lower gi bleeding 4/6/11. lgib distal to ligament of treitz annual incidence rate of 20.5/100,000 ...
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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
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