- Torrential/massive PR bleeders:
- These patients are unstable, tachycardic, hypotensive. They respond to fluids but continue to bleed
- Requires interventional CT angiogram which detects bleeding at a minimum 1mL/min and treats via embolisation.
- As blood is irritant and has an osmotic pull within the colon need 80-100mL/hr PR bleeding to get a positive CT angiography result
- Significant PR bleeders:
- These patients have sudden onset bleeds with clots e.g. passing a bowel motion every 30min-2hrs.
- Admit and observe these patients. Most stop spontaneously.
- Most related to diverticular disease/angiodysplasia.
- Withhold blood thinners and outpatient colonoscopy can be done to confirm diagnosis.
- Concern with bowel prepping these patients is that the bowel preparation can disrupt the clot and trigger more bleeding/morbidity.
- Slow PR bleeders:
- g. 100mL once to 3 times a day.
- Bleeding at this rate will not show up on CT angiography.
- Alternative is a red cell scan which is more sensitive (can detect bleed of 0.1mL/min) but less specific
- Patients also have to be stable as they need to lie in scanner for 4-6hrs to detect bleeding
- Red cell scan relies on GI motility to propel the bleed to define the outline of the bowel to determine its location, hence it is more difficult to localise small bowel bleeds as the location of small bowel is not fixed
- Semi-elective colonoscopy in the hospital with good bowel prep (4L glycoprep) is an alternative, which allows clear inspection and the surgeon can then clip/inject site of bleeding. These colonoscopies can be quite difficult.
- Final resort is combined interventional/colonoscopy approach (Hybrid theatre) where the SMA/IMA can be injected with agents to provoke bleeding e.g. vasodilators, urokinase etc and the bleeding site can then be clipped/embolised.
Useful tip: When doing a colorectal surgery consult about a patient with PR bleeding in ED/on the wards, the common things a registrar/fellow will want to know are:
- Patient factors: age, reason for admission, current medications (antiplatelet therapy, aspirin, warfarin or dabigatran, heparin/clexane), surgical history (previous laparotomy or bowel surgery, haemorrhoid history)
- Onset and type of bleeding: very small episode in setting of constipation or a very large PR bleeding episode with haemodynamic instability (pale, hypotensive, tachycardic?)
- Note view of bleeding: bright red bleeding typical of anal canal bleeding or offensive smelling, tar like melaena?