The lower GI bleeding is defined as a bleeding induced by a lesion located beyond the ligament of Treitz.Externalization is therefore as melena or hematochezia according to etiology and abundance of bleeding.
The origin of the bleeding is the colon in 90% of cases and is usually colonoscopy is the master examination for diagnosis.
Bleeding may nevertheless be related to a lesion in the small intestine, where the diagnosis is much more difficult.
Compared with upper gastrointestinal bleeding, the etiologies of lower gastrointestinal bleeding are more numerous.
Here we will discuss acute gastrointestinal bleeding, microcytic anemia revealing bleeding distilling being treated elsewhere (see Anemia).
The evolution of lower gastrointestinal bleeding is most often to a spontaneous shutdown, emergency situations with hemorrhagic shock being rarer than for high bleeding.
The annual incidence of lower gastrointestinal bleeding in adults is about 20 per 100 000 inhabitants and therefore is much less common than upper gastrointestinal bleeding (100 to 200 per 100 000 population).
DIAGNOSIS:
Examination:
In front of a gastrointestinal hemorrhage, whatever, the first thing is the appreciation of the impact of bleeding: pulse, blood pressure, peripheral signs of shock.
The questioning is trying to quickly locate the pathological context that guides most often to the etiology. Taking drugs is particularly accurate assessments.
Reviews:
Proctosigmoidoscopy colonoscopy or as soon as possible:
The evolution of the hemorrhage is towards the interruption in 90% of cases. We need to then take advantage of this lull to achieve as soon as possible a complete colonoscopy must be done if possible after conventional preparation by polyethylene glycol (PEG).
Colonoscopy is ideally performed under anesthesia. The urgent consideration is rarely feasible, a proctosigmoidoscopy can be made initially without preparation except a few enemas with water. The profitability of colonoscopy is the more important that the review is completed early.
In case of massive bleeding with signs of shock, it is imperative to verify the absence of hemorrhage with original high performing gastric lavage and especially upper gastrointestinal endoscopy of (bleeding duodenal may be accompanied by a bloodless gastric lavage).
The information given in emergency endoscopy are numerous. The cause of bleeding can be detected, but the responsibility for the origin of the bleeding lesion can not be formal only if there is active bleeding at this level.Indeed, in case of heavy bleeding, blood is most often present in the entire colon frame.
Early angiography with clichés and arteriography:
When colonoscopy is not contributory or impossible to achieve because of the abundance of the bleeding, the examination that must be considered is a CTA with early shots that allows both the coeliomésentérique angiography to locate the place of bleeding, if it is active. Arteriography may be considered to perform embolization in difficult situation hemodynamic monitoring.
The risk of ischemic colitis postembolisa tion is almost zero in the absence of surgery or previous vascular disease.
In the acute situation, scintigraphic techniques with labeling of red blood cells with technetium have little space.
Place emergency surgery:
If active bleeding with angiographic embolization failure or if this technique is not available, the surgery can be discussed. This should be considered in case of transfusion of more than ten red blood cell.
You must obviously try to locate the bleeding, ideally preoperatively. In case of failure of various previous investigations, intraoperative colonoscopy may be needed.
ETIOLOGY:
Bleeding colonic origin:
The main colonic bleeding are summarized in Box 1.
Box 1. Major causes of colic origin
Diverticular disease
Benign tumor and malignant colonic
Colonic Angiodysplasia
Ischemic colitis
Endoscopic polypectomy
Infl ammatory colitis
Drug colitis
Infectious colitis
Radiation proctitis
Solitary rectal ulcer
Aortocolique fistula (after prosthesis)
Dieulafoy ulcer (rare)
Varices (rare)
Diverticula:
The first cause of lower GI bleeding is represented by diverticular bleeding which is responsible for about 40% of bleeding.
Diverticular bleeding occurs during the development of 3 to 5% of diverticulosis and colonic represents 13% of the complications of diverticular disease.
Promoting the role of non-steroidal anti-inflammatory is known, as well as taking aspirin. Generally, the bleeding was caused by a single diverticulum, because of a breach at a artériole intradiverticular likely related to mechanical assaulting a stercolith. The rule stops bleeding in 90% of cases.
The risk of relapse is higher by about 10% at 2 years and 25% at 4 years. This is usually not massive bleeding time.If bleeding persists or especially short-term recurrence, the diagnosis of bleeding headquarters is imperative to avoid too extensive colectomy.
When diagnostic colonoscopy, the difficulty of counting the digestive bleeding diverticulum is made difficult because of the very high prevalence of diverticula in the elderly.
If there are blood-filled diverticula, for example in the sigmoid, only the presence of active bleeding or an adherent clot is evocative, highlighting the interest of a colonoscopy performed urgently. Often it is by default, in the absence of other causes of bleeding, as diverticulosis is seen as etiology of bleeding.
Angiodysplasias (Fig 1 and 2, see also figures in the color book):
Angiodysplasias is the second cause of lower GI bleeding, usually in a vascular environment in the elderly. The possibility of an association between bleeding angiodysplasia and aortic valve was often considered (Heyde syndrome) and can be associated with acquired von Willebrand disease.
The association in this age of frequent angiodysplasias to diverticular disease may make it difficult etiological diagnosis.
The prevalence of colonic angiodysplasia in the general population may be estimated at 1% in subjects over 60 years. The frequent association of colonic angiodysplasia and hail complicates potential therapeutic measures.
Considering that approximately 15% of digestive angiodysplasia of the colon and small bowel will be externalized by a gastrointestinal hemorrhage, but microcytic anemia is the most common way of revelation.
The diagnosis of angiodysplasia is most often done by colonoscopy, the preferential seat being cecum. Helical CT acquisition with the arterial phase can also be interesting (sensitivity 70%).
Selective arteriography is sometimes necessary to make an accurate topographic diagnosis.
Colorectal tumor lesions:
Colorectal tumor lesions, benign or malignant, are a cause of lower GI bleeding estimated between 2 and 26% of cases.
The bleeding after polypectomy occur after 1-5% of polypectomy (Fig. 3; see also included in the color specifications). The diagnosis is simple in this case.
The bleeding may be immediate or delayed for several hours, but delayed until 15 days after the gesture. This possibility must be known by the patient, which should avoid long journeys to the waning of this gesture.
Ischemic colitis:
Among the causes of vascular gastrointestinal hemorrhage, ischemic colitis is the most common etiology. Abdominal pain triad of sudden onset of left flank associated with bloody diarrhea is suggestive quickly.
These hemorrhages are rarely important. The location of the lesions is often the splenic flexure. The urgent colonoscopy is helpful in this case to assess the necrotic or otherwise of ischemic colitis which may require a surgical solution urgently.
Infectious or inflammatory colitis:
Colitis, inflammatory or infectious, can cause gastrointestinal bleeding, rarely abundant. Crohn’s disease, more often than colitis, can cause severe bleeding.
Dieulafoy ulcer:
The ulceration is exceptionally Dieulafoy colic seat (5% of cases), and can be the cause of excessive bleeding.
Rectal bleeding origin:
The main source of rectal bleeding are summarized in Box 2.
Box 2. Key root causes anorectal
Internal hemorrhoids
Ulceration thermometer
Anal fissure
Rectal varices (rare)
Solitary rectal ulcer
Radiation proctitis
Rectal bleeding origins are easier to recognize:
– The thermometer ulceration has become rarer with the use of modern thermometers, but remains a common cause of rectal bleeding sometimes extremely abundant (Fig 4, see also included in the color booklet.);
– The solitary rectal ulcer is rarely cause severe bleeding;
– The radiation proctitis (often after irradiation of prostate cancer) can be a source of abundant but not require a persistent bleeding and hemostasis gesture due to anemia it causes rapidly (Figure 5, see. also included in the color specifications).
Original small bowel bleeding:
The main origin of small bowel bleeding are summarized in Box 3.
Box 3. Main root causes small bowel
Angiodysplasia
Malignancy: lymphoma, adenocarcinoma, carcinoid metastases (+ melanoma), stromal tumor, benign tumor
Ulceration of the post-NSAID hail
Crohn’s disease
Meckel’s diverticulum (before age 30)
Duodenal diverticula, jejunal, ileal
Aortoduodénale fistula (after aortic prosthesis)
Ulceration of Dieulafoy
Varicose intestinal ectopic
Polyarteritis nodosa
About 5 to 10% of lower gastrointestinal bleeding are related to a lesion in the small intestine. The accessibility of the small intestine endoscopy is much more limited, the etiologic diagnosis is less clear, largely based on angiography and CT angiography especially now.
The lesions most often involved are:
– Has the ngiodysplasies;
– Malignant tumors they are primitive (particularly stromal tumors) or secondary (metastasis to the small intestine are common);
– Meckel’s diverticulum is a common cause of bleeding, sometimes very abundant: bleeding occurs in order before the age of 30 years linked to gastric metaplasia in the diverticulum, responsible for acid secretion induced ulceration sometimes hemorrhagic.
The demonstration of a Meckel’s diverticulum is not always easy, one sitting in 90% of cases in the last meter of the small intestine;
– Small bowel ulcers associated with Crohn’s disease or anti-inflammatories may also be a cause of bleeding;ulceration Dieulafoy may exceptionally sit in the jejunum and ileum;
– Ectopic varices ileal part of portal hypertension is described;
– The jejuno-ileitis cytomegalovirus sometimes take a hemorrhagic character. They occur in a context usually suggestive of immunosuppression.
The origin of gastrointestinal bleeding linked to a lesion in the small intestine may remain obscure despite the use of various modern techniques including enteroscopy (double balloon endoscopy), scintigraphy with technetium-labeled cells or videocapsule.
The latter has mainly been used in the assessment of occult bleeding and its implementation in the acute phase of a lower GI bleeding has not yet been evaluated.
TREATMENT:
Treatment is of course linked to the etiology of the bleeding. The strategy is different depending on the immediate abundance of bleeding and recurrent character. In extreme emergencies, embolization or surgery may be necessary.
However most of the time, endoscopic hemostasis may be an effective alternative subject to the availability of the lesion on endoscopy.
The diluted epinephrine injection at 10 000th is always possible and often effective. The laying clips or a lasso around the stump of a recently resected polyp pedicle is very effective. Angiodysplasias should not be subjected to coagulation if they do not bleed. In case of bleeding, bipolar coagulation can be effective but sometimes clashes with the coexistence of several angiodysplasias, some in small, inaccessible.
In case of radiation proctitis, argon plasma coagulation is the reference treatment. In case of diverticular bleeding, the difficulty is to recognize the responsible diverticulum.
In our experience, this is rarely possible.
If there are recent signs of bleeding at a diverticulum, an adrenaline injection hemostasis is effective.
Mortality lower gastrointestinal bleeding is about 5% and the percentage of patients undergoing surgery as a result of the bleeding was 15%. Mortality of course depends on the age and comorbidities. Transfusion requirements are often lower than in case of upper gastrointestinal bleeding except for lesions of the small intestine less accessible to the etiological diagnosis and frequent source of recurrence requiring transfusion.
CONCLUSION:
The lower gastrointestinal bleeding are less common than upper gastrointestinal bleeding, often less abundant and mostly colonic origin. The diagnostic strategy is focused on colonoscopy should be performed to better emergency during the first 24 hours after full preparation by PEG.
The therapeutic difficulties of these hemorrhages occur especially when lesions located at the small intestine, etiological diagnosis difficult and whose inaccessibility to routine endoscopy does not allow simple gesture for hemostasis as the colon.