Case study notes:
Cancer usually presents as Chronic anemia/GI bleeding, but this lecture focuses on acute lower GI bleeds
DDx of anemia: Microcytic (iron deficiency from nutrition or chronic bleeding), normocytic (acute blood losss, anemia of chronic disease), Macrocytic (B12/folate deficiency)
Acute GI Bleeding
10% Overall Mortality (~ 40% if recurrent)
10% require OR
10% Lower, 85% Upper, 5% SI
10% Upper GI Bleeds: Hematochezia- is due to rapid transit upper GI bleeds until proven otherwise
10% Upper GI Bleeds: Syncope
Lower GI Bleeds
Epidemiology
GI Bleeding distal to Ligament of Treitz account for 15% of GI Bleeds with a 4% Overall Mortality
Presentation (depends on location / quantity)
Hematochezia - distal, rapid
Melena - proximal, slower, digested blood
Acute Blood Loss Anemia
Orthostasis (30%), Syncope (10%)
Shock (20%)
Initial Resuscitation & Treatment (same as all hemorrhagic shock)
ABCs
Correct coagulopathy & platelet dysfunction
Octreotide drip + PPI drip
ICU Admission
Acute Lower GI Bleeding - Etiology
Diverticulosis (33%); Neoplasia (19%); Colitis/Ulcers (18%: IBD, ischemia, infectious, radiation); Idiopathic (16%); Angiodysplasia (8%); Miscellaneous (8%: post endoscopy, anastomotic bleeding, arteriocolonic fistula); Rectal Outlet (4%: Hemorrhoids, fissures, solitary rectal ulcer - rule out with rigid proctoscopy)
Lower GI Bleed Patterns
~ 80% stop spontaneously; ~ 25% recur; 10% idiopathic; 40% > 1 potential source
MASSIVE GI BLEEDS
Etiology of massive GI bleeds
Diverticulosis (50%) 50-80% right sided
Angiodysplasia (30%) ~ 100% Right-sided
Diagnosis
Patient with acute, severe hematochezia
Initial eval + resuscitation --> NG tube aspiration --> copious bile, no blood take to colonoscopy, otherwise:
EGD --> if negative then colonoscopy --> negative exam, hematochezia: hasn't ceased --> arteriography; has ceased --> small bowel studies
Localizing Procedures
Bleeding scan - non-invasive, highly sensitive; prolonged time to test, poor localizer, no therapeutic option, only tells you if they are still bleeding
Technetium sulfur colloid based
Sensitive to rate of 0.1 – 0.5 cc/min (30-60 mL/hr)
Poor localizer - antiperistaltic flow in some, ABD location not always relective of GI location (eg. redundant sigmoid in RLQ), most feel role is limited to pre-angio screening; NEVER TRUST A BLEEDING SCAN FOR LOCALIZATION
Angiography - acurate localization, increased accuracy with active bleeding, potential therapeutic intervention; nephrotoxicity, procedural risks, must have ongoing bleeding to localize - some promote extra-aggressive resuscitation to encourage continued bleeding
Requires 1 – 1.5 cc/min (60-90 mL/hr) active bleeding
100% Specific, 30-50% Sensitive
Start with SMA - more likely right sided source
Interventions:
Vasopressin/octreotide (Stops 90% but 50% recur)
Embolization (80 - 90% effective, 5-20% infarction rate, minimize risks with superselectivity)
Colonoscopy - potentially precise localization, potential therapeutic interventions; procedural risks, decreased localization with active bleeding
Early colonoscopy associated with: improved localization, decreased length of stay
****Does not appear to: decrease mortality, decrease need for OR, decrease need for transfusion
Therapeutic Limitations: Thinner-walled colon, greater surface area at risk, main role is with angiodysplasia, tatooing can help localize if goes on to OR
CT Scanning
New multi-detector row CT scanners are 90% sensitive and 99% specific for massive GI bleeds (compared to Angio)
OBSCURE GI BLEEDING
GI Bleeding that persists/recurs without identifiable source despite upper and lower endoscopy and SBFT
First: Repeat endoscopy
Then: Capsule endoscopy and angiogrophy are often helpful
Capsule Endoscopy: Noninvasive means of visualizing SI; 11x26 mm video capsule with 8 lead sensor array connected to recorder on belt; Takes 2 images/second over 8 hr (~55,000 images); Reviewable as video or individual images; Clear liquids before and during +/- Bowel Prep before.
50-70% yield with obscure bleeding (Better than Push Enteroscopy (26%), Better than SBFT (8%) & Enteroclysis (20%))
Better yield with ongoing bleeding
Avoid if possible stricture - don't want to have to do surgery to retreive capsule
Push Enteroscopy
Max yield = 150 cm (typically 50-75 cm), Facilitated c over-tube, Potentially therapeutic
Intraoperative Enteroscopy
Can visualize entire SI in 90%; Dxic yield 60-88%
May have added benefit with negative capsule study
As adjunct to Total Colectomy to minimize risk of post op rebleeding
Difficult & time consuming;
Risk: Small bowel injury, SMV injury, prolonged ileus
Double Balloon Endoscopy
Can perform from above or below
80-90% success in complete SB passage
Takes 90 – 110 minutes on average
Similar yield as Capsule Study (~60%)
1-4% Complication Rate (including pancreatitis)
Role: Non-op therapy based on Capsule study; use when capsule contraindicated (stricture, etc…), positive SBFT
Acute Lower GI Bleeding Etiologies
Diverticulosis (33%); Neoplasia (19%); Colitis/Ulcers (18%: IBD, ischemia, infectious, radiation); Idiopathic (16%); Angiodysplasia (8%); Miscellaneous (8%: post endoscopy, anastomotic bleeding, arteriocolonic fistula); Rectal Outlet (4%: Hemorrhoids, fissures, solitary rectal ulcer - rule out with rigid proctoscopy)
Massive GI Bleeding - Diverticulosis (50%) 50-80% right sided; Angiodysplasia (30%) ~ 100% Right-sided
Angiodysplasia (aka AVMs, vascular ectasias, etc…)
Most common GI vascular anomaly
Ectatic, dilated, thin-walled vessels with arteriovenous fistulas
Typically seen in pts > 60 yo
Can be venous or arterial
Pathogenesis theories: 1. Chronic low grade venous obstruction; 2. Chronic mucosal ischemia; 3. Congenital
Epidemiology: 1-2% on Autopsy Studies; Up to 25% in pts > 60 yo; Usually asxic; Multiple in 40-60% (usually clustered, 20% distant synchronous lesions)
Seeing angiodysplasia without bleeding stigmata does not mean you've found the location of bleed
Associated Conditions: Chronic Renal Failure; Von Willibrand’s Dz; Aortic Stenosis (Heyde’s Syndrome, risk decreased after AV replacement)
Decreased coagulability is likely common mechanism
Risk of Bleeding: Unknown; Once Bleeds – high risk of re-bleeding; Incidentally discovered lesions do not warrant treatment
Location: Colon; SI; Stomach; Duodenum
Colonic Angiodysplasia Location: Cecum – 37%; Ascending – 17%; Transverse – 7%; Sigmoid – 18%; Rectum – 14%; (L sided bleeding only rarely occurs from angiodysplasia)
Characteristics of Angiodysplasia Bleeds contrasted to Diverticular Bleeds: Multiple prior episodes; Risk factors (ESRD, AS, vW Dz); Venous Bleeding
Diagnosis
Angio = Gold Standard
Colonoscopy ~ 80-90% sensitive - sensitivity decreased by narcotics (vasoconstriction), classic picture: 5-10mm Cherry Red, Fern-Like pattern
Treatment
Endoscopic Bipolar coagulation
Angiography +/- Vasopressin +/- embolization
Surgery: R hemicolectomy alone --> 37% recurrent bleeding risk
Adjunctive: Estrogen, Octreotide, Thalidomide, Diverticulosis (all uncontrolled data)
Diverticulosis
See in 40% of 50 yo pts & 80% of 90 yos
80% located in the Left Colon
> 50% of Diverticular Bleeds are on Right: thinner walls, wider tics --> greater vascular surface area at risk
Pathogenesis: decreased fiber --> decreased stool bulk --> increased peristaltic pressure --> increased intraluminal pressure and hypertophied muscularis
Laplace’s Law: t~pr; t/p~r
Inc. radius on right --> increased tension --> angiodysplasia
Dec. radius on left --> increased pressure --> diverticulosis
Complications of Diverticulosis: Bleeding (5%) and Diverticulitis (20%) (--> abscess 50%, obstruction 30%, free perferation 15%, fistulization 5%)
Diverticular Bleeding
Seen in 5% of cases; 20% & 60% risk of rebleeding after 1st & 2nd episodes; 25% are massive; 90% stop spontaneously
Endoscopic Treatment
50% reduction in short term rebleeding with gold probe technique in one study
Also is supported by some for inversion/banding while others advocate clipping
Challenges: difficult visualization, high risk of perforation
Mesenteric Angio
Surgery