Localisation of lower gastrointestinal bleeding with 99mTc red blood cell scan and single photon emission CT (SPECT).

To cite: Umer A, Townshend C, Tandon R. BMJ Case Rep Published online: [please include Day Month Year] doi:10.1136/ bcr-2015-213214 DESCRIPTION An elderly man with chronic renal insufficiency presented with recurrent lower gastrointestinal bleeding. He had been admitted with similar symptoms 6 months earlier, and a colonoscopy had revealed a bleeding vascular ectasia, which was clipped successfully. On this admission, he was initially evaluated with a capsule endoscopy and a colonoscopy. The colonoscopy revealed old clotted blood, diverticulosis, internal haemorrhoids and a small sigmoid polyp (not biopsied). No active bleeding was seen. A 99mTc labelled red blood cell scan was subsequently performed, given its ability to better detect lower bleeding rates (0.1 mL/min)