Lower GI Bleeding

1. Lower GI Bleeding 4/6/11

2. 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

3. 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)

4. 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 • Comorbiditiesmust be considered in the diagnostic and therapeutic phases of the care plan • Current increased patient exposure to antiplatelettherapy associated with treatment of cardiovascular conditions may increase the comorbid challenges in patients with lower gastrointestinal massive hemorrhage

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

6. 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

7. 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

8. 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

9. 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

10. 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

11. 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

12. 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

13. 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

14. 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

15. 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

16. 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%

17. 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

18. 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%

19. 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 • Gelfoampledgets, coils, and polyvinyl alcohol particles • Arteriography also has complications • arterial thrombosis, distant arterial emboli, and renal toxicity from dye

20. 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

21. 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 ileorectalanastomosis • 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.

22. Algorithm