Lower GI Bleeding 4/6/11

LGIB Distal to ligament of Treitz Annual incidence rate of 20.5/100,000 Male predominance Incidence of significant bleeding increases with age May suggest changes associated with the small intestine and colon Reflects the prevalence of diverticulosis and angiodysplasia in the elderly

LGIB May present as melena or hematochezia Melena typically suggests bleeding from a more proximal source (colon or small intestine) Hematochezia suggests left colonic, rectal, or anal sources Upper gastrointestinal hemorrhage may present with rectal bleeding given blood’s cathartic effect and rapid intestinal transit (10-15% of cases)

LGIB Most often the intestinal bleeding resolves spontaneously Once it resolves, investigations should begin to identify the potential sources On occasion, the intestinal hemorrhage does not resolve Creates hemodynamic compromise Ongoing hemorrhage demands aggressive medical and surgical management Oftentimes patients are plagued with significant comorbidities that complicate their individual resuscitation Comorbidities must be considered in the diagnostic and therapeutic phases of the care plan Current increased patient exposure to antiplatelet therapy associated with treatment of cardiovascular conditions may increase the comorbid challenges in patients with lower gastrointestinal massive hemorrhage

Etiology Diverticula Angiodysplasia Ischemic colitis Inflammatory bowel disease Intestinal tumors or malignancies NSAID-related nonspecific colitis Meckel’s diverticulum Anorectal diseases

Diverticular disease Outpouchings of the mucosa and submucosa through defects in the muscular layer of the bowel at sites of penetration of the vasa recta Thinning of the media in the vasa recta predisposes to intraluminal rupture: focal injury may occur from trauma related to a fecalith incidence spans a range of 15% to 48% relatively rare event affecting only 4%–17% of patients with diverticulosis

Diverticular disease Operative management is indicated when bleeding continues unabated and is not amenable to angiographic or endoscopic therapy Should be considered in patients with recurrent bleeding localized to the same colonic segment In a stable healthy patient, the operation consists of a segmental bowel resection (usually a right colectomy or sigmoid colectomy) followed by a primary anastomosis

Angiodysplasia Thin-walled arteriovenous communications located within the submucosa and mucosa of the intestine May be congenital or acquired, isolated or multiple In the acquired form, distortions of the postcapillary venules may arise as a degenerative lesion associated with increases in intraluminal pressure Results in thickening and ectasia The vessels eventually entangle as tufts within the submucosa and erode into the mucosa proper

Angiodysplasia Colonoscopic criteria Mucosal surface contains a cherry red lesion that is typically flat Greater than 2 mm in size Have a “fern-like” appearance A central feeding vessel is not always visible

Occult Hemorrhage Occurs infrequently no more than 5% of all patients admitted with LGI massive hemorrhage Frequent recurrences create chronic anemic states in patients and require occasional admissions for transfusions May harbor angiodysplasias in the small intestine or right colon May benefit from small bowel contrast radiography or capsule endoscopy Elective angiography with cecal magnification may reveal small angiodysplasias

Occult Hemorrhage If the hemorrhage recurs and investigations fail to reveal the source, a variety of provocative diagnostic angiographic studies have been described Most studies prefer to incite bleeding using either heparin or thrombolytics Once the site of bleeding is identified, it may be difficult to control without surgery Prepare and hold an operating room Once the location is identified, a superselective catheter is left in the distal artery During surgery, the surgeon can palpate the catheter within the vessel and direct the surgical resection

Initial Assessment Establish IV access (large bore) and start IV fluids restore volume and replete red blood cell deficiencies Labs CBC, electrolytes, coags, type and cross All coagulopathies require reversal! NG tube placed will screen for the presence of upper gastric sources for bleeding Kovacs and Jensen noted 17.9% of LGI hemorrhage presentations involved an upper gastrointestinal source NG tube is effective in detecting prepyloric hemorrhage

Evaluation Digital anorectal examination and anoscopy Rigid proctosigmoidoscopy will allow the examiner to evacuate the rectum of blood and clots Excludes internal hemorrhoids, anorectal solitary ulcers, neoplasms, and colitis Colonoscopy and angiography offer therapeutic intervention Nuclear scanning is purely diagnostic

Evaluation subdivide patients into 3 general clinical categories minor and self-limited major and self-limited major and ongoing Major ongoing hemorrhage requires prompt intervention with angiography or surgery Minor, self-limited may undergo colonic lavage and colonoscopy within 24 hours Major, self-limited need diagnostic tests to determine if they require prompt therapy or observation

Radionuclide imaging Detects the slowest bleeding rates 0.1–0.5 mL/min More sensitive than angiography Unfortunately cannot reliably localize the site of hemorrhage The specificity of small bowel versus large intestine bleeding does not reliably compare with angiography Two general techniques technetium sulfur colloid scans 99mTc pertechnetate-tagged RBCs

Radionucleotide imaging Immediate positive blush (within the first 2 minutes of scanning) highly predictive of a positive angiogram (60%) predictive for surgery in 24% If study did not demonstrate a blush highly predictive of a negative angiogram (93%) the need for surgery decreased to 7%

Colonoscopy If the patient appears stable with self-limited hemorrhage, colonoscopy is the preferred diagnostic study Major benefit depends on ability to provide a definitive localization of ongoing active bleeding and the potential for therapy Many landmarks for colonoscopy may be obscured during hemorrhage Once the endoscopist highlights a bleeding source, the region requires a tattoo to mark the site If the hemorrhage continues and fails medical management, the tattoo assists in localizing the hemorrhage Therapeutic armamentarium i thermal agents such as heater probes, bipolar coagulation, and laser therapy Injection therapy uses topical and intramucosal epinephrine Mechanical therapy includes endoscopically applied clips

Angiography Diagnostic and therapeutic Acute, major hemorrhage with ongoing bleeding requires emergency angiography Patients with an early blush during nuclear scintigraphy may benefit from therapeutic angiography May define a potential source for hemorrhage in occult and recurrent gastrointestinal hemorrhage Requires a hemorrhage rate of at least 1 mL/min Yields range from 40% to 78%

Angiography Highly accurate localization provides for focused therapy Intraarterial vasopressin infusion 0.2 U/min up to 0.4 U/min Systemic effects and cardiac impact may limit maximizing the dosage Controls bleeding in 91% of patients Bleeding may recur in up to 50% of patients Arterial embolization Superselective mesenteric angiography with microcatheters in the vasa recta Vessels as small as 1 mm Risk of intestinal infarctions of larger selective vessels may exceed 20% Provides immediate arrest of the bleeding Combination of agents to control bleeding Gelfoam pledgets, coils, and polyvinyl alcohol particles Arteriography also has complications arterial thrombosis, distant arterial emboli, and renal toxicity from dye

Operative therapy Few patients currently require surgical treatment Hemodynamically unresponsive to initial resuscitation Site of hemorrhage localized, but available therapeutic interventions fail to control the bleeding Patient mortality increases with their transfusion requirements Once reaches 6–7 units and the hemorrhage remains ongoing, surgical intervention becomes eminent First objective in surgery focuses on the location of the intraluminal blood with the goal of segmentally isolating the possible sources of bleeding if no source appears obvious, may consider intestinal enteroscopy

Operative therapy If the source of bleeding cannot be found, and it appears to arise from the colon, the surgeon should perform a subtotal or total colectomy Stable patients will tolerate a primary ileosigmoid or ileorectal anastomosis Unstable patients require an end ileostomy with closure of the rectal stump or a mucous fistula Once stable, the patient may return for ileostomy closure. The rectum and sigmoid colon require reexamination endoscopically to assure no bleeding persists.

Algorithm