Diverticular bleeding

Clinical History

Overweight female patient presenting to emergency complaining of red blood from anus, without abdominal pain and fever. Medical history included cholecystectomy, osteoporosis, hypertension, diabetes on metformin, chronic obstructive pulmonary disease, warfarin anticoagulation because of previous thromboembolism.
Physically found in stable haemodynamic conditions, without peritonism and abnormal findings at digital rectal examination.

Imaging Findings

Urgent laboratory assays revealed arterial blood gas values within normal limits, international normalized ratio 1.85 within therapeutic range, haemoglobin drop from 11.2 g/dl to 9 g/dl within four hours.
Meanwhile, urgent multidetector CT showed extensive diverticular disease of the sigmoid colon, without pericolonic inflammatory changes indicating acute diverticulitis and signs of perforation or abscess formation (Fig. 1a). Compared to unenhanced images, multiplanar maximum-intensity projection (MIP) reconstructions from arterial-phase enhanced acquisition (Fig. 1b-d) detected appearance of contrast extravasation in the sigmoid colon lumen consistent with active bleeding, originating from the dome of a diverticulum, which increased moderately on the corresponding portal venous-phase images (Fig. 1e, f).
The patient remained stable during conservative treatment including blood transfusions and withdrawal of anticoagulation. Two days later, endoscopy confirmed diverticulosis without signs of active bleeding or tumour.

Discussion

Diverticular haemorrhage (DH) represents the second most common cause (approximately 40% of cases) of lower gastrointestinal bleeding (LGIB) in adults after angiodysplasia, and may occur in 1-5% of patients with colonic diverticular disease (CDD). DH results from rupture of damaged arterial vessels at the dome or neck of a diverticulum, and is strongly associated with use of anticoagulants and nonsteroidal anti-inflammatory drugs (including aspirin), with right-sided or bilateral colonic involvement by CDD, and with risk factors and other manifestations of atheromatous disease. DH is heralded by melaena, haematochezia or rectal bleeding, with signs of haemodynamic instability in 15-20% of cases. Compared to acute diverticulitis, in DH patients are generally older, abdominal pain and fever are usually absent [1-6].
Following stabilisation including blood transfusions, nowadays multidetector CT is widely employed to investigate diverticulitis and LGIB promptly and non-invasively. With appropriate technique, CT identifies significant active bleeding with 91-92% sensitivity and 95% specificity, accurately shows the bleeding site and may suggest the cause. Retrograde colonic opacification with diluted contrast medium (CM) should be avoided in the setting of LGIB. A preliminary unenhanced CT acquisition is helpful to demonstrate pre-existing hyperattenuating intraluminal contents such as clots, faeces, pills, sutures or clips which could be misinterpreted as bleeding. Intravenous CM administration is warranted unless contraindicated, best with an additional arterial-phase acquisition. Variably shaped extravasation of intravenous CM in the bowel lumen is the hallmark of active bleeding, typically follows the attenuation of enhanced blood vessels and changes its appearance over time, usually increasing and extending more distally from the arterial to the portal venous phase. Even without identifiable CM extravasation, substantial diverticulosis may suggest DH as the underlying cause of bleeding [7-10].
Due to the high prevalence of CDD, DH will likely be increasingly encountered. DH often resolves spontaneously but almost 15-20% of patients require intervention. In LGIB colonoscopy is usually delayed 12-48 hours after bowel preparation and CT, to enhance the chances of detecting and controlling haemorrhage. Endoscopically identified bleeding, visible vessels and adherent clots are treated using a combination of epinephrine injection, coagulation and endoclips. Rebleeding occurs in one-half of patients [1, 11-14].
Selective mesenteric angiography and embolisation safely allows treating massive or persistent LGIB from different causes including DH, when endoscopic treatment is unfeasible or unsuccessful. TAE is definitive in 50% of cases, or allows stabilisation and bowel preparation before surgery which is reserved for refractory bleeding [11-14].

Differential Diagnosis List

Final Diagnosis

Active bleeding from diverticular disease of the sigmoid colon.

URL:	https://www.eurorad.org/case/13070
DOI:	10.1594/EURORAD/CASE.13070
ISSN:	1563-4086