Page 29 - Gastrointestinal Bleeding (Xuất huyết tiêu hóa)

CHAPTER 20 Gastrointestinal Bleeding 303

Endoscopic Hemostasis diverticular bleeding in which 65% of patients rebled and 43%
Colonoscopic hemostasis of actively bleeding diverticula has been required surgery or interventional radiology. 272 20
reported using MPEC, epinephrine injection, hemoclips, fibrin Endoscopic band ligation has also been reported as treatment
glue, rubber band ligation, endoloops, or combinations of epi- of colonic diverticular hemorrhage. A 2012 study from Japan of
nephrine and MPEC or hemoclips. 28,271,274-278 If fresh red blood 29 patients showed that band ligation was successful and safe,
is seen in a focal segment of colon, that segment should be irri- with an 11% rate of early rebleeding and the need for surgical
gated vigorously with water to remove the blood and identify the resection in only one patient with bleeding from an ascending
underlying bleeding site. If bleeding is coming from the edge of colon diverticulum. 280 Owing to the potential risk of full-thick-
a diverticulum or a pigmented protuberance is seen on the edge, ness wall entrapment in the right colon, however, band ligation
a sclerotherapy needle can be used for submucosal injection of may increase the risk of perforation. 281 Diverticulitis has also
epinephrine (diluted 1:20,000 in saline) in 1 mL aliquots into 4 been reported after band ligation. In a Japanese study, banding
quadrants around the bleeding site. Subsequently, MPEC at a was reported to yield lower rebleeding rates than hemoclip-
low power setting (10 to 15 W) and light pressure can be car- ping; 282 however, many of the patients were treated by remote
ried out for a 1-second pulse duration to cauterize the diverticular hemoclipping treatment, that is, placement of the clips at the
edge and stop bleeding or flatten the visible vessel, or hemoclips neck for diverticular closure when the bleeding point was in the
can be applied. A nonbleeding adherent clot can be injected with base of the diverticulum.
1:20,000 epinephrine into 4 quadrants, 1 mL/quadrant, after
which the clot can be removed piecemeal by guillotining it with Angiography and Surgery
a cold polyp snare until it extends 3 mm above the diverticulum. Angiographic embolization can be performed in selected cases of
The underlying stigma is treated with MPEC or hemoclips (see diverticular bleeding, but with a risk of bowel infarction, con-
earlier). trast dye reactions, and acute kidney injury. One study found that
After endoscopic hemostasis of a bleeding diverticulum is com- routine angiography prior to surgical resection is not helpful in
pleted, a permanent submucosal tattoo should be placed around reducing the overall risk of complications. 252
the lesion to allow identification of the site in case colonoscopy Surgical resection for diverticular bleeding is rarely needed
is repeated or surgery is performed for recurrent bleeding. After and is reserved for recurrent bleeding. The decision to operate is
colonoscopic hemostasis, patients should be told to avoid aspirin best guided by colonoscopic, angiographic, or radionuclide imag-
and other NSAIDs and take a daily fiber supplement on a long- ing studies that demonstrate the likely segment of colon from
term basis. which the bleeding is emanating, and by the presence of medical
In 2000, Jensen and the UCLA CURE group published their comorbidities. Diverticular bleeding is usually mild in patients
results on urgent colonoscopy for the diagnosis and treatment without major SRH, and the risk of surgical complications is
of severe diverticular hemorrhage and reported that 20% of increased in older patients. Blind subtotal colectomy, often per-
28
patients with severe hematochezia had endoscopic stigmata, sug- formed in the past when a definite bleeding site could not be
gesting a definitive diverticular bleed. This group of patients, identified, should be avoided if possible.
who underwent colonoscopic hemostasis, had a rebleeding rate
of 0% and an emergency hemicolectomy rate of 0%, compared Colitis
with 53% and 35%, respectively, in a historical control group
of patients who had high-risk stigmata but did not undergo The term colitis refers to any form of inflammation of the colon.
colonoscopic hemostasis. No rebleeding had occurred after 3 Severe LGI bleeding may be caused by ischemic colitis, IBD, or
years of follow-up in the patients who underwent colonoscopic infectious colitis.
hemostasis. Ischemic colitis can present as painless or painful hematoche-
In another report from the UCLA CURE group of 63 patients zia with mild left-sided abdominal discomfort (see Chapter 118).
with definitive diverticular hemorrhage who were treated with The painless subtype usually results from mucosal hypoxia and
endoscopic hemostasis, the rebleeding rate was 4.8%, and the is thought to be caused by hypoperfusion of the intramural ves-
rate of surgery or angiographic embolization for rebleeding was sels of the intestinal wall, rather than by large-vessel occlusion or
only 3.2%. 273 The investigators carried out treatment with injec- embolization, which is often painful and clinically more severe
tion of epinephrine and hemoclipping of the SRH in the base of with worse outcomes. The incidence of ischemic colitis is esti-
the diverticulum (and on either side of a stigma to obliterate the mated to be 4.5 to 44 cases/100,000 person-years. 283 Most cases
underlying arterial blood flow) and injection of epinephrine and do not have a recognizable cause.
MPEC of SRH at the neck. Approximately 50% of the diverticu- Risk factors associated with ischemic colitis have been reported
lar SRH were located at the neck and 50% at the base; more than to include older age, shock, cardiovascular surgery, heart failure,
55% of the diverticula with SRH were found at or proximal to chronic obstructive pulmonary disease, ileostomy, colon cancer,
the splenic flexure. Complete hemostasis was documented with abdominal surgery, IBS, constipation, laxative use, oral contra-
a DEP by absence of blood flow after treatment, and absence of ceptive use, and use of an H2RA. 283-286 The superior mesenteric
blood flow correlated with lack of rebleeding. artery supplies blood to the right colon (cecum, ascending colon,
A 2012 study from Japan of 87 patients who underwent endo- hepatic flexure, proximal transverse colon, and midtransverse
scopic clip placement at the mouth of a diverticulum for acute colon), whereas the inferior mesenteric artery supplies blood to
bleeding revealed a 34% early rebleeding rate, with the major- the left colon (distal transverse colon, splenic flexure, descending
ity of rebleeding episodes occurring from diverticula located in colon, sigmoid colon, and rectum). The colon has an abundant
the ascending colon. 279 The high rebleeding rate in this study 279 blood supply, but the watershed area between the superior and
can be explained by the vascular anatomy of colonic diverticula inferior mesenteric arteries has the fewest collateral vessels and
and the placement of hemoclips away from SRH that lie in the is at most risk for ischemia. The colon normally receives 10%
base of a diverticulum. Because there is bidirectional arterial flow to 35% of cardiac output, and ischemia can occur if blood flow
in diverticula and an arcade of 2 different arteries, treating with decreases by more than 50%. Although ischemia is most likely
hemoclips at the neck of the diverticulum when the SRH is in the to occur in the watershed area of the splenic flexure, it can occur
base will not seal the artery under the stigma; therefore rebleed- anywhere in the colon. 287
ing rates would be expected to be high. The acute rebleeding The diagnosis of ischemia is usually made by colonoscopy,
rate in this study 279 is similar to that for the medically treated but in severe cases of large-vessel ischemia, “thumbprinting”
patients in a report from UCLA CURE of the natural history of may be noted on plain films or colonic wall thickening on CT.