical value in acute lower gastrointestinal haemorrhage. Widely divergent results have been reported, and many surgeons are reluctant to proceed to colectomy on the basis of one such study alone. In UK practice, moreover, the availability of this technique does not lend itself to managing a patient with recurrent haemorrhagic shock.
Helical computed tomography scanning
The rapidity of helical CT scanning (Sabharwal et al., 2006) permits the maintenance of intravascular concentration of contrast throughout a scan and provides accurate visualisation of vessels. In a pilot comparison of helical CT (2 h after admission), conventional angiography (3 h after admission) and colonoscopy (4 h after admission), five of seven patients with lower gastrointestinal bleeding had positive CT scans. By contrast, conventional angiography was positive in only two of seven patients. This experience suggests that, in acute lower gastro - intestinal haemorrhage, helical CT may have a role as a screening tool, allowing patient selec- tion for directed therapeutic angiography.